Think Fast: Exposure Quiz!

40d
+0
+2/3
---

1. 1DmkIIn
2. -1/3
3. -2/3 to -1

OK, I can see that what looked like the tail of the fish to me is a splash. The rest looks like some object in the water

Sorry to be a bit late with the answer. The woman screamed. I saw that the gator had a white bird in its maw in the bright sun. As I moved to sun angle I dialed in -1 stop. Why? The gator, in the middle of the frame and the metering pattern, was very dark and the dirt was pretty dark too. The 40D needs less light to yield the same histogram as the MIII so I instinctively put in some extra minus. In the first two frames of the four or five in the sequence in the sun were made at 1/4000 sec (all at f/5.6). In those the histogram was dead solid perfect. There was no room to the right. In the next three frames more of the dark gator filled the frame so you would expect and the exposure dropped to 1/3200 at f.5.6. One would expect that the whites would have been burned but instead, there was a bit more room on the highlight end of the histogram. Why? I think because of the angle of the sun. Even though the gator was in the sun the angle of the sun was reduced as it got closer to me and thus there was effectively less light on the scene. So far so good.

Now the animal slips into the dark shadow of the boardwalk. I change the -1 stop to -1/3 stop. Why? Not as much need to save the whites with the Cattle Egret now in the shade... There were about 20 burned pixels on the Cattle Egret that went away when I underexposed .2 stops during the BreezeBrowser conversion. Minus .1 probably would have been fine.

To my mind, I had nailed both exposures and this was confirmed by both the histogram and the very few flashing highlights in the shadow images. I showed the photos to a guy and to the woman who had screamed. I explained my exposure choices to them. I saw the guy the next day and he confided in me that when I had walked away the woman had said to him, "What the **** does he know?" I thought that that was pretty damned funny.

So my answers would be: 40D, -1, and -1/3. Had I had a MIII in my hand, they would have been: MIII, -2/3, zero.

If I had had a D-300, it would have been D-300, -1 1/3, and -2/3 (though I have never made an image with this camera I am a good listener...)

If you used less light for the images in the shade than for the images in the sun, you lose 20 points. The same goes if you added light at any time. If you kept the same exposure, subtract 10 points. Lots of folks did pretty well and got the concept that they needed to subtract more light in the sun. And for Mr. Curry-check, the exposure for the shadowed images was 1/200 sec. at f.5.6. That's four full stops (4 1/3 from the first images) lighter than in the sun. So either 12 or 13 clicks would have been needed. Sorry Charlie; no time for that!

The good news is that the original ABP will eventually be reprinted in China though we have run into a dozen delaying problems; it contains the finest treatment of exposure theory on the planet.

Additional questions or comments welcome.

ps: to Christian: yes, as Blake said, Evaluative metering. And anyone using spot-metering in this situation would be worse off than the manual exposure folks, AND, I would bet anything that anyone using a spot or an incident meter could not figure the right exposures in these two situations even if they had an hour to get it right!

Well I'm just glad I was only .33 off I said -1, and -1 for my D300... I can live with that.

Maxis Gamez said:

So, if I was photographing another WHITE bird in the same light AS image ONE, would you still go to -1??

Click to expand...

(BTW, "if I were..." is correct.)

That is not at all accurate. It would depend on the tonality of the background and the size and position of the white bird in the frame. And you have forgotten that there was a big black gator head in the middle of the image... If you photographed a bright white bird in the same light, however, you would likely be fine with by setting either 1/4000 or 1/3200 sec. at f/5.6 manually.

As I said, those who wish to learn exposure theory need to go back to the original "The Art of Bird Photography: and study the great chapter on exposure. Otherwise, they are doomed to fail when an amazxing situation with a challenging exposure takes place right in front of them. BTW, you are in good company; several very talented photographers flunked the quiz.

"If I had had a D-300, it would have been D-300, -1 1/3, and -2/3"
Right on!

D300 user.
James

Maxis Gamez said:

Hey Robert,

What if your camera is set to Manual?? The meter does not count!

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Of course the in-camera meter counts, providing reference for exposure... unless you are using a reference value like sunny f/16 or hand-held incident meter. Manual mode simply means you have to dial in both parameters yourself.

Chas

I’ll play.

First off I would already have the camera set in Manual Mode to a sunny f/16 equivalent exposure (no meter necessary). In FL the sun is a bit more intense (closer to the equator) as it is at higher altitude (thinner atmosphere) so 1/1000 @ f/8, ISO 200. I can quickly alter the exposure for black or white subjects from the baseline. And, I typically have the camera set to Spot Meter Pattern. Being pro-active and complusive, I already know the comp necessary to render white bird correctly (plus 2 EV). The comp should be the same for the white bird in the sun or shade assuming there is no specular highlight or shadow influencing the metering pattern. I am simply placing the tonal value where it belongs on the histogram.

It takes me just as much time to dial in comp in Av, as it does to alter one of the parameters in Manual Mode with Spot Meter Pattern.


As mentioned, I agree ... at times it is best to play the odds Av with Eval. And, this scenario may well be a Hail Mary! I do know in Eval I could only initially guess at the correct comp, with the tonal values and sizes relative to the frame varying within each image. Honestly, I have a bigger problem with Eval, than I do with Av.

It is important to note their are Metering Modes and Metering Patterns, and understanding the difference is key in determining proper exposure as it relates to subject size and tonal value relative to the background. If the above statement is confusing to you, I highly recommend you take a class from someone with a firm grasp of the fundamentals. Mastering the fundamentals allows the photographer to concentrate on image aesthetics and creativity, expanding ones visual horizons.

Best,

Chas

Very interesting. Next comes Part 2: After you've made a fast and smart decision about exposure, as Art did, what do you do with the image when you get home?

As shot:



I would 1) set white point to get the most out of the whites and ensure that they're white. 2) Apply S/H to the gator to bring out shadow details. 3) Apply a curves adjustment layer to the gator to enhance contrast.

David:

Personally, I like the "as shot" image better than the second post. In the second post, the back of the gator look like it is overexposed to me and does not have the detail that the "as shot" does. And the white wings of the Cattle Egret look burned out in the second image compared to the "as shot"

JMHO

Dave

Dave S said:

David:

Personally, I like the "as shot" image better than the second post. In the second post, the back of the gator look like it is overexposed to me and does not have the detail that the "as shot" does. And the white wings of the Cattle Egret look burned out in the second image compared to the "as shot"

JMHO

Dave

Click to expand...

With white feathers in direct sunlight, these flat spots at the top of the histogram indicate that the image is underexposed. The whites in the edited version aren't burned out, but that's just a technical point. We like what we like, and I can't dispute your personal preferences.