View Full Version : Exposure advise needed
puggle
22nd of February 2009 (Sun), 11:28
I was taking shots of people attending an art exhibit in a small gallery and had difficulty understanding what I did wrong to get them properly exposed.
There was track lighting above, with many spot lights pointed towards the artwork on the walls. This caused the people to be underexposed and the walls and artwork, overexposed.
I tried spot metering, but that washed out everything and did not work.
Here's an example:
344278
Here's the EXIF data:
5D
16-35 L Lens
Focal Length: 35mm
Apperture: f/2.8
Shutter: 1/250 sec
ISO: 200
Can anyone help??
SkipD
22nd of February 2009 (Sun), 11:32
The problem isn't as much one of choosing exposure settings as it is getting the shadowed subject lit up a bit more. Here's where fill flash would help tremendously.
You sometimes need to control contrast in a scene by adding (or at least redirecting) light into the scene.
Grimes
22nd of February 2009 (Sun), 11:34
Well, the guy is wearing a hat which caused the window light to cast a shadow on his face - didn't help much. If there were no hat, I think the picture would have been much better.
For other places in the gallery with people not next to windows, you would probably need to use a fill flash to light up the people properly. Is flash photography allowed in the gallery?
puggle
22nd of February 2009 (Sun), 11:52
Thanks! Yes, flash was allowed, but I didn't think I needed it.
The subjects seemed to be lit very well. There was plenty of ambient light.
I believe the lighting directed towards the walls and artwork was so much stronger, it threw off the metering and underexposed the people.
I used Evaluative metering mode. I suppose you're right and there's no choice and I should have used a fill flash. Thanks for the advise!
puggle
22nd of February 2009 (Sun), 11:57
Here's another example:
344285
puggle
22nd of February 2009 (Sun), 11:59
I had another thought -
Should I have tried AE Lock? I could have focused and metered on a dark area, locked exposure, recomposed and than shoot. Would that have solved it without a fill flash?
tonylong
22nd of February 2009 (Sun), 12:24
We don't often realize by sight how much contrast there is with back-lit subjects because our eyes adjust to the shadows when we look at the subjects. Camera meters do a similar thing -- if you spot-meter on a darker subject the meter will adjust to brighten the subject. However, as you've noted, the brighter areas will then be overexposed.
You have three solutions in this type of setting: the simplest is, like has been suggested, using fill flash. When you do, you want to make sure to let enough "ambient light" in so the sene around shows as much normal illumination as you want, and you typically want the flash power to be either bounced or somehow modified to keep the subjects from having the over-bright "flash snapshot" look.
Without flash, the easiest approach would be to get the subject in a position where they have little backlight and as much illumination from the front as possible. Choose an exposure that will show light on them as much as possible without blowing background lights. Use of a histogram would help here.
The last approach, if you can't help the backlighting, is to make a creative decision: something will have to give, either an underexposed subject or an overexposed backlight. Use as much shadow and highlight recovery as you can in post-processing. Some people get quite good results shooting backlit subjects, but for most of us it is a real challenge:)!
mrkgoo
22nd of February 2009 (Sun), 13:25
We don't often realize by sight how much contrast there is with back-lit subjects because our eyes adjust to the shadows when we look at the subjects. Camera meters do a similar thing -- if you spot-meter on a darker subject the meter will adjust to brighten the subject. However, as you've noted, the brighter areas will then be overexposed.
You have three solutions in this type of setting: the simplest is, like has been suggested, using fill flash. When you do, you want to make sure to let enough "ambient light" in so the sene around shows as much normal illumination as you want, and you typically want the flash power to be either bounced or somehow modified to keep the subjects from having the over-bright "flash snapshot" look.
Without flash, the easiest approach would be to get the subject in a position where they have little backlight and as much illumination from the front as possible. Choose an exposure that will show light on them as much as possible without blowing background lights. Use of a histogram would help here.
The last approach, if you can't help the backlighting, is to make a creative decision: something will have to give, either an underexposed subject or an overexposed backlight. Use as much shadow and highlight recovery as you can in post-processing. Some people get quite good results shooting backlit subjects, but for most of us it is a real challenge:)!
In such a backlit example, I guess it's a compromise between the background and subject. If you were to try and correct in post, is it better to expose for one, or find a middle ground?
