## 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.

## My Midnight Rainbow Quest – Tougher Than I Thought

I just recently looked a little deeper into some rainbow geometry and discovered that this challenge could be a lot harder than I first imagined. But for those of you who have no idea what I’m talking about, here’s a little history –

## The Facebook Quiz

This all started with one of the little quizzes I put on my personal Facebook page from time to time. This one went like this:

A friend, John Gilbert, responded:

Bogus question, Bruce. Answers D, E and F are unicorn answers. I’ll take B, high noon, for 500.

John Gilbert’s 4:56 pm Facebook comment on July 12, 2019 to above post
Although John was a photographer for the Navy, now he is an artist. You can check out his website www.johngilbertartist.com.

to which I responded,

You started well but still wound up with the fourth-best answer (just behind D)….

My 3:31 am response on July 22, 2019

Then:

By the way, the correct answer to the quiz could be either A or C. If you can’t handle more than one correct answer on a multiple-choice question, pick C (more large rainbows will be seen then because more people are awake around dusk than dawn). The animation below shows how a rainbow changes with the movement of the sun. (The black face on the ground represents the top of the shadow of the observer.)

## The Contest

To speed things up, I then asked our local Kendall Camera Club for help by creating a contest for the best nighttime rainbow picture. I am now extending that contest to all of my readers. Here are the rules:

### Contest Rules

1. I’ll give the equivalent of a six-pack of your favorite brew (within reason) for the best picture of a rainbow at night. I said six-pack equivalent because a corresponding discount for any of the products or services of Bee Happy Graphics (see our Products and/or Services pages) may be substituted at your request.
2. The contest will run at least another month but may continue until we get a chance to get our own rainbow pictures (which will not be part of this contest), or until I give up all hope of completing this quest. If there are not enough entries at the end of the contest, the prize need not be awarded.
3. You can enter your image by emailing the file to admin@BeeHappyGraphics.com.
4. Composition does count. Photos of real rainbows will be given precedence, but just in case I overstated the possibility of that occurring, “Photoshopped” rainbows will be accepted.
5. I will announce the close of the competition and the beginning of the voting process in a comment to this blog post. I will explain the voting process in that same comment.
6. At least three weeks after the announcement from Rule 5 above, a winner will be announced. If any entry has three or more votes, the one with the most votes will be the winner. If no entry has that many votes, then I will take an informal survey among my closest family and friends, and pick the winner. The decision of the judges (as defined above) is final. This prize may be combined with other promotions.
7. Since this is a photo contest, I should mention that the photographer retains all rights to his/her image. We get to use your image only to run and publish the results of this contest.

So far, there have been no entries.

## The Physics

As I mentioned at the beginning of this article, the geometry doesn’t look good.

Figure 1 shows the angle that a light ray bounces off of a single raindrop. In Figure 2 (which is a view looking down, with the blue-hashed region being a rain cloud), one can see that as the sun’s rays all come in as parallel lines from the same direction, the five representative raindrops, and all others from which the blue light rays bounce at the same angle into the observers eye are all along the same line of sight, and therefore all reinforce each other. A single raindrop doesn’t reflect a lot of light and it takes the light of a lot of raindrops to make the rainbow visible. Similarly, the raindrops reflecting red light into the eye from a slightly different angle form along a slightly different line of sight and also reinforce each other.

### The Problem

But using flash, the geometry is different; the light source and the eye can now be represented by single points. But unless you were the navigator of a Coast Guard buoy tender or something, you may have forgotten a lesson from high school geometry; that the set of all points for which the angle between those two objects is the same defines a circle, not a line. In Figure 3, the angle between the flash and the eye is the same for Representative Raindrops A and B, and all other dark blue points on the outer circle (there is no rain along the pale blue segments of that circle). Unfortunately, each point on that circle is along a different line of sight from the observer and the light rays do NOT accumulate in the eye. To make matters worse, the red light reflected from Representative Raindrop C (on the circle of red light) IS along the same line of sight as the blue light from Representative Raindrop B (and the other colors of the spectrum from raindrops directly between them), which tend to cancel out into white light. This means you will see no rainbow.

## Where Does That Leave Us

The original purpose of this article was to throw in the towel and admit defeat, but as I was getting the materials together, I’ve already come up with a couple of new ideas that need to be explored. But the busiest part of our art festival season is now upon us and the rainy season doesn’t start in South Florida until around June, so this is not the rainbow of promise, but one of hope. Stay tuned. (And if you have a photograph of a nighttime rainbow, please send it.) Thanks.

