Tips For Using Exposure Compensation

I’ve already discussed some of your camera’s limitationsarticle. In another articlelink I discussed the three equally-important methods to control how much light your sensor collects and the side effects of each method. Today’s discussion is about how to use your camera’s semi-automatic exposure modes. We will briefly review some of the earlier principles but will move beyond the single basic assumption that most experts cover as we discuss the impact that metering modes have on your camera’s control of an image’s exposure.

Why Not Manual Mode?

Although Manual mode gives you the best control, there are times when lighting conditions change too fast. And sometimes it is just more convenient to use one of the advanced auto-exposure modes. This lets the camera set the exposure level by adjusting one of the three controls – shutter speed, aperture, or ISO – while you control the other two. For Canon cameras the mode is called Aperture-Priority if you set the aperture and ISO (and let the camera control shutter speed), Shutter-Priority if you set the shutter speed and ISO (letting the camera control aperture), and Manual Exposure with Auto ISO if you set the shutter speed and aperture (leaving the camera ISO). Never let the camera control more than one variable. Keep in mind, the camera now has TOTAL control to adjust the exposure; your two controls are only for the side effects – motion blur for shutter speed, depth of field for aperture, and noise for ISO. Although your two parameters always have an impact on exposure, the camera gets the last word and uses its parameter to overcome those impacts. If you want to have any say at all about exposure, you must use exposure compensation. But why would that be necessary?

What The Camera Considers

The main reason you need to use exposure compensation is that the camera programmer has no clue as to where you are pointing your camera or what kind of picture you are taking. So s/he is forced to make assumptions. (There is an old saying about when you ASSUME you make an ASS of U and ME. Unfortunately in this case, as an inanimate object the camera is incapable of accepting its share of the responsibility.) The most important assumption the camera makes is that your picture (subject) is of average light intensity. No matter what you shoot, the camera will let in enough light to make it a medium gray (or colors that would translate to medium gray with black-and-white film). Many times this is fine, but nobody likes gray snow in their winter vacation pictures or pictures of the rare gray bear from their trip to Yellowstone. To make your snow white again, you would need to apply a positive exposure compensation before taking your first shot to tell the camera to let in more light than it really wants to (for a brighter subject than it was expecting). To bring those black bears back to life, you would need to apply a negative compensation. Regardless of the subject, to tweak the exposure in subsequent shots, increase the exposure compensation to make the picture lighter, and decrease the compensation to make it darker. Once you’ve nailed it, you shouldn’t have to change the compensation on later pictures of the same subject, even if the lighting changes. You should be prepared to change the exposure compensation every time you change subjects, but not every time the light changes (that’s the only reason those three auto-exposure modes are so attractive).

And this is where most discussions of exposure compensation end.

What The Camera Can’t Consider (But You Must)

The camera can’t differentiate between your subject and its background. It further assumes that everything you might be interested in is at the same gray level. It’s fine if that happens to be true. But if they are not the same level, and if you go from a close up of the black bear (in an obviously lighter background) to a general landscape shot that includes the bear, then you might need to change the exposure compensation, or you might want to change your metering mode.

Metering Modes

The metering mode determines how much of the view is considered in adjusting the exposure. On Nancy’s Canon EOS 7D, there are four modes. Spot metering, as you might guess, covers the smallest part of the center of the screen – about 2.3% of the viewfinder area. Next would be Partial metering, covering 9.4% of the total area. Then they get a little trickier. Center-weighted average metering gives an undisclosed, but presumably larger center area most of the weight, but does consider everything else in view. Finally, Evaluative metering, in which “the camera sets the exposure automatically [ed: read as “magically”] to suit the scene”. Right.

For consistent exposure compensation, the area considered should be smaller than the size of the subject if you want exposure compensation to behave as described in the “What The Camera Considers” section. If your backgrounds are more stable (whether or not they happen to be the equivalent of a medium gray), then a wider-looking metering mode might be better. Then you might be able to go from shooting a (black) crow to a (white) ibis as you hiked the consistently-lighted trail without having to adjust the exposure compensation at all. But this is starting to get into personal preference. Experiment with all of your metering modes and decide what works for you. Just be aware that if your settings or situation changes (as when you are metering on the background and the subject moves ‘too’ close, or when you are metering on the subject and then widen out for a cover shot), the computer may start behaving in the opposite manner than what you were expecting. Now you know why. It is (probably) just because you and your camera weren’t on the same page as to what was the important part of the picture.

I hope this helps you work with your camera instead of against it in your efforts to get the best shot. Good luck.

Our Latest (Toughest) Canoe Trip

We May Not Have To Trade In Our New Canoe After All

As I mentioned in the discussion on our page for Royal Terns, I managed to flip our new canoe shortly after Nancy got that shot. Although I believe that was the first time I’ve ever done that to Nancy, it really damaged her confidence. She has been more hesitant about our canoeing adventures ever since. She has even been considering trading in our new canoe for another model. It might be too early to tell, but that may have all changed after our last trip out of Lake Kissimmee State Park.

Our New Canoe

We bought the Kevlar Flex-core Wenonah Escape, a 17½-ft, 53-pound canoe, because our old 75-pound, 17-ft, aluminum Grumman seemed to be getting heavier every time we used it. We got that canoe less than six months before our Cedar Key trip and had used it only about eight times. But we had already noticed that although our new canoe was faster in calm conditions, without the small keel of the Grumman, it was much more sensitive to weather conditions. Especially in a crosswind, the weight distribution of our gear was now critical; too much weight aft and the wind would tend to turn the vessel away from the wind, and having the center of gravity too far forward would turn the canoe into the wind.

