E-M1 random overexposure

barry13

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Hi,

I took a bunch of photos at a high school Lacrosse game at night this week... I wound up switching to a manual focus legacy lens (Takumar 50mm f1.4) after finding that my ZD tele zoom was too slow (too much motion blur) in the low-light.

With the MF lens, several of the pictures were badly over-exposed. It happened with portraits on the bleachers as well as with action shots on the field.
The camera is set to the default metering modes, auto-ISO, and was in Aperture Priority mode. The lens was stopped down 1-2 stops.

On one of the bleacher portrait shots, the camera chose ISO 4000, 1/50sec, and on the next shot, from the same position, it chose ISO 4000, 1/100sec.
The first was badly over exposed; the second was fine.

I was able to fix the first in RawTherapee - auto levels in RT set EC to -0.32, Contrast +24.

The camera is an E-M1 with current firmware.

Has anyone else noticed random over-exposure problems like this?

Thanks,
Barry
 

bassman

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Haven't noticed it, but 1 stop wouldn't seem to be "badly overexposed". In that situation the light isn't changing and you might be better off setting the exposure manually and then not changing it.
 

pdk42

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Hmmm - changing the shutter speed from 1/50 to 1/100 is only 1 stop and I wouldn't think a 1 stop difference could result in a shot being "badly overexposed". Can you give us some examples?
 

Klorenzo

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The camera is set to the default metering modes, auto-ISO, and was in Aperture Priority mode. The lens was stopped down 1-2 stops.
If you have strong light sources in your pictures (like the sky) or very clear or very dark elements then even a small change in the framing could result in a different exposure.
If this is the case, the correctly exposed picture should contain more bright elements than the overexposed one. Bright in the real world scene, not in the final picture. If so, you can work around this in many ways: manual, center/spot metering, auto exposure lock, exposure compensation, etc. the best option depending on the situation (and personal preferences).
 

David A

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If you have strong light sources in your pictures (like the sky) or very clear or very dark elements then even a small change in the framing could result in a different exposure.

+1

If the court area and players are important, set the exposure for a shot of them that looks "correct" to you, then lock the exposure, That way changes in framing which include or exclude light sources or brightly lit areas from the frame as you shoot action in different parts of the court won't affect your exposure. As long as the overall level of lighting doesn't change, or one part of the court isn't more brightly lit than another part, you'll be set.

Alternatively swap to spot exposure mode or centre weighted since these will base exposure on the centre of the frame and will be less influenced by brighter areas like light sources which are more likely to intrude at the edges. Since you're photographing a sport, the action you're interested in is more likely to be in the centre of the frame.

The default metering mode averages the whole frame area and is going to be most strongly influenced by bright or dark areas in the frame. Unless what you're interested in is in one of those bright or dark areas you're more likely to find the area you're interested in under or over exposed if you're using the default averaging method because it takes the whole of the frame into account and what you're interested in is a smaller part of the frame which may not represent the "average" lighting level of the whole frame.
 

barry13

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Hi,

Thanks for the responses...

I went through all the pics again, and for the most part, the ones which are over-exposed do have more dark trees or dark sky in parts of the frame.

However, there are 2 portraits I took on the bleachers, and one of them is over-exposed and the other is fine; there's nothing dark in the frame, so I don't know what happened. I did fix it in raw though.

I will try spot exposure or center-weighted next time.

Barry
 

barry13

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Bleacher examples attached; taken within seconds of each other.

Oddly, the correctly exposed one has more dark areas at the top of the frame.

Barry
 
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mattia

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Of those two shots, I think the one on the left is actually underexposed (although pleasingly so), and the one on the right is exposed well, if a little brightly for my personal tastes. As in it doesn't seem to have any blown highlights (can't confirm without the full file), and can easily be dialed back a little to something that looks more balanced.
 

Growltiger

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What was the lighting? You say it was at night. There is a problem with some types of stadium lighting where the light changes level and colour at 60Hz, i.e. 60 times a second.

This is not seen by the eye, but it means that both exposure and colour balance are basically random. All cameras face the same issue.

Next time try a sequence of identical shots using high speed continuous. You may be able to see the changes shot by shot, if so it will confirm this is the problem. At least some of the shots will come out correctly.
 

Klorenzo

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Hi,
I will try spot exposure or center-weighted next time.
Spot exposure is almost unusable if not done right. You will have strong variations in exposure for every micro change you made in framing. Try this at home :) and use it only with manual mode or with exposure lock.
 

Klorenzo

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Bleacher examples attached; taken within seconds of each other.

Oddly, the correctly exposed one has more dark areas at the top of the frame.

Barry
The rule is: the brighter the scene, the darker the picture you'll get (and reverse) in other words everything gets flattened towards middle gray. But the bright/dark areas must be quite big to be relevant and should not "compensate" for each other as usually happens.

In this case is just the opposite, as the second picture has 2/3 of bright areas.

One possibility is that, in the second pic, you made a first framing including the dark elements, half-pressed the button, and then pointed down the camera a little. In this case, obviously, the metering was done on different elements from the final ones.
Or you or the subject, with the half-pressed button, changed position throwing more reflected light into the camera.

As mattia I think the exposure I'd prefer is somewhere in the middle, not knowing the actual colors, tanning, etc.
 

barry13

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As in it doesn't seem to have any blown highlights (can't confirm without the full file), and can easily be dialed back a little to something that looks more balanced.
Hi, the gray sweatshirt is blown out, but I was able to adjust it from RAW.

Barry

Sent from my SM-N900T using Mu-43 mobile app
 

Growltiger

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I think it is those ones that give the problem, although I'm not certain.

Like I say, next time take say 30 photos at Continuous high speed, of exactly the same thing, and see if they all look the same. If I'm right, you will see a lot of variation between them. If this is the case there is nothing wrong with the camera, it is just the lights.
 

Klorenzo

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