## “Oak Tree Graveyard” – Our First Night Photograph

When we discovered Big Talbot Island State Parkwebsite north of Jacksonville one morning toward the end of April, 2010, Nancy saw Boneyard Beach and decided we needed to come back late in the afternoon for further investigation.  The elevation for most of the tree-clad island is about twenty feet.  Atlantic storms over the millennia have eroded the bluff to the beach and continue to knock trees down to the beach.  We returned while it was still light, worked our way down to the beach and took “Trees In Their Twilight” just a few minutes after sunset.  The camera was on a tripod for the 0.8-second exposure.

Since we expected a near-full moon to rise within the hour, we stayed around and took “Oak Tree Graveyard” less than an hour later, one third of the way through nautical twilightdefinition.  It was so dark we needed a flashlight to change the settings on the camera.  That picture took a 65-second exposure (about 8,000 times as long as your average selfie), which gave the sensor a chance to pick up light you didn’t even know was there.

This is the one area that the sensor is better than your eye. As I mention in Limitations You Should Know About Your Digital Camera (Or Phone)!, your brain doesn’t benefit from staring at something longer than 15 secondssource.

During that 65 seconds, I took our little LED flashlight (so as not to overpower the almost non-existent ambient light) and shined the light back and forth over those nearest three trees in the foreground.  I recall “painting with light” like this the whole 65 seconds, but Nancy distinctly remembers stopping after fifteen seconds 😕.  If you sweep slowly to cover the target in one pass, you might miss a spot. Or if you linger too long in one area, you will create a “hot” spot.  I recommend sweeping faster and making as many passes as you can to take advantage of the averaging effect.

What amazed me when the image finally appeared on the back of the camera after the shutter closed, was that the orange glow was still there. We’ve since gained more experience with night photography (for example, see Nautical Twilight In The Glades, Seven-mile Bridge At Twilight, Midnight In The Pinelands). Now we know that there are enough photonsdefined bouncing around at even the darkest hour so that if you left your shutter open long enough you could make it look like a bright overcast day (there would be nothing casting a shadow). At midnight, the light level could be about 1/160th that of “Oak Tree Graveyard”, meaning you would have to increase the exposure time, aperture, and/or ISO to gain over seven f-stops to get its sky to that same level of brightness. But the horizon would be blue again by then because the orange glow only lasts an hour or two, depending on atmospheric conditions.

### Epilogue

After getting “Oak Tree Graveyard”, we headed back up the bluff and back along the trail to the van. In an open area in the woods along the way, we saw an unbelievable firefly display as we have never seen before (or since), but were too tired to stop for pictures. Nancy has been kicking herself about that decision ever since.

## Tell It To The Judge: In Defense Of Photographers & Canvas

To be transparent, I must say I’ve developed some theories about the biases of art critics and the judges of art festivals, based mostly on their selections of art to be awarded prizes at these festivals (and maybe my own biases).  I’ve noticed certain patterns that I was hesitant to discuss here until I had taken the time to formally learn something about art.  That hasn’t happened yet, but we did have an opportunity to discuss photography (more specifically, nature and wildlife photography) with the judges at one recent art festival and I feel compelled to address one aspect of that discussion.  My comments on the other aspects may wait until I satisfy my original goals/requirements.  Today’s comments involve canvas.

## The Judges’ Remarks

One of the judges said, “I’ve Never Seen A Photograph On Canvas That I Like”. There were three judges at the table when Nancy approached them. Their views were all consistent. Other remarks included “When I see a photograph on canvas I think the photographer is trying to impersonate a painter” and ‘When I see a picture wrapped around the edge of the canvas, it makes me think they are adapting a larger picture to a frame that is too small.’ One judge pointed out that painters don’t paint the side of their canvas.

## Our History

Those familiar with our website know there are already two places where I’ve referred to painters as pre-photographers:

You also know I’ve even chided fellow photographers for not keeping up with the times Stop Thinking Like A Film Photographer!.

## A Dose of Reality

Painters like Leonardo di ser Piero da Vinci (1452-1519) and Georges Seurat (1859-1891) (see the first note in “A Question About Pixels”) are just two examples of artists who led society into the future, not followed. I’m sure if Leonardo had a camera, he would have used it in a flash (forgive the pun, I couldn’t help myself). These two and their peers would be saddened (or worse) to think that painters now feel unable to keep up with society and judges feel a need to artificially reserve materials and techniques specifically for painters in an effort to level the playing field.

