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  1. #11
    gma
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    Maybe you need finer ground glass than the old glass you are using. It is very easy to grind glass for a new screen. Use two pieces of glass precut to size and put a small amount of fine corborundum grinding compound ( for automotive valve grinding ) on one of the sheets. Press the two pieces together and move in a circular motion applying even pressure all over the surface. You can check the progress by washing and drying the glass. You will see exactly where you need more work. When finished you will have two new screens. I saw this on another website. It works great.

    You can also use a piece of "Lexan" polycarbonate plastic. You can achieve a fine texture with #320 or #400 sandpaper and/or auto finish rubbing compound.

  2. #12

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    Try vaseline ...

    Quote Originally Posted by bmac
    ... main thing I am looking for is a clearer (not necessarily brighter) view when I stop the lens down ...
    I've had the same problems on occasions, particularly in low light. Did a bit of investigation and Prof Leslie Stroebel suggests that at high magnifications (most esp in low light) the surface of the ground glass can interfere with focusing the image.
    He suggests 1. using a lower mag loupe i.e 4x rather than 8x
    and 2. try a small smear of vaseline on the critical spots for focusing on the ground glass.
    Must say, I haven't tried the 2nd suggestion yet myself (still trying to get someone else to buy a pot ) but using a lower mag loupe definately helped.

  3. #13
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    The Toyo I use is a 3.6, so I dont think magnification is the problem. I think it is a combination of my poor night vision (low light) and my cruddy groundglass. I can't do much about my night vision, but I have ordered an acid etched ground glass to see if that makes much of a difference. Maybe we need to invent the autofocus 8x10
    hi!

  4. #14
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    Have a look at www.largeformatphotography.info/gg.html

    I have a screen made by a US company called Brightscreen (www.brightscreen.com) I'd say that I gained a stop on the original Linhof two part ground glass and fresnel, but the image is "coarser" and the frensel is part of the screen, not a removable addition. On balance, it is an improvement, but not as much as I had hoped.

    Do you already use a fresnel, or are you using just a plain GG ? A fresnel lens will spread light across the viewing screen more evenly, making the image appear brighter. Beatie sell these as seperate items and they are relatively cheap (compared with the actual Beatie screens). Would that solve your problem ?

  5. #15

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    I got a Beattie screen for my 4x5 Toyo Field, and decided it just didn't work for me. With my Nikkor 75/4.5 it was impossible to see the entire frame at once; I had to move my head around and try to mentally piece together what I was seeing. While I prefer a bellows hood in the field, I like to use a reflex hood sometimes, and it won't allow seeing more than the central area. It worked very well on 150 and up though, but so much of my shooting is wide angle that it just wasn't usable to me. Oh well.

  6. #16
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    Hi Brian

    You can improve your night vision take vitamin A and D or only A and it will improve!
    But it can take at least 2-3 weeks till it gets better!
    Maybe it helps more then a new screen!

  7. #17

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    Quote Originally Posted by gma
    Does anyone else ever wipe the ground surface of the glass with a very thin coating of WD-40. It makes the image a lot brighter.
    Does this really work? Which surface are you wiping, the lens side?

  8. #18

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    I've thought about trying the Velveteen screen, but the manufacturer has quit making them "temporarily". Has anyone else used this product?

  9. #19
    gma
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    Matt,

    WD-40 on the ground glass side very, very thinly applied with a cotton ball will give some gain in brightness. I haven't seen that it changes the plane of focus at all.

    gma

  10. #20
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    Quote Originally Posted by Jan Brittenson
    I got a Beattie screen for my 4x5 Toyo Field, and decided it just didn't work for me. With my Nikkor 75/4.5 it was impossible to see the entire frame at once; I had to move my head around and try to mentally piece together what I was seeing. While I prefer a bellows hood in the field, I like to use a reflex hood sometimes, and it won't allow seeing more than the central area. It worked very well on 150 and up though, but so much of my shooting is wide angle that it just wasn't usable to me. Oh well.
    The bad thing about fresnel screens is they have to be matched to the focal length of the cameras lens to get a good full frame view. If you wanted to go crazy with the situation you could get a separate focusing back for your shorter focal lengths with a matched screen mounted on it.
    Gary Beasley

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