Zeiss 5cm f/1.5 Sonnar Contax mount

I found one made somewhere around 1953 -- I shot my first roll with it last night on the R2C -- the lens is no doubt wonderful. I'm a little concerned because a large number of frames were off on focus. I was just shooting a test roll of my daughter sitting in her high chair - and the back of her chair was in sharp focus. I was shooting slightly stopped down from f/1.5 - probably f/1.8ish -- so it may be my eyes -- because other stationary objects I shot were in pretty good focus.

I just ran another roll through my Contax IIa - and just focused and kept the subject centered and made the image. I'll process the roll in a bit and take a look at the focus. If it's fine - I'll run another roll through the R2C -- I know the two cameras are worlds apart as far as focus accuracy goes - so I probably just need to be more careful with the R2C.

Has anyone had similar experiences with the R2C / 5cm f/1.5 combo?
 
One sample shot taken with 1950's Contax IIa and Zeiss-Opton T Sonnar 50mm/1.5
lens at wide open f/1.5. My film was Rollei Retro 100 developed in Agfa Rodinal.

"Catch you..."

 
outfitter said:
On the other hand, I have a pre-war 1.5 that was aftermarket coated but has a chip in the front element. Harry CLA'd the lens (and replaced the front element) and it is a fine lens today. For me this demonstrates servicing the old Sonnar 50mm/f1'5 lenses is more important than what version it is - I would spend more on the CLA than for the lens.
Click to expand...

I would test this lens thoroughly. For premium lenses, elements were in general part of a matched set, and you aren't supposed to mix-and-match individual elements. Henry should know this.

There is a possibility that the lens will be fine, but there's also the possibility that the lens will focus correctly at infinity but not focus accurately at other distances.

Regarding the lens that isn't focusing correctly, I would check collimation of the lens. The postwar Sonnar is very easy to reset collimation, as long as all of the original lens elements are present.
 
I've had good luck (not 100%) swapping out glass on Sonnar formula lenses, including CZJ 5cm F1.5's. Some care went into selecting the element and group for the exchange. I found that re-using the fixture was important as some individual fitting took place, and shimmed the lens with the new configuration. I've also adjusted spacing on rear modules before shimming the lens. If it is done properly, results can be as good as the originals. I suspect that Henry Scherer does a lot of testing on any swap-out that he performs.
 
Brian Sweeney said:
I've had good luck (not 100%) swapping out glass on Sonnar formula lenses, including CZJ 5cm F1.5's. Some care went into selecting the element and group for the exchange. I found that re-using the fixture was important as some individual fitting took place, and shimmed the lens with the new configuration. I've also adjusted spacing on rear modules before shimming the lens. If it is done properly, results can be as good as the originals. I suspect that Henry Scherer does a lot of testing on any swap-out that he performs.
Click to expand...

Brian,

do you know what the exact focal lengths are of the different Contax mount Sonnars ? Thanks,

Roland.
 
Roland- it's a "nominal 52.4mm". It's got to be close, as you cannot use a cut on the RF cam as the M-Mount Leica Summicrons (and others) do. I've seen the 1980's J-3 spec sheets call it 52.5mm. And I have a 1970's Modern Photo test of a Contax III with 5cm F1.5 Sonnar call it a 52.3mm.

I have a TTL viewer that can be used to check focus, and then compared against the camera's RF. I test at 3ft, 15ft, 30ft, infinity. Adjust element spacing and the Shim until they pass the "multi-point calibration".

Same way that I made an RF-Coupled lens out of the front of a J-8 and the Back of a retina Xenon.

http://ziforums.com/showthread.php?t=138

Now: THOSE optics are mismatched, but it still gives accurate focus at all distances.
 
Did you resolve this issue?

I recently picked up a R2C, but haven't finished my test roll.

notraces said:
I found one made somewhere around 1953 -- I shot my first roll with it last night on the R2C -- the lens is no doubt wonderful. I'm a little concerned because a large number of frames were off on focus. I was just shooting a test roll of my daughter sitting in her high chair - and the back of her chair was in sharp focus. I was shooting slightly stopped down from f/1.5 - probably f/1.8ish -- so it may be my eyes -- because other stationary objects I shot were in pretty good focus.

I just ran another roll through my Contax IIa - and just focused and kept the subject centered and made the image. I'll process the roll in a bit and take a look at the focus. If it's fine - I'll run another roll through the R2C -- I know the two cameras are worlds apart as far as focus accuracy goes - so I probably just need to be more careful with the R2C.

Has anyone had similar experiences with the R2C / 5cm f/1.5 combo?
Click to expand...
 
Very interesting info in this thread🙂 I was very fortunate to find an extremely nice 50/1.5 CZO Sonnar here on RFF. It's become my favorite lens.
 
Brian Sweeney said:
Roland- it's a "nominal 52.4mm". It's got to be close, as you cannot use a cut on the RF cam as the M-Mount Leica Summicrons (and others) do. I've seen the 1980's J-3 spec sheets call it 52.5mm. And I have a 1970's Modern Photo test of a Contax III with 5cm F1.5 Sonnar call it a 52.3mm.
Click to expand...

Thanks, Brian !

Any idea on the Canon 50/1.4 LTM ? 😉

Roland.
 
Okay- Making an LTM Sonnar. The Canon is made to the Leica standard of a nominal 51.6mm. Shim the CZJ SOnnar for a sweet spot at 6ft~8ft. Go for wide-open and close-up. Then, stop down a little for infinity. The Sonnar focus shift works in your favor. I've only had two J-3's that this was not good enough for: on those I set the rear module in closer to the front.
 
Brian Sweeney said:
Okay- Making an LTM Sonnar. The Canon is made to the Leica standard of a nominal 51.6mm. Shim the CZJ SOnnar for a sweet spot at 6ft~8ft. Go for wide-open and close-up. Then, stop down a little for infinity. The Sonnar focus shift works in your favor. I've only had two J-3's that this was not good enough for: on those I set the rear module in closer to the front.
Click to expand...

Exactly. 🙂 Forgot about the shift, that should do it.

A pity that the Canon's RF cam doesn't turn (like on a Summicron, for instance).

Now I have to find another Opton T ....

Thanks !

Roland.
 
Last edited:
I resolved the issue by sending the lens in for a CLA - along with the R2C (the R2C RF was out of whack as I suspected) --

I'll post up some images when I finally get to the rolls of film -- I'm only a hundred roll or so behind 🙂
 
I'm still determined to make a 50mm F1.5 Opton for the Leica. The Canon Focus Mount should do the trick, but none have come along to me with dead glass. The 50/1.8 is CLOSE, as is the Summarit. Each of those mounts requires some additional work. I've not decided which one to attack.
 
Brian Sweeney said:
I'm still determined to make a 50mm F1.5 Opton for the Leica. The Canon Focus Mount should do the trick, but none have come along to me with dead glass. The 50/1.8 is CLOSE, as is the Summarit. Each of those mounts requires some additional work. I've not decided which one to attack.
Click to expand...

Well? Have you done it, Brian?
 
You must log in or register to reply here.
Back
Top Bottom