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  1. Thread: Barrel lens

    by Dan Fromm
    Replies
    9
    Views
    139

    Re: Barrel lens

    Well, if you want really long exposures. Or poorly-timed short ones.

    Brand? Leiss or Zeica.

    Remember, NJ is the state of exits and abrasion.
  2. Re: Diffraction. When does it really matter with LF?

    focal length/entrance pupil is dimensionless.
  3. Re: Diffraction. When does it really matter with LF?

    But it isn't affected by focal length. Effective aperture, a dimensionless number, is what matters.
  4. Re: Diffraction. When does it really matter with LF?

    Well, it can't be corrected.
  5. Re: Diffraction. When does it really matter with LF?

    Re Greg's post #17 above, +1. Sharpness is overrated.
  6. Re: Diffraction. When does it really matter with LF?

    Inexpensive at on-line used book stores.
  7. Re: Diffraction. When does it really matter with LF?

    Bryan, your gut is mistaken. See, for example, H. Lou Gibson's Close-Up Photography and Photomacrography, EKCo publication #N-16.
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    669

    Re: Worthy Linhof Contenders

    Please educate me. I'm not sure why this is so. My tiny 2x3 Graphics seem to be unusable with lenses that won't clear their lens throat, but some -- not all -- lenses with large rear elements can...
  9. Re: Diffraction. When does it really matter with LF?

    You're right. Stupid typo, corrected. Thanks for spotting it and telling me.
  10. Re: Diffraction. When does it really matter with LF?

    The rule of thumb is that resolution measured in line pairs/mm is limited by diffraction to 1500/f number. At f/1, the limit is 1500 lp/mm. At f/22 the limit is 68 lp/mm. And so on.

    Another...
  11. Replies
    31
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    3,497

    Re: Recognizing dagor type G-Clarons

    If you believe claims in the catalogs, its the other way 'round.

    G-Claron claimed coverage @f/22 (mm)

    f dagor plasmat

    150 191 189
    210 280.5 260
    240 319 298 ...
  12. Replies
    31
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    3,497

    Re: Recognizing dagor type G-Clarons

    Re Dagors' and clones' focus shift on stopping down. My dagor type G-Clarons (150, 210 and 3 240s that I've sold) have/had none. My Boyer Beryls (85, 90, 135, 180, 210, 210 S and 250) have none. ...
  13. Replies
    31
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    3,497

    Re: Recognizing dagor type G-Clarons

    Jody, the G-Clarons are very roughly parallel to Symmars. The original Symmars were dagor types, replaced in the 1950s by plasmat types. The VM says that the plasmat types were better corrected...
  14. Replies
    31
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    3,497

    Re: Recognizing dagor type G-Clarons

    Thanks for the kind word.

    Comparing weights never occurred to me. I just looked at the catalogs, which don't show weights. One would have to get examples of all focal lengths of both types and...
  15. Re: Shutter swap - possible or not recommended..?

    #0 is #0 is #0. But and however all of the Copal #0 shutters I"ve seen have preview settings and "T"speed. I have a 90/8 SA paperweight that is in a Compur #00. No preview, no "T." OP, check...
  16. Re: Aspherical, Apo(chromatic) & ED (extra low dispersion) lenses - whats the differe

    Sigh. Another closet Marxist, confusing inputs with results. Another person taking marketing fluff seriously. ED glass may make reducing aberrations easier. Aspherical elements likewise. For...
  17. Replies
    9
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    475

    Re: Aerostigmat 10'' 250mm f/4.5

    Karsten, are you sure there's an f/4.5 Tele Raptar? I ask because it isn't mentioned here https://alphaxbetax.com/wollensak-lens-and-shutter-compendium/ or in the catalog at pacificrimcamera.com.
    ...
  18. Replies
    9
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    475

    Re: Aerostigmat 10'' 250mm f/4.5

    I have no experience with the Aerostigmat, but it is a tessar type that was designed in the 1930s. Aerial camera lens optimized for distant subjects. It should be a good enough lens but as...
  19. Re: Cambo 4x5...how to know how wide you can go

    Congratulations. Its what we all do.
  20. Re: Bellows Extension Factor & Flash Photography