The Cedar Key Trip


We were in Cedar Key for the 53rd Annual Old Florida Celebration of the Arts, but decided to stay around for a few days to explore. When we began the canoe trip that morning, it was a beautiful, sunny day. The winds remained about 5 knots throughout most of the day. Our first stop was on the first island, Atsena Otie Key, about a mile south, to get pictures of downtown Cedar Key. Then we were off to Seahorse Key, a couple of miles further to the southwest, to get lighthouse pictures and such. The “Royal Terns” was one of Nancy’s last photos, taken just before 5 pm. The wind started to pick up as we headed back to Cedar Key. By the time we passed Grassy Key (about 2/3 of the way back), winds were approaching 15 knots and we were in the trough of a chop that was higher than one foot. As the wind was picking up, I was spending more and more effort maintaining our course and less force was devoted to making forward progress. I was wearing out, so decided that I needed to shift some weight forward. That’s when I made some critical errors in judgment. Without alerting Nancy, I raised up just enough to lift a gear bag over the next thwart. But that was too much. I clearly overestimated the stability of the canoe and the seriousness of our situation. We flipped.

To see the Note click here.To hide the Note click here.
So how should we have handled these conditions? There’s always more than one way to skin a cat, but I should have first told Nancy what I was about to do. Instead of staying in the trough, we could have let the wind help us to a downwind heading (which is much more stable). Then Nancy could have stabilized the canoe with her paddle while I made the necessary ballast adjustments. And although I tended to attribute my lack of judgment to a lack of familiarity with our new canoe, I can’t guarantee the Grumman would have survived the original operation either.


Most of our gear was in dry bags but Nancy hadn’t put away her best camera and lens before we started the crossing. From the water, we righted the canoe, rounded up and returned most of our gear to the canoe, and from inside the waterlogged canoe, paddled or swam to shallower water west of Atsena Otie Key. There we could stand up and touch bottom, bail out the canoe, and continue to the Cedar Key harbor. From there, we immediately called Canon to see how best we could preserve the equipment. They said we didn’t need to do anything except mail it to them so they could take care of it. But they couldn’t. We had to buy a new Canon EOS 7D body and 100-400mm zoom lens. Oww.

Lake Kissimmee State Park

At Lake Kissimmee State Parkofficial website, there is the Buster Island Loop Paddling Trail, which winds over eleven miles. Nancy has brought her school camping club here before and they have canoed this trail. We planned to follow our traditional routine of launching just west of the bridge to the cow camp, heading west along Zipprer Canal into Lake Rosalie, then south to Rosalie Creek, where we paddle to Tiger Lake, then east-northeast to Tiger Creek.

To see the Note click here.To hide the Note click here.
For what it’s worth, on an earlier trip with Nancy’s school camping club, it was at a spot on Tiger Creek, just before you get to Lake Kissimmee, on a decent beach before the line of trees on the right (south) side that parallels the Lake Kissimmee shore, that they found the subject model for Barred Owl.


Tiger Creek leads to Lake Kissimmee, and then it’s a shorter paddle northwest to the east entrance to the Zipprer Canal. From there, the journey ends at the State Park Marina, just a short hike around the water structure from the starting point.

The Trip

This trip started normal enough. It was mostly sunny at first and windy, but we didn’t feel the wind below the banks, and especially in the tree-lined sections of Zipprer Canal. Lake Rosalie was another story. By then, the wind was seventeen to twenty-four knots out of the southwest, which means its fetch was essentially the whole length of the lake. As we entered the lake we were paddling directly into waves of at least 1½ feet. We were paddling full speed ahead and Nancy was really getting pounded riding up (and down) in the bow. (Where I came from, you’d have to pay at least a quarter to get this much excitement). It was Nancy’s understanding that we should be hugging the shoreline where it would be flatter, a misconception apparently held by many people. It is only flatter near the windward shore, where there is no fetch, or distance the wind has blown over the water to build up the waves. On the leeward (away from the wind) side where we were, there is no relief; the waves are as high as they are going to get.

Protocol

Whether in the front or the back, a straight stroke along the side of the canoe will tend to turn the canoe away from that side. Normally, the two paddlers would be stroking on opposite sides of the canoe – one on port and one on starboard (right as you face forward) to cancel out their individual turning forces. You should change sides on a regular, but not too frequent basis. When one needs to change sides, they call out so both paddlers change sides together. The weaker paddler (or the photographer if they are not the same person) would usually be in the bow. The stern paddler is normally responsible for course corrections and casual maneuvering. S/he does this by adding a little side flip or “J” to their stroke as necessary. If the strength of the paddlers is the same, few “J”s would be necessary. In other circumstances, they may be required on every stroke. Tight curves, as found in many creeks in Florida (like the two mentioned below, for example), require turning effort from both paddlers. Nancy taught canoeing in her previous day-job. She knows more strokes than I do and is very good.

