I bet no one knows enough to answer THIS question... !
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From: ray on 15 Jul 2010 12:14 On Wed, 14 Jul 2010 20:52:04 -0400, Scotius wrote: > Why is it that camera lenses are round, but pictures are square? Hmmm? > Tell me that ya' smarteys! 1) the pictures taken by most cameras I'm familiar with are rectangular rather than round. 2) it's a lot easier to make a round lens. 3) it's a lot easier to make film and/or sensors rectangular.
From: Peter on 15 Jul 2010 12:20 "Scotius" <yodasbud(a)mnsi.net> wrote in message news:fsms369k0lm01f67vj3at5odi4pmhljdh7(a)4ax.com... > Why is it that camera lenses are round, but pictures are > square? Hmmm? Tell me that ya' smarteys! I'll answer hen I get a round to it. -- Peter
From: ray on 15 Jul 2010 13:35 On Thu, 15 Jul 2010 12:20:16 -0400, Peter wrote: > "Scotius" <yodasbud(a)mnsi.net> wrote in message > news:fsms369k0lm01f67vj3at5odi4pmhljdh7(a)4ax.com... >> Why is it that camera lenses are round, but pictures are square? Hmmm? >> Tell me that ya' smarteys! > > > > > I'll answer hen I get a round to it. I have some extra round toit's I can spare - how many do you need?
From: BF on 15 Jul 2010 19:29 On 7/14/2010 8:52 PM, Scotius wrote: > Why is it that camera lenses are round, but pictures are > square? Hmmm? Tell me that ya' smarteys! What a bunch of worthless answers.
From: Paul Furman on 15 Jul 2010 23:48
Scotius wrote: > Why is it that camera lenses are round, but pictures are > square? Hmmm? Tell me that ya' smarteys! :-) veeery interesting question! Many reasons... though I think it may actually make sense in some limited situations. Lenses generally need to zoom or focus, which works well with round helix/spiral thread designs, although maybe not, maybe a brilliant piece of thinking outside the box could make fantastic cheap, lightweight, *better* squared lens bodies. The out of focus circles would look funny if they were square. I had a super-8 camera with a square iris and it did show this with shooting into the sun where flare highlights were apparent. If you think square bokeh looks cool or don't mind (it usually doesn't matter), you could grind lenses square after polishing (or even cast form them in rectangles) to reduce size & mass, but think about that scenario; you would be making the lens slower - removing some of the potential of the lens to gather light. In the case of an enormous lens or let's say telescope mirror... there might be significant savings but I never heard of a telescope built that way... maybe it's been done? Some more observations on bokeh shape... sometimes you will see 'cat's-eye' bokeh circles in the corners of a fast wide-ish lens, instead of circles, you will see eye-shapes where the edge of the lens or part of the barrel occludes the full aperture. Or sometimes it's a circle with the edge sliced off square on one side by part of the camera box. This can look cool and I recall it's more common on short flange mount rangefinder lenses like some really drool-worthy Leicas, etc. I'm not sure how it would sort out with a squared off lens though. For sure you'd want a squared aperture... or maybe not, I dunno, it could end up looking pretty weird. Those cat's eyes are at least one form of vignetting (dark corners). I can't say if that's the main cause of vignetting but it's a common lens aberration which is more of a problem in wider lenses so it could be the same issue. Here's an example of a square lens (sort of): http://www.mir.com.my/rb/photography/hardwares/classics/eos/EF-lenses/EF2035mmf3545USM/EF2035mmf3545USM_HbrianB.jpg You see that on compact P&S pretty often too. I think it's really just a lens shade and designed to be outside the cat's eye realm or to not matter given the range of the camera. The flare reducing advantages may be more valuable than the vignetting losses. I have one of these: http://www.cameraquest.com/jpg4/SL_125_1a.jpg and never saw any cat's eye, since it's a longer lens, and especially at macro distances, there won't be any conflict. OK, I thought of one common implementation of genuinely squared lenses: Fresnel lenses, like you might see stuck to the back window of a van in the 1970's or on an overhead projector in school or a lighthouse beacon. I've even seen people take photos with fresnel lenses and it can be sort of not too bad <g> but they aren't generally considered to be of photographic value. There could be ideas there for some wonderful future camera technology though... who knows? Digital pixels are rectangular so maybe a way to take advantage of that. Fresnel telescope: http://gizmodo.com/386539/fresnel-telescope-will-spot-m+class-planets-30-light-years-away |