Focus shift on Zeiss-Opton Sonnar 50/1.5
I ran a roll of 400iso Agfa Vista quickly through my Kiev IIa with my new Opton Sonnar 1.5. It looks like there's some focus shift. All of these photos were taken with the lens wide open. The one where the focus is on the "to-do" sign, the lens was actually focused on the gentleman behind it.
The photo of the man in his office was focused on him. The photo of the woman was focused on her ... it seems like the closer I am to the subject, the less noticeable the focus shift.
Is there any rule I can go by to adjust for focus shift, or is there some modification i can make? i.e. get it re-collimated or lean forward a certain amount?
I've used this camera/rangefinder with other lenses and am pretty confident in the rangefinder calibration.
Please forgive the crude scans ...
Any advice is appreciated.
I have the older non coated Jena 1.5 Sonnar on a Contax 11A and there is no focus shift with this combo. Possibly a slight incompatibility between the lens and the Kiev? I used to have a Kiev and had trouble getting my focus right, could have been a bad sample though.
Of course at 1.5 you will need a very accurate R/F.
is the opton made for a nikon or contax mount? There is a slight difference, which doesn't matter much for 35mm and wider, but with 50 and up does make a difference of focus shift.
You can find a full discussion here...http://www.cameraquest.com/NRF-Contax.htm
and keep in mind that the Kiev was made by Ukranians using the Soviet system of "Quality is Job 2!"
I don't believe Zeiss-Opton ever built its lenses for Nikon rangefinders. If someone knows something different on that front, let me know.
I know all the hubbub about the Ukranians and quality. I believe it got gradually worse but this Kiev IIa is a fine camera that's comparable in construction and operation to my Contax IIa ... it's just that my Contax is getting CLA'd at the moment.
I ran another roll through this afternoon, in daylight rather than indoors. Focusing was better but Walgreens messed up the neg scans so I'm rescanning myself. Will post when through.
Originally Posted by summicron1
I have several 50 1.5's -one Opton and 2 Jena
Haven't run into the problem myself but have certainly read about it and I think Zeiss discontinued the modern versions for Canikon recently but I wont speculate on the reason.
I really like the lens and it enjoys probably 85%-90% preferential treatment on my II.
I have the Jupiter 12 and went through 3 to finally get a decent one of those but the jury is still out and I'll probably come up with anothe wide solution.
OP, do you have a wide for your Kit and care to comment…anyone?
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The early Kiev is comparable/identical to a Contax II (but not the Contax IIa). When you're shooting at f/1.5 at a close distance, your depth of field is razor thin. OK, not quite that thin, but there isn't much room for error, and to-and-fro movements might fall outside of the lens' depth of field.
I myself haven't had any issues with close focusing of the f/1.5 Sonnar.
I would also check infinity focus of the lens. If that is off, then your other distances will be off, as well.
In your sample photos, the difference between the point of focus and what you thought was the point of focus is much too far to simply be to-and-fro movement of the camera.
I definitely would check the rangefinder calibration and then infinity focus of the lens. I probably would try the lens on a different body.
Also, make sure that the serial number on the front of the lens matches the serial number of the rear group. It should be engraved on the outside of the lens collar.
The idea here is to eliminate as many variables as possible for the lens misfocusing.
Last edited by elekm; 05-16-2013 at 11:13 AM. Click to view previous post history.
How some people will test is to use a yardstick with small tape markers that show the point of focus. You might want to give this a try yourself. It's just one roll of film.
You'll want to keep the camera stationary to eliminate camera movement as a possible cause. And you might want to use a measuring tape that goes out about eight or 10 feet.