## My Responses

Now I’d like to address some of their remarks individually.

“When I see a photograph on canvas I think the photographer is trying to impersonate a painter”

A few months before this conversation, a painter at another prominent festival in Florida won Best Of Show and \$10,000 for impersonating a photographer. I know another artist who uses pencil to imitate black & white photographs. This is called realism, which apparently artists have tried (with varying degrees of success) throughout history, most notably in the Realist Movement of the mid-nineteenth century.

So here’s a question: if canvas-using photographers are impersonating painters, who was Leonardo impersonating when he painted the two versions of Virgin of the Rocks in oils on wooden panels? A sculptor, maybe? Maybe a carpenter like the protagonist in his famous mural
“The Last Supper”? Or maybe that particular impersonation has been reserved for the judges.

“When I see a picture wrapped around the edge of the canvas, it makes me think they are adapting a larger picture to a frame that is too small.”

Well maybe that’s why painters do it. After all, contrary to the one judge’s declaration, some painters do paint the sides. But have you ever see a painter warp the image around the edge so that at some angle it creates an illusion and looks like a continuation of the front image (as described in the Canvas section of our Services page)? While we are at it, have you ever seen a painter camouflage their signature to make it less distracting (which solves a problem some critics have complained to photographers about)? Here’s how we do it ( Our New Technique For Signatures & Titles). Come on, painters, try to keep up!

“I’ve Never Seen A Photograph On Canvas That I Like”

I recently heard from another wildlife photographer about a time when a judge took a liking to one of her images, but then left without comment. When the judge came back the second time, he asked if she had another copy of that image that wasn’t printed on canvas. Fortunately, she did, because that second copy won her the second-highest award in the festival.

In our booth and online, I’ve discussed the magical properties of canvas. When people see one of Nancy’s images on canvas they are more likely to ask “Is this a painting?’ or are more likely to comment that it looks three-dimensional. For some strange reason, it is also perfectly acceptable to print a particular photograph larger on canvas.

People have offered a couple of explanations for this. The first argues that the texture of the canvas disguises any lack of resolution. The second, getting psychological, suggests that canvas invokes some painting mentality, making the viewer less critical (nobody ever asked an eighteenth-century master how many pixels were in his/her brush). Both explanations sound plausible to me, but being a pragmatist, I just run with what works.

So it is especially disturbing, and sad, that a judge would make a statement like this. Photographers follow the same rules of composition and the same principles of art, but for a judge to admit that these are not important, to me is an admission that the judges don’t really know what makes a piece of art special and are just grasping at fads or straws.

At least that’s how I see it (I guess now is a good time to remind you that the views expressed in this blog are not necessarily those of management). So what’s your view. If any of you can make better sense of these judges’ remarks, your comments are also welcome.

## Ideas For Shooting The Solar Eclipse In Miami With Phone Or Camera

I have some ideas for shooting the eclipse by either phone or SLR camera.  For those who haven’t heard, the next eclipse will be Monday, August 21st. In Miami, the eclipse will start around 1:30 pm, which is right after local apparent noon (when the sun crosses due south of us around 1:24 pm and is 77° above the horizon). The eclipse will last about three hours, by which time it will have reached an azimuth (compass bearing) of 261° and dropped to a height of 44°. At its peak just before 3 o’clock, it will be 64° above the horizon at a bearing of 243° (west-southwest). At that time, less than 1/5 of its diameter will be visible in South Florida, which means that about 22% of the sun’s area will still be showing, and the sun will still be a little less than 1/4 of its normal brightness (for lack of anything better at hand, I used Photoshop’s Count Tool to figure the sun’s brightnessHow).

### Shooting With Your Phone

In the news, they mentioned that you could use your smartphone to view the eclipse, but they warned that if your phone wasn’t eclipsing the sun (directly between you and the sun, obstructing your direct view) you could get seriously hurt, and since there are no nerves inside your eyeball, you wouldn’t immediately know the damage that was done. For that reason, you may want to use it in selfie mode.  You may also want to wait until the eclipse is close to its peak (although I have taken some test shots of the sun with no apparent damage to my phone).  There are a few problems with this approach, however. For one thing, the glare from your phone’s glass surface and/or the bright sunlight could make the image on the phone hard to see. On the other hand, if you actually wanted pictures, having yourself (or something else) in the foreground could improve the composition of the photograph.  But-

1. The resolution for the selfie camera may not be as great as on the regular camera. (I explain why bigger is better on the Bee Happy Graphics FAQ page).
2. My selfie camera doesn’t have controls for flash, exposure, white balance, and other things; these features being listed in the order of their importance.

