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    Interview About Making Dry Plates

    A week or so ago, Graham of Homemade Camera Podcast had me on his show to talk dry plate making.

    http://homemadecamera.com/e70-jason-lane-and-chromatic-abberation/
  2. Re: Extremely Dumb Questions about Lens Systems (Specially Cooke triplet)

    It is correct: a super non-technical variant of the most generic “inverse of optical power” definition for the benefit of the OP while tying it in to his other q’s. “It is a design value” is key. ...
  3. Re: Extremely Dumb Questions about Lens Systems (Specially Cooke triplet)

    1) focal length is how far from the film the lens has to be held to produce an image that’s in focus. It is a design value, and indicates how wide a view the lens projects onto the film.
    2) field...
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    Re: New starter from Australia

    Welcome aboard! From someone who is also a veteran of sleepless astrophotography nights.
  5. Re: A DIY 123mm f/8 Cooke split triplet for 4x5

    I’m going to use that in a meeting in the near future
  6. Re: A DIY 177mm f/8 Cooke triplet for 4x5 from off-the shelf lenses that YOU can bui

    You can get it to work, but it won’t be a rapid rectilinear as off the shelf achromat are the wrong lens shape to correct spherical. You will be able to correct distortion, lateral color and, with...
  7. Re: Making Lenses With Shorter Focal Length from Cheaper Materials

    I think my advice was good luck. I have not seen 3D printed lenses implemented in the professional optical design world. I have seen attempts — funded research and simple prototypes — but attempts...
  8. Re: A DIY 123mm f/8 Cooke split triplet for 4x5

    Dan that made me chuckle. For future reference, GOTS = government off the shelf GFE = government funded equipment.

    Thorlabs has a very few…all the wrong shape for minimizing spherical...
  9. Re: A DIY 123mm f/8 Cooke split triplet for 4x5

    Dan I looked at COTS lens designs which would need meniscus lenses. Meniscus COTS lenses are rare and the right set that would be needed don’t exist unless something has changed in the past 2-3...
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    Re: Pencil of Rays

    Just to be clear I’m not a mathematician :) , I’m a lens designer. I design optics that are built (the initial prototypes by me) and used in imaging and laser systems and which do what they’re...
  11. Re: A DIY 123mm f/8 Cooke split triplet for 4x5

    Nice work. The 0.1mm airgap between the two front lenses is tight. Can you reverse the order of those two front positives and pull them apart slightly?
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    Re: Pencil of Rays

    A good site. Very basic, but he knows optics and more importantly looks like he has a “feel” for how they work.
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    Re: 6 1/2 x 8 1/2 cameras?

    No problem and good luck! Whole plate format is a great format. The aspect ratio is really nice.
  14. Re: Which would be easier to build - 8x10 SLR or TLR?

    Fine fine. :) But a roof prism for it would be glorious
  15. Re: Which would be easier to build - 8x10 SLR or TLR?

    The cost of the 13” diagonal roof prism required to cover 8” x 10” would feed my teenagers McDonald’s cheeseburgers and fries every day for approximately 25 years.
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    Re: 6 1/2 x 8 1/2 cameras?

    You read the length measurement wrong. I’m showing the bottom of the holder, so length from rib to end is 232mm. What you thought is the rib is actually a spring-loaded wood strip inside the holder...
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    Re: 6 1/2 x 8 1/2 cameras?

    What you need are antique Premo Camera plate holders, with a film sheath adapter to shoot film. I can spare one to get you started, though I don’t think I have an insert to load film in it.
    ...
  18. Re: turner-reich 12" convertable antastigmat fungus removal

    The “flower” looks like a speck of dust was trapped in the balsam layer when first cemented, causing separation over time. Balsam separation and oxidation at the edge.
  19. Re: turner-reich 12" convertable antastigmat fungus removal

    Knowing that lens it’s likely balsam. They almost universally suffer from it. If you post a good picture I can tell you pretty quick.
  20. Re: turner-reich 12" convertable antastigmat fungus removal

    Absolutely not! That is not a threaded retaining ring at all. The “threads” are stray light reducing baffle cuts. The barrel is one solid piece of brass.

    An internal centering ring sits...
  21. Re: turner-reich 12" convertable antastigmat fungus removal

    Turner Reich Anastigmats are 10 elements in 2 groups. Kind of like a Dagor, but two additional pieces of glass bonded on to get around the Dagor design patent and still provide similar level of...
  22. Re: What is the Most Difficult Large Format Photography

    LF DSO or planetary astrophotography is ludicrously impossible enough that — with no exceptions I can think of — only large, professional observatories could accomplish it.
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    Re: orthochromatic film?

    I would use them professionally without question, if they had what I needed. They often don’t (as you may guess), so other sources of a wider variety of stock and custom windows/filters are Rainbow...
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    Re: orthochromatic film?

    TBH if I wanted to accurately replicate ortho look with panchromatic film, I wouldn’t limit myself to photo filters. I would look somewhere like Edmund Optics or Thorlabs which has a wider...
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    Re: orthochromatic film?

    Of course, if you want the look of plates, then you can just shoot plates.
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    Re: orthochromatic film?

    Doremus, I think what you’re missing, and perhaps what Jim has in mind, is that the response of classic Orthochromatic film continues down in to the ultraviolet. Modern panchromatic film has been...
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    Re: Reusing Film and Glass Plate

    Hey Randy,

    If you reuse it yourself, you can run it through the dishwasher at the toughest setting to clean. If you process C-41, run the plates/film through the bleach or blix to remove the...
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    Re: 6 1/2 x 8 1/2 cameras?

    tdicorcia, what width WP holder does your camera back require? If you measure, I can check my collection which has a variety of different widths.
  29. Re: Equivalent of Massive Dev Chart for Paper Developers ?

    I followed the recommendations in the boxes of paper until I realized they all say about 1-2 minutes in whatever developer. So now I just develop for 1-2 minutes (specific time depending on how...
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    Re: 6 1/2 x 8 1/2 cameras?

    Whole plate is my favorite format, so whole plate format dry plates will always be available. I’ve been bugging Steve Lloyd at Chroma Camera to produce a WP format camera .. I think it would garner...
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    Re: Lens Cleaner

    Not IMO, but the old Navy optician I used to work with preferred Dawn. I just cleaned a telescope primary mirror last weekend with 15 years of accumulated pollen, dust, etc from being regularly...
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    Re: Lens Cleaner

    Anything will abrade a glass surface if you apply pressure. The key is not to apply pressure, and it’s a technique to learn. Kimwipes are almost universally used in shops when needed, as they are a...
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    Re: Kodak Dry Plates

    Drew I’d suggest starting at ISO 12 and bracket +/- 1 stop as initial test. Since they’re ortho you can develop them under a safelight...don’t pull them until they look too dark in the developing...
  34. Re: Please help ID this 4 x 5 Holder/Adapter

    Definitely DeJur...I own one and have a sst of these for a bunch of different sized negatives. It’s a two-piece holder, which allows me to make enlargements from my dry plates since it accommodates...
  35. Re: What kind of lens bends an image without distortion?

    They do if you mount it at the end of a stick, or “precision aligned opto-mechanical structure” as it’s called in engineering terms.

    Btw assumptions and preconceived notions are the enemy of...
  36. Re: What kind of lens bends an image without distortion?

    A scanning mirror (adjustable orientation first surface mirror) is the simplest optical device to accomplish this. Since you are forming an image with a camera, the negative or digital image can be...
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    Re: Lens Design for Special Purposes

    You are essentially setting up a projector for a closer screen. Think overhead projector, slide projector, etc.

    You just need to readjust distance of your lens from the source (commonly called...
  38. Re: 8x10 Photography Compared to 4x5 Photography?

    8x10 is nice to shoot for contact prints, and the subjects for portraits I’ve shot at 8x10 seem to enjoy the experience better. Since I typically shoot dry plates I made, cost doesn’t factor in too...
  39. Re: Is it possible to practice the art of "seeing"?

    Yes, always. I’ve envisioned far more photographs than I’ve taken.
  40. Re: Lane Dry Plates: What is a practical ISO rating?

    If it’s from the same box then I’d check for problems elsewhere: Lens settings, developer exhaustion, etc. The plates are very consistent. Metering thru the filter would address UV variations. ...
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