Since we’ve owned this new canoe, I’ve had to make modifications to the standard tandem canoeing protocol/etiquette. As a crosswind picks up, I’ve started making sure the stern paddler (which is I) is stroking on the lee side (or on the same side as the wind is trying to blow the bow) to better counteract that force. When the wind is really strong, I ask the bow paddler (Nancy) to shift so that we are both on that side.

Lake Rosalie

At first, we are paddling directly into the wind. Our next waypoint, the next creek entrance, hidden in the tall grass, is about 45° off the port (left) bow. The problem is, under our current wind conditions I soon discovered that if I let the bow get over 30° off the wind, then even with both of us paddling hard from the leeward side or even using one of the turning strokes, it takes quite a while (and a lull in the wind) to bring the bow back on course. Paddling in the trough of an occasional 2-foot chop isn’t something I was going to let happen. As we got into the middle of the lake (and the bearing to our waypoint approached the beam), the waves are slightly smaller and the wind shows signs of weakening (at least part of the time). We changed course so the wind came from about 30° off the starboard bow, which is as far off the wind as I felt we could reliably recover from. Then we eased off on the power a bit (when not recovering from a gust) and let our leeway (the sideways direction and speed that the wind is impacting us) make up the difference in course angle. We eventually find and enter Rosalie Creek.

Rosalie Creek is narrow, winding, picturesque, and protected for the most part. Nancy is able to photograph. There is some current, which makes station-keeping a little more difficult, especially since I’m already tired. We enjoy the view and the rest, and then we enter Tiger Lake.

Tiger Lake and Lake Kissimmee

As we enter Tiger Lake, we see an osprey catch a fish. Then an eagle tries to take the fish. We watched a remarkable aerial display that lasted at least five minutes. The osprey had a tighter turning radius but the eagle was never far behind. Finally, the osprey dropped the fish. Maybe it decided that it was expending more calories defending the fish than it would have gained from eating it. The eagle made a low pass looking for the fish, but unsuccessful, it flew off, as did the osprey in the opposite direction. Just a few minutes later the osprey flew by again and grabbed another fish (without interruption).

Although not quite as strong, the wind is still alive and well. But we are a little more rested. From Tiger Lake, our next waypoint, Tiger Creek, is close to directly downwind. The wind is now helping with our speed. But the waves, which are growing as we cross the lake, are trying to broach the canoe (turn it sideways to the wind, possibly burying the bow in a wave or capsizing the boat when it gets in the trough). This takes heavy corrective paddling from the stern paddler as every wave goes by until we reach Tiger Creek.

Tiger Creek is wider than Rosalie but still serpentine. Again, Nancy is taking pictures (including close-ups of a snail kite eating lunch).

In Lake Kissimmee, our intended track was to the northwest just off the windward shore of the lake, and the lake was full of water plants so the waves aren’t too bad. The wind had even started subsiding. We found our way to the canal entrance and then to the marina. Although we were completely bushed, we did manage to get the canoe secured back on top of the van right at sunset.

Conclusions

This wasn’t our longest paddle. We’ve done more than fifteen miles on a day trip on more than one occasion. The most recent time was around Snake Bight east of Flamingo (which is at the end of the road in Everglades National Park). And even though almost half of that trip was through water about two inches shallower than the canoe with a thick muddy bottom, the weather was mild and the trip wasn’t as tough as this one. (Interestingly enough, on our last trip to Flamingo, Nancy mentioned canoeing to Ingraham Lake, which is at least ten miles west of Flamingo. Now that would be quite a day trip for us.)

But more importantly, the wind and waves were worse on this trip than on the Cedar Key trip that caused us to capsize. I’m hoping that was enough to rebuild Nancy’s confidence. Stay tuned.

Lutz Arts And Crafts Festival Planned For December

Yes, the GFWC Lutz-Land O’ Lakes Woman’s Club, Inc is already making plans for this year’s festival. It is scheduled for December 5th and 6th at Keystone Preparatory High School at 18105 Gunn Highway in Odessa from 10 am to 5 pm on Saturday and 10 to 4 on Sunday. They are expecting 30 thousand visitors this year to almost 300 artists. Admission is free but there is a five-dollar parking fee.  For more information, see gfwclutzlandolakeswomansclub.org/annual-lutz-arts-crafts-festival/.

This will be our third consecutive appearance at this festivalprevious. We will be outside, as usual. We have received recognition on both of our previous visitsblog. So what can we expect this year? If you are north of Tampa in early December, come see for yourself!

Subsequent Screech Owl Stories

Since the nesting screech owls left us (see Our Screech Owl Image – The Rest Of The Story, which is about the subject owl family in our image “Mother Screech Owl with Fledgling” (a link to that page is in the article)), we’ve had a few noteworthy encounters with our local screech owls. In the most recent, we may have saved a life, but I’m getting ahead of myself.

In Our Neighbor’s Yard

A few years ago, we were outside with our good friend and former wild bird rehabilitator April Kirkendoll (whom we last mentioned in Nancy’s Photos Are In Book About Bees), when we heard the blue jays squawking in a neighbor’s mango tree. That usually means there is a snake or hawk in the vicinity, so we walked across the street to investigate. As we peered through their chain-link fence, we saw a screech owl fall out of a tree onto the ground. April hopped over the 6-ft fence, retrieved the bird, handed it to Nancy, and then hopped back over the fence. As she inspected the owl, April lifted one wing and then pointed out a large dark area of skin. “This bird has been poisoned!” Apparently, the owl had caught a poisoned rat (or mouse), possibly still alive, but weakened. The poison works by thinning the rat’s blood so much that it ultimately dies from internal hemorrhaging. Whatever eats the rat could suffer the same fate. We buried the owl in the garden.

