To underexpose or overexpose?

[FlyingPete]

OK, I know the real answer is to get the exposure right, but what if you have a situation with a large variation in light, where there is no correct exposure to get everything in the scene?

Last night I was shooting a concert, the camera's meter predictably can not handle the lighting, and makes a complete screw up of the situation, the situation being a the artist floodlit with a dark background. The typical camera response here is to over expose the artist to try and bring out the background. In this particular instance exposure compensation of around 1-2 stops under worked quite well.

This got me thinking though, when I let the camera do the work I ended up with a white artist with no detail, mainly clipped out to white, no recoverable detail, even in RAW, by correctly exposing the foreground, the background became very dark, however I was surprised how much detail was recoverable still from the background.

Is it better then in difficult lighting to err with caution and under expose, correct later and avoid over exposure at all costs? It seem to me that you will have better luck fixing an under exposed image with a digital than an overexposed one.

[scottbergerphoto]

You have really only one option in a fluid situation, when the lighting isn't uniform across the image. Decide what is the most important element in the image and expose for that using a spot or partial spot meter. You will get overexposed areas and underexposed areas, but your main subject will be properly exposed. Shoot Raw and avoid underexposure of the main subject, as this gives you alot of noise when you recover the detail from the underexposed areas. You can use a zoom lens to make your meter function as a spotmeter-just zoom in on the subject to fill the viewfinder, lock in the meter reading and zoom out to recompose.
When dealing with a static situation like a landscape, you can take a series of pictures, usually two, one for the highlights and one for the shadows, taken at precisely the same spot on a tripod and combine them.

[tim]

Good advice Scott, I especially like the way of using the zoom lens to help a partial meter operate as a spot meter.

I tend to underexpose rather than overexpose, as with RAW it's easier to fix the former than the latter. Of course if you underexpose your main subject at ISO 1600 then increase the exposure the noise will be horrible, and even after noise reduction it won't look great. On the other hand it'll still be better than a white blob.

[PhotosGuy]

I've usually tried to get the primary subject exposed correctly in RAW & then adjusted the rest in PS.
The opposite of your situation, the 3rd shot here (http://photography-on-the.net/forum/showthread.php?t=84621) was an exposure for the shadows, & adjusted for the highlights in RAW processing.
As Scott said, "Decide what is the most important element in the image and expose for that."
Learn the rules. Learn when to break them! ;)

[FlyingPete]

Excellent advice guys, good stuff, now I have an excuse to get a EF1200 and use it for spot metering :D

It is very much a balancing act, last night I was fortunate that I really only had to worry about the correct exposure of the main subject, pretty serious when you have to compensate for up two stops though. Spent the first 10 minutes or so getting my exposure right.

An other interesting observation of my SLR from the last 10 months or so, I have shot concerts for around 6 years now, but not with a SLR until recently. It is harder to get a good shot with an SLR than a P&S in these lighting condiditons, but when you do get it, it is a really good shot far above the standard of shots I was getting from previous cameras.

[robertwgross]

I agree with Tim. That is a situation to try partial metering. The camera meter will try to give you a solution based on the center (the artist) and mostly ignore the dark background. Then, if you do a +1/-1 exposure bracketing around that, you ought to get something good.

---Bob Gross---

[blue_max]

I take it flash was not an option as it can be just the job when there is too much contrast.

Graham

[tim]

I take it flash was not an option as it can be just the job when there is too much contrast.

Flash is generally not allowed at concerts or during theatre.

[FlyingPete]

Flash is generally not allowed at concerts or during theatre.

That would be right, the usual: Please turn off cellphones, no video or flash photography.

Nothing like a flash going off in your face whilst trying to perform. Also under some circumstances ruins the atmosphere.

[Andy_T]

You can take advantage of the cameras exposure bracketing function (5 fps is very good for this). Better 2 images too much, than completely missing the shot.

