[LRflex] Re: Z + N = ? OT (maybe)
- From: Richard Ward <ilovaussiesheps@xxxxxxxxxxx>
- To: "leicareflex@xxxxxxxxxxxxx" <leicareflex@xxxxxxxxxxxxx>
- Date: Tue, 7 Jun 2011 20:28:49 -0400
On Jun 7, 2011, at 6:25 PM, George Lottermoser <imagist3@xxxxxxx> wrote:
> Not sure if this will help Richard - yet it demonstrates the point I tried to
> make
> regarding lens being (or not being) perpendicular to sensor.
> <http://paulturounetblog.files.wordpress.com/2007/08/view-camera-movements.pdf>
> see especially page 3
> and
> <http://www.trenholm.org/hmmerk/HMbooks5.html>
>
> Regards,
> George Lottermoser
George,
I like the document you linked to. Saved it to my iBooks App as a potential
reference in case I have an opportunity to pull out my 4x5 Camera and go
shooting with it ever again. My personal View camera is a Busch Pressman with a
fair bit of geared and non geared front lens movements built into it, for a
'Press Camera' anyway they're nice movements. Once upon a time I did use a
Mono Rail in College. I've actually got a perspective control lens on my wish
list for use on an SLR, but I'm not in a huge rush at this point with learning
M photography being such a higher priority for my time.
I relate these things in hopes of showing that I have practical first hand
experience with using tilt, with using rise, and with using swing. The view
camera arguments you put forth don't seem to me to counteract my discussion of
the physical properties of the imaging sensors in question.
The best response I can come up with at this point is the following
thoughts. Not sure how strong they are, I'm grasping for analogies and
situations at this point.
a) Didn't the view camera world need to transition to lenses of different
designs to achieve peak image quality with the advent of medium format sized
digital backs rather than the use of roll or sheet film for image capture? The
sensors in those backs didn't react to light rays in the same manner as film
and beyond a certain megapixel count some film lenses couldn't cope in that
environment? Were'nt by definition every single shot taken with these sensors
unbound by the rigid sensor, lens, and body, structures of dSLRs, yet the
physical designs of the sensor were causing imaging problems.
b) In the world of dSLRs, excepting tilt shift lenses, aren't all the lens
designs based on an assumption of rigid lens mountings, rigid camera bodies,
and rigid sensor placements? Would it be reasonable to expect a lens designer
to attempt to be designing lenses for such solid structured environments to be
designing them to cope well with the tilts, swings, and skews of a view camera
environment? Or rather that he would spend little effort designing to offset
any uncolumnar lens,body,sensor alignments when formulating a lens. If the lens
design assumes perfect lens to sensor alignments and it isn't that way, I have
no problem thinking such a situation mightngo terrible awry in some
circumstances.
c) The problems I refer to at the sensor are from the physical structure of the
sensor itself screwing with the light rays being sent back for recording by it.
That the sensor behaves at it's best when receiving light rays within certain
set parameters. That when those rays are arriving ouside that certain set of
angles the physical structure of the sensor is able to turn perfectly
reasonable circles of confusion, lens resolution, etc into image signals that
aren't perfectly reasonable.
I suspect I'm making a hash of arguments someone other than I could make a lot
better.
Sincerely
R. In Mi.
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