Nancy, The Rehabilitator

This last January, our next-door neighbor brought us a screech owl that he picked up at the corner 7-11 (see post on our Bee Happy Graphics Facebook page – that photograph was taken by another non-photographer good friend, Isabella Baldovino). That owl had knocked itself unconscious by flying into one of the 7-11 windows. After consulting with April, we monitored it all day, but it was ready to release that evening.

Nancy about to release revived screech owl (iPhone photograph by our good neighbor, Kristi Sellars)
Figure 1: Nancy about to release a revived screech owl (iPhone photograph taken by our good neighbor, Kristi Sellars)

An Owl Returns To Our Nest Box

A few weeks ago, we were excited to notice an owl face looking out the opening of our nest box. Nancy noticed a resemblance to the owl she released in January. She saw the owl several days in a row, and then it disappeared briefly, then came back, and so on. After one absence lasted at least a couple of days, Nancy decided to check the nest box. From the side door, she saw the owl was still there. She was able to pick it up and noticed two eggs. The owl was very lethargic. It didn’t squawk, attack, or even defend its nest. In fact, it would barely open its eyes. We could easily feel the ridge of the breast bone.

Screech owl in nestbox with two eggs
Figure 2: Lethargic mother screech owl with two eggs

Nancy put the owl back in the box and consulted our expert. Together, they theorized that the mate, which we had not seen, may have been poisoned, but before disappearing permanently, brought the poisoned meal to the mother. We tried force-feeding the mother a small piece of raw chicken, but she wasn’t having any of that. We later brought a small dish of wax worm larvae and chicken pieces and placed it in the nest. The next morning, the food was gone. the next dish with larger portions met the same fate. At this point, the owl was a little more lively. We gave her another dish of food. The next morning, the food and the owl were both gone. We left another dish of food, hoping she would return, but the next morning the food was still there, and she was still gone. April had warned us that without the male, she might abandon the nest to save herself. We haven’t seen her since.

What About The Eggs

Screech owls lay their first three eggs a day apart, but then begin to slow down a bitRef 1. Although their average clutch size is four eggs, they have been known to have as many as six. April told us that the mother doesn’t start incubating until they are all laid so that they all hatch about the same time.

The second day after the mother disappeared, I estimated that the oldest egg must be four days old. We decided we’d better do something about those eggs soon. We called the rehab centers in our area but had to leave messages. They never got back to us. April sent us one link for building an inexpensive incubator (“The $3, 30-Minute Egg Incubator”), but I’m sure there are others online. After reviewing those instructions, we started scrounging up materials. We started with an old heating pad and eventually wound up with the rig shown info Figure 3 below. I learned a few things in the process:

Homemade ad hoc incubator
Figure 3: The final version of our ad hoc incubator

I set it up in the shop so it wouldn’t affect or be affected by the air conditioner. In hindsight, the air-conditioned environment would have been more stable. I started with just the heating pad, which had three settings: just a little low, too high, and way too high. While it was on the medium setting I tried adding layers of towel as insulation, with marginal success. Then I put it on low and added an incandescent light for fine-tuning. These parts were just lying on our shop table. I would change the distance from the bulb to the egg to change the temperature. I was using a neighbor’s (the one who took the picture in Figure 1) old-fashioned oral thermometer and began checking the temperature every five minutes, increasing the time as the temperature stabilized in the target range (99°Ref 2 ±1°).

Turns out the heating pad was a bad idea. After some initial luck, the temperature would swing from one end of its range to the other (and beyond). I concluded that for consistency, the placement of the thermometer was crucial. The problem was that the temperature gradient created by the heating pad was too great; the surface of the pad might be over 100 degrees, but one millimeter away would be substantially less.

I unplugged the heating pad and got a box to control the hot air from the lightbulb. Using the box, the distance between egg and bulb wasn’t as critical to the temperature as the height of the open edge of the box, which could be adjusted as needed. And the bulb-heated air temperature was much more consistent throughout the chamber and more important, throughout the egg. I got to the point where I was rotating the egg 1/3 of a revolution four times a day, and would only check the temperature twice between rotations (and none at night).

The End Of The Story?

Alas, after three days on the incubator, tragedy struck. I won’t go into details but would like to warn you to make sure your box is well supported. Although it was probably too early to tell, candling the remains of the last egg did not reveal any signs of development.

Nonetheless, we are going to declare this experience a success. Most likely, we saved the mother screech owl from certain death. It is even possible that after a year or so, she will have recovered, found another mate, and could even return to the nest box to raise another family. As for the eggs, the cards were stacked against them from the beginning. According to the Barn Owl Box Company (Ref 1), even under normal conditions, only half of all screech owl eggs hatch (compared to over 80% for some owl species). But these weren’t normal conditions. And what about the father, and this recurring poisoning theme? That is up to all of us. Nancy and I, and many of our friends, are trying to do our part. Are you?

Thanks for listening. If you have any questions, comments, or suggestions, leave them below.

