underexposure and noise

I just read this in a review for the Canon EOS-1D Mark IIn:

"As with most dSLRs, however, you must be careful not to underexpose your images. Noise can be seen very clearly in images that are too far underexposed."

A year ago I started deliberately underexposing in RAW while shooting basketball games with my 40D and have been doing it ever since. I bring the brightness up in DPP and haven't noticed a noise problem.

Is this problem just with older cameras like the 1D Mark 2n?

Depends on how much you underexpose, what ISO, and how picky you are. Try recovering 2 stops of an ISO 1600 shot and view at 100%

The ability to suppress noise is getting better with each generation of cameras but, just like audio recording, low in ---> high out brings the noise floor up with the signal.

If you're gonna miss with digital, it's best to miss slightly to the high side so that when you bring your overall level back down a hair, you drive the noise floor lower.

Just out of curiosity, would you mind posting one or two of your intentionally under exposed efforts? I'd be really curious to see what your resultant images look like.

Any camera, regardless if its a point and shoot or DSLR, produces significantly more noise if not exposed properly, especially if its underexposed.

Why are you purposely underexposing your photos?

Ivoryplum wrote in post #7062211
Why are you purposely underexposing your photos?

As a guess, I would say he is underexposing to use a higher shutter speed to stop action in a poorly lit gym. Others have posted on this topic. The concept interests me but I have not as yet tried it.

Ralpho wrote in post #7062162
A year ago I started deliberately underexposing in RAW while shooting basketball games with my 40D and have been doing it ever since. I bring the brightness up in DPP and haven't noticed a noise problem

If you do not notice any noise problem, then everything is dandy, isn't it? Although the question is, how you know that you are effectively underexposing.

Btw, which ISO are you using?

Well, I've gotten less fill than I'd like in plenty of shots with every camera I've used, and been forced to boost the shadows...and I've sure gotten more noise doing that.

I do similar, underexpose Rugby (sport) shots. Its not deliberate as such just a result of me needing at least 1/500th speed even when on 1600 ISO and low light. In winter it means the first half shots are fine, second half they start to be underexposed and often end up 1.5 stops or so by full time.

If you compare the photos, especially of shadows of a properly exposed and underexposed shot from the same game you do see a lot more noise on the underexposed (when brought up in PP to a sensible exposure).

You might want to pop over to www.luminous-landscape.com and read about the theory behind "Expose to the Right" with RAW files. It's just the opposite of what you are doing.

amfoto1 wrote in post #7063235
You might want to pop over to www.luminous-landscape.com and read about the theory behind "Expose to the Right" with RAW files. It's just the opposite of what you are doing.

I'll make it a little easier for yall

http://www.luminous-landscape.com/tutorial​s/expose-right.shtml

amfoto1 wrote in post #7063235
You might want to pop over to www.luminous-landscape.com and read about the theory behind "Expose to the Right" with RAW files. It's just the opposite of what you are doing.

Well, of course they are talking about the opposite. They are talking about underexposing then pushing the exposure in PP to make up for a less-than-adequate ISO/shutter speed capability.

This isn't about "good exposure practice", but still gets used in these types of situations to get a shot that would otherwise be motion-blurred. the noise is something you have to deal with, though.

If your camera is at it's highest ISO setting and your aperture is wide open and the shutter speed you need is not going to expose correctly, then this is your last resort.

I honestly consider ISO1600 to be about the limit for anything but small prints on the XXD bodies, ISO3200 requires some noise reduction and forgiveness. I think if I found myself really needing to push a 40D ISO3200 shot another stop I would either get faster glass or give up shooting that venue.

I have written about ETTR a lot, but I still don't have a single comprehensive piece.

Now only shortly.

1. Perfect ETTR is trial and error. The following technique does not ensure (and none other ensures), that the exposure will be perfect; it only helps judging if the exposure was perfect.

2. The in-camera histogram and the clipping indication are based on the preview embedded in the raw file. This preview is created just like any in-camera JPEG, using the respective settings.

3. In order to coax the camera into displaying a histogram and clipping indication, which are representative the raw image, one has to "neutralize" the camera's actions involved in the process of creating that JPEG image.

This means

a. turning off sharpening (0, the leftmost position),
b. turning off contrast adjustment (0, the middle position),
c. turning off saturation adjustment (0, the middle position),
d. turning off color tone adjustment (0, the middle position).

Of course, a,b,c and d can be set in a picture style.

e. selecting sRGB for color space (it is possible, that certain models would require AdobeRGB),
f. using a neutral white balance template, also called Uni-WB (as it results in unity coefficients). This is the greatest factor.

Such a setup results in an ungly, greenish, useless preview and thumbnail, except for judging the exposure. The method is not perfect, for there is no way with the present cameras to avoid demosaicing and the color space conversion, which involves the nonlinear mapping as well. However, it works reliably. I have been using this all the time with my 40D, and the flashing indication is within less than 1/3 stop from the raw exposure.

I have a WB template for the 20D and one for the 40D, downloadable for the 20D and for the 40D.

This template should be stored on each card as write-protected to avoid accidental deleting. One can switch between the template and any other WB method.

If anyone has or creates a Uni-WB, it can be verified by Rawnalyze: the "as shot" WB coefficients are displayed on the Histogram panel. They should be between 0.95 and 1.05.

Further, long-long discussions and explanations on this subject can be found at
here and here and here

JeffreyG wrote in post #7063514
If your camera is at it's highest ISO setting and your aperture is wide open and the shutter speed you need is not going to expose correctly, then this is your last resort.

I honestly consider ISO1600 to be about the limit for anything but small prints on the XXD bodies, ISO3200 requires some noise reduction and forgiveness. I think if I found myself really needing to push a 40D ISO3200 shot another stop I would either get faster glass or give up shooting that venue.

Heh! I had to shoot my 1DM3 with a 70-200 at f/2.8 ISO 3200 this summer at an event with poor lighting, so I ended up underexposed by a stop or more -- not a pretty sight even with the III! I eventually did pack it as the night darkened!

FlyingPhotog wrote in post #7062192
The ability to suppress noise is getting better with each generation of cameras but, just like audio recording, low in ---> high out brings the noise floor up with the signal.

If you're gonna miss with digital, it's best to miss slightly to the high side so that when you bring your overall level back down a hair, you drive the noise floor lower.

Just out of curiosity, would you mind posting one or two of your intentionally under exposed efforts? I'd be really curious to see what your resultant images look like.

Okay, here is one I took recently with my 40D. I put camera in Manual mode and select following settings: ISO is 1000. Aperture 2.0, Shutter speed 500. 85mm Canon lens.

That produces varying degrees of underexposure, mostly between one and two stops. Then I use brightness control in DPP to compensate.

Content warning: script