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  1. #1
    cooltouch's Avatar
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    What to do with a Tessar 300/5.6

    I have a Carl Zeiss S-Tessar 300/5.6 in barrel that I bought at a swap meet almost 20 years ago, and have never done anything with. It's a big, heavy lens in a very nicely machined barrel. The guy I bought it from said it came out of a paint comparator. Still, I figured a Tessar is a Tessar is a Tessar, so I bought it, thinking at the time I might cobble together a tube for it and turn it into a spotting scope.



    More recently I've been wondering about its potential as a photographic lens. When I point it to a brightly lit window and hold a flat white surface behind the lens, it shows a circle of coverage of about 10", but it's noticeably soft on the corners. It has no aperture mechanism, so f/5.6 is all there is.

    I don't have a large format rig yet, but it seems to me it wouldn't be too difficult to adapt to LF, but given the level of softness on the edges it would probably have to be restricted to 4x5.

    Aren't there accessory irises or masks that can be attached to lenses to provide smaller apertures? And if I had to have a shutter, I've heard of Packard shutters, so I suppose I could adapt one of those. Seems like a fair amount of expense, though, which makes me wonder if it would even be worth it.

    Alternatively, I'm thinking it might not be that difficult just building a spotting scope and then use a camera adapter for 35mm. I have a lathe, so I can machine the tubing to fit the lens. It occurs to me that I might even be able to find one of those cheapo preset teles that used to be popular back 20 or more years ago, and scavange the rear components for aperture control and T-mount, then mount them into the tube.

    Have any of you done anything like this before?

    Best,

    Michael

  2. #2

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    If you would have a Copal or Compur 3 shutter.......
    Even then this lens has a front and a rear group that have to be spaced properly to each other in order to get a maximum result.
    Have a look at the Carl Zeiss or Schneider site for details about this.

    Peter

  3. #3
    df cardwell's Avatar
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    It is an S-TESSAR, not a Tessar. Never intended for making pictures, and really can't.
    You can get a mint 300 Tessar from the last run in Jena for under a hundred bucks that
    is sharp as a laser with fine bokeh, and all that. This S-Tessar is a neato paperweight.

  4. #4
    cooltouch's Avatar
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    Thanks for the Jena tip. Yeah, I reckon I'd be better off doing such if I really wanted a decent lens.

    Can you explain the difference between the S-Tessar and a standard Tessar?

    If I hold a telescope eyepiece up about 300mm behind the lens, things certainly appear sharp.

    Best,

    Michael

  5. #5
    Lee L's Avatar
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    I believe the S-Tessar is a photocopier lens. You've found one of the excellent uses for it: put it in a tube with a focuser and mount your telescope eyepieces in the focuser, then point it at the stars. Makes a dandy rich field short focal length telescope.

    You can also get a T-mount for your 35mm SLR and shoot your kid's soccer games with your new copyscope. Put a puzzled look on all those faces behind the big white lenses.

    google 'copyscope'

    Lee

  6. #6
    Frank Szabo's Avatar
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    I snagged one of these critters some time ago and couldn't really figure what to do with it because of the lack of a diaphram.

    I got the 'brilliant' idea to remount the glass in a new barrel and add a diaphram to the new barrel assembly so split the barrel on a bandsaw, cracked it open, removed the glass, and wrapped it in soft toweling - that's as far as I got - was assigned other fiddling the wife deemed more important. Kept the old barrel to measure for element spacing. I can almost guarantee I'll not be using the 'million-thread-per-inch' metric wrinkles for assembly when I make the new barrel. 20 TPI should be sufficient.

    BTW - I'm a diemaker by trade and do my own SK Grimes type work.

    If I ever get back to the project and get it working, I'll post a photo or three. I know it's not supposed to be that sharp, but some of the high-dollar petzval type aren't either, what with the swirlies and other attributes. The issue was paying $1000 for swirlies or $25.
    ...

    "Beer is proof that God wants us to be happy."

    Benjamin Franklin

  7. #7
    cooltouch's Avatar
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    Quote Originally Posted by Lee L View Post
    I believe the S-Tessar is a photocopier lens. You've found one of the excellent uses for it: put it in a tube with a focuser and mount your telescope eyepieces in the focuser, then point it at the stars. Makes a dandy rich field short focal length telescope.

    You can also get a T-mount for your 35mm SLR and shoot your kid's soccer games with your new copyscope. Put a puzzled look on all those faces behind the big white lenses.

    google 'copyscope'

    Lee
    Cool! I googled copyscope and found this:

    http://www.dma.org/~wagner/copyscop.htm

    At that site, there's a simple blueprint for a copyscope using the exact same lens as what I have. Guess that's what I oughta do, eh?

    Thanks for the tip!

    Best,

    Michael

  8. #8
    Lee L's Avatar
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    Quote Originally Posted by cooltouch View Post
    Thanks for the tip!

    Best,

    Michael
    You're welcome. Have fun!

    BTW, where it says "taped 1/4 20" in the instructions, substitute "tapped". It'll hold better.

    And I bet those guys with the big white lenses shooting soccer games don't get the "color abrasions" that the web page mentions when using eyeglass elements.



    Ya gotta love the internet.

    Lee

  9. #9
    cooltouch's Avatar
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    Hehe.

    I found a few more links regarding this lens. Apparently what the guy who sold it to me said was pretty accurate. If the lens was indeed used in a paint color comparator, then it seems it should be well corrected for color. A couple of the links mention the fact that it is indeed well corrected. It does have a nice multicoating on it too, which I'm sure helps.

    Think I'll mosey on down to the big box store tomorrow and shop for some PVC and sundry other goodies.

    Best,

    Michael



 

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