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  1. #21
    TheFlyingCamera's Avatar
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    It will illuminate 12x20 at f9. Cover adequately, that's a different question. The diagonal of the 16x16 is about the same as the 12x20 diagonal, so if it does cover 12x20, it will cover 16x16 as well. But I think you'd be pushing it for adequate sharpness in the corners wide open. Stop down to f22 or f32 and you'll be good to go, though.

  2. #22
    Dr Croubie's Avatar
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    Meanwhile, just as an addendum to this, I got myself a 150mm G-Claron the other day for a bargain (well, the elements, but I had a few spare shutters lying around).
    It just just just almost covers 8x10 at smallest aperture (I haven't measured yet for a new scale so don't know what f/ number yet).
    I can see daylight through the corners of the GG, but not the full aperture. It's actually only mechanical vignetting at that point, I reckon it'd cover fully if I ground off the front filter ring back to the glass (but don't worry, I'm not about to).
    But of course, 'cover' and 'sharp' are two different words.
    I bought it primarily for 6x17s, so I don't mind that it doesn't cover 8x10, but Im still going to try it on my 4x10 now that I've cut a darkslide in half.

    So if 150mm covers (I'm guessing roughly) 280-300mm, instead of their claimed 189mm, then (theoretically, assuming AoV doesn't change like Apo-Ronars do) a 355mm might cover 650-700mm.
    That's well enough to cover 12x16" (500mm) with movements, 12x20" (600mm) should work stopped down, if you're lucky you might get 16x20" (650mm) out of it (maybe with slightly vignetting and/or soft corners).
    An awful lot of electrons were terribly inconvenienced in the making of this post.

    f/64 and be there.

  3. #23
    LJH
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    There are many reports of this covering 12x20.

    Also on LFPF.

    Dr,

    Have you tried the 150mm as a convertible? All of my G Clarons work well san their front element.

  4. #24

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    Quote Originally Posted by Dr Croubie View Post
    Depends which way you crop (because 14x17 isn't the same ratio as the 2x3 of 35mm).
    (I've done this quickly so someone might want to check my maths)
    17x14" is 431x355mm.
    Crop to 431x287 to get 3x2 aspect
    Then 355*36/431 = 29.6mm.
    at f/9 that also works out to a 35mm DOF of 29.6mm f/0.75 (I'd be stopping down to at least 355mm f/64 to get a semi-reasonable 29mm f/5.4 in 35mm-equiv)

    I'm also interested in G-Clarons for my 12x20 project, but I probably can't afford one (I'll just stick with pinholes for now)
    I wonder what 12x20 pinhole exposure would be like...

  5. #25

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    What do you ULF shooters use for film?

  6. #26

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    Quote Originally Posted by Dr Croubie View Post
    So if 150mm covers (I'm guessing roughly) 280-300mm, instead of their claimed 189mm, then (theoretically, assuming AoV doesn't change like Apo-Ronars do) a 355mm might cover 650-700mm.
    That's well enough to cover 12x16" (500mm) with movements, 12x20" (600mm) should work stopped down, if you're lucky you might get 16x20" (650mm) out of it (maybe with slightly vignetting and/or soft corners).
    Eh? Wot? Schneider claims 64 degrees for the 150/9 plasmat type G-Claron. A 150 that covers 280 - 300 mm at infinity cover 86 - 90 degrees. That's a considerable stretch. Considerable. Why do you believe its possible?

    What to you mean by "AoV doesn't change like Apo-Ronars do?" Fixed focal length lenses don't change angle of view as focused distance changes. Why do you believe they do?

    LJM, the threads you reference aren't that convincing. But I have to admit that some mention simply contact printing, which needs much less image quality than enlarging does. So perhaps with the right subject -- no fine detail towards the edges -- and contact printing ...

  7. #27
    LJH
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    Quote Originally Posted by scheimfluger_77 View Post
    What do you ULF shooters use for film?
    Film.

  8. #28
    LJH
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    Quote Originally Posted by Dan Fromm View Post

    LJH, the threads you reference aren't that convincing. But I have to admit that some mention simply contact printing, which needs much less image quality than enlarging does. So perhaps with the right subject -- no fine detail towards the edges -- and contact printing ...
    Aside from Clyde Butcher, I don't know of anyone enlarging 12x20. Not saying that they're not out there, I just don't know of any. So, anything I refer to in this realm is contact printed.

    I've got the 355mm G Claron on my 7x17 and can't run out of image. Not the the Korona has huge movements. However, once I get around to finishing my DIY 7x17, I'll try it on that. It has a couple more inches of rise.

    I can say, though, that the images that it makes are breathtakingly sharp. I am constantly amazed at the detail. On the attached image, I can pick up blades of grass on the rear group of rocks. Amazing.

    Click image for larger version. 

Name:	7x17 Woolamai Grass.jpg 
Views:	24 
Size:	375.1 KB 
ID:	97755

  9. #29
    Dr Croubie's Avatar
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    Quote Originally Posted by LJH View Post
    Have you tried the 150mm as a convertible? All of my G Clarons work well san their front element.
    Nope, but it looks like I'm going to have to try that too. I'm presuming that they're totally symmetrical, so the focal length doubles?

    Quote Originally Posted by scheimfluger_77 View Post
    I wonder what 12x20 pinhole exposure would be like...
    I haven't built the 12x20 pinhole camera yet, but seeing as I'm officially unemployed as of yesterday that's a project I'll do soon. I've taken 11x14" paper negs with 200mm f/330 pinholes, vignettes a bit in the corners so I'm going to make a 4-500mm one next time.
    One thing I can definitely tell you is that my scanner ain't big enough. Maybe I'll set up my lightbox and snap some shots with my dslr to share on the internets one day.

    Quote Originally Posted by Dan Fromm View Post
    Eh? Wot? Schneider claims 64 degrees for the 150/9 plasmat type G-Claron. A 150 that covers 280 - 300 mm at infinity cover 86 - 90 degrees. That's a considerable stretch. Considerable. Why do you believe its possible?
    Well, all I can say is that I looked through the clipped-corners of my 8x10 GG and I can see the front filter ring through the aperture, at min aperture. If I dremeled that off it'd probably cover 8x10 (which I'm not going to try), as it is you'd at least get 7x9".
    But when I say cover, it may illuminate it and just be mush. So there's only one way to find out what it looks like, I'm going-a-shooting on the weekend by the looks.

    Quote Originally Posted by Dan Fromm View Post
    What to you mean by "AoV doesn't change like Apo-Ronars do?" Fixed focal length lenses don't change angle of view as focused distance changes. Why do you believe they do?
    Sorry, I wasn't clear enough. Shorter Apo-Ronars (according to datasheets) cover 48 degrees, in the very longer lengths they only cover 40 degrees.
    So what I meant was, if a 150mm G-Claron covers just under double its focal length, then if the angle-of-view stays constant for each length and doesn't narrow as the focal length gets longer, then a 355mm G-Claron might be expected to cover just under 700mm.
    (Again, cover means illuminate, no prerequisite to look good doing it).
    An awful lot of electrons were terribly inconvenienced in the making of this post.

    f/64 and be there.

  10. #30
    Dr Croubie's Avatar
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    Quote Originally Posted by LJH View Post
    Amazing.
    Damn straight. Where's this? And where you at? I'm going to want to see this in person one day...

    edit, just saw that it says Woolamai. Thought it looked familiar, I was down that way a bit over a year ago. Pity I didn't have my LF with me (only 645). at the time.
    An awful lot of electrons were terribly inconvenienced in the making of this post.

    f/64 and be there.

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