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    Re: Repro Claron APO II (320mm)

    It has to be a confection. There IS a 420/9 Repro Claron, it is a dialyte type.

    f/3.5 is very unlikely for a process lens. The ebay listing gives a serial number, 412. This isn't in the...
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    Re: Goerz red dot lens

    It is a process lens, doesn't "go with" anything in particular.

    Go to https://www.pacificrimcamera.com/rl/rlGoerzNYmisc.htm, click on the Red Dot Artar brochure (second for left).
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    Re: Why are we here?

    These days I'm here mainly to be helpful. That's why "the list.'"
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    Re: Hello from southwest Germany

    Martin, where in the southwest are you?
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    Re: Tick Season = Lyme Disease risk

    Don't forget Babesiosis.
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    Re: Mystery Kyvytar 240mm f/6.8 in Copal #1

    Hmm. I don't have the time to plow through this https://www.largeformatphotography.info/forum/showthread.php?10255-The-Computar-lens-and-ULF-coverage just now. Happy searching!
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    Re: Any Lenses for 14 X 36"?

    Hmm. Its been a while since anyone asked where to find a 2500/12.5 Apo-Saphir.
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    Re: Any Lenses for 14 X 36"?

    The normal focal length for the format is ~980 mm. 1000 mm elephotos and lenses for aerial cameras don't cover that much.

    Process lenses of that focal length typically cover <= 46 degrees. A...
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    Re: Exposure compensation for small apertures

    Thanks for asking again. You're concerned about shutter efficiency, which has been addressed well earlier in this discussion.
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    Re: Exposure compensation for small apertures

    No. If you're thinking of mechanical vignetting, it is usually caused by the lens' rear barrel. Stopping down diminishes it. To see the effect, take a lens in shutter, open the shutter, open the...
  11. Re: Fujinon 135 5.6 W - Aperture blade issue?

    It isn't a lens issue, it is a shutter issue. Which shutter is your lens in?

    I ask because some of my Copal #0 shutters stay wide open regardless of the aperture setting when the preview lever is...
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    Re: Rodenstock Sironar 150mm

    Interesting. Why do you believe this?
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    Re: Greetings from marseille !

    Try this https://www.google.com/search?as_q=agrandisseur+priox
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    Re: Close focussing distance

    Good point, Sharktooth. You didn't say it explicitly, but the minimum film plane to subject distance is 4 * focal length. Magnification is 1:1. At magnifications around 1:1, its good practice to...
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    Re: Close focussing distance

    Well, minimum focusing distance is easy. 1 focal length, measured from the lens' front (subject facing) node. Since a Symmar's nodes (all versions) are near the diaphragm, measure from the...
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    Re: 203mm Ektar Shutter Help Needed

    Those are the choices. None of the shutters is available new. One relatively cost-effective way to find, e.g., a relatively inexpensive Copal 1 might be to find a relatively unloved lens in one. ...
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    Re: Older vs newer Fujinon 90mm f8's

    OP, according to this: http://www.subclub.org/fujinon/byseries.htm there are three Fujinon NSW lenses, focal lengths 90, 105 and 125 mm, all 6/6. 6/6 means six elements in six groups, i.e., no...
  18. Re: The largest and/or heaviest 4x5" camera ever?

    Joe, don't shout!
  19. Posslibly of interest: a Canadian photographer's machinist

    http://usinage.ericconstantineau.com/index_en.html
  20. Re: Please Read The Book First

    Hmm. The approach suggested in post #15 above is one way to get better-focused searches on any site.

    Here's another way to use Google that allows even better control of the search. Use Google...
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    Re: Schneider-Kreuznach G-Claron 150mm f11

    1:some other number has often been used to indicate relative aperture. In this case, 1:11 means f/11.
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    Re: f/11 G-Claron?

    Anomalies prompt questions. I think that the question you quoted in post #31 above answered your question.
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    Re: Schneider-Kreuznach G-Claron 150mm f11

    There never was a 150/11 WA G-Claron. 210, 240 and 270. That's all.

    For the WA G-Claron brochure I referred to in post #27 above, go to...
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    Re: f/11 G-Claron?

    Look here: http://schneiderkreuznach.com/archiv/pdf/g_claron_wa.pdf

    Coverage is given at the bottom of p. 2
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    Re: Field of view vs focal length

    No, it isn't. I've published a number of articles on the French LF site. "The list" has links to all of them. If QT and his moderators want to copy my articles here, that's fine with me, but they...
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    Re: Field of view vs focal length

    https://www.galerie-photo.com/center-filters-for-large-format-lenses.html
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    Re: Field of view vs focal length

    Y'know, Bob, the wretched things are designed so that when used on the right lens (a) the filter will not vignette and (b) a thin filter mounted on the CF will also not vignette.
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    Re: Field of view vs focal length

    Agree completely. The reason you gave -- mechanical vignetting by a filter mounted in front of the lens -- is incorrect.
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    Re: Field of view vs focal length

    Joe, R'stock and Schneider recommend stopping down at least two stops from wide open when using a CF. This isn't because of mechanical vignetting by a filter in front of the lens as you wrote on...
  30. Re: Installing lens on shutter- tightness question

    There should be a flat surface on the rear cell's shutter side, behind the mounting threads. The cell should screw in until the flat contacts the rear of the shutter's rear tube.
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    Re: Bird Photography with LF

    Re the mentions of using flash. I used to do a lot of closeup work out of doors. Flowers, fungi, insects. KM (ISO 25), Nikon SLR with 1/250 sync speed, small flashes, 105/2.5 MicroNikkor (usually)...
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    Re: A question for the opticians here.

    200/4 MicroNikkor AI/AIS. The aperture is fixed in the barrel, lens elements move to reduce focal length when focusing closer than infinity.
  33. Re: Qhen do aspherically ground lenses date from?

    The first series production lens with an aspherical element that I'm aware of is the Elgeet 12/1.2 Cine Navitar. In C-mount, for 16 mm cine.
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    Re: Measuring old lens threads

    Hmm. Photographer's machinists in the UK. Hmm. Have you asked https://www.srb-photographic.co.uk/ what they can do for you? They used to make custom adapters etc., might be able and willing to do...
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    Re: Info on Rodenstock Sironar convertibles

    https://www.pacificrimcamera.com/rl/00863/00863.pdf See p. 2

    By the way, there's a link to this brochure in "the list."
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    Re: Photomicrography in Large Format

    They are still made and still used. See, e.g., http://www.diatomlab.com/diatom-test-slide-version-2.0.html
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    Re: Photomicrography in Large Format

    Diatoms' structures are very regular. They're used for testing resolution.
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    Re: Process Lens & Close Work

    I think we agree on something. Please read the first sentence of post #6 above.
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    Re: Process Lens & Close Work

    Drew, not to quarrel too much, but tessar type process lenses have 4 elements and are quite asymmetric. I agree with you completely that dialyte type process lenses such as Apo-Artars, dialyte type...
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    Re: Process Lens & Close Work

    The same.



    This is an entirely different question. It depends on the "standard lens." There is no broadly applicable rule of thumb.

    Drew, tessar type Apo-Nikkors have exactly as many...
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