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Thread: Help with Speed Graphic ground glass/fresnel

  1. #11
    Jon Shiu's Avatar
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    Re: Help with Speed Graphic ground glass/fresnel

    Yes, I have a stock Tachihara combo screen. Their instructions do not make sense to me.

    I would go back to your original fresnel screen and ground glass parts, or source new old stock replacements.
    my black and white photos of the Mendocino Coast: jonshiu.zenfolio.com

  2. #12

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    Re: Help with Speed Graphic ground glass/fresnel

    Quote Originally Posted by Jon Shiu View Post
    Yes, I have a stock Tachihara combo screen. Their instructions do not make sense to me.

    I would go back to your original fresnel screen and ground glass parts, or source new old stock replacements.
    Yeah, that’s what I’m gonna do.
    Thank you for your help.

  3. #13

    Join Date
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    Re: Help with Speed Graphic ground glass/fresnel

    Ebay seller "photofinder" , Stephen Shuart, AKA "The Rev" knows just what you need to set up your camera, with or without Fresnel. I never liked the Fresnel in my Graphics because I frequently use very wide lenses like 65 and 58 and much prefer the plain ground glass. If you remove the Fresnel, thin spacer strips have to be placed on top of the ground glass to move it forward. Turns out, the thickness I determined for the spacers (I think around .0300, and much thinner than the Fresnel) is the same as a grey plastic material sold in big hobby shops for model railroad use. This modification is only a sure thing for the original Graphic ground glass. It will not work work for a ground glass of different thickness. I think Shuart has a thicker, "drop in" ground glass that needs no spacers.

  4. #14

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    Re: Help with Speed Graphic ground glass/fresnel

    Neal, the ground glass' thickness is irrelevant. The image is formed on the ground surface, which should face the lens.

    Tbhe OP is somewhat cooked. Graflok backs made by Graflex Inc. for Graphic cameras' ground glasses sit on bosses on the focusing panel casting. Graflex Inc. intended their fresnels to sit between the GG and the lens. Graflok backs' focusing panels made by Graflex Inc. for Graphic cameras and intended to be used with Graflex' own fresnels have lower bosses than focusing panels made to be used without a fresnel.

    There's no guarantee that any fresnel or fresnel-GG sandwich made by a third party will be the right thickness to work properly in a focusing panel made by Graflex Inc.

    The OP's best option is to toss his $100 mistake -- or return it for a refund if possible -- and get a new GG the right size and use it with the fresnel he removed from his focusing panel.

  5. #15

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    Re: Help with Speed Graphic ground glass/fresnel

    Here is what you want.
    https://www.ebay.com/itm/4x5-Graflok...YAAOSw65FXqitK
    Beg to disagree Dan. The ground surface of the glass needs to be on the same plane as the surface of the film in the film holder when the film holder is in place. This can be determined by measurement with a dial gauge. The thickness of the ground glass does make a difference if the Fresnel is to be removed. You are correct that on Graphic backs designed for use without Fresnel have different dimensions.

  6. #16

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    Re: Help with Speed Graphic ground glass/fresnel

    In cameras where the Fresnel is in front of the ground glass, between the ground glass and the lens, the Fresnel, which is a lens, affects the focus on the ground glass, effectively moving the focusing surface forward. If in cameras where the Fresnel is behind the ground glass, but in the frame, then removing it will could throw focus on the film off depending on the design. On Linhofs, the ground side of the glass is always held in the correct plane, regardless of its thickness, and a Fresnel if used is mounted on top from behind. On cameras with frames like Deardorff, the ground glass is mounted in the frame from behind and the ground surface is always on the correct plane regardless of glass thickness. A Fresnel, if used has to go on top like in the Linhof.

  7. #17

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    Re: Help with Speed Graphic ground glass/fresnel

    Neal, you are writing from general principles, not from Graflex Inc.'s practice. Please read the manuals.

  8. #18

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    Re: Help with Speed Graphic ground glass/fresnel

    Yeah, I was cooked, but I did get a new ground glass and returned to my old setup.
    It’s all back in working order.
    I had absolutely no idea what I was buying, since the post was very misleading, but had good reviews.
    Anyway, thanks for putting the record straight.
    Have a nice day

  9. #19

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    Re: Help with Speed Graphic ground glass/fresnel

    Hi Neal
    Thank you for your help and input.
    I got a ground glass and am now back to my old setup, it’s not perfect or the brightest, but it works and I’m happy about that. I should have bought a new ground glass from the beginning, but I pulled the trigger on a very misleading eBay ad and that was a mistake.
    I’m happy where I am and will keep it as it is

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