Why are 35mm film and DSLR sensors not square?

OutLore

OutLore

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Ok, so I'm just thinking about stuff today, and I got to wondering why (most) film isn't square, and leading on from that, why digital sensors aren't square?

The output of a lens (IE the image projected) is round, so surely it would make more sense to have a square plate to expose, not to mention that square sensors/film would "use" more of the lens output.

Anyone know why?
 
If memory serves me correctly when camera makers wanted a smaller format than 120 or square film that needed 'holes' to enable film to be wound from one spool another they used existing cine film, rather than develop a new format, which was non-square i.e 35mm (from 70mm I think). DSLR just carried the format on.

Matt
 
I always wondered this aswell.. in fact, why aren't sensors circular (I can probably answer that myself.. would be harder to make circular sensors)... but still, if you have a circular sensor you'd never have to turn your camera on its side for portrait mode ever again.
 
my opinion:
because there not much to see up above or down below (well my pictures kind of go against that but you know what i mean), square has its place but for the 'average shot' there more peripheral stuff than the higher and lower. also your vision isnt square, hold your hands to the sides and see how far you can see them (huge angle) then try above and below (much smaller angle)
 
Look how expensive Digital Hasselblad backs are, I remember reading somewhere that cost/manufacture came into it.

Might be wrong though...
 
how weird - not even considered that before - and yep I have widescreen eyes............. now that HAS to be a reason for a 50" widescreen plasma.
 
Wigster said:
I always wondered this aswell.. in fact, why aren't sensors circular (I can probably answer that myself.. would be harder to make circular sensors)... but still, if you have a circular sensor you'd never have to turn your camera on its side for portrait mode ever again.
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Landscape and portrait would no longer exist.
 
Liam said:
Look how expensive Digital Hasselblad backs are, I remember reading somewhere that cost/manufacture came into it.

Might be wrong though...
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thats just a size thing, for any given area shape isn't a factor in cost

and 6x6 is lovely but a lot of things work better in portrait/landscape, I sometimes print that way from a square neg
 
The main reason I suspect would be cost and availability of current useable equipment. A square sensor for any given size would require a much larger mirror box, larger viewfinder etc and for what? Digital Cameras were also designed to utilise existing 35mm lenses, these have a specific distance they have to be to allow focusing on the sensor. A square sensor would require a square mirror which would then have hit the rear element of currently available 35mm lenses. Much like a FF camera's mirror would do on a lens designed for a smaller format.

It would be possible to design a completely new camera system that used a square sensor but as people want smaller cameras not larger and they are used to some form of rectangular format I doubt it would sell very well.
 
EdBray said:
The main reason I suspect would be cost and availability of current useable equipment. A square sensor for any given size would require a much larger mirror box, larger viewfinder etc and for what? Digital Cameras were also designed to utilise existing 35mm lenses, these have a specific distance they have to be to allow focusing on the sensor. A square sensor would require a square mirror which would then have hit the rear element of currently available 35mm lenses. Much like a FF camera's mirror would do on a lens designed for a smaller format.

It would be possible to design a completely new camera system that used a square sensor but as people want smaller cameras not larger and they are used to some form of rectangular format I doubt it would sell very well.
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? :shrug:All you have to do is crop of some from each side will not change anything apart from the sensor size....
 
formats
landscape and portrait
not so much cropping

square format isnt really easy on the eye
 
Well, nobody's putting up a decent reason why we don't have square sensors, I think oblong is just the way things developed.
Personally, I much prefer a square frame to compose.
A square sensor with the same surface area as 35mm film, would be no more difficult or expensive to make than the oblong jobs we have now, and it would also make the very best use of round lenses.
Its all pretty much the acedemic anyway, the crop tool cuts any shape you want...:)
 
I think it's got a lot to do with the history of 35mm film and how the original Leica came about. And we've stuck with it. However, if it wasn't popular, it would have been changed.

There is logic to square and I have to say I like it, plus the easy option of cropping either way. But nothing 'visual' seems to be sqaure - books, magazines, paintings, TV, cinema. None of them square.

Interestingly, while DSLRs are 3:2 ratio like 35mm film, compacts are 4:3 and the newest format Four Thirds is obviously the same - more square.
 
joxby said:
Well, nobody's putting up a decent reason why we don't have square sensors, I think oblong is just the way things developed.
Personally, I much prefer a square frame to compose.
A square sensor with the same surface area as 35mm film, would be no more difficult or expensive to make than the oblong jobs we have now, and it would also make the very best use of round lenses.
Its all pretty much the acedemic anyway, the crop tool cuts any shape you want...:)
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Mmmmm :thinking: A fulll frame sensor at 24 X 36mm would have a diagonal length of about 43.5! To get a useable image circle from a 35mm lens to fit on a square sensor the sensor would only be approx 30 X 30mm This would only give an increase in area of about 4% :) or at least that's how I read it ... in a mag the other day :shrug:
 
Rectangular formats were used way before 35mm was ever thought of - and before film was invented. Go to any art gallery and see what proportion of Old Masters used a square canvas. It was natural for the golden mean ratio idea to percolate from art into photography right from the start.