A Better (Simpler) Logan Pro Joiner

Get printable scales(.jpg)
Get printable Foot height table(.pdf)


Our Logan Pro Joiner with its new scales
Figure 1: Close-up of our joiner showing three new scales

As I mentioned on our About Us Page, we have a Logan Pro Joiner (Model F300-2) for nailing our frames together. There are four different things on it that one must adjust before using it. But there are only two important parameters, moulding width and moulding thickness, that are used to make those adjustments. To make your life easier, I made three new scales to put on your joiner for the adjustments that depend on the moulding width.

An additional set of measurement scales to make your use of the Logan Pro Joiner easier
Figure 2: Measuring Scales To Add To Your Joiner

I will discuss how to apply these scales to your joiner and how to use them as we look at each of the adjustments in more detail. I will discuss them in the same order they were introduced in the manual.

V-nail Slider Block Spacing

The Old Scale

The scale on the slider measures the gap between the two V-nails (except the reading on that scale is always ⅜” larger than the actual distance). The manual tells you to set the slider block to match the reading on the vise scale, which measures the width of the moulding across its bottom. This width is the total moulding width minus the width of the rabbet that holds in the glass and is the width that matters in this case. We will call this measurement “W”. They claim that if you do set the V-nail slider to that number, each V-nail will be ¼” from the nearest end of the miter joint. That is not true.

To see the Note click here.To hide the Note click here.
Following their instructions, the average distance (D) from either of the two V-nails to the nearest end of the miter joint would be the length of the miter joint minus the size of the gap between V-nails, all divided by two. In terms of W (the measured width of the moulding):

D = \frac{W \sqrt{2} - (W - \frac{3}{8})}{2}

which reduces to \frac{(\sqrt{2} - 1)}{2} W + \frac{3}{16}

or appoximately \frac{W}{5} + \frac{3}{16}

by dividing the whole expression by the square root of two, the average distance to the nearest edge would be

appoximately \frac{W}{7} + \frac{1}{8} .

The New Scale


The numbers on my new scale (labeled “A” in Figure 1 and “Gap scale” in Figure 2 above) represent the moulding width W, not the gap between nails. In addition, following my scales will put the V-nails 25% of the joint length in from each end, which is also 25% of the moulding width in from each edge of the moulding. I do this because if I were using only one V-nail I would put it in the center. For two V-nails, I conceptually divide the moulding in half and put a V-nail in the center of each half. If the moulding were wide enough to require three V-nails, I would divide the moulding into thirds and put the nail in the center of each third. Is there a structural engineer in the house or someone that knows a better place to position the V-nails? I’m listening.

Attaching the scale

If you download the JPEG (.jpg) file of the scales (click the link just below the title of this article), you can print them either on plain paper or maybe even a 2″ by 4″ label. The red lines and numbers (shown in Figure 2) correspond to the existing scale. After printing, you should compare the distances between a few of the red lines to the same distances on the old scale be sure your printer/software didn’t arbitrarily change the size of the print. Then cut along the blue lines. The black lines and numbers represent the bottom moulding width (W). For the slider block or gap scale, place the edge of the sliding V-nail block on the ¾” mark on the existing scale. Then place my scale on the opposite side of the slider so that the red ¾” mark is lined up with that same edge of the block (as shown in Figure 3).

V-nail slider with new scale
Figure 3: New scale on V-nail slider

Using the scale

To use these scales to press two V-nails into the moulding, just put the V-nail block on W, as you read it from the vise scale. Then do the same to the V-nail Corner Spacing Stop and the Lever Adjustment Block (both discussed below). Then make all other adjustments as prescribed in the manual and lower the pressure foot onto the moulding.

If you needed to press three V-nails, you would press the outer two by following the above instructions to adjust the components at all three scales to a value 2/3 of W. For example, if the measured moulding width was 3″, you would adjust all W settings to 2″. Press the V-nails. Then put the third V-nail into the sliding nail holder only (leaving the fixed nail holder empty). Set the gap (a.k.a. slider block spacing) and the pressure foot placement for 4/3 × W or 4″, leaving the other adjustments the same. Press the last nail.

other options

If you would prefer to set the V-nails as you were before, or even if you would prefer to put them where Logan said you were putting them before, then an additional set of scales could easily be made using the moulding width as the setting instead of actual nail distances, so you would only have to read the vise scale and set everything automatically, without further calculations. Although simplicity was the motivation for this effort, having multiple alternative scales is beyond the scope of this article. But if you need help with that, let me know.

V-nail Corner Spacing

This scale (labeled “B” in Figure 1) is located on the back of the left slider guide (as you face the joiner from the front). The original scale goes from ¼” to ¾” in ⅛” increments, which is a slightly larger range than the V-nail Corner Spacing Stop (on the back end of the right guide) can use. That scale shows the distance the outside V-nail will be in from the corner of the moulding, but it reads more than 1/16” smaller than the actual distance. For example, the position of the V-nail slider in Figure 4 will put the outer V-nail ½” from the corner of the moulding.

My scale would go to the right of the original scale so that both scales are still available. After placing the scale, measure the distance between the ¼” mark on the old scale and the red ¼” mark on the new scale. That is the distance the arrow should be placed from the back end of the slider. It should be ⅛” above the bottom edge of the slider so it can be seen above the slider guide.

New V-nail Corner Spacing scale and arrow
Figure 4: My V-nail Corner Spacing scale with the arrow on the slider

Pressure Foot Placement

For simple moulding profiles that do not require the black moulding spacer, I created a scale (labeled “C” in Figure 1) based on moulding width W to help center the pressure foot over the moulding.

