J
jlduh
Guest
Hi, i don't post often here but read regurlaly what's going on in this section
I've used many different manual lenses on my G1 and i'm facing a strange phenomenon with a Fujinon 50mm 1,4 TV lens (in c-mount): when i compare the test shots i get from it and the ones from my other Super Multicoated Takumar 50mm 1,4 in M42, i get speeds 25% higher with the fujinon c-mount lens (i precise that i've done this test in spot metering in a précise area of the image for light measurement where light was constant and uniform).
How can i interpret this? I was wondering if the fact that M42 lens were illuminating an image circle with a size almost double than the one produced by a c-mount lens could explain this "loss", a part of the image and of the light being "eaten" by things "around" the 4/3 sensor whereas the c-mount lens illuminates almost only the sensor?
An other way to interpret this would be to say that when we mount an M42 lens on a micro 4/3 mount, the adapter is much longer than the adapter for the c-mount which is very thin and that this extra-length is like an extension tube, eating light as we see it when a macro extension tube is used... What do you think?
At the end, on a micro 4/3, did other members of the forum saw c-mount lenses giving speeds 25% or so higher than with "big" lenses (lenses for full frame)?
Thanks for reading and maybe... answering! :thumbup:
I've used many different manual lenses on my G1 and i'm facing a strange phenomenon with a Fujinon 50mm 1,4 TV lens (in c-mount): when i compare the test shots i get from it and the ones from my other Super Multicoated Takumar 50mm 1,4 in M42, i get speeds 25% higher with the fujinon c-mount lens (i precise that i've done this test in spot metering in a précise area of the image for light measurement where light was constant and uniform).
How can i interpret this? I was wondering if the fact that M42 lens were illuminating an image circle with a size almost double than the one produced by a c-mount lens could explain this "loss", a part of the image and of the light being "eaten" by things "around" the 4/3 sensor whereas the c-mount lens illuminates almost only the sensor?
An other way to interpret this would be to say that when we mount an M42 lens on a micro 4/3 mount, the adapter is much longer than the adapter for the c-mount which is very thin and that this extra-length is like an extension tube, eating light as we see it when a macro extension tube is used... What do you think?
At the end, on a micro 4/3, did other members of the forum saw c-mount lenses giving speeds 25% or so higher than with "big" lenses (lenses for full frame)?
Thanks for reading and maybe... answering! :thumbup: