Help me design a 6x7 wideangle camera!
So. I want to build a wide angle camera based on an RB67 back.
I've seen pinhole wideangle cameras based on the RB67 back, so that's kind of the design aesthetic I'm going for (flat), but I want a glass lens.
My basic criteria are:
-Wide-ish lens, quality unimportant (low budget and I want somewhat lo-fi)
-Coverage for 6x7
That's it. I was thinking I could source a shuttered lens off an old rollfilm folder, but the widest one I've seen is 75mm, and they all require long bellows for focus.
Can I use a lens intended for a smaller format? Can I just mount some other lens in an old leaf shutter?
How wide do you want to go? That's the $64,000 question.
Last edited by keithwms; 03-08-2008 at 06:44 PM. Click to view previous post history.
Reason: P.S. And do you want infinity focus?
Well If you get a used RB-67 body pretty cheap (eBay or KEH) and then you could get a 50mm (25mm equiv. in 35mm) or if you want really wide there is always the 37mm (18mm equiv. in 35mm) this seams like the easiest and most reliable way to go. I can speak for the 50mm lens mine is very sharp and contrasty, it's the lens I use the most. You just have to pay attention to the floating element position, it really makes a difference on the edges.
Last edited by 23mjm; 03-08-2008 at 06:52 PM. Click to view previous post history.
For width, somewhere in the range of what a 28-35mm lens does on a 35mm camera, as width=money.
Also infinity focus is good, but what does that require from the camera design? I mainly will be making images of things within 10m, if that makes any difference.
I thought about the RB's native lenses, but I don't want the RB in between 'cos I want this to be a sling-it-o'er-your-shoulder-and-carry-it-about camera, and don't particularly need reflex viewing.
I made a nice wide rig from a 4x5 enlarging back. You can put any lens on it. Don't need GG to focus, you can make distance markings on the rails. For now I put a 65mm lens on it, but it can go much wider. Normally I put a 6x12 back on it or shoot 4x5 quickloads.
The RB lenses are *heavy* and I can't mount them on anything less than a sturdy rig. A crown graphic, for example, can barely take 'em, in terms of stability. So it depends what your vision is for this rig.
For infinity focus, you must be able to bring the lens quite a bit closer to the film plane than you would for closer-up work. Also, at infinity you will have the smallest useful image circle and are hence most likely to have vignetting.
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Okto, the safest way to get a lens that will cover 6x7 is to get one made for a 6x7 camera or a larger format. There's no guarantee that a lens made for a smaller format will cover 6x7.
As far as coverage is concerned, 10m is as good as infinity. So, for that matter, is 20x focal length.
For focal length, to get roughly the same horizontal angle of view on 6x7 as on 35 mm with a 28-35 mm lens, you'll need something in the range 50 - 70 mm.
Just for curiosity I took a look at what www.keh.com has today. Nothing in shutter and really inexpensive.
It sounds to me like you somehow got a RB67 roll holder and are looking for something to do with it. Is this the case? If so, unless you're a skilled woodworker/machinist, you'll probably be better off buying a used Century Graphic (these will take an RB back) and a 65/6.8 Angulon or Raptar/Optar. Optar is Graflex' house brand, nearly all are rebadged Raptars. These 65/6.8s are the shortest relatively inexpensive lenses for 6x9, will do better on 6x7. Leitmeyr 65/6.8 Weitwinkels (also sold by Spiratone as "Hamburg") are less expensive but much harder to find.
You might also get a used RB and lens to fit it, as has already been suggested.
What you want is a graflex XLRF. They will take your RB back without modification. If you want to get fancy check this out: http://www.skgrimes.com/paqpro/index.htm
Or, possibly a rotating back, a little bit of luck and some hunting on ebay. Personally, I use this approach (though I need to build another lensboard, as Keith just had to have one...)
I know of several 47mm Super Angulons for sale, that are specc'd to cover 6x9. Cheap is relative, figure $3-400 minimum, KEH has a 65mm angulon for around $250, though you could probably find an RB 50mm C for not much more (~$300). I do realize that the image circle on the 50C is restrictive, movement wise, but I bet everything, including the view camera, would come out far cheaper than a used Hassy Flexbody.
I was also going to suggest a 65mm Angulon, if you want a lighweight lens that covers the format. It covers 6x9, so if what you want is a light, wide rollfilm camera, you could get a 65mm Angulon and a Graflex 6x9 back and build some sort of box camera, presuming you don't just want to use a 2x3" Graphic.
A 2x3 Graphic would be a lot easier, but its body is added unnecessary thickness/weight for this application. The Angulon looks like a winner, so the only critical thing to figure out is a focusing method.
Can retrofocus lenses be used in a unit-focus fashion for this application?