Lever adjustment block scale (and arrow)
Figure 5: Lever adjustment block scale

Cut out the Pad scale (see Figure 2) and place it to the left of the lever adjustment block (the same side as the Pro Joiner label, as shown in Figure 5 above) so that the red edge line is on the edge of the top plate, as shown in Figure 1. To place the arrow, slide the lever adjustment block all the way back (in Figure 5, that would be to the left). Then place the arrow above the edge of the top plate.

When setting up the joiner, put the arrow over W. It is that simple. But our 1½” stretcher moulding, for which W is 1″, has a ridge along the outer edge of the moulding that is ⅜” wide. The simplest way to handle that is to pretend there is a symmetrical ⅜” wide ridge on the other edge of the moulding; add ⅜” to W, and set the pressure foot to that 1⅜” value. On the other hand, if that moulding had an obstacle only on the inner edge instead, you would subtract ⅜” from W, and set the pressure foot to the resulting ⅝” value, in the case of our example.

Adjust Foot Height

This is the setting based on moulding thickness instead of W. The size of the V-nail used is also a factor, but that is also based on moulding thickness. Unfortunately, I have not yet found a good way to attach a scale for this adjustment. Just follow the instructions in the manual; they are pretty straight forward. The lever handle should be just a little above horizontal when the moulding first contacts the V-nails, and should be the same angle below horizontal when the lever handle bottoms out. The precise angle is not important here.

Below is a table that relates the moulding thickness to the number of threads that should be exposed above the lever height wheel (there are twelve threads per inch on the lever shaft). The table is preliminary, but you could download the .pdf file (look just below the title of this article) and you could even attach it to the top plate of the joiner if it is helpful. After you improve it, please send me a copy.

Table relating pressure foot height to moulding thickness
Figure 6: Lever height and moulding thickness

Odds and Ends

Stacking V-nails

We haven’t ever deliberately stacked V-nails, as discussed on Page 6 of the manual, but we have tried a different brand of V-nail that is longer than the largest Logan. We use the AMP (a Fletcher Company) 15mm Mitre-Mite V-nail (their longest), as mentioned in Figure 6, for our 1½” stretcher moulding. It works well on our Logan joiner.

Glue First

We used to apply glue to the miter joint and then immediately use the joiner to put our frames together. After the beginner’s luck wore off, we noticed that the joints weren’t as tight as we would have liked. Then I stumbled onto a couple of websites that suggested gluing the frame together first using a band clamp and then V-nailing the corners after the glue dries. One of those references was an old article on the Logan Graphics blog. We haven’t had any problem with that since.

That’s All, Folks

That should about cover it. If you have any questions, or shortcuts, or any other suggestions for improvement, let me know in the comment section below. And if not, then thanks for listening.

Answers To “Is This Picture Level?”

A few weeks ago, I asked a few questions about a picture of me on the Turner Riverlink. I even offered a reward for the best answers. Here are my answers.

First Question

NO, the picture is not level. The photographers’ usual reference point for getting a picture level is the horizon. One of the rules of composition says that your horizon must be perfectly straight (unless it is so far off that the viewer will know that you did it on purpose).

To see the Note click here.To hide the Note click here.
What some people call “The Rule of the Horizon Line” is just an implementation of the Rule of Thirds. In the section “Horizon Lines” in his article Using Leading Lines and Horizon Lines in Photographic Composition, Todd Vorenkamp discusses both aspects.


But what if the horizon is not available, as in this picture? Nasim Mansurov, in his article The Importance of Straightening The Horizon and Aligning Lines, discusses (and shows examples of) several options for getting your picture straight. But he didn’t mention this situation.

Bruce on Turner River (annotated)

Q2: How Do We Straighten It?

First, let me say what won’t work: allegedly horizontal elements on a canoe, like seats and thwarts, even in calm water, can be expected to deviate from horizontal as a matter of routine. This case, as it turns out, is no exception. So what can we use?

When you have a calm body of water, as we do here, and the horizon is not visible, you can still depend on the levelness of the water. As I discussed in Reflections – My Answer To “What’s Wrong With This Picture (Version 2)?”, the angle of incidence of a reflected light ray equals the angle of reflection, which means, since the surface of the water is a horizontal plane, that the reflected object will be directly under the object itself, or the line between the two will be vertical, or 90° from the horizon. In the picture above, I have identified four different reference lines. Once you are convinced that this works, you really only need one. Two things make this more challenging, however. There are floating obstacles obscuring good reflection candidates. Also, as I discussed in “Reflections…”, the reflection won’t look exactly like the reflected object due to the changed perspective. Since identifying the exact point reflected may be subject to slight errors in estimated position, the further they are apart (meaning the longer the line connecting them) the better because the error in the angle needed to rotate for the picture to be level is proportional to the positional error divided by the distance apart (for small error angles). In the above picture, the flower (labeled “A”) is an easy choice, but it and its reflection are close together. The hole in the canopy (“B”) and the more prominent branch (“C”), although less identifiable in the reflection, do have good separation distances. “D” shows that in a pinch, when no well-marked points are available, you could even use the point on a curved line where the slope of the curve and the slope of its reflection are the same (or parallel). Expect a higher positional error in cases like that.

