Is it possible to make a rectangular lens?

Started Aug 2, 2013 | Questions thread
Barrie Davis
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Re: Is it possible to make a rectangular lens?
In reply to D Cox, Aug 3, 2013

D Cox wrote:

Barrie Davis wrote:

bobn2 wrote:

Mikhail Tal wrote:

That way it could be much smaller since it would not need to waste space that is not covered by the rectangular image sensor. The other option is a circular sensor that outputs circular images but that is not as space-efficient, so a rectangular lens, if possible, would seem to be ideal. It would also allow for a larger sensor for a given body size as the sensor could take up much more space in the lens mount. Essentially you could put a full frame sensor in a body the same height as current NEX and m4/3 bodies.

The whole of the lens contributes to making every point on the final image (that's why a large aperture lens forms a brighter image) - the difference with your rectangular lens is that each point of the final image would be a tiny rectangle, instead of a tiny circle.

Out of focus features would be rectangular not round, so the bokeh would be unusual. Moreover, the image field would still extend outside the final frame, it would be elliptical, so the scheme wouldn't be any more efficient in terms of lens space used.

Out of focus highlights in an image echo the shape of the diaphragm opening, whatever it is, so only if the diaphragm is also manufactured to be square or rectangular will the OOF highlights be so shaped, except maybe, when fully open. Focused zones will not show the effect at all.

Aperture plates can be made any shape, and introduced into the lens through a slot in the lens barrel... in the style of 'Waterhouse' stops.

Fancy Shapes of Waterhouse stops

I have myself made a star-shaped aperture plate with it producing a field of varying brightness stars overlapping each other..... it originated in an out of focus image of a piece of shiny but very crumpled kitchen foil, illuminated with a spotlight.

A Christmas tree is a good subject for this kind of experiment.

A Green Shield Stamp Company catalogue cover was once done, with shield shapes obviously, and printed in duotone green. That was 40 years ago approximately, in UK. That was the only time I have seen the "specialy shaped out of focus highlight" technique used in a commercial application... that is, instead of just demonstrating the fact that it is possible!

https://www.google.co.uk/search?q=Green+Shield+Stamps&sourceid=ie7&rls=com.microsoft:en-us:IE-Address&ie=&oe=&gws_rd=cr&ei=Dpj9Ue7gBsaX1AWqwYDIBQ

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Regards,
Baz
:
"Ahh... But the thing is, these guys were no ORDINARY time travellers!"

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