Using Exposure Compensation to deliberatey underexpose

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Scheelings

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I think all M9 users know that under less than ideal lighting conditions (low light), it is better to underexpose and retain shutter speed than to decrease shutter speed (and risk motion blur) or increase ISO beyond a certain amount (grain).

Given the ability of the raw files to recover very well from underexposure, have any of you decided to simply leave the camera on 'A', but shift the exposure compensation dial to underexpose by 1 or 2 stops?
 
In low light, leaving ISO at 640, shooting raw and using the appropriates shutter times and apertures will optimize the analog signal-to-noise ratio and dynamic range of the raw data. The meter reading becomes less important.

In a way, this give you 2 to 3 stops of psuedo-auto ISO. Instead of using in-camera electronic amplification above ISO 640, the required image brightness (a.k.a. ISO) can be adjusted globally during post-processing.
 
In low light the camera meter becomes useless since it tries to average the very dark shadows.

So take control and set the exposure to manual, take test photos and check their histogram in review until you find the best exposure for the situation.

If you use auto exposure in low light, the camera with its reflected light meter will always give you longer exposure time.
 
Hsg said:
In low light the camera meter becomes useless since it tries to average the very dark shadows.

So take control and set the exposure to manual, take test photos and check their histogram in review until you find the best exposure for the situation.

If you use auto exposure in low light, the camera with its reflected light meter will always give you longer exposure time.
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That's my feeling. The screen and the histogram are an "instant Polaroid" -- and a lot more use than the Forscher Polaroid back for my Nikon F.

Cheers,

R.
 
My habit has been to use the ISO 1250 setting before risking motion blur or underexposing too much. ISO 1250 may not be ideal, but the amount of noise is acceptable to my eyes.
 
Nobody actually answered my question. Perhaps I should have been more clear.


I normally shoot manually in low light conditions, however since the ambient light level can vary significantly, it takes time to make the required adjustments.

I thought perhaps I could speed it up by using "A" and tricking the camera into automatically and constantly underexposing (by say 2 stops) by using the exposure compensation dial.

Theoretically this would give me the highest possible shutter speed, whilst continuously underexposing each image without me having to manually make the adjustment.
 
If I want to constantly underexpose my image manually, how is it possible for me to rely on the '> 0 <' indicators in-camera? Since you aren't informed by how much you are underexposing....

... unless the exposure compensation dial will indicate '0' when underexposed / overexposed?
 
Not sure about the M9, but the M8 does work well using this method with RAW files. The process was originally described in the Leica forum. With an M8, the ISO is left at 160 and a -3 [the highest it will go] exposure compensation is dialed in. This works well, and gives the equivalent of 1250 without the noise. This works either shooting on A or metering manually. The RAW converter in Photoshop does the rest. I am now trying it at ISO 320, but have not done it enough to see how well it will work.
 
Scheelings said:
I normally shoot manually in low light conditions, however since the ambient light level can vary significantly, it takes time to make the required adjustments.

I thought perhaps I could speed it up by using "A" and tricking the camera into automatically and constantly underexposing (by say 2 stops) by using the exposure compensation dial.

Theoretically this would give me the highest possible shutter speed, whilst continuously underexposing each image without me having to manually make the adjustment.
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Yes, you describe it correctly. Whether you actually gain something in terms of speed is something you need to try out yourself.
 
I do not own an M9 any longer, but when I did, in low light I would set ISO to 640 and the lowest shutter speed that was appropriate to avoid camera shake. Pushing the under exposed shots in ACR would render better results than exposing correctly at higher ISOs.
 
ajramirez said:
I do not own an M9 any longer, but when I did, in low light I would set ISO to 640 and the lowest shutter speed that was appropriate to avoid camera shake. Pushing the under exposed shots in ACR would render better results than exposing correctly at higher ISOs.
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That is what I have been doing since many years also with film (typically 400 or 800 ASA), and do now with the 240 (except, with the 240 I can rely on auto iso up to a max. that I set to 1600 ASA, typically).

For a night scene to look like a night scene you wouldn't want full auto-exposure in the first place - the picture wouldn't look like a night scene.

So: set your max. ISO, open your lens, set your speed to the lowest you can hand-hold and do the rest in post.

Roland.
 
jaapv said:
Revolutionary thought: Take the camera off "A" and start exposing manually.
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Right on

I tried boosting luminance with camera and computer and found no difference. Another internet myth debunked like surge marks and gentle agitation.

I will pass on a few tricks.

Use ACR color and luminance grain reduction. Two changes. Do the color first as it is easier to see color dots go away . Second do it as a smart object on layer two. The reason is you can make a luminosity mask to target the NR to the darker areas of the image. Lastly make a group of layer two only and mask it with an edge mask that keeps the luminance NR from touching the edges softening them. An edge mask looks like an ink drawing of the photo.

I suggest putting this into an action. And do not forget you can paint on a mask with black, white , grey, and adjust opacity so it does exactly what you want.

Promise you will get really fine images.
 
jaapv said:
Well, normally it involves my pet hate: guessing exposure by EVcomp. ;)
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What is there to guess? Either you use the camera meter (M or A, auto-ISO or not) or you don't (M with external meter or eyeballing the exposure). Exposure compensation is just an offset. You can compensate even when going fully manual.
 
presspass said:
Not sure about the M9, but the M8 does work well using this method with RAW files. The process was originally described in the Leica forum. With an M8, the ISO is left at 160 and a -3 [the highest it will go] exposure compensation is dialed in. This works well, and gives the equivalent of 1250 without the noise. This works either shooting on A or metering manually. The RAW converter in Photoshop does the rest. I am now trying it at ISO 320, but have not done it enough to see how well it will work.
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Thankyou! This was the info I was looking for!
 
Corran said:
This is exactly how it works in every camera/meter I've ever used. The exp. comp. dial is the same thing as changing the ISO, basically.
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OK, Thanks for that - that would be useful using the same trick in manual mode in low light conditions where there is high dynamic range (which might trick the light meter)...
 
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