BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="henry link" data-source="post: 1392334" data-attributes="member: 6806">Thanks for the measurements, Ed.I should have mentioned that in order to compare the results of the earlier test of the 8x56 and 8x42FLs to the test of the 7x42 FL and 8x42 Ultravid done at a different time and place I had to resort to equalizing the background "exposure" values for the two tests in iPhoto and then applied the same equalization to the crops. Changes in the angle of the sun cause the test brightness values to wander. I may have cooked up a fix for that. I plan to glue an object to the edge of the paper and trace its shadow with pencil. Then all subsequent tests will be set up for the sun's shadow to match the tracing. Then, of course I still have to get the binocular optical axis perpendicular to the paper, something I've just been eyeballing so far.The biggest surprises for me in the light transmission numbers that you and Ron generate are how very high they are and how closely clustered. In this last test, for instance, I have no trouble  seeing the difference in brightness between the FL and the Nikon LX-L by just looking through the binoculars, I would have guessed it's between 5-10%, closer to 10%. The tiny differences your numbers indicate are not something I expect to be able to see at all. From published tests I would have guessed the FL would have transmission around 94-95% (440-450nm), the Ultravid and EL around 89-91% and the LX-L maybe 86-87%. I was also very surprised to see the closeness of the Ultravid and EL in both color bias and light transmission. They look like they could be two samples of the same binocular.Henry</blockquote>

Verification