Photons Missing In Action

Started Nov 24, 2009 | Discussions thread
OP Marianne Oelund Veteran Member • Posts: 7,746
T-stops are the primary result

Bob GB wrote:

The only question I have so far is if you have measured the pupil and the focal length of these lenses? I suspect that the nominal f/stop and focal length for a given lens is just approximate values from the vendor.

The % efficiency figures are based on the nominal maximum aperture, thus as you pointed out, could change somewhat if the actual aperture differs.

However, I consider those values to be of only secondary importance. The primary data is the T-stops, which are still accurate, as that is what my tests actually measured.

I know it is more work.

Yes, and I may get around to looking at some of these, at least. If so, I will add the information to this thread.

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