If anyone knows please help . . . |
Why are camera lenses always round when every way we view them are square.
Am i missing something obvious, or are we wasting portions of an image.
The film or sensor is normally a rectangle. The extremities of most lenses aren't good anyway.
Syrette 48,649 posts
Seen 19 hours ago
Registered 14 years ago
Fitting a square peg in a round hole wouldn't work.
Was this really a burning question that was eating you up inside?
Sadly yes. I was watching an advert for cameras and it made me wonder.
Fair enough! Old 120 film is / was square which I suppose makes the most efficient use of the lens (as opposed to rectangular 3/2 format). Also we perceive the world in widescreen so it does kinda make sense.
Having square or rectangular camera film is much more efficient too. If we had round film, much of it would be wasted.
Oh yeah, hey no worries mate
Sorry dude. Thanks for the info
Making square or rectangular lenses is much more complicated than circular ones. Also the best bit of the lens is in the middle, you don't necessarily want to use the edges, especially on less expensive lenses. That's why stopping down the aperture (which uses a smaller area of the lens) often results in better image quality.
Lenses that are very good right across the frame with the aperture fully open are usually (though not always) very expensive.
neilka 20,012 posts
Seen 15 minutes ago
Registered 12 years ago
While we're at it does anyone know why Battenberg cakes are square?
mal 27,726 posts
Seen 7 hours ago
Registered 15 years ago
Quite a few compact cameras (especially towards the cheaper end) have apparently rectangular front lenses. I guess they're made circular then ground down, but still, it is possible.
I guess the reason most aren't is that lenses do rotate as they focus normally. Even if the front element doesn't rotate there are all sorts to bits of glassware in there and they all move* to enable focussing and zooming. Simplest, lightest and most reliable way to do that is to mount them in a screw thread and turn them using internal gears.
* On interchangeable lenses at least the back element is static. That's not neccessarily true in compact cameras.
Cheers everyone, there is some useful info here.
I think i can consider my question truly answered.
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