Exposure reciprocity

dadaR6 · Aug 3, 2004

I always have a problem deciding which exposure to choose when i am shooting some scene. I give you an example so it is easier to understand.
Let say you want to take a picture of a landscape where everything is static, and focus at infinity. Your camera gives you the following setting: f/8 and shutter 1/125. Why would you choose this exposure instead of f/5.6, 1/250 or f/11, 1/60. The amount of light will be the same, everything is focus at infinity, so my guess is that the DOF will not change much.

So what will be the difference between the 3 pics ?

Thanks in adance for your responses.

voodoocat · Aug 3, 2004

Generally you want to stop down to the optimal apeture for a given lens. Usually it is 2-3 stops from the widest apeture. I generally go with F8 unless my composition needs more DOF. If you utilize hyperfocal chart, you can use the fast shutterspeed possible with a given composition to avoid any uneccessary bluring from movement.

Big Mike · Aug 3, 2004

The DOF will change but when you are at infinity it's the close end of the field that will change. So if you don't have anything close to you in the foreground...there will not be much difference.

Lenses have a so called "sweet spot". They are not at their sharpest when fully open or fully zoomed out.

When in this situation, I make sure that the aperture is a few stops smaller than wide open and that the shutter speed it quick enough to eliminate any camera shake.

ksmattfish · Aug 3, 2004

The example you give (no movement, subject at infinity) is one where many different settings would probably work.

But if you were trying to get some stuff in the close foreground you would want the longer DOF provided by a smaller aperture when hyperfocused. If the wind were blowing then you might want a faster shutter speed to freeze the blowing leaves and grasses (or you might want a slower shutter speed to record that motion).

dadaR6 · Aug 3, 2004

Ok thanks for your answers. I have another question though.

Will it affect the color saturation of the image? If it does not how would you increase the saturation?