Century Tele-Athenar Disassembly

Univer · Joined: 30 Jun 2009 Posts: 282

Hi All,

I recently "adopted" a Century Precision 230mm/3.8 Tele-Athenar (cine lens, c-mount) which badly needs an interior cleaning. No fungus, as far as I can tell, but copious amounts of dust.

I was wondering whether anyone had had occasion to disassemble one of these Athenars. There are lots of likely-looking screws all over the barrel, but I know better than to lash out and start unscrewing them at random, unless there's no other option.

I know this is a rather simple design, and I have the feeling I'd be able to get to all the surfaces that need attention if I could simply get the barrel apart (with some reasonable prospect of getting it back together properly). All suggestions are welcome!

And if the DIY approach isn't a viable option, I'd be very glad indeed to have a recommendation for a technician who'd be willing and able to work on the lens. So far, the repair people I've contacted have told me they don't work on cine lenses (even though I've made clear that this particular cine lens is every bit as large as a conventional 135mm SLR lens).

Thanks for your help!

Cheers,

Jon

cooltouch · Joined: 15 Jan 2009 Posts: 9097 Location: Houston, Texas

I own a couple of Tele-Athenar IIs, which are not cine lenses. They were actually made for 35mm still work. The front barrels don't rotate for one thing. My lenses are both achromatic doublets, so all the critical glass stuff is up at the very front of the lens. All the rest is just tube and focusing helical. Except with mine, it also has two optical flats -- one all the way up front and one all the way in the rear. The one up front is held in place by the hood. Unscrew the hood and the front flat comes out. The rear flat, as I recall, requires a bit of disassembly of the lens to get to it, but this should be easy to do. If yours has these optical flats you'll likely want to remove them too because they'll probably need cleaning as well.

Anyway regarding removing the doublet, on mine it's real simple. There is one very small allen set screw that holds the group in place. On mine, it's found on a section of tube just below the hood. Loosen the screw -- it doesn't have to be removed -- and just unscrew the optical unit -- the secton of tube -- from the barrel. As I recall, the doublet is not air-spaced, so that's all you have to do to gain access to it.

Hopefully your 200/3.8 will be just as easy. Probably will be, I'm thinking. These are not complicated lenses and are easy to work on.

Univer · Joined: 30 Jun 2009 Posts: 282

Hi Michael,

I thought I remembered that there were a few people who owned Athenars - thank you so much for coming to my rescue.

This is definitely a plain Tele-Athenar, with rotating front barrel. I do think it shares a design incorporating the optical flats.

Armed with your good advice, I went searching for allen-head set screws, and found a total of three: all of them, interestingly, located near the mount end of the lens, rather than near the front. Once I lay my hands on a small enough allen-head wrench - my 1.5mm is too big - I'll try cautiously loosening them and see what happens.

My lens's hood doesn't unscrew - or at least, it doesn't seem to want to. But there is a standard retaining ring securing the front element, and I may be able to unscrew that. In any event, I'll try to screw off the hood another time or two before going that route.

I'll add some photos this evening to make matters clearer. I know this is a simple lens, so it's doubly frustrating not to be able to get into it for cleaning.

Thanks, as always, for your kind assistance.

Cheers,

Jon

cooltouch · Joined: 15 Jan 2009 Posts: 9097 Location: Houston, Texas

Glad I could help, Jon. If your lens has a hood and there's a joint to the main barrel, it's threaded on. It just might be very tight. On my 500mm, the first time I took my hood off, it took me and another fairly burly guy to get it unscrewed. It probably hadn't been off in 20 years or more. You probably know this but I'll state it anyway, when unscrewing something like a hood you want to be careful that you're not squeezing it out of round as you try to get it loose.

Also, chances are, if you remove that first retaining ring you see, you'll just be removing the front optical flat, if you lens uses them.

As for not finding any allen screws at the barrel end, I'd suggest that you look very closely. The set screw that holds my lens's front group in place had paint covering it. I count a total of 12 set screws on mine, including the ones for the aperture and focusing rings.

Univer · Joined: 30 Jun 2009 Posts: 282

Hi Michael,

Thanks again. Ugh, this lens has got about the same number of screws, but most of them are tiny slotted-head screws rather than allen-head screws. I did examine it more thoroughly, however, and my count of allen-head screws is now up to four - all located near the mount end. It's all slotted-heads up near the hood.

Speaking of which, I think I need to borrow your friends, because I can't get that hood to budge. I've tried every trick I can think of, and I can't seem to shift it. (I even found my eye wandering in the direction of the WD-40, but I quickly came to my senses.) I can readily see what you're saying about the front retaining ring: that would indeed get me access to the front optical flat, but nothing else.

For what it's worth, it looks like my lens has all the optics closer to the mount end. At least that's where most of the dust seems to have gathered. Smile

FYI, I sent a note to Schneider in California - they own the Century brand now - to ask whether they would be able to perform a cleaning. (I wouldn't have bothered, except for the fact that the Web copy seemed to imply an ability to work on vintage lenses.) No response as yet.

I did try to get some useful pictures, but I wasn't happy with the results. I'll give it another try.

Thanks again for all your help!

Regards,

Jon