Best regards,
Andy

[scottbergerphoto]

A word about under/over exposure and Raw. ACR will allow you to recover at least 1 stop overexposure in Raw with no loss of image quality. In addition, 1/2 of all the image data is recorded in the right most segment of the histogram. If your image isn't using that part of the histogram, that data is lost and is not recoverable. That's why when you try to recover data from shadows even at low iso's you get noise. The software is putting back what wasn't there to begin with. To get the most out of your sensor, adjust the exposure so that your histogram almost touches the rightmost end of the graph. Then in ACR reduce the exposure to a normal exposure.
I usually calculate a normal exposure based on a modified zone system (Black, Dark Grey, 18%Grey, Light Grey, White), take the picture and then adjust my exposure to move the histogram to the right. Using this method, I avoid the noise created in shadow recovery.

[CyberDyneSystems]

I've been trying to get my RAW exposures as hot as possible without blowing highlights...

I am finding that the popular belief that this will help overall image quality is quite true.. that the more to the right I can get an exposure the better the end product will be.

My rule of thumb therefore is as hot as I can get it without blowing out highlights or details in the subject.

[PhotosGuy]

To get the most out of your sensor, adjust the exposure so that your histogram almost touches the rightmost end of the graph. I'd like to point out that you need to have a FLAT white to "almost touches the rightmost end of the graph." If you have a stage light in the frame, or maybe a chrome reflection of the sky, or a bright background that isn't lighting your subject, then your exposure will be off. Like I screwed this shot up. (http://photography-on-the.net/forum/showthread.php?t=43761&highlight=sunliner)

[scottbergerphoto]

I'd like to point out that you need to have a FLAT white to "almost touches the rightmost end of the graph." If you have a stage light in the frame, or maybe a chrome reflection of the sky, or a bright background that isn't lighting your subject, then your exposure will be off. Like I screwed this shot up. (http://photography-on-the.net/forum/showthread.php?t=43761&highlight=sunliner)
Not at all. There doesn't have to be any white in the image. You are intentionally overexposing the subject to move the histogram to the right. As long as you do that in Raw and don't extend past the right end of the histogram, all the data is captured. You just reduce the exposure in ACR. This is completely different than film. As an example, if you were shoot an 18% Grey card with no adjustments for exposing to the right, you would get a single peak right in the middle of the histogram. In exposing to the right, you would overexpose that 18% Grey card by almost 2 stops to move that peak to the near right end of the histogram. Then in ACR, you back off the exposure to the normal exposure. This is to make up for the fact that the sensor does not collect data evenly across the histogram. When you don't use the rightmost part of the histogram, you lose 1/2 the data your sensor is capable of collecting. You basically convert an 8mp camera to a 4mp camera.

[starzphalling]

ACR??

[jfrancho]

ACR??ACR = Adobe Camera Raw.

[Curtis N]

If you have a stage light in the frame, or maybe a chrome reflection of the sky, or a bright background that isn't lighting your subject, then your exposure will be off. What I HOPE you're saying is that it's generally OK to clip extremely bright elememts, such as light sources or reflections of light sources off chrome or glass, if that's what it takes to properly expose the subject.

Are you saying you should have "blown out" the sunlit sky in the background of the photo of the car you referred to, in order to properly expose the car?

For example, candle flames in a photo of a person lit only by said candle light. You would need to underexpose the person badly in order to avoid rendering the flames as completely white.

[PhotosGuy]

What I HOPE you're saying is that it's generally OK to clip extremely bright elememts, such as light sources or reflections of light sources off chrome or glass, if that's what it takes to properly expose the subject.
Are you saying you should have "blown out" the sunlit sky in the background of the photo of the car you referred to, in order to properly expose the car? Yes, that's it. The subject was supposed to be a car, not a car in a sunset, as I'd planned to cut the car out anyway.
(The sky could have been 'saved' by taking 2 exposures & blending them in PS though.)
There doesn't have to be any white in the image. True, but if I'd thought I had time, I would have put one in, aimed the cam down to exclude the sky & chimped a shot to get the white exposed to the right. <Delete> & take the shot. I've learned more about RAW since then, & might have just take the "white" exposure off the car now.
There a many ways to reach the right exposure. Since I always carry paper for WB, I also use it for most of my exposures. Read it & open up 8 clicks which works well for me.