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Carl Zeiss Jena 50mm F2.8 Tessar - Focusing to Infinity
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PostPosted: Mon Feb 25, 2019 11:12 am    Post subject: Carl Zeiss Jena 50mm F2.8 Tessar - Focusing to Infinity Reply with quote

Hi All

I'm a recent convert (or is it addict) to using old legacy / vintage lenses on modern DSLR's

I bought a Carl Zeiss Jena 50mm F2.8 Tessar (circa 1962/63) from a charity shot and when attached to my Sony A6000 it focuses to infininty OK. The focus ring is a little tight and wont turn to the bottom end of the close up distances.

With that in mind I bought another Carl Zeiss Jena 50mm F2.8 Tessar from a different charity shop (this one has DDR written on it - serial number implies about 1967). However with the same adapter and same camera it will not focus to infinity !

Any ideas on why this would be? The DDR version is in excellent condition, but I was a little upset about the infinity issue ! It is obviously OK focusing close up for portraits macros etc.

Thanks

Phil


PostPosted: Mon Feb 25, 2019 11:30 am    Post subject: Reply with quote

Are they m42 Tessars? I've had this problem most often with Canon FD but never m42. Could be a tolerance issue with the second one. The first one probably has old grease and needs to be cleaned out.
My universal solution, or rather workaround for focus issues on m42 and m39 is to use helicoid adapters. As a bonus you get almost macro close focus. Only works on mirrorless though.


PostPosted: Mon Feb 25, 2019 1:28 pm    Post subject: Reply with quote

blotafton wrote:
Are they m42 Tessars? I've had this problem most often with Canon FD but never m42. Could be a tolerance issue with the second one. The first one probably has old grease and needs to be cleaned out.
My universal solution, or rather workaround for focus issues on m42 and m39 is to use helicoid adapters. As a bonus you get almost macro close focus. Only works on mirrorless though.


blotafton, yes they are M42 adapters, I had to google helicoid adapters as I am fairly new to vintage lens usage. I started in the summer of 2018 and I am really enjoying focusing manually and seeing thes old lenses brought back to life. I have acquired a whole set of nifty fifties, some 28 mm and mid range zooms. I particular like prime lenses.

This latest Tessar is the only lens I've had focus to infinity issues with

Thanks


PostPosted: Mon Feb 25, 2019 3:58 pm    Post subject: Reply with quote

Welcome to the addiction. Smile
Do the screws look unmolested? If someone has been into it to relube it, they may not have put it back together correctly.
Anyways, a lens tech should be able to get them both working like new.


PostPosted: Mon Feb 25, 2019 4:25 pm    Post subject: Reply with quote

Is it aluminum version or MC later auto version?


PostPosted: Mon Feb 25, 2019 9:54 pm    Post subject: Reply with quote

Pancolart / Lightshow


The lens is black , not sure about any MC.

Where do I look for screws?


PostPosted: Tue Feb 26, 2019 9:23 am    Post subject: Reply with quote

bwfcnottingham wrote:
Pancolart / Lightshow


The lens is black , not sure about any MC.

Where do I look for screws?

I don't know what lens you have without seeing pictures... Any screws, element retaining rings that show signs of abuse will tell you that someone with less skill/experience was inside the lens, some lenses hide them better than others.


PostPosted: Tue Feb 26, 2019 12:40 pm    Post subject: Reply with quote

What is the furthest distance to which you can get focus?
Knowing that distance you can get a good idea if someone has improperly mounted the helicoids of the focusing mechanism during a lens cleaning/lubrication.


PostPosted: Tue Feb 26, 2019 7:31 pm    Post subject: Re: Carl Zeiss Jena 50mm F2.8 Tessar - Focusing to Infinity Reply with quote

bwfcnottingham wrote:
Any ideas on why this would be?


The threads where the inner and outer parts of the helicoid screw together must use the correct channel, or the focusing will be off. You can't just screw them back together carelessly (unless you get very lucky) without messing up the focusing. In short, there are several different ways to screw them back together (and they will appear to fit just fine), but only one way is the right way.

Without the experience to know which channel is the right one, the only way to fix it is to try each channel one at a time until you find proper infinity focus again.

Assuming this is the problem with your Tessar...


PostPosted: Tue Feb 26, 2019 11:35 pm    Post subject: Reply with quote

If this is your lens: https://youtu.be/e3jezCKW4QY ?

Take good grip on the lens (focus ring included) with left hand and turn front lens part counter-clockwise. It should unscrew. Be careful front glass might pop out already. Then the the real problems begin.


PostPosted: Wed Feb 27, 2019 12:28 am    Post subject: Reply with quote

Pancolart wrote:
If this is your lens: https://youtu.be/e3jezCKW4QY ?

Take good grip on the lens (focus ring included) with left hand and turn front lens part counter-clockwise. It should unscrew. Be careful front glass might pop out already. Then the the real problems begin.


I will attach a picture tomorrow night, the camera is in the bedroom and the wife is asleep !!!


PostPosted: Thu Feb 28, 2019 10:17 am    Post subject: Reply with quote

Thanks everyone for your kind words and help.

I don't feel confident taking the lens to bits and attempting a repair .

I've got a tesssar where the focus ring is stiff and cannot get the close ups but does do infinity and another tessar that will do close ups but not infinity . So in theory I have the full range covered.

My main purpose of my nifty fifties ( and I've acquired a few in a short period) is portraits / headshots .

I might try a repair in a few months when I have more time to spare .

Thanks again everyone .

Slightly off topic...can anyone reccomend a good seller of an industar 55mm f2.8? I've seen some great pics created with it and think it would be an amazimg street lens for the summer events in the city of Nottingham