Once you have a reference line, most editing software has a horizon-straightening feature, or at least the ability to rotate the image until your reference line is vertical. For what it’s worth, this image needs to be rotated about 8⅓° clockwise. To see the corrected version, go to the bottom of our Red Mangrove Maze image page, where you can also find the identity of the person who took this picture.

Bonus Question

For the last question of the article, which was a math problem to find my age, see the note below.

To see the Note click here.To hide the Note click here.

Timeline for age problem

As you can see in the above illustration, there are three related timespans (years before 2008, years after 2008, and total years); if you know any two, you can find the third. This is true whether you are talking in years or percentages. We want the answer in years, but we only know one of the three. As a percentage, we know two of the three, so we can (and will) know all three. What we have to do, then, is find a relationship between years and percentages.

Twelve years is less than 19% of my current age,

or 12 \leq 0.19 \times Age

Age \geq \frac{12}{0.19} \approx 63.2

Actually, I’m about 64½.

Your reward (including bonus) would be \frac{1}{0.81} \approx 1.23 times the original award, meaning your bonus would be about 23%.

And The Winner Is…

There were four responses to the original post. All addressed the title question. Nobody addressed the follow-up or bonus questions. The judges have concluded that the first correct answer and winner of this contest, receiving ten dollars off of any Bee Happy Graphic product or service, and all bragging rights, is M. Alexander (former member of Kendall Camera Club). Congratulations!

Tips For Setting Up Your Booth Canopy

We have a Trimline Canopy by Flourishabout, with lower StaBars and a small (30″) front awning. Although we’ve also heard good things about the Light-Dome canopywebsite, I don’t know how many of the following tips would apply to other manufacturers. Not all of these concepts are brand-specific, however.

Booth at ArtsFest in Stuart February 11, 2017
Our booth at ArtsFest in Stuart on Saturday, February 11, 2017

This will not replace the setup instructions provided by the manufacturer. I refer to the latest information on the Flourish website as appropriate (I’ve noticed they have made a few changes since we bought our canopy in 2010), and suggest you read your instructionsFlourish and even watch their video (For ours it would be TrimLine Canopy Detailed Setup Video With Chris) before starting.

Storing Gear

We don’t completely disassemble our poles after each show. Since we carry all tent gear and art in our van, we follow something very similar to the “Fastest set up” on Page 8 of the “Trimline Canopy 10′ x 10′ Instructions for Assembly” (373.pdf). Specifically:

Illustration of roof poles with rafter hardware attached
Figure 1: How we store our Rafter Base Poles (from Page 3 of the “Trimline Canopy 10′ x 10′ Instructions for Assembly”)
  • The rafter base poles have rafter base joints and corner joints attached, as shown in Figure 1 above.
  • The Ridge Pole has Ridge Support Joints on both ends. The Riser Poles get stored with the Rafters.
  • The Awning Ells are attached to the long awning pole (described as the no-color 116½” pole in the “Trimline Awning Assembly Instructions” (394.pdf). The short poles for the side of the awning are stowed with the Rafters.
  • The legs are stowed in the “Rest-Stop position” with the top half against the Rest Stop Button. The StaBar Ell or 3-way is attached, as is the foot and the LD (a.k.a. Awning Support) Ell (as appropriate). All of these attachments are locked in their base positions.

We store the tent walls and other small parts in a large tote box (outside dimensions 32″L x 20″W x 18″H).

Setup

We set up our canopy with the heat/wind vents on the sides instead of front and back so that I don’t have to reach over the awning to open the vent. The downside of this is that if the tents are too close together, I may have to open the vents from inside the booth.

Illustation showing map of tent and offset for raising roof
Figure 2: Sample Booth Setup Scenario

When placing the roof in position, either while assembling or afterward, place the wall that will go up first exactly 24″ inside (toward the center of the booth from) its final position.

To see the Note click here.To hide the Note click here.

This is assuming a ten-foot tent with legs in the Rest Stop position (roughly 79″ long). It is based on the Pythagorean Theorem (Notice that in Figure 3 below, the roof poles, legs, and ground form a right triangle with the ground being the hypotenuse since the legs connect to the roof poles at a 90° angle. The general formula (in case you have longer roof poles and/or longer legs) would then be

Offset = \sqrt{(PoleLength^2 +    LegLength^2)} - PoleLength


Its two adjoining walls should be in line with their final position. Which side of the roof goes up first may be dictated by the placement of neighboring tents and other obstacles. For example, if you are in a line of booths that are being set up with their back wall against the curb and both of your neighbors have already set up, you should place your back wall two feet from the curb, meaning the front wall will be 24″ further out in the street but the sides will in their correct plane (see Figure 2). As you tilt the top up and attach your back legs first, their foot will land against the curb (see Figure 3).

Illustration showing how much canopy moves when raising tent
Figure 3: How the roof creeps as you install legs

When attaching the roof to the frame, we connect the straps and buckles on the vent sides and the wide Velcro on the rafter sides. But if we were to connect the thinner corner Velcro straps at that time, they would get in the way of hanging the weights.

