Posted by David Bostedo on January 7, 2012 at 10:29 PM
Depends on how you define "overexposure". If what you're going for is a high-key shot, then it's the correct exposure. Scenes that you think should have a lower exposure, but wind up high-key, are probably overexposed.
"Overexposure" is something of a subjective concept, and is based on what you want the photo to look like. You might see people say an image is overexposed. What they mean is that it's overexposed compared to how they, or perhaps most people, think it should be exposed. But depending on your intentions as the photographer, it might be a good exposure.
There are certain things where most people would say an image is overexposed - blown out whites in an otherwise moderately exposed (non high-key) shot being the most obvious example. Photographers typically aren't trying for small patches of blown out whites, so most would say it's overexposed. But if, for whatever reason, you want those whites blown out, then it's a good exposure.
Posted by Joe Rogers on January 7, 2012 at 10:49 PM
The answer to your question is no. For example.....If I were photographing a young lady in a white dress on a white background,I would be aiming for the same exposure on my SUBJECT as when using a low key background. On the white background the whites will not be blown out nor will her white dress. They should both contain detail. The white background will appear solid white but still will not be blown out. As a general rule you will be putting about a stop to a stop and a half more light on the white background to acheive an almost pure white, but, still, not enough to overexpose it. If you were photographing a white flower on a white background the same principle would hold.
Joe Rogers
Posted by Alan Olander on January 8, 2012 at 9:40 AM
To get the white flower on the white background you do have to "overexpose" from the meter reading. The meter will give you middle grey, so you are overexposing just not so much that tones are blown out. Just as it is recommended to "overexpose" a snow scene so the snow is white not grey.
Posted by Joe Rogers on January 8, 2012 at 10:39 AM
Alan, this type of thinking will get you in trouble. You are not overexposing anything. The reading from your gray card will render the white flower gray because it is the correct exposure for the gray card. Your brain has to interviene and tell you that to get white you are going to have to open up two stops to render the tone as the correct white. If you use an incident meter which measures the light falling on the subject instead of the light reflected from the subject you will get a white flower by setting your camera exactly as your incident meter indicates. This may only sound like a matter of semantics but in reality you are not overexposing anything. Joe Rogers
Posted by Alan Olander on January 8, 2012 at 11:07 AM
Yes, it does sound like a matter of semantics. I wasn't talking about using a grey card or an incident meter, I was simply talking about metering a scene (with the cameras' meter) and adjusting exposure to compensate for a mostly white scene (preferably watching the histogram). It is "overexposing" in terms of what the meter is telling you; a matter of definition, I guess.
'High key' and over-exposure are two different things. High key is a 'presentation' or interpretation of the scene that is photographed. Over-exposure means that there is a lack of textural detail in areas of the scene that should have detail.
In the example given above, (the white dress against a white background) would be a 'high key' photograph. It would be over-exposed if there were no discernable detail in the dress (folds in the fabric, or texture in the material).
In my experience, if one is using a digital camera, or transparency film, good detail in a textured white subject will be recorded when the exposure is about 1-2/3 stops above neutral grey. If one is using a color negative material, good detail may be recorded when the film is exposed up to 2-1/2 stops above neutral grey. I have seen gelatin-silver prints made from B&W negatives, developed in pyro, that have detail 4 stops above neutral grey (very careful printing was required!). The bottom line with exposure of high values is they should look bright, but not harsh and have detail if it was present in the scene.
--P
Posted by Mark Stahlke on January 8, 2012 at 1:37 PM
I like Preston's explanation. It just needs an example. Here is a high key white on white image. It's not over exposed, it's correctly exposed.
Posted by Joe Rogers on January 8, 2012 at 1:53 PM
Mark, what a wonderful example. What a wonderful image!
Joe Rogers
Wonderful photograph, Mark; and a perfect example of high key.
Would it be possible for you post the image to this thread?
Thanks, sir,
--P
Posted by Mark Stahlke on January 8, 2012 at 2:44 PM
This is an example of a high key white on white image. It's not over exposed, it's correctly exposed.
I like to make a distinction between "normal" exposure and "correct" exposure. The camera's meter wants to make everything a mid-tone (18% gray). That's the "normal" exposure but it's not necessarily the "correct" exposure. This image required about two stops more than "normal" to achieve the "correct" exposure. Had I shot this at the meter's "normal" exposure, the flowers and background would be mid-tone gray and therefore underexposed.
Discussion
12 replies"Overexposure" is something of a subjective concept, and is based on what you want the photo to look like. You might see people say an image is overexposed. What they mean is that it's overexposed compared to how they, or perhaps most people, think it should be exposed. But depending on your intentions as the photographer, it might be a good exposure.
There are certain things where most people would say an image is overexposed - blown out whites in an otherwise moderately exposed (non high-key) shot being the most obvious example. Photographers typically aren't trying for small patches of blown out whites, so most would say it's overexposed. But if, for whatever reason, you want those whites blown out, then it's a good exposure.
Joe Rogers
If this helps, I wasn't using (or didn't mean to imply) "overexposure" as a negative word. I was just using it as a technical term.
In the example given above, (the white dress against a white background) would be a 'high key' photograph. It would be over-exposed if there were no discernable detail in the dress (folds in the fabric, or texture in the material).
In my experience, if one is using a digital camera, or transparency film, good detail in a textured white subject will be recorded when the exposure is about 1-2/3 stops above neutral grey. If one is using a color negative material, good detail may be recorded when the film is exposed up to 2-1/2 stops above neutral grey. I have seen gelatin-silver prints made from B&W negatives, developed in pyro, that have detail 4 stops above neutral grey (very careful printing was required!). The bottom line with exposure of high values is they should look bright, but not harsh and have detail if it was present in the scene.
--P
Joe Rogers
Would it be possible for you post the image to this thread?
Thanks, sir,
--P
I like to make a distinction between "normal" exposure and "correct" exposure. The camera's meter wants to make everything a mid-tone (18% gray). That's the "normal" exposure but it's not necessarily the "correct" exposure. This image required about two stops more than "normal" to achieve the "correct" exposure. Had I shot this at the meter's "normal" exposure, the flowers and background would be mid-tone gray and therefore underexposed.