Hi,
Thanks for all input - so too for the off list ones!
although it was meant for brevities' sake that I wrote 'after ruling out all
other explanations', I see now that it's a little awkward for everybody
thinks up different causes. Sorry for that. Let me say that the observed
phenomenon is NOT due to narrower focal lenghts and less varied brightness
measurements.
Tests were extensively done; evenly lit subjects (like the suggested sky and
test bank lights) as well as average everyday situations (cityscapes,
landscapes and portraits). Meterings are done with MX and MZ5n (both matrix-
and spotmetering tests done). Latter camera's exposure meter was serviced
and exactly calibrated.
When comparing slides the exposures of the 85/18 K are consequently 1/2-1
stop too light/bright. When obtaining exposure measuring with the 50/1.4 A
and using this exposure on the 85/1.8 K it gives the same (proper) slides as
with the 50/1.4. This means that it's only when using the TTL (no matter
which camera - be it MX or MZ5n) measuring that I constantly must compensate
for every different lens. So, that also means that if I'm using a seperate
light meter, I encounter no problem for the apertures are OK.
Furthermore, when comparing the positioning of the aperture-communicating
lever inside the lens mount with the other lenses on a given f-stop, the
levers are not at the same (physical) position.
The lenses are (among others):
50/1.4 A which is OK,
85/1.8 K which overexposes 1 stop,
135/2.5 K which overexposes 1/2 a stop.
Todd wrote:
Basically unscrew the screws on the mount
on the back of the lens, some lenses have them on the part that sticks into
the camera too. Once those are off you can take off the mount. Then you
can remove the aperture ring (be sure not to lose the little ball bearing
that makes the aperture click!) From there you can see where this lever is
linked directly to the aperture ring.
My question is: how does the aperture ring look like? Is the lever
inflexibly attached to the ring or is there any room for adjustments?
Thanks very much,
Hugo.
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