I've been trying to compare my MF lens normal primes: M50 1.4, M50 2.0, and M40 2.8.
I've been using the stop down method with my k200d: set camera to "manual", set aperture, press green button to let camera meter and for camera to set shutter speed.
I noticed that with my M50 1.4 that the it exposes fine @ full open, however once I start stopping down to smaller apertures, the shots tend to be overexposed. Not sure yet if it's a consistent overexposure. I'd post some 'controlled shots' but my camera's original lithium batteries have finally died so I can't do so.
It seems I don't get this with the M40. Haven't quite noticed it with M50 since I've been taking test shots mainly wide open. Do I have sticky aperture blades on my M50 1.4 or something? Once I get some more batteries (another post .... as my rechargeables don't seem to work on the camera, works on the flash though)
Of course it could all be due to the dude behind the lens