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Thread: Are all grain focusing tools created equal?

  1. #31

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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by bob carnie View Post
    for years 76-80 I did thousands of colour enlargements the focusing device was very tall with a mirror about halfway up that you could eyeball from a standing position.. made of plastic ... no complaints about sharpness.. I have not seen this unit again on the market...
    Attachment 169564
    I think this is what you refer to. It a Paterson Major Focus finder
    I have a major problem finding the grain in 4x5, 6x9 or 35mm film. But as I have virtually no sight in my left eye I'm sure it is me and not any of the finders I've tried..
    regards
    Tony

  2. #32
    bob carnie's Avatar
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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by tonyowen View Post
    Attachment 169564
    I think this is what you refer to. It a Paterson Major Focus finder
    I have a major problem finding the grain in 4x5, 6x9 or 35mm film. But as I have virtually no sight in my left eye I'm sure it is me and not any of the finders I've tried..
    regards
    Tony
    Hi Tony

    No this is not it , one would actually look at the mirror to focus , no need to bring your eye to the unit.

    Bob

  3. #33

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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by Ted R View Post
    Thank you, however I beg to differ, my understanding is that the illuminated negative is the object, located in front of the lens, and the projection onto the paper is the image, located behind the lens. Thus depth of focus applies to the projected image.
    Normal practice is too focus wide open and, after focusing, stop the lens down to optimal aperture.
    This would change the depth of field in front of the lens as you stop down but you could not focus critically wide open if you were changing the depth of focus. The film must lie within the depth of focus.

  4. #34
    Jon Shiu's Avatar
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    Re: Are all grain focusing tools created equal?

    For focusers with adjustable eyepiece and line, circle or other reference, your eye must be the same distance from the eyepiece when focusing as when you calibrated it. I guess that's obvious, though.

    For the ground glass type of focuser your eye can be whatever is comfortable distance and it doesn't matter.
    my black and white photos of the Mendocino Coast: www.jonshiu.com

  5. #35

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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by Bob Salomon View Post
    Normal practice is too focus wide open and, after focusing, stop the lens down to optimal aperture.
    This would change the depth of field in front of the lens as you stop down but you could not focus critically wide open if you were changing the depth of focus. The film must lie within the depth of focus.
    No, the film lies within the depth of field not the depth of focus. The negative is the object and depth of field applies to the object space not the image space.

  6. #36
    Jac@stafford.net's Avatar
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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by Ted R View Post
    No, the film lies within the depth of field not the depth of focus. The negative is the object and depth of field applies to the object space not the image space.
    Cat fight!

  7. #37

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    Re: Are all grain focusing tools created equal?

    Does the efficiency of a grain focussing device depend upon the viewer’s eyesight?
    I’m sure that ‘years ago’ I was able to use grain focusers. But It seems I cannot longer ‘see the grain’ on any negative although I can determine if the image is sharp on the enlarger’s baseboard.
    I’ve recently tried three different Paterson focus finders using 4x5, 6x9, 6x6 and 35mm roll and sheet negative film [B&W and colour] and two different enlarger lenses – all trials of which failed to show any grain or even light/dark ‘shadows/shades’ from the negatives.
    All finders were focused to my eye and the finders were situated in line with the enlarger’s optical axes.
    I’ve almost no sight in one eye [but have full peripheral vision], I’m 77, and normally wear glasses.
    Regards
    Tony

  8. #38

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    Re: Are all grain focusing tools created equal?

    Quote Originally Posted by bob carnie View Post
    for years 76-80 I did thousands of colour enlargements the focusing device was very tall with a mirror about halfway up that you could eyeball from a standing position.. made of plastic ... no complaints about sharpness.. I have not seen this unit again on the market...
    I'm thinking you are remembering the Mitchell... Tall, almost flesh colored, no base, but with a point that touches the image plane, and and the viewing lens almost looks like it came out of a 35mm slide viewer???

    I have one somewhere that I use for poster sized prints...

    Steve K

  9. #39

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    Re: Are all grain focusing tools created equal?

    It was also sold by UNICOLOR.

  10. #40

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    Re: Are all grain focusing tools created equal?

    Unless I missed something, no one has mentioned one other worthy device, albeit not as able to use corner-to-corner as the ones with the big, rectangular mirrors. It is the Bestwell Microsight, which I have used for decades and, just discovered, is still being made. I contacted them two days ago, after having acquired another. sheerly by chance, in perfect shape other than a very dusty mirror. I contacted the company about cleaning it, and was surprised at the reply: "a bit of glass cleaner and a lens cloth"! I tried it with a microfiber cloth, extremely gently -- it worked, so I even did it on my veteran one, which has always been capped when not in use, but over 40+years, it gained a little dust.
    I can't recommend this same treatment for every product; the Bestwell uses what they call a microdot mirror. It certainly appears to be a front-surface mirror. Anyway, I just thought I'd pass it on.
    Ulophot

    Sine scientia ars nihil est.

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