Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,571   Posts: 1,545,572   Online: 1031
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 21
  1. #11

    Join Date
    Mar 2005
    Shooter
    Multi Format
    Posts
    3,407
    Quote Originally Posted by matt miller
    Here's the ebay listing: http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1

    I just tried removing the rear element & it didn't change much. I turned the lens around & held it up to the ground glass & that didn't change much either. Could improper spacing cause it to be that far off? I noticed that the rear element is missing 2 numbers compared to the front. Weird.
    Matt, the rear cell's s/n often has the leading digits truncated. 1194375 on the front cell, 94375 is OK

    I don't agree with Jim Galli that its possible to assemble the front cell of a tessar incorrectly and not know it real fast. The first element is planoconvex [front (| or a meniscus (( ], the second is biconcave [ front )( ]. Check that. The front cell should bulge out in front, curve in at the rear. This is pretty far-fetched, but are you sure that there are two elements in the front cell?

    Good luck, keep us posted,

  2. #12

    Join Date
    Feb 2004
    Location
    Iowa
    Shooter
    Multi Format
    Posts
    829
    Images
    7
    If the front group comes apart I can not figure it out. How many elements does a tessar have & in what grouping are they? The lens shows four reflections, two large & two small, whatever that means. I really need to learn something about lenses.

    I've attached a photo of the back of the front group. To me, it appears there is only 1 element in the front & one in the back. The back is quite a bit thicker however. The front element bulges toward the front & appears to be flat on it's back side. The rear element bulges toward the rear & is flat on it's back side.

    After looking closer at my camera, it appears that it is set up (infinity stops & RF) for a 5" lens, not the 6" lens that came with it. Figures.

  3. #13

    Join Date
    Feb 2004
    Location
    Minnesota Tropics
    Shooter
    Multi Format
    Posts
    735
    Matt (and others help, please). Would a 135mm lens work on that bed? If it would, hit me with a PM. I'll send you a not-so-hot but working 135mm lens in shutter with retaining ring, gratis. I have a bunch of things to ship tomorrow, so sooner is better.

  4. #14
    Seele's Avatar
    Join Date
    Feb 2004
    Location
    Sydney Australia
    Posts
    194
    Matt,

    The Tessar consists of four elements in three groups, two air-spaced at the front and a cemented doublet at the back. The f/4.5 version of that period are usually constructed in the way that the rear doublet was spun into its cell, therefore it is a sealed unit, so no problem with having missing bits there.

    At the front, the two single elements were spun into their own cells, and they screw into each other, then into the front of the shutter; the inner one is a negative while the front a positive.

    Judging from the last attached photo of the close-up of the inside of the front cell, it seems like the inner negative is missing; the inside thread of the cell should be what holds the the negative cell in place. Without the negative, the focal length will become much much shorter (and the correction right out of the window), thus explaining why the image can only focus when the lens is racked that close to the focussing screen.

  5. #15
    medform-norm's Avatar
    Join Date
    Dec 2004
    Location
    Netherlands
    Shooter
    Multi Format
    Posts
    863
    Images
    1
    We second Seeles feeling that there's an element missing from your lens. Guess it's time for a word with whoever sold you that thing.

    The rangefinder cam should not matter, nor the fact that the camera was intended for a different focal length.

    (And maybe Jim can give a discount on the Xenar to help out a fellow APUG-ger.)

  6. #16
    Ole
    Ole is offline
    Ole's Avatar
    Join Date
    Sep 2002
    Location
    Bergen, Norway
    Shooter
    Large Format
    Posts
    9,281
    Blog Entries
    1
    Images
    31
    Also: The rear group of a Tessar has almost zero power, it is mostly for correction. No Tessar is convertible.
    -- Ole Tjugen, Luddite Elitist
    Norway

  7. #17
    MikeS's Avatar
    Join Date
    Jan 2005
    Location
    Newport, TN USA
    Shooter
    4x5 Format
    Posts
    220
    Images
    3
    Quote Originally Posted by jjstafford
    Matt (and others help, please). Would a 135mm lens work on that bed? If it would, hit me with a PM. I'll send you a not-so-hot but working 135mm lens in shutter with retaining ring, gratis. I have a bunch of things to ship tomorrow, so sooner is better.
    Yes, a 135mm lens would work fine on that camera! As it's a Speed Graphic, if the focal plane shutter is in good working shape, then having a working shutter on the front isn't as important!

    -Mike

  8. #18

    Join Date
    Feb 2004
    Location
    Iowa
    Shooter
    Multi Format
    Posts
    829
    Images
    7
    Quote Originally Posted by jjstafford
    Matt (and others help, please). Would a 135mm lens work on that bed? If it would, hit me with a PM. I'll send you a not-so-hot but working 135mm lens in shutter with retaining ring, gratis. I have a bunch of things to ship tomorrow, so sooner is better.
    jj,

    Thanks for the offer. I'll take you up on it. (see pm) I'd like to use a lens that will match up with the bed scale, infinity stops, & RF. Maybe a 135 is it. If not, I'll be sure you get it back in the same condition. Thanks.

    I've contacted the seller about the lens, but have received no reply yet.

    Thanks for the help everyone.

  9. #19

    Join Date
    Mar 2005
    Shooter
    Multi Format
    Posts
    3,407
    Quote Originally Posted by matt miller
    <snip> The lens shows four reflections, two large & two small, whatever that means. <snip>
    As you've been told already, a tessar consists of two single elements in the front cell (in front of the diaphragm) and a cemented doublet in the rear cell (behind the diaphragm). You should see four strong reflections and no weak ones from the front cell, two strong and one weak from the rear. The weak reflection from the cemented doublet's glass-cement-glass interface can be hard to see.

    It seems that you've been had. Or perhaps the seller has a problem. At the least a price adjustment is in order.

    BTW, why did you get a 3x4 Speed Graphic? And why not a Pacemaker?

  10. #20

    Join Date
    Feb 2004
    Location
    Iowa
    Shooter
    Multi Format
    Posts
    829
    Images
    7
    Quote Originally Posted by Dan Fromm
    why did you get a 3x4 Speed Graphic? And why not a Pacemaker?
    I don't really know the difference Dan, so I can't say. This is my intro to Graphics. I wanted something quicker than my 8x10, that I can handhold & focus with RF or bed scale. What's the difference between a speed & a pacemaker?

Page 2 of 3 FirstFirst 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin