Search:

Type: Posts; User: Mark Sawyer; Keyword(s):

Page 1 of 168 1 2 3 4

Search: Search took 0.14 seconds.

  1. Replies
    18
    Views
    807

    Re: Lens Not Focusing, What is the Cause?

    I'd start by checking the focal length of the front and rear elements separately. The lens being a fairly symmetrical Plasmat, each should focus at about 240mm. (Tell me if I'm wrong, folks;...
  2. Replies
    6
    Views
    404

    Re: Multicoating on a lens

    It's the internal air-glass surfaces that are most critical. Missing some coating on the front element means a bit of light will reflect back outwards into the world, have very little effect. On...
  3. Re: Dallmeyer or Vitax diffuse focus in action?

    Contrast can be controlled much more in the negative's exposure/development and in printing than by choice of lens, so don't go by that. The Dallmeyer and Vitax are the same design, same number of...
  4. Re: Dallmeyer or Vitax diffuse focus in action?

    Dallmeyer's original intention with the "soft focus" feature was to increase depth of field, not give a softer image. It kinda did, sort of, in a way... But the by-product of having a softer image...
  5. Re: How different are Tessars from different companies?

    "For 99.9% of my work I use a 4x5 view camera." John Sexton

    http://www.photovisionmagazine.com/articles/sexton.html
  6. Re: How different are Tessars from different companies?

    Sexton's work tends to be 4x5 and enlarged, so there's a whole 'nother lens involved. Just to muddy the waters...
  7. Re: How different are Tessars from different companies?

    Yup, wasted half an hour of my time... :)
  8. Re: How different are Tessars from different companies?

    There were several types of new glass, including new variations of crown glass created by Otto Schott for Zeiss around 1887 through to 1893 that made anastigmats possible. (The old crown and flint...
  9. Re: How different are Tessars from different companies?

    Yes, they more or less the same or there are noticeable differences...
  10. Re: How different are Tessars from different companies?

    The bigger differences come in speeds, dates, and coatings, or lack thereof. In my observations, the super-fast f/3.5s aren't as sharp as the f/8s, even at equivalent f/stops, with others falling in...
  11. Re: Greta Thunberg wet plate photos by Shane Balkowitsch

    Agreed, but I've seen it done. :(
  12. Re: Greta Thunberg wet plate photos by Shane Balkowitsch

    Yup, that's the one I was posting about.
  13. Re: Greta Thunberg wet plate photos by Shane Balkowitsch

    Sodium or ammonium thiosulfate are toxic to plants. I have a two-year-old bare spot in my back yard where a student dumped a pint or less of fixer.
  14. Re: Greta Thunberg wet plate photos by Shane Balkowitsch

    Looks pretty close to me. Just very flat lighting in the shade on a very fair complexion.

    Hoping he didn't do wet plates of an environmental activist in an environmentally sensitive area, then...
  15. Replies
    6
    Views
    9,432

    Re: Bellows and lensing question

    To put it simpler, get a modern lens with the same focal length as your Petzval. It will focus in the same place. It's a focal length thing. Focal lengths just do that. You know, focus at a...
  16. Replies
    3,220
    Views
    786,837

    Re: Some Soft Focus Lens Sales Information

    I think if you varied the spacing between the front elements (as Wollensak did with their f/4.5 Tessar), and used it with the anachromatic rear element, you could open up a tear in the space-time...
  17. Replies
    3,220
    Views
    786,837

    Re: Some Soft Focus Lens Sales Information

    The Boyer Opale is an interesting lens, one of the few to use chromatic aberration rather than spherical aberration to achieve its softness. I've been told it is a Tessar with the glass types in the...
  18. Replies
    94
    Views
    16,601

    Re: Rapid View Portrait (RVP) Pictorial lens

    Most lenses have just under a quarter-inch of threading for the flange. For Cooke's three turns, that's about a 13 tpi thread. (A 12 tpi thread would be exactly a quarter-inch of threads.) That...
  19. Replies
    30
    Views
    1,230

    Re: 8x10 Macro Photography lens Question

    For 1:1, I'd recommend a process lens. Those are optimized for around 1:1, and often close down to very small stops, which is helpful with the reduced depth of field at close focusing distances. ...
  20. Replies
    94
    Views
    16,601

    Re: Rapid View Portrait (RVP) Pictorial lens

    13 threads per inch is 13 threads per inch, regardless of the diameter. Cookes used a course thread that threaded on with three turns, every lens, every size! They also chamfered the start of the...
  21. Replies
    30
    Views
    1,230

