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Archive 2011 · Spot metering with 1DIV

Lutefisker
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p.1 #1 · p.1 #1 · Spot metering with 1DIV

When shooting theatre or dance under very low & harsh light and spot metering, the exposure occasionally changes abruptly resulting in blown out exposures. In the example below, shooting aperture priority, spot metering, ISO 6400 and f2.8, the shutter speed on the previous and subsequent frames was 1/125 and 1/100. The shutter speed in the example was 1/6.

These intermittent blown exposures can be single frames or a whole series of frames and may depend (altho I'm not sure) on whether I'm continuing to hold down the back button focus. The focus point was on the edge of the girl's shoulder. This problem only seems to occur under spot metering--which I only use with harsh stage lighting.

Any ideas?

http://rickjohnsonphotography.smugmug.com/Other/2011-Misc/i-KK9XHtM/0/X3/DIV1060-X3.jpg

Jun 12, 2011 at 01:40 PM

SeverianTL
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p.1 #2 · p.1 #2 · Spot metering with 1DIV

Lutefisker wrote:
...
Any ideas?

Manual instead of aperture priority.

Continuing to hold the "AF-On" button will lock the exposure only when in one shot AF mode with evaluative metering. Never shot a 1D of any variety, but this behavior (exposure lock) is the same for every Canon DSLR that I'm aware of.

Jun 12, 2011 at 02:05 PM

Claude
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p.1 #3 · p.1 #3 · Spot metering with 1DIV

Maybe that the spot missed the dancer and metered on the dark background (?)
Claude

Jun 12, 2011 at 02:19 PM

Monkey Falls
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p.1 #4 · p.1 #4 · Spot metering with 1DIV

Presumably, it metered primarily on the background. I think the spot meter on the 1DIV is about 3.8%, so it's small, but it could have metered on her shoulder and the backdrop, giving you the blown highlights.

I would also recommend manual exposure and adjust your shutter and aperture manually as the lighting changes. It can be challenging, but the alternative it what you have already experienced.

Jun 12, 2011 at 03:49 PM

TomKayser
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p.1 #5 · p.1 #5 · Spot metering with 1DIV

In theater photography youll never use anthing else than manuell metering. Try it, youll see : it works

Jun 12, 2011 at 06:49 PM

Lutefisker
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p.1 #6 · p.1 #6 · Spot metering with 1DIV

I was shooting in AI servo with exposure tied to the focus point.

I shoot manual when I'm in a gym or dome where the lighting is relatively even and I don't need to be making many changes. But on the stages where I shoot, the lighting is extremely uneven & it changes frequently. When combined with the fast action across the stage, I can't imagine it is possible, at least for me, to be fast enough to follow the subjects and be changing exposure on the fly. Under the conditions where I shoot, I'm certain that the electronics already do better at exposure than I ever could. My expectation is that if I can understand when the electronics fail, I can adjust the settings or my technique to minimize the failures.

Jun 12, 2011 at 07:02 PM

Alan321
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p.1 #7 · p.1 #7 · Spot metering with 1DIV

Were you shooting in continuous mode, or just one shot at a time ?

- Alan

Jun 13, 2011 at 01:50 AM

Lutefisker
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p.1 #8 · p.1 #8 · Spot metering with 1DIV

Some, if not all, was continuous.

Jun 13, 2011 at 01:57 AM

Alan321
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p.1 #9 · p.1 #9 · Spot metering with 1DIV

It is just possible that the mirror is sticking a bit and that it is not always fully down between shots when the metering is being done for the next shot. This might affect AF too if you're in AI Servo mode. The result can be overexposure because the meter is not seeing the image or not seeing the right part of the image. I've had this problem on a 1D2.

Single shot mode is not likely to be affected because the mirror is down so much longer that the meter can get a good look at what it's meant to see.

A slower frame rate could help but is not the cure.

- Alan

Jun 13, 2011 at 02:45 AM

dswiger
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p.1 #10 · p.1 #10 · Spot metering with 1DIV

I thing spot metering in that venue is not a good solution.
To small a metering area & lots of opportunity to hit the wrong spots in the scene.
I would go for evaluative, w/EC if needed if you expect the lighting to vary that much.

If the lighting were consistent, I might even go manual.

Dan

Jun 14, 2011 at 02:19 PM

eric_m
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p.1 #11 · p.1 #11 · Spot metering with 1DIV

If the light is constant, I use manual.

If the lighting changes frequently, I use Av with exposure compensation dialed in to taste.

Never had an issue like this. I use the matrix metering mode and not spot metering, to take an initial reading, and then bias the exposure from there.

Eric

Jun 14, 2011 at 04:40 PM

Alan321
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p.1 #12 · p.1 #12 · Spot metering with 1DIV

You could also try using multi-spot metering to cover a range of lighting conditions and then use that info to set an exposure manually.

- Alan

Jun 15, 2011 at 11:22 AM

Lutefisker
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p.1 #13 · p.1 #13 · Spot metering with 1DIV

Thanks all for the responses. I think I've figured out a few things with your help. One is that the blown exposures were a result of the focus point missing the target and exposing on the black curtain background. Secondly, once an exposure was incorrectly set, it did not change as long as I kept the back button depressed (it may be that the exposure will only change when center-weighting is used). Although I may experiment with using center-weighted, I think it's probably best to return to using evaluative metering and frequently re-establishing exposure.

I can't rule out a sticky mirror playing some role as Alan suggested. Hopefully, I have a chance to test the new settings sometime soon.

Rick

Jun 15, 2011 at 12:22 PM


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