Leveling The Tent

Roof Poles

We don’t see many other artists do this, but we use a small level to make sure our walls, and subsequently our panels, are vertical (and our roof poles and StaBars are horizontal). As you can see in Figure 4, it is important to have your framed pieces against the wall and straight. With all four legs in their lowest (“Rest Stop”) position, find which corner is highest by placing the level along your roof poles on all four sides (and “follow the bubble”). Since the poles sag over time due to the weight hanging from them, you should take measurements at more than one location along each pole. The leg in the highest corner will remain in its lowest position. Lengthen the adjoining legs as appropriate. Since one can only raise a leg in 1¾” increments, it is possible that the ‘true’ adjustment will fall between two holes. Pick one.

Illustration comparing leveled and unleveled canopy frame
Figure 4: Leveling the tent

StaBars

Since the lower bars are only held by thumb screws, positioning is continuous (no 1¾” increments), so we could do an even better job of leveling them than we do with the top bars. But because of the way our panels hang from the horizontal bars (see www.beehappygraphics.com/panels.html), it is more important to get the lower bars parallel to the top bars than it is to get them level. After measuring the change in length of the leg (which should be in agreement with the formula

HeightDifference = AdjustmentHoles \times 1.75" ,

move the StaBar joint up accordingly. After measuring each leg for each festival for about nine years, I came up with a shortcut.

Top and bottom sections of canopy leg, showing added markings
Figure 5: New markings on canopy legs

Notice in Figure 5 that I labeled the holes in the top section of the leg and pre-measured, marked, and labeled the correct adjustment distances on the bottom of the leg. This has already saved me much more time than the time I invested in making these improvements. The figure also mentions my suggestion for Version 2. Although the important measurement is the distance from the bottom edge of the StaBar Joint to the top of the foot, it would be better to have the markings and labels on the top edge of the StaBar Joint so you can read them without having to bend over so far to look under the joint.

Weights

Trimline canopies come with Ground Screws and 10” Steel Spikes for anchoring the canopy to the ground. These are almost never allowed at the art festivals in Florida that we attend. We can use weights anywhere. Flourish has their GreatWeightsabout, heavy-duty vinyl bags that will allegedly hold up to 40 pounds of sand or pea rock, at an additional cost. We built our own from parts readily available at any hardware store, namely a 30″ section of 4″ PVC pipe with a flat endcap, a bag of cement, and an eyebolt with nuts and washers. Ours weigh 34 pounds; some festivals want more, but our panels and art hanging from the roof make up the difference. Construction details for the weights will have to wait for another day (in the meantime, email me or comment below if you need details). We hang the weights from the canopy with ratchet tie-downs and strap them to the leg with a bungee cord at the top and bottom. It is very important not just to have them dangling but to have them held firmly in place (so they don’t turn into wrecking balls in heavier winds). If you look closely, you can see our weights in action in the picture at the top of this article.

Our Skirt

Typically, the bottom of our walls are less than three inches from the ground, so we were amazed to see how far up from the ground our panels (and art) got wet after a rain. To solve this, Nancy got some clear plastic sheeting to wrap around the bottom of the tent before the walls go up. The plastic should come at least 24″ up from the ground, plus a couple of inches extra on the ground. Ours is at least 4 mils thick. We need about 42 feet to go around all four walls. We use the clear 2″ shipping tape to attach it to each leg (which works much better if you get the skirt up before it starts raining). Start with one of the front legs, and then go around past the back legs to the other front leg. At this point, there should still be about eleven feet of plastic to go across the front, but while the tent is open we roll up the extra and stow it behind the nearest weight. When we close up, we pull out that last bit of skirt, stretch it across the front, and tape it to the last/first pole. Then we lower the front wall and secure the tent according to the manufacturer’s instructions.

Instead of using the skirt, we recently considered extending the walls about 18″ and including straps to keep the bottom of the wall lying on the ground under all circumstances but Nancy decided it wouldn’t keep the walls as clean as our current method does.

The Awning

Occasionally awnings are not allowed, but we usually put up a front awning. It doesn’t go up while setting up the tent, and it is the first thing to come down after closing on Sunday afternoon so that it is out of the way of other artist vehicles coming in to drop off or pick up their supplies. We also take it down Saturday night so that we don’t have to lose sleep over the weather or other artists driving to their tent. The awning zips to the same zipper the front wall would use, but there is another zipper on the bottom edge of the awning for attaching the wall.

Daily routine

Our procedure Saturday and Sunday mornings would be to unzip and roll up the front wall, unzip it from the roof and set it aside, attach the awning poles, zip on the awning to the roof, and attach it with the bungees to the awning poles. Then we would zip the front wall back up to the awning and leave in the rolled position (on immediate standby in case of sudden severe squall). Finally, we would reconnect or adjust the Velcro at the top edges of the front walls and the corners of the canopy. Saturday and Sunday evening we would reverse this procedure.

In Case Of Rain

During light rain, we would stay open and continue working with customers. I would move the LD or Awning Support Joint on one side, which is normally at the top of the leg as described in Step 3 of the “Trimline Awning Assembly Instructions”, up as high as I can get away with and lower the joint on the other leg a couple of inches or as much as it takes to stop the water from forming a puddle in the middle of the awning that would ultimately spill over onto unsuspecting customers. If the rain became too severe, we would drop the front wall and hang out with whatever crowd needed a dry place in the middle of a storm.

In Closing . . .

That’s about everything we’ve learned so far. I hope it helps. If you have a better solution, or a solution to a different tent problem that could save our readers some grief, please explain in the comment section below. Thanks!