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Focusing Problems with the Zeiss Contax G 90mm



Hi folks,

I just got my G2 but the 45mm is still on backorder. I am tempted to get a 90mm. However, I have read that there are focusing problems with it. Can anybody elaborate on that? How do you achieve exact focus with the 90mm?
The real issue with the 90 is one of DOF. When the lens is used wide open and the subject close, the Depth of Field can be only a few millimeters and this can result in images that appear to be out of focus. It is just a question of being aware of DOF and there is no problem.
Limited depth of field is a reality, but not the actual issue here.

The reason there appear to be differences of opinion regarding the G2's focusing ability is that the cameras differ!

The culprit is not the camera's inherent ability but, rather, it's calibration as it comes from the factory. A *properly calibrated* G2 will accurately and consistently focus the 90 at any aperture and distance - better than a good AF SLR in my experience.

I probably just had a run of bad luck, but it took me three bodies (all new) and two service calls to get it right. I put up with this because the lenses are spectacular, and I refused to let them go. My last purchase was perfect right out of the box.

The body has separate calibrations for each lens; at one point service got the 90 perfect and threw off the 45!

Hopefully my experience was unusual. I love my G2 and all its lenses, and would go through it again if necessary.

Thanks for your input guys. I read in another website that the trick was to step a bit further than 1m when using the 90mm wide open. Or, focus manually. After reading the manual, I found that G2 focusing is quite similar to the RX's distance/focus scales.

Dan, your comment made me nervous. The serial number of my G2 starts with 0625**. What was your latest G2's serial number? I hope mine would have come from the same batch of good ones.
Mine's 0666**, but I doubt that makes any difference.

I found a strong (but not perfect) correlation between accurate distance readout at all distances and correct focus with all lenses. For ex&le, the one that focuses accurately is the only one of the three that displayed .50m at .5m, 7.0m at 7m, 12m at 12m, etc.

My empirical guideline based on personal experience indicated that if actual and displayed are within roughly 1 "display unit" you're likely to be OK. But the display could be off a little and the focus perfect, or the reverse.
Here is a comprehensive link concerning the "art of focusing the G cameras". http://www.contaxg.com/document.php?id=5

I found it quite useful.

As for me, I will do some test shots soon, in order to check if my G2 is well calibrated. After analyzing my last films, I'm not sure. I will compare it to a Minolta 9000 AF - the interesting side effect is comparing the Contax primes to a 28-80 Minolta zoom...
.. I tried these recommendations of contaxg site with my G2 already. But I could not see any differences in my pictures.

My shots got alsways in focus, even with the 90mm and wide open at 1m. No problems there at all.

Just my 2 cents

Just got an email that my 45mm will arrive either tomorrow, Friday or Monday next week. Looks like the 90mm will wait 'til Christmas.

Anyway, thanks for all you input, guys.
I too have heard about the poor focusing 90mm. However the one i had never gave any problems, though I used a G1.
Some say to rotate the camera body slightly to help it achieve correct focus then re-compose, but i never did.
I no longer have this as i sold it because i have a tendency to the shorter lengths. I have only a 28mm an 45mm now and they are great lenses.(but you knew that already).

I have to add that my breakthrough was always shooting in CAF-mode when it comes to 90mm-portraits. Avoid focus-lock in that situations.

The slight movement of the persons head can be enough to get it out of focus.