Hi John:
I agree. the increase in size caused by a revolving
back is (for me anyway sinc I backpack an 8X10) not
worth it. I can get the same correction by tilting the
tripod head. For a studio camera it would be ok, but
not for a field camera.
Tyler.
--- John Sparks <[EMAIL PROTECTED]> wrote:
> It's all geometry. I don't think you need to worry
> about this unless you
> allow enough shift, rise or fall so that the lens
> moves beyond the edge of
> the tunnel (note that you can get more shift by
> using swing on both front
> and back standards, see a good view camera technique
> book). If your tube is
> smaller than the amount of shift you allow, then you
> need a clear line from
> the lens to the edge of your tube to the edge of the
> film. The worse case
> is with the widest lens you allow with the max shift
> in the corners of the
> film.
>
> Oops, I forgot about rear swing. Rear swing will
> cause problems even
> without shift. You just need to draw some pictures
> giving max swing and
> shift with the shortest lens you want to use (at
> infinity the distance
> between front and rear standards is aprox the focal
> length of the lens,
> closer focus uses more distance between front and
> rear standards). Shorter
> lenses generally need less swing and tilt and allow
> less shift (smaller
> coverage) so this may be all more theoritical than a
> real problem, but a few
> drawings should make this more clear.
>
> Having used cameras with rotating backs vs
> reversable backs (ones you can
> take off to swap from horizontal to vertical), I
> much prefer the smaller,
> lighter and simpler camera you get with a reversable
> back to the rotating
> back. Having some tube arrangement at the back
> other than the flat metal
> ones I've used is going to be even more awkard,
> especially since this makes
> the camera thicker and harder to use with short
> lenses.
>
> John Sparks
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of
> Bradley Small
> Sent: Wednesday, January 24, 2001 10:27 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [Cameramakers] rotating back
>
>
> Wayde --
>
> I am not sure we have addressed it. I am talking
> about the back not the
> lense and bellows area. When I create this tunnel
> between where the rear of
> the bellows ends and the film plane begins, will I
> not risk interfering with
> the flow of light?
>
> -- Bradley
> ---------- Original Message
> ----------------------------------
> From: "J. Wayde Allen" <[EMAIL PROTECTED]>
> Reply-To: [EMAIL PROTECTED]
> Date: Wed, 24 Jan 2001 09:21:49 -0700 (MST)
>
>
> >> The question I have is with size. At what point
> does a vignetting
> >> problem occur?
> >
> >I think we've kind of already answered this one.
> >
> >- Wayde
> > ([EMAIL PROTECTED])
> >
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>
>
>
>
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