Sonnar 50/1.5 .. what the-?

[TheHub]

I picked up a Contax IIIa today, with a Sonnar 50/1.5. The focus makes some funny noises, the advance is a little rough and the meter is hopelessly optimistic, but otherwise the camera works fine. In the shop I noticed funny rainbow hues in the lens, but I dismissed them as just reflections.

Later on I noticed that they weren't reflections ... is that the coating coming off or something? 😕 I became worried, but I finished off my sample roll and developed it. There do not seem to be any side effects, at any aperture (I even shot at f1.5 but nothing funny showed up.) So,

Should I put a hood on it?
If I shoot into the sun is it going to flare like crazy?
Is this lens unusable for color?

I'd like to get some RFFers opinions here ...

 

[hans voralberg]

The noise is probably lubricant dried up? And that rainbow looks suspiciously like some sort of oil? It's not too difficult to open up the lens and see for your self though, and why not shoot a roll of color anyway ?

 

[ray*j*gun]

The man to answer the question is Brian Sweeney. However I use a hood on most older lenses since the coatings are basic or non-existent. Shoot some color and see how it looks.....its your best test.

 

[Sonnar Brian]

It's probably Newton's Rings from separation of the elements. I've read on this forum that the later Zeiss lenses used a new type of cement, replacing the Canadian Balsam typically used. More of them seem to develop this problem.

Use the lens with a hood. It is not performing at 100%, but should give good results.

For the body: a CLA should take care of any roughness to the wind. INspect that the shutter is capping during winding at high speeds. I've had two Contax's develop shutter problems, a CLA helped.

 

[furcafe]

Per Mr. Sweeney's post, that's separation you're seeing. I have a CZ 50/1.5 w/similar edge separation, but not all the way around the lens. Mine performs nicely despite the separation. I did a comparison w/an un-separated Zeiss-Opton Sonnar using both B&W & color & couldn't tell the difference. I didn't any contre-jour shots as part of my tests, but I wouldn't be surprised if the separated lens is more susceptible to flare. Using a hood is always a good habit, anyway.

I picked up a Contax IIIa today, with a Sonnar 50/1.5. The focus makes some funny noises, the advance is a little rough and the meter is hopelessly optimistic, but otherwise the camera works fine. In the shop I noticed funny rainbow hues in the lens, but I dismissed them as just reflections.

Later on I noticed that they weren't reflections ... is that the coating coming off or something? 😕 I became worried, but I finished off my sample roll and developed it. There do not seem to be any side effects, at any aperture (I even shot at f1.5 but nothing funny showed up.) So,

Should I put a hood on it?
If I shoot into the sun is it going to flare like crazy?
Is this lens unusable for color?

I'd like to get some RFFers opinions here ...

 

[raid]

It seems to be decementing. Fixing this problem will cost you too much money, so use a lens hood and hope that things will not get worse. Flare may get worse and maybe the light transmission gets affected slightly.

 

[Sonnar Brian]

If you get the optic out, working some index matching oil from an immersion microscope lens will get rid of the Newton's rings. I've done that with one lens, working fine 6 years later.

 

[jmkelly]

I agree that it looks like separation of the middle element. If you are handy with a spanner - or even with just a small-blade screwdriver - you could also consider replacing it with an element from another Sonnar, or a J-3.

I had a 1945 CZJ Sonnar that arrived with a similar problem in the rear triplet. The first shots I took with it (on the R-D1, in color) were fine but I took it apart anyway. The triplet came out in three pieces, like it had never been cemented at all. The individual lenses were in PERFECT shape - seriously, coating intact and not a scratch or cleaning mark on them - much better than the rear triplet in any other Sonnar or J-3 in my collection.

So I sent it to John at FocalPoint to be re-cemented. IIRC it was something like $200 - just a little less than what I paid for the lens itself. Hard to justify in the budget, but I felt it was worth it.

 

[TheHub]

Thank you for all the responses 🙂

I was quite happy with the sample roll from last night - actually relieved and very happy. There didn't seem to be any adverse effects, but we'll see when the sun's out. I will be picking up a hood today. It's a shame, but separation aside the lens inside is in excellent condition 🙂

As for the rough advance, that started suddenly last night for some reason. I took off the advance dial and applied a very small amount of oil to the little gear inside. Now it's quite smooth.

I know on Nikon RFs (like the S2) the front plate comes off quite easily. Is it that easy with the IIIa? I'd like to take a peek inside, and see if I can find the focus gears. A little oil on them might quiet them down.

The shutter sounds fine. A little loud maybe? but I've never used a Contax before so I have nothing to judge against.

 

[jmkelly]

Yes I believe the front plate comes off easily - you just have to gently work it around the two lower external-mount dogs on the focus ring.

The shutter is metal so it does not have the "slap" of the cloth Nikon shutters. But it is still pretty quiet. If you have maintenance issues, I and a lot of others here can recommend Eddy Smolov. He can get your camera working properly with a very quick turnaround, and is relatively inexpensive.

 

[TheHub]

uh-oh ...

uh-oh ...

So I shot two rolls of film today. The lens does flare, but it doesn't look like anything out of the ordinary - with or without a hood, which I bought this morning.

A different problem has cropped up. I've attached two pictures which show white banding on the left side (these lines are visible on a few frames, not the whole film, and I used similar shutter speeds.) They were shot at 1/50, 1/100 and maybe 1/250. The lines would be consistent with a shutter breaking late/early, but the Contax IIIa shutter goes vertical, not horizontal. What's going on here?

 

[TheHub]

Here's a photo of the shutter from the back. Is it a little crooked or is it just me? Would that make a difference?

 

[Sonnar Brian]

That does make a difference, and means that it might not "cap" as you advance the film. If it does not cap, you will get a streak on your negatives. The shutter might not completely close. With the back off, fire the shutter at various speeds and advance it. Look for light seeping through the shutter.

 

[TheHub]

I don't see any light leaking through, at any speed.
I still don't understand how a vertically traveling shutter can leave vertical stripes 😕

 

[Sonnar Brian]

My Contax IIIa left a stripe on the negative "similar" to this because the shutter was partially open as the film was advanced.

There could be another explanation, such as a light leak through the back door. I would keep an eye on the shutter.

 

[AJS Lamb]

I've got a coated Zeiss Opton 50mm f1.5 Sonnar, am I right in thinking that the filter size is 40.5mm?

Incidentally, I'm using this recent acquision on my M3 thanks to one of Amedeo's adapters and I don't think I've ever seen such sparkling glass on a lens.

 

[jmkelly]

I've got a coated Zeiss Opton 50mm f1.5 Sonnar, am I right in thinking that the filter size is 40.5mm?

Yes, I believe it is

 

[ray*j*gun]

40.5mm is the correct size for a Zeiss Sonnar 1.5.

 

[AJS Lamb]

John and Ray

Many thanks for your replies.

 

[nomadia]

this looks similar to the original poster's lens issue. any workaround to minimize the effect of separation while i i save up for a lens fix? or is this hopeless? thanks.