ZM Sonnar Focus Shift?

D

drjoke

Well-known
Local time
9:47 PM
Joined
Apr 12, 2007
Messages
217
Is the lens still optimized at 2.8 for newly released ones? I got mine about 2-3 months ago and through unscientific tests it seems to focus accurately at 1.5. I don't have a digital RF, so it's not so convenient for me. Does anyone else have experience?
 
Apparently Zeiss never stopped selling the F2.8 version. If you want it sharp wide open, then you have to send it to them for adjustment. Shoot a newspaper from close range, with the camera at 90° and on a tripod, and see if there is a shift and where the focal plane is.
 
mfogiel said:
Shoot a newspaper from close range, with the camera at 90° and on a tripod, and see if there is a shift and where the focal plane is.
Click to expand...

Or you can download some focus test chart from Internet:
http://www.focustestchart.com/chart.html
http://regex.info/blog/photo-tech/focus-chart/
http://photo.net/learn/focustest/

I did the test with my vintage Sonnar and Nikkor 50mm lenses from 1950's here:
http://www.rangefinderforum.com/forums/showpost.php?p=651295&postcount=14

And another vintage lens 'test' without chart:
http://www.rangefinderforum.com/forums/showpost.php?p=650528&postcount=8
 
Last edited:
In Oberkochen this year (May) when I picked up a 50/1.5, I was told by Dr. Nasse that focus is now optimised for full aperture. He also said that for a rule of thumb, if you treat d-o-f as being all BEHIND the point of sharp focus, you will not go far wrong.

Several months later, using this rule of thumb, I have been very pleased and indeed the Sonnar is may favourite 50mm lens out of quite a choice. It's nothing like as sharp or evenly illuminated at full aperture as a Summicron but I love the signature of this lens. Then again I generally prefer 35mm lenses anyway...

Cheers,

Roger (www.rogerandfrances.com)
 
is there any way of telling if the new lens one is buying is optimized for f1.5 focus at close range, other than testing it out?
no markings on the lens or by serial number?
 
xayraa33 -- is there any way of telling if the new lens one is buying is optimized for f1.5 focus at close range, other than testing it out?
no markings on the lens or by serial number?

Not that I know of, but next time I talk to Zeiss, I'll ask (I'm waiting for the near-legendary 85/2, which I have been promised this month, so I have an excuse to contact them).

Cheers,

Roger (www.rogerandfrances.com)

Update: I'm still waiting for a reply (and an 85/2)

Article now finished, including d-o-f tests at nearest focusing limit. Dr. Nasse's rule of thumb is slightly oversimplified (or I misunderstood him -- much likelier).

The d-o-f grows much faster behind the focused point, but also grpws in front od it. Using the brilliant schematic from Another Member (thanks, but I can't find the post), if a lens with no focus shift is

___[]____

then the Sonnar is more like

_[]______


than

[]_______

as you stop down, using [] as the focused point and ________ as depth of field

Cheers,

R.
 
Last edited:
Roger Hicks said:
Not that I know of, but next time I talk to Zeiss, I'll ask (I'm waiting for the near-legendary 85/2, which I have been promised this month, so I have an excuse to contact them).

Cheers,

Roger (www.rogerandfrances.com)
Click to expand...

Thanks Roger, a way of knowing which version of the lens there is in a dealer's stock would stimulate sales for Zeiss, for those who want a fully f1.5 optimized lens (or not) straight out of the box.
One can then shop with confidence.
 
Roger Hicks said:
In Oberkochen this year (May) when I picked up a 50/1.5, I was told by Dr. Nasse that focus is now optimised for full aperture. He also said that for a rule of thumb, if you treat d-o-f as being all BEHIND the point of sharp focus, you will not go far wrong.
Click to expand...

Roger,
Thank you for that info. I wonder if the DOF charts for this lens can be used as a method to determine how focus shift will affect the final image?
 
I got my lens from a dealer who held no local stock and had to order from Zeiss directly (from Japan?). Then was I more likely to get one optimized at 1.5?
 
Hi Roger - I was reviewing your book Rangefinder earlier this evening. Nice compilation and use of VC lenses. Would be nice if you wrote a book on lenses that fit the Leica and their performance [kind of small portable paperback].

Just a suggestion. Best Regards - Paul
 
35mmdelux said:
Hi Roger - I was reviewing your book Rangefinder earlier this evening. Nice compilation and use of VC lenses. Would be nice if you wrote a book on lenses that fit the Leica and their performance [kind of small portable paperback].

Just a suggestion. Best Regards - Paul
Click to expand...
Dear Paul,

Thanks for the kind words, and the suggestion, but alas, it's increasingly difficult to persuade a publisher to buy a book that doesn't have 'Photoshop' in the title. this is one reason why I am putting so ,much work into www.rogerandfrances.com (see also my reply below).

Cheers,

R.
 
Last edited:
drjoke said:
Roger, can you please show us nice pics taken with your Sonnar at 1.5?

Thanks!!!
Click to expand...
As soon as I have finished this reply, I'll be back at work on a free article on the Sonnar for www.rogerandfrances.com, which should be up in a couple of weeks (I have to finish it and get it to California, after which the web-master will have to get it on the site). I'm starting a new series of free articles, 'First Look', which relate to equipment I've recently received and/or especially like.

They'll be less detailed than magazine tests (for which, after all, I get paid) but they'll also have more pics than most magazine tests. For example, the Summarit piece (all but finished) has well over 20 pics taken on the M8 with the 35, 50 and 90, and should go up at the same time.

They're a blatant 'hook' to try to get people onto the site and subscribe, because I don't take advertising, and frankly, the site doesn't make a lot of financial sense without more subscribers. But I live in hope!

Cheers,

Roger
 
i an wondering - did anyone made a test between old sonnar, jupiter 3 and new sonnar. i saw many photos fromnew sonnar and i never noticed some real problem with that shift. i think that people on forums made that thing bigger than it is.
 
nzeeman said:
i an wondering - did anyone made a test between old sonnar, jupiter 3 and new sonnar. i saw many photos fromnew sonnar and i never noticed some real problem with that shift. i think that people on forums made that thing bigger than it is.
Click to expand...
Seconded. See revised post 6.

Cheers,

R.
 
You must log in or register to reply here.
Back
Top Bottom