Exposure question

  • Thread starter Thread starter RobC
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RobC

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Ok don't flame me too much.


if a scene is particularly bright but the subject is dark (bird against white cloudy sky) do I under or over expose ?

I've got it into my head that I should over expose if it's bright and it's not sitting right in my teeny tiny brain.
 
How big is the bird :D
It depends on the overall scene which comprises of the dark bird and the white sky.

The camera will give a correct exposure if the scene is 18% grey (12% on some digital cameras AFAIK)

Assuming a dark bird and a white sky:

If the bird is largish in the viewfinder then the camera may see an 18% grey scene and no compensation is needed.

If the dark bird comes closer and is taking up most of the scene then the camera assumes that it is an 18% grey scene with poor lighting and will overexpose, you need to dial in some underexposure in this case.

If the dark bird goes further away and the white sky is taking up most of the scene then the camera assumes that it is an 18% grey scene with bright lighting and will underexpose, you need to dial in some overexposure in this case.

It is normally easier to take a substitute reading.

Have a read of this http://www.talkphotography.co.uk/forums/showthread.php?t=115623&highlight=exposure+hand+bird
especially the posts by tdodd
 
Thanks for that.

My head's now exploded !!

I'll read the thread agin in the morning, I may have better luck understanding it ;)
 
A good idea when shooting in tricky conditions is to take a meter reading of a general scene, make a note of the settings and set the camera to manual at those settings. This will give you a pretty good ballpark to start with. Shooting RAW also gives you more latitude to adjust the exposure in post processing.

If you think about things in the terms of what light is hitting the subject, it doesn't matter if it's a grey fence or a white bird, the light hitting them is the same. If it is in shadow, as it is if you are shooting against the light, think about it, then you need to adjust for that. It's mainly a thought process rather than any black magic.
 
RobC said:
Ok don't flame me too much.


if a scene is particularly bright but the subject is dark (bird against white cloudy sky) do I under or over expose ?

I've got it into my head that I should over expose if it's bright and it's not sitting right in my teeny tiny brain.
Click to expand...

yes you need to overexpose , as the subject is slightly darker than the back lighting ,,,
 
Remember the aperture range from black to white is 5 stops with 2 and 1/2 stop equal to 18% gray. A fully white shot open up 5 stops from your meter reading. As there is some darker part in the shot open up 2 to 3 stops. A shot like this is a no go, you cannot satisfy both parts of the shot.
 
classcams said:
Remember the aperture range from black to white is 5 stops with 2 and 1/2 stop equal to 18% gray. A fully white shot open up 5 stops from your meter reading. As there is some darker part in the shot open up 2 to 3 stops. A shot like this is a no go, you cannot satisfy both parts of the shot.
Click to expand...

Nobody yet noticed todays deliberate mistake :bonk:
 
classcams said:
Nobody yet noticed todays deliberate mistake :bonk:
Click to expand...

Apart from it being wrong on lots of counts? ;)

Black to White is between 6-7 stops depending on your sensor's dynamic range.

darkest tone in which you want to retain detail is between 2-2.5 stops down from mid grey, lightest tone in which you wish to retain detail is between 2-2.5 stops above mid grey. Then above and below this you will have black and white.

This may help
 
LOL. I just did. :D

A simple trick for photographing birds against the sky is to meter off grass and use that setting. It's not ideal but it gets you well in the ball park.

Another method is to extend your hand up towards the sky as far as you can and meter from the underside of your hand (mimicking the actual situation with the bird) and use that setting.
 
Just come over again when it is sunny :lol::lol::lol:

I have a good book if you want to borrow it :lol::lol::nuts: soemone gave it me the other day :shrug:
 
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