    No, you can move the flash closer to the subject. Since you're shooting still lifes, you can also fire the flash four times to get double the exposure.
  21. Re: Bellows Extension Factor & Flash Photography

    Hmm. Are you acquainted with Guide Number arithmetic? To get more light (brighter) on the subject, position the flash closer to it. To get less light, farther away. You can also reduce...
  22. Re: Cambo 4x5...how to know how wide you can go

    That's right. If you look at the back, you'll see that it is what is called a reversible back. You can remove it -- same process as removing a lens board or detaching the bellows -- and rotate it...
  23. Re: Cambo 4x5...how to know how wide you can go

    You have set the camera up correctly. For set up, see https://static.cambo.com/Files/SC2_Manual.pdf

    If you reverse the rear standard, with no bellows fitted the two function carriers (the parts...
  24. Re: Cambo 4x5...how to know how wide you can go

    Not probably. Certainly.
  25. Re: Cambo 4x5...how to know how wide you can go

    Lou is right. I have 2x3 and 4x5 Cambo SCs. When the tripod mounting block is positioned between the standards it limits how closely they can approach each other. The solution is, as the OP...
  26. Re: A source of valuable data on French lens makers and their products.

    I agree. When I was deciding whether to write my Berthiot article I bought a copy of their Berthiot pamphlet. It too doesn't have a serial number. Their original idea of limiting the number of...
  27. Re: A question about focal length

    152 mm
  28. Re: What do you use to support your heavy, long, big and old lenses on your LF camera

    On my Cambo(s), I use a mutilated Cambo SC standard to support my heaviest lens, a 900 mm Apo-Saphir.

    On my failed Baby Bertha, I used an inexpensive lab jack to support a 2x3 Graflex RB Ser. B...
  29. Re: Voigtländer Petzval 3B 2 inch Diameter NEED HELP

    Prescriptions are normalized to 100 mm. For other focal lengths, multiply the 100 mm specifications (radii, thicknesses, spacings) by "other focal length"/100.
  30. Re: Voigtländer Petzval 3B 2 inch Diameter NEED HELP

    What do you think the first four items in the list are?
  31. Re: Voigtländer Petzval 3B 2 inch Diameter NEED HELP

    maxi, you can find prescriptions here: http://www.dioptrique.info/base/m/m_voigtlaender.HTM
  32. Replies
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    Re: Blocked from responding?

    We're not allowed to reply to for sale posts. Read the rules at the top of the for sale section.
  33. Re: What y'll know about cheap non shutter wide angle 75mm lenses

    Hard to find, not always too expensive, 75/14 Berthiot Perigraphe VIa.
  34. Replies
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    240

    Re: Sinaron 5.6 / 210 mm Smallest Aperture

    Pardon me for jumping in. It isn't a question of wrong scales. Leaf shutters' diaphragms typically go from fully open to "very small opening." They don't have lens specific stops. For some...
  35. Replies
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    326

    Re: Compound shutter repair or replace?

    Jimbo, if your camera is a Speed Graphic -- it could be a Crown -- why don't you use the focal plane shutter?
  36. Replies
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    973

    Re: Are There New Shutters for Old Lenses

    Joe, thanks for the report.
  37. Re: Centre filters for UWA lens - rear element instead of front

    Drew, you may be thinking of the Reflex Nikkors (500 mm, 1000 mm and 2000 mm), which take small filters in the rear. They must be used with a filter in place. The filter set includes clear, red,...
  38. Re: Centre filters for UWA lens - rear element instead of front

    I wrote an article that addressed this. There's a link to it in the list. Read it. If you don't remember what the list is or where to find it, please ask.
  39. Replies
    25
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    973

    Re: Are There New Shutters for Old Lenses

    Joe, I have a Calumet tester too. I'm not sure that it works with the aperture stopped way down. Haven't tried because I've sometimes had to put the light source close to the shutter. I recall...
  40. Replies
    25
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    973

    Re: Are There New Shutters for Old Lenses

    A thought about leaf shutters. The conventional wisdom is that they run slow at higher speeds. This is usually based on measurements taken with shutter speed testers that measure the time between...
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