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  1. #21
    Toffle's Avatar
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    Quote Originally Posted by Andrew Moxom View Post
    ...I see Chamonix doing absolutely nothing about this. Unless they give people spare fresnels as they get scratched from being on the back in harms way!!! The fact is, they have a turd and want us to polish it! I hate to think what this will do for their resale value!!
    Indeed... the whole issue gets a big WTF??? from me. I'm not even a Chamonix customer and this has me ticked off. This should be fixed... and pronto. The cost of fixing a problem like this should be seen as an investment in customer relations and future sales.
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

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  2. #22
    wildbill's Avatar
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    Quote Originally Posted by Andrew Moxom View Post
    Vinny, I might try that...... Or see how much it would cost to get the thing modified to work as it should!! I see Chamonix doing absolutely nothing about this. Unless they give people spare fresnels as they get scratched from being on the back in harms way!!! The fact is, they have a turd and want us to polish it! I hate to think what this will do for their resale value!!
    I almost installed mine on the outside this afternoon then I realized (as you did) that it'll get scratched to hell. I'll stick with the staples version for $8.

    This situation is similar to the problem with Chamonix's bubble levels. They have said to have new ones which are better (don't leak out) and actually accurate but they aren't recalling the bad ones. I've replaced mine twice and asked for the new ones but no luck yet. It's impossible to line all three levels up on my camera back.

    As for the turd polish, if word gets out that that turd polish will fix this issue, the price is going to go up!
    www.vinnywalsh.com

    I know what I want but I just don't know how to go about gettin' it.-Hendrix

  3. #23

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  4. #24
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    Quote Originally Posted by Andrew Moxom View Post
    The fact is, they have a turd and want us to polish it!
    This reminds me of one of the Fundamental Laws of Sh*t: "you can't polish sh*t... unless it's really old."

    The other Fundamental Laws that I recall are: sh*t rolls down hill; and, you can't throw sh*t without getting some on yourself.

    I think there are seven more but alas I do not recall them.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  5. #25

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    Geez,

    And you guys think the LF forum is vitriolic. O.K. maybe curmudgeon Dan gets cranked up...

    I posted this over on LF and thought it mght be appropriate here.

    Keith, look me up when you're down CNMS way.

    Cheers, Steve

    "I think I understand the technical issues now. The confusion in the thread seems to exist because people are talking about several different things at once, technical and economic (support) issues.

    The solutions seem to be:

    What can the user do?

    1) Remove the fresnel. The GG is in the proper place.

    Drawbacks: the image is now quite a bit darker.

    2) Remove the Chamonix GG and Chamonix fresnel, and install an aftermarket fresnel IN PLACE OF THE GG (not the Chamonix fresnel) that has a "frosted" side facing the lens, so that the image-forming surface is in the same place as the Chamonix GG. Then install a cover glass to protect the fresnel. The fresnel is now effectively BEHIND the GG and the image-forming surface is in the same (correct) place. This is the "Ebony" or "Maxwell" option referenced on the Chamonix website.

    Drawbacks: You pay unless Chamonix does.

    3) Have someone re-mill the GG frame to work with the existing fresnel.

    Drawback #1: Shipping and wait if you have Chamonix, Ritter, etc do it, cost if Chamonix doesn't do it gratus.

    Drawback #2: If the back is re-milled to relocate the GG, it will no longer work with a plain GG or with the Ebony/Maxwell option mentioned above, and may not work with any other fresnel of a different power.

    Note: Personally I would not modify the back to be non-standard and to work only with a fresnel of unknown characteristics.

    So you just have to pick which one you want.

    Unless Chamonix picks up the tab, you're going to get darker on the screen or lighter in the wallet if you want accurate focus under all conditions.

    I'm not sure what Chamonix does at this point. They're sort of, well, screwed, but they did it to themselves. I'd probably offer what Mike suggested, send us the frame/camera and we'll fix it and pay shipping. I don't think they can send out "fix it" kits since many of the cameras have been re-sold so they wouldn't know who really has one, or for that matter, if all the cameras have the same problem given the QA/QC. As a business entity, Chamonix clearly needs to make the quality assurance/quality control a little more balanced with the apparently superb craftsmanship they exhibit.

    Cheers, Steve"

  6. #26
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    On a Linhof Technika, the fresnel is to be placed on the rear after the ground glass, so lens focus directly on GG. Grooved side of fresnel towards GG. The fresel is retained by help of a spring loaded clip in each end of GG length. Fresnel is convenient for eye focusing and needed when making light-metering direct on GG (according to owners manual). For this measurement, set meter f to 1.0 and set lens f to recording setting. Make measurement for exposuretime.

    I suggest you check depth of film holder to distance of GG from film holder face with a caliper, and then try to rearange fresnel, f.x. turn it so opposite face faces GG or, if possible set it on outside GG.

    Regards, Morten
    I have an photographic memory,
    only - I'm out of film......!

  7. #27

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    The more I have thought about this, the more naïve I feel about understanding the optics of Fresnels. I likely was incorrect in my prior post. I assume that if the Fresnel is on the inside of the ground glass as with the Chamonix, that the plane of focus on the Fresnel/ground glass combination is different than the plane of focus on the film. If so, is the difference between the two identical to the thickness of the Fresnel? If this is the case, it should be easy to measure the thickness of the Fresnel and then calculate the effect for different focal length lenses focused at different distances and at different apertures. If the focusing problem only relates to the thickness of the Fresnel, then one solution would be to adjust the distance between the lens and the film plane by that amount.

    On the other hand, I am not sure that the problem is that simple. Does the image, in fact, focus precisely on the front surface of the Fresnel or at some place within the grooves or perhaps on the back surface of the Fresnel, which would be the same as the surface of the ground glass? Does it matter if the grooves are facing away from the glass or pressed against the glass? Does the fact that the Fresnel, itself, acts like a lens effect the position of the plane of focus by creating an aerial image and if so where is that located and how is it different than the plane of focus of the film?

    To summarize, am I correct in assuming that the image focused with the Fresnel is in front of the film plane by an amount identical to the thickness of the Fresnel or is there more at work here?

  8. #28
    Andrew Moxom's Avatar
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    Its not about the thickness of the fresnel but more about the light transmission/lens effect of the fresnel. The focus/film plane is checked at the factory with the GG installed. Then the fresnel is installed in front of the GG, shifting the focus by a small amount. The amount of focus shift varies based upon the focal length of lens being used and is not a constant amount regardless of focal lengths used. The constant is the GG internal surface which translates to the same as the film plane.
    Please check out my website www.amoxomphotography.com and APUG Portfolio .....

  9. #29
    Ian Grant's Avatar
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    Stick the fresnel behind the GG, which is what I did with my Crown Graphic. Get an acetate cover sheet (used for reports etc) from Staples & cut to size if you want to protect the fresnel.

    Ian

  10. #30

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    I hope this doesn't offend anyone who has one of these but I expect used cost of this model Chamonix to be affected. I'll just buy a used one at a good price and replace the defective GG/fresnel.

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