10-09-2011, 03:57 PM
[quote name='Vieux loup' timestamp='1318173586' post='12241']
My wording probably was not great if it insinuates that you had not read the article. Far from me think that <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
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<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />
Which is why I started my reply in a general rather than directed at you <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='
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This has everything to do with the fact that tolerances for digital need to be much, much tighter than for film. Film is quite forgiving, because the emulsion has a thickness, or depth if you like, which provides quite a bit of leeway. After all 0.2 mm emulsion thickness is 2/3 of the FF CoC, and 100% of the APS-C CoC. A sensor doesn't have this leeway, at a capture thickness or depth of 0 (zero). Furthermore, ever increasing megapixels make this even more acute, let alone all the pixel peeping <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.
I don't think the material itself has to be stiffer at the same thickness or in all directions. After all, carbon isn't along all of its axes. As long as the optical path up to and including lens, sensor, and maybe VF stay the same at all times, we're done. This can be achieved with certain plastics, even if that means thickening walls to a much larger degree than metal. It won't add a lot at all to the weight or cost if you ask me <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. Of course, I could be wrong here. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />
Kind regards, Wim
My wording probably was not great if it insinuates that you had not read the article. Far from me think that <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />[/quote]<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />Which is why I started my reply in a general rather than directed at you <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />Quote:I just wanted to draw the attention to the necessity of getting lenses adjusted WITH the body they are intended to be used with, which nobody thus far had brought forward.
This has everything to do with the fact that tolerances for digital need to be much, much tighter than for film. Film is quite forgiving, because the emulsion has a thickness, or depth if you like, which provides quite a bit of leeway. After all 0.2 mm emulsion thickness is 2/3 of the FF CoC, and 100% of the APS-C CoC. A sensor doesn't have this leeway, at a capture thickness or depth of 0 (zero). Furthermore, ever increasing megapixels make this even more acute, let alone all the pixel peeping <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.Quote:However, I disagree with you on the "engineered plastics" issue. In theory, of course it is possible to design a camera body with synthetic material that is far stiffer than steel. However price considerations do that that is not done and I have never seen any reference for instance to the use of hight quality carbon being used. If you have other info, I'd be delighted to learn about it. I still believe there is a reason why the pro bodies of Canon and Nikon have metal structure!
I don't think the material itself has to be stiffer at the same thickness or in all directions. After all, carbon isn't along all of its axes. As long as the optical path up to and including lens, sensor, and maybe VF stay the same at all times, we're done. This can be achieved with certain plastics, even if that means thickening walls to a much larger degree than metal. It won't add a lot at all to the weight or cost if you ask me <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. Of course, I could be wrong here. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....