brian_hirschfeld Posted February 1, 2011 Share Posted February 1, 2011 <p>I am just doing the intellectual exercise of creating a 617 camera design, I created this in sketchup (sizes are correct for this part I believe) <img src="http://brianhirschfeldphotography.com/wp-content/uploads/2011/02/FLAT.jpg" alt="" width="1024" height="739" /><br> I was wondering if someone could tell me the distance needed from the film plane for a 90mm lens adapter, the depth of the body is .9 inches, thanks, </p> Link to comment Share on other sites More sharing options...
leicaglow Posted February 1, 2011 Share Posted February 1, 2011 <p>The distance to where, the center of the lens? That would be 90mm. And this is a 6x17 sensor?</p> Link to comment Share on other sites More sharing options...
karl_schuneman Posted February 2, 2011 Share Posted February 2, 2011 <p>This is actually a Large Format type question, as You may not find a Medium Format lens with a cover circle for the 617 format. Distance from the mounting flange to the film plane is not the same for all lens. Also have to consider the shutter type you will also be using.</p> <p>Check out the list at this site for lens cover circle: http://www.largeformatphotography.info/lenseslist.html<br> I have a 617 camera with a Rodenstock Grandagon that has a cover circle of 221. This is measured at the min f/stop. it is reduced at wide open.</p> <p>Good Luck</p> Link to comment Share on other sites More sharing options...
ondebanks Posted February 2, 2011 Share Posted February 2, 2011 <p>I presume you are thinking of something like a 90mm Super Angulon? Then you need Schneider's data sheets which give the flange focal distance etc. for each of their lenses in shutter:<br> http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/super-angulon/</p> <p>Remember to also allow for the thickness of a helical focusing mount behind the shutter.</p> Link to comment Share on other sites More sharing options...
brian_hirschfeld Posted February 2, 2011 Author Share Posted February 2, 2011 <p>Yes the center size is 6x17. </p> Link to comment Share on other sites More sharing options...
paul.droluk Posted February 2, 2011 Share Posted February 2, 2011 <p>Every model of 90mm lens has a different FFD (flange focal distance) and even within the same model, FFD can vary +/- 0.5%. Due to these variations, you will need a method of spacing the lens from the film plane in a very precise manner. Typically this is done with a Cone and a Helical Focus Mount, which is referred to as a Cone Assembly. The Cone Assembly needs to be within about 1mm of the FFD, with the final 1mm being adjusted with the HFM using a ground glass... this is how the Fotoman system works. You could also use a collimator... this is how Horseman, and Linhof set their lens distances.</p> <p>FFD is measured from the film plane to the front of the lens board (or HFM). Remember too, the film plane will be some distance behind the back of the body... from your drawing, I assume you're considering a roll film back of some sort. Similarly, the GG must be spaced from the rear of the body to the exact depth as the film in the holder.</p> <p>You can get a better idea of how this all works by downloading the instruction manual for Fotoman Roll Film Panoramic Cameras... http://www.fotomancamera.com/technical.asp</p> Link to comment Share on other sites More sharing options...
brian_hirschfeld Posted February 2, 2011 Author Share Posted February 2, 2011 <p>Ok, so I designed this cone it has 1.8 walls and allows the proper space for film plane. What diameter does the hole have to be through which you mount the lens? <img src="http://brianhirschfeldphotography.com/wp-content/uploads/2011/02/617-Correct.jpg" alt="" /></p> Link to comment Share on other sites More sharing options...
leicaglow Posted February 2, 2011 Share Posted February 2, 2011 <p>Brian, I think we're just guessing at what you're trying to do at this point. From your last diagram, it looks like you're making a cone to attach a lens on the front and a sensor on the back? The diameter totally depends on the lens you are using. If you're using a large format lens, then a 90mm Super Angulon/Grandagon type lens typically uses a number 0 shutter. A Copal 0 shutter requires a 34.7mm hole (see http://www.skgrimes.com/lensmount/shutmt/index.htm).</p> Link to comment Share on other sites More sharing options...
brian_hirschfeld Posted February 2, 2011 Author Share Posted February 2, 2011 <p>great thanks, yes here I was creating the cone that will be attached to the "body" which is in the back of the picture.</p> Link to comment Share on other sites More sharing options...
brian_hirschfeld Posted February 2, 2011 Author Share Posted February 2, 2011 <p>here is the finished cone, ready for a 90mm lens, now for the film magazine, does anyone know the dimensions (size, diameter) of a 120mm spindle? thanks for the help, <br> <img src="http://brianhirschfeldphotography.com/wp-content/uploads/2011/02/Cone.jpg" alt="" width="1336" height="993" /></p> Link to comment Share on other sites More sharing options...
dan_fromm2 Posted February 3, 2011 Share Posted February 3, 2011 <p>Brian, what's a spindle?</p> Link to comment Share on other sites More sharing options...
shane_booth Posted April 8, 2011 Share Posted April 8, 2011 <p>25mm diameter, and 67mm long. From experience I would buy a lens first and design around that.Would hurt to buy a roll of 120 either before you ask how to count film spacing<br> Heres mine: Link to comment Share on other sites More sharing options...
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