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  1. #11
    grommi's Avatar
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    Thank you so far for the replies.

    It is not commonly known that f.e. fresnel screens do not show the real depth of field, it's shown always much bigger and on the final picture it is much smaller. Even a ground glass screen shows a bigger dof because of the "thickness" of the ground layer, but comes much closer to the final result. I have selfmade single element lens with a quite big aperture and many aberrations and was shocked how much smaller the real dof on the pics was compared to the fresnel screen image. Sometimes the screen makes a huge difference and the better screen on first sight might be the worse choice.

    After all, it could be the best solution to get a working Zenith B and pass on the mirror lock-up. The screen image is not so dark as on the early post-war cameras and it has a usable prism. And you have a weapon for self defense :-D

    To get an impression of what I'm talking about here's a "real" picture. Neither microprisms nor split images make any sense with such a lens.


    nighthawk at the diner by imagesfrugales, on Flickr
    Last edited by grommi; 12-26-2013 at 02:07 AM. Click to view previous post history.

  2. #12
    AgX
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    Quote Originally Posted by grommi View Post
    It is not commonly known that f.e. fresnel screens do not show the real depth of field, it's shown always much bigger and on the final picture it is much smaller. Even a ground glass screen shows a bigger dof because of the "thickness" of the ground layer, but comes much closer to the final result. I have selfmade single element lens with a quite big aperture and many aberrations and was shocked how much smaller the real dof on the pics was compared to the fresnel screen image. Sometimes the screen makes a huge difference and the better screen on first sight might be the worse choice.
    This is the first time ever I hear such about a fresnel screen.
    That screen, as the classic field lens, acts to bend the rays comíng from the rear of the taking lens through/from the ground glass to the eye of the photographer, by this yierlding even brightness over the whole ground glass.
    By they do not ad DOF.
    Due to the staggered construction of a fresnel lens such can add distortion and this added distortion may hamper focusing.

  3. #13
    Ricardo Miranda's Avatar
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    Search/ research Edixa and Exa cameras.
    My cameras:
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    Nikon F4, F4S, F401S, F601, F801, F801S, F50, F55, F60, F65, F70, F75, F80, F90, F90X, EL2, FE, FM, FG, FG-20, EM

  4. #14

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    Quote Originally Posted by winger View Post
    I have a Pentax H1a and never used to have a problem seeing the DOF preview. The only reason I do now (and not a big problem seeing it) is that I've been shooting 4x5 more and it's easier to see it there. Whatever screen it has is the least annoying screen I've used. I have a couple with split image ones and they drive me bonkers.
    But your Pentax lens has a manual/auto switch not all auto M42 lenses have one, the Fuji lens I use does not.
    When you stop down a split image spot goes black a microprism goes black so they are not compelling.
    There are three outers you can get clear glass which does not show any depth of field but is bright.
    Plain ground glass which will be real dark,
    and Frenel ground glass which is brighter these last two do show depth of field/focus.
    The OP needs to be careful what he asks for.
    A Zenith is an ok camera he may have to 'Stick'...

  5. #15

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    The OP is starting out with a very difficult set of requirments. With the price of film (and perhaps processing for color) and printing, the price of the camera quickly becomes a minor precentage of total outlay for for film photography.

    Therefore, it is logical to move to a system that has features that you absolutly cannot compromise on. For your needs, interchangable screens would seem to be a non negotiable requirement. For film systems that would put Nikon, either a F or F2 on top. There were several other systems with this feature available in the 1970's but the sheer number produced when current now makes Nikon the most available on the used market.

    Really, I can sympathize with your dislike of focusing aids. I too cannot abide them and use the 1-10 screen, matte with grid lines, for all my OM bodies. The OM-1 or OM-1n is another good choice with a brilliant viewfinder. The standard matte screens are the 1-4 and 1-10 (the 1-4 does not have grid lines). The cameras are fairly well available but accessories such a focusing screens somewhat less so.

    Unless you are absolutely already heavly invested in M42 lenses I fear the search will turn out to be a frustrating experience.

    I know you said do not recomend other systems and 'that you know what you want' but realistically just wanting something does not make it available, at least for the price you want to pay.
    Last edited by pen s; 12-26-2013 at 09:53 AM. Click to view previous post history.

  6. #16

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    Quote Originally Posted by pen s View Post
    ... The standard matte screens are the 1-4 and 1-10 (the 1-4 does not have grid lines). The cameras are fairly well available but accessories such a(sic as rare matt) focusing screens somewhat less so.
    And how cheap are Ming vases?

  7. #17

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    Quote Originally Posted by Xmas View Post
    And how cheap are Ming vases?
    Don't quite get the reference Xmas. My argument is sound and logical. The extra expense of a useable systen that has the specific requirments the OP desires will quickly fade into the background as ongoing film and printing costs are considered. Any M42 mount camera with a plain matte screen will be quite old. Will it work properly? What if you have to spend extra money to have it repaired? Early GG screens were very dim with dark corners. I suppose one could deliver a early 70's Spotmatic to a repair person to see if a adapted matte screen could be fitted but here again there is quite a lot of expense and such a modification must be done precisely to insure accurate focusing.

    I just don't know if there is any practical way to achive the OP's goals with a severly limited budget.

  8. #18

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    either of the plain ground glass OM screens in nice condition are a bit more expensive than one Zenith typically 4x Zenith = One off screen?

    They are sought after collectors.

    Film is cheap if you are existing on cast of bulk.

    Your logic is ignoring the OP's text.

  9. #19
    grommi's Avatar
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    Quote Originally Posted by pen s View Post
    ... but realistically just wanting something does not make it available, at least for the price you want to pay.
    That's a good point of course. I never thought I could need a system camera with exchangeable screens. But indeed my budget is very limited.

    Probably I should check some different models at the next camera fair. And I just watched through the Zenit B finder, it's dark but not too dark to be unusable and it's dof is much more accurate than the bright fresnel screens. The latter are great for many purposes but for some applications they are not the best, to put it mildly.

  10. #20
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    Just because some cameras say you cant switch screens doesnt mean you cant modify it to take it out and possibly put another in. In the past i have removed the newer lumibrite screen from a junk om40 body (which does not support swapping screens) and installed it into a om4t. People also used to take apart the focusing screen holders on the nikon system and sandwich a newer screen into an older holder. Many of the current dslr screens on prosumer cameras can be removed and swapped with a cut down screen as well for focusing aid. So if you are really dedicated to this m42 system then try cutting a similar screen of the same thickness and replacing the prism screen. All matte screens are common for micro/macro, and astrophotography. You can also try to make one with a piece if glass and scotch magic tape thats frosted. The glass needs to accommodate for the thickness of the tape to give you correct focus.

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