gpop wrote:
>> it appears a lot of Canons don't meter correctly unless you manually stop down the lens with the DOF preview button.<<
I don't understand this comment, or does the DOF preview button have a function I'm not aware of for a manual aperture lens?.
the way I understand it is that the body doesn't have a way of knowing what f-stop you have chosen. The only way to get a proper meter reading is to act as if the lens is wide open all the time, and to get the proper reading for stops other than wide open, you need to press the DOF preview, so the lens actually stops down to the f stop you have selected and then take the reading with the reduced amount of light coming in just like it will be during exposure.
I use a Nikon D7000 and on that body I can tell the camera what lens I am using in a custom lens preset. Once selected, the camera knows the focal length and f-stop range, allowing it to meter as if I am using a chipped lens that tells the body what's up. Since my 85mm is not chipped, my D90 body would not recognize the lens, and I was forced to shoot in full manual mode, without any metering. The Canon body I read about seems to be somewhere in between, at least letting you meter even if they don't know the lens.
gpop wrote:
my (limited) experience suggests to me that canon cooks the metering with oem ef glass, as I think all my non-oem meter poorly from 1.4-2.8, give or take.
I've only tried this with a few fast EF primes, but if I twist the lens a bit so the contacts don't mesh, I'll get different metering by at least 1/2 stop.
There is no contacts that can mesh on the Rokinon, except for the chipped Nikon version that costs $30 more and would actually work on some of the newer low cost bodies that won't meter with old MF glass. I don't know if there is a chipped Canon version available.