Multiple Exposure shots - Why?

[DoleWhipDVC]

Hi folks, I'm back with another question for all you pros out there. I notice when I go to several flicker accounts that many captures are done with several exposures. I have a Canon 40 D and have played with the feature myself, but am not sure what the advantage is. Obviously a person can pick from the 3 exposures to get the "best" lighting effect; but beyond that what's the big deal? I can set a three exposure shot with the 40D: normal ev, +ev and -ev. Is there any reason to do this other than seeing the difference in lighting effect? Is it a post processing thing?

Since so many of the great photographers here on the Dis use the method, and I'm thinking those folks tend to get their light levels correct from the start, they wouldn't need to shoot at different ev levels, so there must be more to it. What don't I know about exposure bracketing that I should know?

 

[JoeDif]

Multiple exposure are an essential part of HDR photography to allow for a greater dynamic range. Some HDR shots can contain 5 - 7 different exposures.

Also, if you are shooting in a tricky lighting situation, you can hedge your bets by bracketing exposures, -1, 0, +1, etc,

 

[zackiedawg]

Well one reason is as you mentioned - some folks use exposure bracketing to get the right exposure in tricky lighting by taking 3 frames and choosing the best.

But another reason bracketed exposures are used is for 'HDR' post processing. HDR, or High Dynamic Range, is a popular style of post processing where three or more exposures - generally at least one for shadows, one for midtones, and one for highlights, are merged together to cope with extreme dynamic range which cannot be captured in a single frame - such as a very dark bird standing in a shadow with a very bright sunny sky in the background. In general, HDR is any merged and stacked set of photos meant to capture a wider dynamic range and compress it into a single photo - however, many HDR merging programs include 'tone mapping' which allows individual adjustments to the various intensity of the shadows, highlights, and midtones when blended together - this can be used to minor effect, to help preserve or enhance contrast in a scene, or can be used very strongly to create those fantasy artwork-looking HDR photos with extreme saturation, contrast, haloing, shadowing, detail outlining, etc.

 

[photo_chick]

I bracket often. In some lighting situations you can't guarantee you have it right in camera and it's a necessary tool for me. The histogram is a great tool to have in camera, but it won't always tell you the whole story in a glance. To me in those difficult lighting situations it's faster just to bracket than to spend ten minutes standing on site analyzing the histogram to make sure I have what I want.

 

[MarkBarbieri]

I also bracket a lot. Sometimes it is because the light levels are changing rapidly and I don't have time to work out my exposure. A good example was when I shot Fantasmic! recently. I couldn't count on auto-exposure because the scenes had pretty extreme lighting (fire, explosions, spotlights, etc).

I also do it when I'm dealing with scenes that have really bright areas and really dark areas and I'm not sure whether I'm going to want focus on the dark or light parts of the picture. Having bracketed shots allows me to defer that decision until post production.

I also use bracketing for HDR, but I really don't do much HDR.

There are downsides. Obviously, it chews up memory and fills your buffer much faster. It also means that you can't time things to get the exact moment you want.

I'm not sure about others, but with my cameras, when I set it to continuous shooting mode and shoot a burst, it goes through the bracket sequence and then stops. That makes it easy to keep track of where I am in the sequence.

By default, my cameras shoot in normal, underexposed, and then overexposed. I switched it to go under, normal, over because it seemed more natural. I think I'm going to switch to over, normal, under instead. I usually set my bracket to something like -2, -1, and 0. I do that because I'm usually more interested in preventing blown out highlights than I am in pulling up shadows. When I do that, the 0 shot is the shot I like about 40-50% of the time, so I'd prefer that I see it first when I go through my shots in post production.

 

[Goofdad]

Multiple exposure are an essential part of HDR photography to allow for a greater dynamic range. Some HDR shots can contain 5 - 7 different exposures.

Also, if you are shooting in a tricky lighting situation, you can hedge your bets by bracketing exposures, -1, 0, +1, etc,

Bracketing can be done with either Exposure or Focus - if you're not sure of exactly what exposure or focus to set, rely on bracketing and pick the best one after you've shot them - you capture the moment and have options after the fact.

But the HDR (High Dynamic Range) is where many people are going with this. If you're not sure what HDR is, Google/Wiki/etc.
Basically, a camera sensor - even the BEST and most expensive ones - do a poor job "seeing" wide ranges of light/dark when compared with your eyes.
A camera can NOT see the brightest and darkest parts of a scene the way your eye can. Ever get that backlit effect where bright lights are behind you subject and they appear as shadows? Have you ever taken a photo inside a church or cathedral? It's very hard to get a nice exposure - you either see the (brighter) stained glass windows or (darker) alcoves and vaulted ceilings - But not BOTH.
HDR allows your camera to "see" both by taking multiple shots and combining them into one "high range" image (the combining is done with software in post production).

HDR images can look extremely realistic or be pushed a futuristic/fantasy look - there are a wide range of creative options once you have the multiple exposures ready to process.

 

[wbeem]

Since so many of the great photographers here on the Dis use the method, and I'm thinking those folks tend to get their light levels correct from the start, they wouldn't need to shoot at different ev levels, so there must be more to it. What don't I know about exposure bracketing that I should know?

There are plenty of circumstances where the dynamic range that we see with our eyes is beyond what a camera can capture. It's not a matter of getting light levels correct - the light levels simply vary so much that the camera can't process it.

Here's a perfect example - the roof at Tusker House in Animal Kingdom.


Tusker House by wbeem, on Flickr

You have extremes on both ends here. The sunlight coming through those cloths above and blow out, and the shadows on the balcony are black with darkness. I shot this as a 9-exposure bracket to capture the range of highlights & shadows to combine in one HDR image that lets you see the whole scene.

I grabbed all the light levels that my camera (Nikon D700) can handle, and no single exposure captured all of them.

 

[DoleWhipDVC]

Good information, thanks for responding. I do love that HDR look, and I see the point about a camera not detecting the light range as well as a human eye. Thanks again to all that replied.

 

[traylorc]

There are plenty of circumstances where the dynamic range that we see with our eyes is beyond what a camera can capture. It's not a matter of getting light levels correct - the light levels simply vary so much that the camera can't process it.

Here's a perfect example - the roof at Tusker House in Animal Kingdom.


Tusker House by wbeem, on Flickr

You have extremes on both ends here. The sunlight coming through those cloths above and blow out, and the shadows on the balcony are black with darkness. I shot this as a 9-exposure bracket to capture the range of highlights & shadows to combine in one HDR image that lets you see the whole scene.

I grabbed all the light levels that my camera (Nikon D700) can handle, and no single exposure captured all of them.

Great explanation...and more importantly...nice shot.