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  1. Re: quality problem with printfile negative pages

    I don't understand the issue, it seems to me that if the white label is less opaque, when you make a contact print the contrast with your permanent marker will be greater.
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    Re: New Zeiss apertures to f-stop converter

    If you know the f-number, then take the next lowest standard f-number and use this formula to find the increment in fractional stops:

    increment = log [ (f-number / next-lowest-f)^2 ] / log(2)
    ...
  3. Re: Popular Photogenic Sites/Locations in Yosemite NP

    This is a good point, you know people often ask what camera St Ansel used, but rarely ask the important question of what size tripod they need to fit in his tripod holes.

    Some of the easily...
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    Re: Technique for focusing "into your scene"

    I'm guessing there are distinctions in use: many amateurs now concentrate on landscape or perhaps portrait LF photography. While in the days when LF photography was a heavy professional tool and...
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    Re: What is my 4x5 area on the glass?

    Your ground glass is fine. The frame against which the ground glass is mounted has the open area of a 4x5 film holder (which is really about 96x120mm as Oren said). The 9x12 box is to help people...
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    Re: DIY PX28 or 4SR44 Battery

    The 6 volt PX28 or 4LR44 alkaline battery is not common in stores as far as I know, but it is easy to find on US ebay for ~$1-2 a piece (I don't know about Canadian ebay). The 4SR44, silver oxide...
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    Re: Technique for focusing "into your scene"

    Other people have explained that the 1/3 rule of thumb isn't really accurate. It also predates digital BTW. But anyway, the simple explanation for the difference in these rules of thumb is that the...
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    Re: a fake Topcor 90mm f5.6 (Horseman)?

    Okay, these pictures are good and clear some things up. The lens you have seems to be the proper front and back of the 90mm. And the 105/3.5 has a larger front cell than rear cell, suggesting it is...
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    Re: a fake Topcor 90mm f5.6 (Horseman)?

    It's not a "fake" in the sense of a counterfeit. The question is whether it's been modified inappropriately.

    From the Horseman manual you linked, the 105/3.5 is a reversed Tessar design with one...
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    Re: Fujinon-W flash problem (M/X)

    The more common problem is that the M delay timing mechanism is sticky and causes the shutter to not release when the trigger is pressed. You might have a combination of two issues: the shutter...
  11. Re: Question about Aperture Scale Compatibility

    The f-number is the focal length divided by the diameter of the entrance pupil. The entrance pupil is the image of the aperture formed by the elements in front of the aperture. So if you look at...
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    Re: Kalosat lens, DIY

    I looked up the index of refraction and dispersion of fused silica before posting, to be not-completely-uninformed. The dispersion of fused silica is not much different from N-BK7 (most common crown...
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    Re: Kalosat lens, DIY

    I had not previously heard of the Kalosat lens. Using single meniscus lenses ("landscape lens") for a soft focus effect is a longstanding traditional use. LFPhoto member Reinhold Schable has...
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    Re: Interesting article on lens design

    Photography blogs write about optics very badly.

    These papers are a clever solution to an analytical mathematical problem, and maybe some derivative of the technique will trickle into lens design...
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    Re: Petzval Formula DIY?

    If you like experimenting, probably the easiest thing to do would be to get some achromats (cemented crown-flint doublets) and experiment with different combinations of focal lengths and spacings of...
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    Re: Photographing stars, 4x5

    For much of the 20th century Kodak made glass plates with various specialized emulsions that astronomers used - different emulsions had different color sensitivities. Some of the commonly used...
  17. Thread: Cougars

    by reddesert
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    Re: Cougars

    I saw a mountain lion once while mountain biking (in the state park next to UCSC, where deer are common and lions are present). It avoided me. Actually I barely saw the lion at first, I just noticed...
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    Re: Ansel Adams' portrait of tragedy

    As you noted, the paper and Jocasta's left arm both point from the edges to the center of the image, at the queen and Oedipus. Also, the sapling tree and post behind Oedipus forms a third leg of a...
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    Re: Shutter repair

    Electronics cleaner used to contain CFCs before they were banned, now it mostly contains lightweight hydrocarbons. CRC electronics cleaner is mostly naphtha (US meaning), ethanes, pentanes - the...
  20. Re: Elmar 135mm: Will it cover 4x5? LSM to Copal adapter?

