Paris

by Jon

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Take the 2-minute tour ×
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It's 100% free, no registration required.

If I am photographing a scene with a lot of dark background, how can I use the histogram to tell if the exposure is correct? For instance, at an outdoor concert in which the performers are moderately illuminated but their surroundings are dark. Or a view of a cityscape viewed across a dark body of water and with a dark sky above it? In other words a scene in which much of it is expected to be almost or totally black. When shooting RAW in such a situation, what should the histogram look like to make the final processed image dark without being noisy? And without the black areas becoming posterized?

Night Flight

share|improve this question
    
The histogram should be the same no matter if you shoot RAW or JPEG. It is calculated from the preview JPEG, right? –  Esa Paulasto Jul 31 '13 at 7:56
    
Yes, but you certainly don't want a peak in the middle of the histogram if most of the image should be pure black... –  Michael Clark Aug 1 '13 at 1:59

2 Answers 2

The general rules for histograms still apply, it's just that most of the "weight" of your histogram will be leaning to the left:

Your aim will be the same: keep as much of the data in the histogram from clipping at the right hand edge, without leaving too much way down the left hand side. You should be able to see some data reaching all the way across the histogram to the right, even if it's low compared to the higher peaks over the left.

If it goes flat on the right like this, it's underexposed:

If you have very bright highlights, such as the lights in that picture, it will be unrealistic to avoid all clipping without underexposing quite a lot, hence the small uptick on the right of the first histogram above.

I've shown mono histograms here just for illustration (and because it's what I found with a quick Google search) but the same goes for RGB histograms.

share|improve this answer
1  
That is the conventional wisdom, but as you can see from the example posted, it results in posterization of the blacks. Which way does the exposure need to move so the blacks don't get so blotchy? –  Michael Clark Mar 28 '13 at 1:32
4  
Is your monitor calibrated correctly (particularly for black point)? I don't see posterisation of the blacks there, and there's no reason that it should have any more than any other 24 bit image, unless you're trying to boost the shadows after RAW conversion or something. You will get noise, and minimising that is just about using the fastest lens and lowest ISO you possibly can. –  thomasrutter Mar 28 '13 at 1:41
2  
I'm not seeing posterization either and my monitors are calibrated regularly. –  John Cavan Mar 28 '13 at 1:50
    
I use the X-rite system for monitor calibration. The original photo was cropped from 5184X3456 to 3872X2581, then reduced to 1536X1024 for web sized viewing. After uploading to SE, it is being displayed in the page on my monitor at 630X420. At that size the posterization is minimized quite a bit. If you view it at 1536X1024 the posterization is more evident. –  Michael Clark Mar 28 '13 at 13:34
    
There is no posterization in that image, which I confirmed by checking in an image editor. Maybe you are referring to noise - there is a fair (but not unexpectedly high) amount of noise, worsened in this case by the JPEG compression. –  thomasrutter Mar 30 '13 at 7:18

A histogram is meaningless in this situation. Only a spot meter could give you a correct exposure. And even then it would be difficult because your subject is moving.

share|improve this answer
3  
Spot metering and looking at a histogram afterwards are not mutually exclusive. The histogram thomasrutter posted would be useful as it shows clipping of highlights. Apart from the fact that much of the histogram may be to the right, I don't think it's any less useful in a scene like this as with a more balanced scene. –  MikeW Mar 28 '13 at 5:08

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.