PhotosGuy
22nd of February 2009 (Sun), 14:32
Should I have tried AE Lock? I could have focused and metered on a dark area, locked exposure, recomposed and than shoot. Would that have solved it without a fill flash? Maybe, but getting off Exposure Mode = auto exposure (0) would be my advice. This shows how the subject can affect the exposure & why manual keeps me worry free:
Post #47 (http://photography-on-the.net/forum/showpost.php?p=5191658&postcount=47)
Click the "Thread: Need an exposure crutch?" link at the top-right if you'd like more info on exposure.
puggle
22nd of February 2009 (Sun), 14:44
...manual keeps me worry free:
Hmmm, I didn't even think of trying manual for those conditions. I usually reserve manual mode for when I use strobes. I think you're advise just might work. I'll Try it next time I'm at the gallery!!!
tonylong
22nd of February 2009 (Sun), 15:24
In such a backlit example, I guess it's a compromise between the background and subject. If you were to try and correct in post, is it better to expose for one, or find a middle ground?
Without fill flash, then yes, you need to think through a compromise. Franks suggestion of using Manual is pretty much a necessity, unless you really want to hassle with Exposure Lock, since the camera will always want to meter in a way that will try to bring either the highlights down, way underexposing the front subjects, or bring the front subjects up, way blowing the background.
Your first shot would be very difficult to pull off. You "expose to the right" by setting a spot exposure to get the highlights right against the edge -- try using your meter and manually adjusting a bright spot with important detail to be right against the edge of the scale for a starting point, take a shot, and check your histogram. It's hard in this setting to get a good exposure for the whole scene, because of the bright backlighting. Fill flash:)!
Your second shot actually has much more of a chance -- in fact, in post processing you could try to restore shadows and come up with an OK result.
To shoot the scene, you want to set an exposure for the scene (see Franks clues on setting a scene exposure for the hand) and, since the background highlights are more subdued you have a much better shot at getting a pretty well-balanced exposure. Again, check your histogram and nudge the highlights to the right and you will have the best chance of retaining good shadow detail. Again, you will likely need to touch things up in the computer, but it will be much better to work with.
Hope things work well!
mrkgoo
22nd of February 2009 (Sun), 15:34
Without fill flash, then yes, you need to think through a compromise. Franks suggestion of using Manual is pretty much a necessity, unless you really want to hassle with Exposure Lock, since the camera will always want to meter in a way that will try to bring either the highlights down, way underexposing the front subjects, or bring the front subjects up, way blowing the background.
Your first shot would be very difficult to pull off. You "expose to the right" by setting a spot exposure to get the highlights right against the edge -- try using your meter and manually adjusting a bright spot with important detail to be right against the edge of the scale for a starting point, take a shot, and check your histogram. It's hard in this setting to get a good exposure for the whole scene, because of the bright backlighting. Fill flash:)!
Your second shot actually has much more of a chance -- in fact, in post processing you could try to restore shadows and come up with an OK result.
To shoot the scene, you want to set an exposure for the scene (see Franks clues on setting a scene exposure for the hand) and, since the background highlights are more subdued you have a much better shot at getting a pretty well-balanced exposure. Again, check your histogram and nudge the highlights to the right and you will have the best chance of retaining good shadow detail. Again, you will likely need to touch things up in the computer, but it will be much better to work with.
Hope things work well!
Thanks for the valuable insight - my question was regarding whether it's better (given that you don't cut shadows entirely nor bright values - so the compromise is already met) to expose for the shadows and bring the highlights back in post, or expose for the background and bring UO the shadows? I guess this is dependent on what is more important for the image? The subject in the given example, I suppose.
tonylong
22nd of February 2009 (Sun), 16:04
Thanks for the valuable insight - my question was regarding whether it's better (given that you don't cut shadows entirely nor bright values - so the compromise is already met) to expose for the shadows and bring the highlights back in post, or expose for the background and bring UO the shadows? I guess this is dependent on what is more important for the image? The subject in the given example, I suppose.
Well, you have a grasp of the challenge:)!
A creative choice has to be made -- there may be highlights that you want retained, and ones that can be sacrificed. If you expose for the shadows, the camera will try to lighten the shadows to a medium tone, which will likely blow more highlights than you'd like, at least in your first shot.
This was where my spot metering advice came in: spot meter on the brightest area that has important detail and adjust your settings to bring your meter reading up toward the end of the scale. Assume that the very end of the scale represents pure white (no detail will be present). From there, you estimate what "value" the spot you are metering needs to take. For snow on a bright day, for instance, you can push the exposure for that snow up pretty high, say 1 2/3 stops. The same thing for bright clouds or if you are facing the part of the sky that is brightest on a sunny day.
So, in the first scene you could have, say, brightened the outdoor scene a little and kept some outdoor detail. It would not have gained you much, but maybe a little. There is only so much you can do. Or, you could have chosen something indoor to attempt an average exposure for the indoor scene, and started from there, but exposing for the shadows (the couple) would have made everything else pretty overexposed. And, bear in mind, once you blow hightlights they can't be recovered. With shadows, the main problems you have in recovering them is noise, and with increasing brightness a flat lack of contrast. A good flash exposure using bouncing would be better with a more natural look.
mrkgoo
22nd of February 2009 (Sun), 16:10
Well, you have a grasp of the challenge:)!
A creative choice has to be made -- there may be highlights that you want retained, and ones that can be sacrificed. If you expose for the shadows, the camera will try to lighten the shadows to a medium tone, which will likely blow more highlights than you'd like, at least in your first shot.
This was where my spot metering advice came in: spot meter on the brightest area that has important detail and adjust your settings to bring your meter reading up toward the end of the scale. Assume that the very end of the scale represents pure white (no detail will be present). From there, you estimate what "value" the spot you are metering needs to take. For snow on a bright day, for instance, you can push the exposure for that snow up pretty high, say 1 2/3 stops. The same thing for bright clouds or if you are facing the part of the sky that is brightest on a sunny day.
So, in the first scene you could have, say, brightened the outdoor scene a little and kept some outdoor detail. It would not have gained you much, but maybe a little. There is only so much you can do. Or, you could have chosen something indoor to attempt an average exposure for the indoor scene, and started from there, but exposing for the shadows (the couple) would have made everything else pretty overexposed. And, bear in mind, once you blow hightlights they can't be recovered. With shadows, the main problems you have in recovering them is noise, and with increasing brightness a flat lack of contrast. A good flash exposure using bouncing would be better with a more natural look.
Thanks for that. You bring up a good point about lost highlights vs lost shadows - both are 'bad', but recovering things near the high end are easier than recovering shadow detail due to noise. This makes me see that (especially if it's a dark subject vs light background) I should probably compromise highlights (trying as best not to clip them), so I can reduce noise in the shadows. Again, very dependent on what you want to achieve with the shot. This is enlightening! thank-you!
SkipD
22nd of February 2009 (Sun), 16:17
A white reflector panel could have been held near the camera's position to reflect a bit of the ambient light (especially the outdoor light) back toward the person in the first shot.
Whether or not there was enough ambient light in the second shot for a reflector to be effective is not something I can judge from the photo.
puggle
23rd of February 2009 (Mon), 08:17
A white reflector panel could have been held
Good suggestion! I should make it a point to bring mine with me next time.
sapearl
23rd of February 2009 (Mon), 08:36
Hi Puggle - coming to the party a bit late here, but I've been in exactly the same situation, and it's a challenge to get pleasing, nicely exposed results.
I regard galleries like badly lit wedding receptions. The lighting is designed to feature the work and not the observers. You have pools of high intensity light mixed with deep shadows that destroy detail. This can easily create a 5-stop exposure range.
For this reason I always shoot these venues in MANUAL MODE. I also use bounced flash for fill, either 400 or 800 ISO, drag the shutter at a slower speed around 1/40 - 1/60 to allow some ambient light to creep in, and set the aperture for about f/6.3 - f/8. That last along with shutter speed depends upon how bright the room is. My flash is a 580ex and I have the little white card extended, and may tilt the head forward slightly.
Check out this link: http://pearlphoto.blogspot.com/2007/09/envisioning-cleveland-exhibit-opens-at.html
This was an art show in which I exhibited back in 2007. The photos were in an inside room lacking any window light, quite dim, with very small but intense track spots. My results were not perfect, but they were far better than had I just used the camera on AUTO with no fill flash. I also shot everything RAW which gave me more recover latitude, and then made some exposure adjustment layers during PP to bring back both highlight and shadow detail. Hope this helps :D - Stu
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