    The casualphotophile article on the Tele-Elmar / Sonnar makes heavy sledding of some lens design facts or opinions. A reason the Sonnar design is less common than the double Gauss, especially for...
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    Re: Identification, please

    Yes, there are two sliding locks on the rear of the front standard (it's usually called a standard, not a stanchion) that are visible in some of your pictures. These release the front frame that...
  22. Re: Burke & James Press 4x5 rotating back- light leaks solved?

    Thanks for the pictures! Glad to have my curiosity about how it works placated without having to mess things up by taking it apart.

    I think if it were bent enough to be the source of light leaks,...
  23. Re: Burke & James Press 4x5 rotating back- light leaks solved?

    Thanks for this. I looked at mine and modern film holders seem to seat in place fine, so I guess it doesn't have the "problem" width.

    To clarify something, this light leak doesn't have anything to...
  24. Re: Is it a linear progression between 90mm and 150mm?

    When asking whether something is "linear" you always have to qualify, linear in what variable?

    In this case, for example, focal length, image size on the film, field of view in degrees, or...
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    Re: Shooting The Christmas Star . . .How?

    It depends what kind of picture you are trying to make.

    At closest conjunction Jupiter and Saturn were 0.1 degree = 6 arcmin apart (for comparison, the moon's apparent diameter is 30 arcmin).. ...
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    Re: Putting together lenses from scratch

    Surplus Shed has some threaded barrels and retaining rings intended for people to build telescope eyepieces, that may be useful if you can figure out ways to mount the elements to the ring or within...
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    Re: Copal No 1 Shutter Stopped Firing

    I just tried this with a very similar looking Copal shutter (like yours it has the two aperture scales, probably originally for a convertible Symmar), and there is a little detent between the two...
  28. Re: Tilt an old lens a teeny bit off axis to improve image. Anyone ever heard of this

    Lens aberrations depend on the focus distance. So it's possible you were using lenses computed for "normal" ranges like infinity to 1:10, but focusing it at a large reproduction ratio of 1:4 to 1:1...
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    Re: The first war to be photographed?

    I like attempts at historical deduction, but when that Errol Morris discussion went into the third page of if-this-no-maybe-that, I began to sympathize with Thomas Kuhn, whom Morris claims (no...
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    Re: Developer trays

    This is a delightful project.

    I don't have a good developer tray story, but this reminded me of a developing tank. I was in high school and struggling to learn B&W developing with my dad's old...
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    Re: Jeff Wall essay on Anthony Hernandez

    Thanks for that. A really interesting read. I appreciated Wall's placing this work in the context of "street photography" both evolving from it and against it.

    A few of the photos can also be seen...
  32. Thread: Still Smokey

    by reddesert
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    Re: Still Smokey

    FWIW I was camping and hiking in Yosemite from Oct 26-31. At the beginning on Oct 26 it was noticeably hazy in the Valley and at night there were many visible particles in a flashlight beam, as if...
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    Re: Meniscus lens iris "sweet spot"???

    Lens design books have discussions of this. In Warren Smith's "Modern Optical Engineering" he works it out that the ideal position for the stop is about 1/6 of the focal length in front of the lens,...
  34. Thread: Avedon

    by reddesert
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    Re: Avedon

    Good article,
    it's interesting to think of someone as top of their game as Avedon (whether we like him or not) still striving for acceptance or to make a break into a new kind of work.

    Something...
  35. Re: Any tips on how to repair lenses with Balsam Separation?

    Methylene chloride is a very strong solvent that is a significant health hazard (as in, touching it momentarily won't poison you, but major inhalation or skin exposure can cause various kinds of...
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    Re: Review of new Ansel Adams book!

    Rebecca Senf is giving Internet (virtual) talks/presentations on the book and subject periodically, in lieu of a book tour I imagine. There's one next on Oct 21, 2020. If you miss that there might...
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    Re: Tripods in lightning storms?

    Lightning can do weird things, the potentials are so high that it will jump across objects that are insulators under "normal" voltages. (Rubber caps on tripod feet or rubber soled shoes are no...
  38. Re: Disasterous Consequences

    Picture 4 here shows the retaining ring not fully seated into the lens board. When this happens, the rear element may also not be fully screwed into the back of the shutter, and there could be light...
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    Re: Flash Firing Before Shutter?

    Are you sure that the shutter doesn't have an M/X switch and that you haven't accidentally bumped it to M since the previous time you used a flash? Because M sync will cause exactly what you're...
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    Re: Gregory Crewdson's 'An Eclipse of Moths'

    I guess that most of you who are familiar with Crewdson's work know that it's highly staged and lit. The behind the scenes photos at the first link Randy posted show a few examples, such as (if this...
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