You will need fill flash on your foreground subject, and the flash will probably need to be less than two feet away to be effective.  But that means the camera is in regular (non-selfie) mode and both aiming and pushing the shutter button could be a pain.  A short timer, if your app has one, could be helpful in pushing the button.

### Shooting With A Camera

First, you will need neutral density filters, not just for the proper exposure but unless you shoot in Live View mode it is more important that the filters can adequately protect you looking through the viewfinder.  For that, a 10-stop filter is not enough (but a 12-stop filter, if it existed, could be (at your leisure, you can check out the Bee Happy Graphics blog for another reason a 12-stop neutral-density filter would be better than a 10-stop). A 15 or 16-stop filter would be even better in this case. Focus on the horizon before attaching your filters and lock in your focus.

If using a zoom lens, begin as wide as possible; it is easier to find the sun before zooming and avoid the dangers of trying to peek around the camera.  You will need exactly the same focal length or amount of zoom that you needed when you took pictures of the moon. Most experts feel anything less than a 300mm lens is a waste of time. Remember that your shutter speed should be 1/(focal length x crop factor) or faster if you not using a tripod, but even with a tripod there may be no reason to go with less. The aperture (f-stop) setting is not critical since all the action is at infinity but should be small enough (large enough number) so that you can keep the ISO at its lowest value.

If you are planning to capture the whole eclipse in a sequential composite photograph, decide how many images you need, subtract one, and divide that number into 180 minutes (the duration of the eclipse). If you want a string of six suns in your picture, each picture will be 180/5 or 36 minutes apart. The camera will probably not be locked down to the tripod for the duration, but the focal length of the lens and other settings should be the same for the entire series.

The only way to get something in the foreground (for better composition), is to go for multiple exposures and combine them manually. At the designated time, take the sun shot and while the camera is strapped to the tripod, record your camera settings, remove the filters, change the settings as needed and shoot the foreground. For multiple exposure shots, they usually advise changing only the shutter speed, but I’m not sure it matters in this instance. If changing the shutter speed alone is not enough, I’d change the f-stop before changing the ISO. Now record the settings of the foreground shot so you can repeat as necessary. If you must change the focus for the foreground shot, be sure to refocus on the horizon before putting the filters back on. Return the camera settings to the sun shot values. You may now move the camera on the tripod to compose the next shot. I mentioned that the sun will be putting out only 1/4 of its normal light at the peak of the eclipse here in Miami. This means the exposure of your foreground shot will change by two f-stops. The exposure of your sun shots shouldn’t change.

### Final Words

Since this is such a rare event, you may not want to put all of your eggs in one basket. This means changing the settings of your camera (bracketing, if you will, checking the histogram, and perhaps rechecking the focus), which may mean taking several sequences simultaneously and taking good notes.

I’ve discussed some of your options, with some of the pros and cons of each one.  While I try to cover the technical aspects, you are the artist and the compositional issues are all yours.  It might be a good idea to get up early tomorrow and get some moon shots just for practice.  The moon will be just a waning (shrinking) crescent.  Moonrise here in Miami will be 4:37 am tomorrow and 5:40 Sunday (sunrise is 6:56 both days).

Well, that’s about it.  Have fun, don’t look directly at the sun, and let me know how it worked out for you.  I’d even be willing to post some of your pictures (with adequate credits of course).

## Best (and Worst) Angles For Whale Pictures

The March before last, we returned to Antarctica (Nancy’s favorite continent) with Cheesemans’ Ecology Safaris. Nancy broke her ribs in 26-foot seas in the Drake Passage the second day out, but still managed to make all the shore excursions. Her technical support staff hasn’t yet processed the pictures from that trip, but we do have some suggestions for those who might find themselves putting around in the vicinity of whales.

The article is on our website (www.BeeHappyGraphics.com/WhaleAngles.html). Although you still can’t get to it from the menu system, it is available from both the FAQ and site map pages. Enjoy, and let me know if I forgot anything. Thanks.