Why are the images from my 50 1.8 G so dark?

Started Apr 1, 2013 | Discussions thread
joejack951 Senior Member • Posts: 2,682
Re: Why are the images from my 50 1.8 G so dark?

hirejn wrote:

The lens doesn't affect exposure. For example, if ISO 100, 1/250 @ f/8 is the correct exposure, it will be correct regardless of what camera or lens you have, even with medium format. Something else is the factor, or the lens is broken.

In a perfect world, the lens does not matter but it's a known fact that all lenses have a t-stop value (light transmission) which differs from the f-stop by some (usually small) amount. You can verify this by mounting a simple prime lens and then shooting at the same settings with a complicated zoom. Your exposure will be off by 1/3 stop in many cases. Video lenses are specified by t-stop as that allows more perfect exposure matching which is critical for video work.

The Nikon 200-400/4, with its very complicated design, has a t-stop of around 5 if I recall correctly, about 2/3 stop different than its f-stop value.

 joejack951's gear list:joejack951's gear list
Nikon Coolpix AW100 Nikon Coolpix P7700 Nikon D300S Nikon D3S Nikon AF-S DX Nikkor 17-55mm f/2.8G ED-IF +5 more
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