Yep. I've seen that sited elsewhere as well. Apparently adding the pins improved film flatness substantially. Truthfully, I've used Graflex backs of all vintages and I've never really seen much of any issue at all with any of them. Granted, I stop down considerably for my work so shooting wide open may have shown more of an issue with some of the holders had I done that.
All other things being acceptable, grinding or machining down on the edge of the film holdre would be the plan. At least it would be my plan too. Best plan I can think of. There aren't a lot of options otherwise, seems like. GL
Yep, thats the only thing I can think of as well. Grinding down on the camera isn't an option for me. I'd rather ruin the back for the sake of experimentation. Ruining the camera, not so much.
I can offer my experience from designing/building a metal camera to take the RH/10 which is standard on the 2 x 3 Crown. (see my apug thread)
The top and bottom , and the left side you are referring to, were designed as light traps. The right side light trap is on the Graflex RH/10 rollfilm holder as a little ridge. If you try to grind the camera's left light trap off, not only will the camera be butchered, but, in my experience, unless you machine it flat to about 0.002 thou inch ( 0.050 mm) or less, and then add another light trap further out,, it will leak light.
Also you might have to modify the clamps to press the Horseman tighter than the original design.
For you comment about film flatness, I query what lens you are going to use?
And how do you know it is perfectly sharp across a perfectly flat focal plane?
Particularly, on wider apertures ( lower f/-) , I have pondered it is possible the original 90 ~ 105 mm lens designers might have been quite happy with a little bit of belly in the 6 x7 film plane. ( ??)
And how is the lens going to be more parallel to the film, regardless of what better, "superior" back you use?
Here is a measurement I took with vernier caliper of one old RH/10 holder on top/bottom of each pin roller [ inch] 0.206, 0.197, 0.202, 0.202.
Let us assume my shaky hands and eyes got it right, what is there to do anyway with a "warp volume" of 0.005 inch ( 0.127 mm)
Is it going to affect your ability to focus anyway?
Have fun, but i ( as others above) hope you don't butcher your Crown for an ill advised reason you read on some internet crap !
wombat2go, thanks for chiming in with input from your experiences. Like I said, I'm going to modify the holder.
Regarding the lens and film flatness bits, this is my point. I don't care about slight variances here and there whether it be film flatness or the particular lens and how it projects across the plane of the film. All I care about is that it makes the pictures that I want. Nothing else matters. The question is simply will a slight modification to the roll film back provide a usable solution? I think the answer is yes and now I've got a nice little experiment to see if I'm right
Ideas from anyone else? There must be someone here who's actually done this, no?
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To clarify, I know that I bought the holder because it is supposed to be superior to it's Graflex counterparts, but at this point this whole thing is just for the sake of experimentation. If it works that'll be great and if it doesn't thats totally cool too seeing as it'll be easy to pick up another holder that fits without modification and carry on without much concern
Well, I bought my Miniature Crown to use and DID carefully grind down the ridge on my Crown. It is hard to tell that the modification was done and now I can use my Horseman holder on it. Now I use Grafmatics, the RH12 Graflex back and the Horseman 6X9 backs. In fact I may try to put a Mamiya 4.5X6 back on it.
By the way, the same requirement applies if you wish to use a Horseman back on a Mamiya Press or Universal with the G back.
If you do not have a Digital Caliper ( http://www.amazon.com/s/ref=nb_sb_no...ital%20caliper ) get one. It makes camera work much easier.
I too would modify the holder, not the camera, provided the holder has sufficient material and will not be weakened by the reduction in thickness. I do not currently have a 2x3 Crown to check how much could safely be removed from the back.
Large Format Film Holder specifications, http://home.earthlink.net/~eahoo/page8/filmhold.html , for 2 x 3 is the front surface of the film is to be .197 inch from the edge of the holder ± .007 inch.
I too have measured the backing plate on my Graphic roll film holders and found a similar variation as wombat2go but all distances are within film holder specs.
Film flatness is only an issue when doing critical work such as architecture or close up/macro work. If you take a roll of film and run it through a Graphic RFH without pin rollers and one with pin rollers the film bows less at the center of the film gate on the holder with the pin rollers than it does in the one without the pin rollers.
See http://www.graflex.org/helpboard/viewtopic.php?t=6391 for tips on Graphic/Graflex RFH problem solutions.
Bob, thanks for chiming in with your experience. Interesting to hear that you've had success with this. My plan is to grind down the holder sometime this weekend. Should be a fairly quick job to take off 1.5mm.
Shutterfinger, thanks for chiming in as well. Good to see confirmation of some of the numbers there.
The 2 Graflex RH10's and the RH/8 here are all within about 0.197 +/- .003 inch
The newest one, a Singer with the blue handles, is close to parallel on all 4 pin ends,to the limit of my calipers within 0.001 inch ( 25 micrometre)
A 103 mm lens in 6 x7 at f/8 focussed close in (at 3 metre) can have a DOF of 350 mm which corresponds to +/- 0.25mm or +/- 0.010 inch of throw on the film plane.
Boring numbers, but they put the accuracy of parallel film in perspective. The Singer back prices range from $80 to $100.
The 2 x 3 Crown design actually is intended for the user to fine tune it using the front standard adjustments and the ground glass.
The rails need to be dropped to the second click.
For example-For mid to long distance work,
For side to side sharpness, set each rail stop so that infinity focus is even, that no side ever goes beyond infinity.
The lens can be tilted down slightly so when the tree-tops etc are at infinity, the foreground will always be on the sweet side.
For example 1 degree, or 1 mm (0.025 inch) of down tilt on the lens board might be a good setting to bring the lower foreground slightly into the DOF.
It is also possible to pre-set a small amount of front rise.
Then lock all the adjustments, and just use the camera with the rangefinder.
However the cameras won't fold up when set like that. I have an old video bag to carry them.
For close up work,(and the bellows can extend out out to about 160mm) it is probably best to set the camera case- by case.
The 2 x 3 Crown here is quite tight after the knurled screws are locked, except there is a little bit of flex in the lens tilt.