    Re: 8x10 Macro Photography lens Question

    Weston's Pepper No. 30 is about twice life-size, and was made with a run-of-the-mill 210mm Zeiss Tessar, and I've never heard anyone complain about its quality...
  22. Replies
    30
    Views
    1,230

    Re: 8x10 Macro Photography lens Question

    It would be helpful for the OP to let us know the magnification. As Pere noted, 1:1 is different from 1:5. And very different from 5:1.
  23. Replies
    94
    Views
    16,601

    Re: Rapid View Portrait (RVP) Pictorial lens

    Congratulations! As there's nothing behind the mounting threads to grab onto on these, you need a flange or an iris mount. You could try making a tight-tolerance lensboard hole that you can thread...
  24. Re: Have you found exotic developers worth it for 8x10?

    Good advice, and it's what I've done. I went through that early phase of this developer vs. that developer, and found that while there were differences, they were all pretty good. HC110 has the...
  25. Re: Have you found exotic developers worth it for 8x10?

    Plain ol' HC110 does everything I could expect. I suppose I could dress the bottles up in sexy doll-size lingerie, like an "exotic" dancer and see if it made any difference...
  26. Replies
    17
    Views
    409

    Re: Help with Kodak 2D back

    I'm unclear, is the plate holder thicker than a standard film holder? Also, have you checked to see it's in registration with the ground glass for focusing?
  27. Replies
    69
    Views
    8,804

    Re: What Makes a sellable photograph?

    Agreed, and this confirms my theory that Marcel Duchamp's "Fountain" is by far the most successful work of Art in history. Also one of the most appreciated...
  28. Replies
    18
    Views
    1,004

    Re: New Carleton Watkins Book

    It wasn't unusual for a good 19th century compass to have a level more than equal to today's spirit and bubble levels.
  29. Replies
    69
    Views
    8,804

    Re: What Makes a sellable photograph?

    "What makes a sellable photograph? "

    Umm, someone willing to buy it?
  30. Replies
    9
    Views
    492

    Re: Mystery Georz lens?

    You may have to remove the glass from the mount to see what the construction is. I'd guess a WA Dagor with the identifying markings gone, but who knows...
  31. Re: First Post! - How Do I Measure My Bellows Extension To Calculate Bellows Exposure

    Unless you're using telephoto lenses, the rear nodal point is around the aperture's location. If you want to find your rear nodal point, focus your 135mm lens at infinity, and measure 135mm forward...
  32. Re: Current sources for having a lens flange made?

    For anyone keeping track, Grimes has responded wit a quote of $150 for an aluminum flange, $285 for brass.

    Tempe won't quote a price without seeing the lens, even though I offered all...
  33. Re: Current sources for having a lens flange made?

    Thank you, Bob!
  34. Replies
    0
    Views
    135

    Layout of a Morrison Leukoscope lens?

    I recently purchased a No. 1 Morrison Leukoscope lens. It arrived hazy and dirty, but cleaned up quite nicely, with no flaws to the glass at all. :) I kept careful track of each cell as I...
  35. Current sources for having a lens flange made?

    I recently bought a rather large brass lens needing a flange, (a No. 1 Morrison Leukoscope). Big and heavy enough, and historically important enough that I figured I'd splurge on having a proper...
  36. Replies
    18
    Views
    1,004

    Re: New Carleton Watkins Book

    I've ordered the book in question, but it's en route so I don't know what it will have to say or show. But I found this image of Watkins' camp in my files from my own expeditions into the wilds of...
  37. Replies
    18
    Views
    1,004

    Re: New Carleton Watkins Book

    Considering the transportation issues, the need to set up a functional wet darkroom for every location, and the process itself, taking a minute or two to level whatever support was being used would...
  38. Replies
    13
    Views
    620

    Re: 450mm lens with 420mm bellows draw?

    No problem! Just shoot things that are a little beyond infinity...
  39. Re: Stress of Buying Lenses - Sight Unseen / Reputation

    Thank you for the kind words, Darr!

    Not to drift the thread too much, but I wonder how the price of an original 9-inch P&S VQ would compare to the price of the Cooke PS945. Did it drive the price...
  40. Replies
    23
    Views
    1,461

    Re: Is This Art?

    Pretty much anything anyone labels as art is art. Try thinking of something that absolutely cannot be art.

    But that nagging question remains... is it good art?
Results 1 to 40 of 6718
Page 1 of 168 1 2 3 4