Posted by Lance Warley on December 18, 2008 at 1:17 PM
I've never had the opportunity to shoot scenes that are predominantly white snow. I have, however, had plenty of opportunities to shoot scenes of predominantly white birds.
The articles on snow say overexpose 1-2 stops, the camera averages to 18% grey, etc.
If I overexpose white birds, I burn the birds...no details at all. The last post I did of a white bird was underexposed by 2 full stops.
I understand that I would want to expose to let as much light in as possible without burning the whites, but that is never plus 1 for birds for me, especially on a sunny day.
I'm sure this is easy to understand when you can actually experiment with it, but it hasn't snowed here for a little while...27 years.
Can anyone explain this to a non-MENSA member who can't experiment, please?
Posted by Larry Puckett on December 18, 2008 at 2:04 PM
In one case you're talking about the background (snow) while with the other its the foreground or main objects (birds). In the case of the snow the expanse of white fools the camera and any darker foreground subjects will be underexposed unless you correct by adding 1-2 stops exposure. With the white birds you need to compensate since due the darker background the camera will base its exposure setting on it and allow too much of the light off all those white feathers resulting in an overexposure of the birds--LJP
Posted by Mike Poe on December 18, 2008 at 9:05 PM
Lance,
You might want to provide a little more information on your camera settings. Manual vs Auto. Spot vs. Matrix.
e.g. If someone is applying the +1-2 compensation with todays cameras on snow scenes using matrix metering one should see a scene that is overexposed as the camera already has a calculated the correct exposure unless almost the entire scene is blanketed in white.
I would like to know your settings on the Great Egret shot. It would surprise me that you were spot metering on the bird and still had to underexpose the shot by 2 stops.
When in Evaluative metering mode, the entire scene is "evaluated" for exposure. It's pretty simple. If the scene averages out to be lighter than 18% reflectivity, it will tend to underexpose. If it averages out to be darker, it will tend to overexpose. A snowy scene that is predominantly white will be underexposed and the whites will be dirty or grey.
Your egret scene is mostly dark with the bird occupying 30-40 percent of the scene, maybe? This type of image will almost ALWAYS result in that white bird being overexposed no matter how good of a metering system a camera has built into it. The meter does what its told, it's not an intelligent device and it can't read your mind. What's more important to you? Not blocking up the dark background or not clipping the whites of the bird? The meter doesn't know what area of the scene is important to you. It averages out the scene the best it can using sensors throughout the frame and computer algorithms. It recommends an exposure that can best deal with the high-key nature of the scene. Since it is mostly dark, it will probably want to overexpose to bring out as much detail in the dark areas. Your white bird gets overexposed too.
Does that help, Sparky?
Posted by Lance Warley on December 19, 2008 at 10:51 AM
Discussion
6 repliesThe articles on snow say overexpose 1-2 stops, the camera averages to 18% grey, etc.
If I overexpose white birds, I burn the birds...no details at all. The last post I did of a white bird was underexposed by 2 full stops.
I understand that I would want to expose to let as much light in as possible without burning the whites, but that is never plus 1 for birds for me, especially on a sunny day.
I'm sure this is easy to understand when you can actually experiment with it, but it hasn't snowed here for a little while...27 years.
Can anyone explain this to a non-MENSA member who can't experiment, please?
You might want to provide a little more information on your camera settings. Manual vs Auto. Spot vs. Matrix.
e.g. If someone is applying the +1-2 compensation with todays cameras on snow scenes using matrix metering one should see a scene that is overexposed as the camera already has a calculated the correct exposure unless almost the entire scene is blanketed in white.
I would like to know your settings on the Great Egret shot. It would surprise me that you were spot metering on the bird and still had to underexpose the shot by 2 stops.
Mike
My setting for the Egret were Av mode, Evaluative metering.
I usually don't spot meter on birds. Mike's right - when I spot meter, I don't have to vastly underexpose.
I get the gist of it from your responses. Now all I need is about 3 inches to play with.
When in Evaluative metering mode, the entire scene is "evaluated" for exposure. It's pretty simple. If the scene averages out to be lighter than 18% reflectivity, it will tend to underexpose. If it averages out to be darker, it will tend to overexpose. A snowy scene that is predominantly white will be underexposed and the whites will be dirty or grey.
Your egret scene is mostly dark with the bird occupying 30-40 percent of the scene, maybe? This type of image will almost ALWAYS result in that white bird being overexposed no matter how good of a metering system a camera has built into it. The meter does what its told, it's not an intelligent device and it can't read your mind. What's more important to you? Not blocking up the dark background or not clipping the whites of the bird? The meter doesn't know what area of the scene is important to you. It averages out the scene the best it can using sensors throughout the frame and computer algorithms. It recommends an exposure that can best deal with the high-key nature of the scene. Since it is mostly dark, it will probably want to overexpose to bring out as much detail in the dark areas. Your white bird gets overexposed too.
Does that help, Sparky?
Thanks.