See here for what the Golden Mean is: http://en.wikipedia.org/wiki/Golden_ratio

Rectangles are better for portraits which was a main function of photography in the early days. Off the top of my head, I think 6x6 is the only square format there is. It is much harder to get a strong composition using a square frame, the rule of thirds doesn't work, with the centre of the frame becoming the main focal point. Many square photos are printed as rectangles, anyway, which means the film is wasted.
 
Splog said:
Mmmmm :thinking: A fulll frame sensor at 24 X 36mm would have a diagonal length of about 43.5! To get a useable image circle from a 35mm lens to fit on a square sensor the sensor would only be approx 30 X 30mm This would only give an increase in area of about 4% :) or at least that's how I read it ... in a mag the other day :shrug:
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Well, you're right, but the question was why aren't they square, although the sensor could conceivably be 36x36 for a usable image circle, shirley..:)
 
12 on 120 ie 6x6 is the only square format left, but there have been others over the years, 126 and 127 films both were processed in a square format and were developed (pun intended) by Kodak for the masses, but most people prefer rectangular images and thus demand has brought about the current situation.
 
Wigster said:
I can probably answer that myself.. would be harder to make circular sensors...
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Be a bitch trying to find a frame for your prints too!
 
joxby said:
Well, you're right, but the question was why aren't they square, although the sensor could conceivably be 36x36 for a usable image circle, shirley..:)
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Well Shirley would be wrong. Draw a 24mm x 36mm rectangle and then draw a circle around it with the corners of the rectangle touching the corners of the circle, now do the same with a 36mm square and you will find that the circle is quite a bit bigger.

Also, the corners would be quite soft and suffer from vignetting, so an allowance would have to be made for the circle to be even larger to give a good quality image across the frame.
 
EdBray said:
Also, the corners would be quite soft and suffer from vignetting, so an allowance would have to be made for the circle to be even larger to give a good quality image across the frame.
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Don't we have this all ready ?

I'm thinking if it covers 36 sideways, it ought to cover 36 vertically, I dunno, I'm not 35mm literate...Doris...:)
 
Looks logical to me, 36x36 is great for....err....round photos...:LOL:
 
I'd love the ability to have a square format built in-camera as I square crop 75% of the time. That is all. Canon - make it so!
 
joxby said:
givvover

http://www.michaelkenna.net/imagearchive.php
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"... very few images lend themselves well to square composition. In general it is the most difficult format to work with, and most design strategies for a square frame are concerned with escaping the tyranny of its perfect equilibrium...
... occasionally a precise symmetrical image is interesting.... however a few such images quickly become a surfeit. It is fairly normal for photographers who work consistently with a square-format camera to imagine a vertical or horizontal... and crop later" - Michael Freeman, The Photographer's Eye, Focal Press

Maybe you can consistently make square format work but most of us can't. I do sometimes shoot 6x6 and try to use the whole frame but much of the time I'm really using the camera as a 6x4.5.
 
Its all about opinions, Micheal Freeman is just expressing his.
Personally, I feel short changed with oblong, it looks like a good bit of the frame is missing, things just don't seem to fit.
Its the half full/half empty glass perspective, probably...
 
The useable image circle of the lens is really the bit that counts as it that which has to best cover the sensor size! Try drawing it at 36mm :thinking: and then at 30 mm!
 
Interesting discussion....

Here's another (slightly related) query. With all the talk of how TV's, books etc are not square, I noticed that most, if not all, GPS screens are also rectangular. However, with a GPS, the long side is on the wrong side - IE I want to be able to see more of where I'm headed, not what's either side of me.

I struggle to see why GPS manufacturers haven't picked up on this, and made their screens "portrait" :thinking:
 
OutLore said:
Interesting discussion....

Here's another (slightly related) query. With all the talk of how TV's, books etc are not square, I noticed that most, if not all, GPS screens are also rectangular. However, with a GPS, the long side is on the wrong side - IE I want to be able to see more of where I'm headed, not what's either side of me.

I struggle to see why GPS manufacturers haven't picked up on this, and made their screens "portrait" :thinking:
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Interesting question :) My first SatNav was actually in 'portrait' (Ipaq) :cool:
 
Polaroid is square.

Not sure what that proves :LOL:
 
Circular would be the best use of the lens. One of Kodak's first consumer cameras produced circular images. When you finished the roll, you sent it back to Kodak who processed the film and returned a newly loaded camera to you along with your ciurcular prints.

The best thing about circular prints is that you don't have to worry about the horizon being level!

There were some 35mm cameras which produced a 24 x 24mm square image and others which were 24 x 32mm until 24 x 36mm was used as a standard. This is twice the size of the image when the film is run vertically through a cine camera. The cine image is about 18 x 24mm - about the same size as a DX format DSLR sensor.


Steve.
 
I wonder if digital might change things a bit? Would you like a camera with a square sensor? That could be instantly switched vertical or horizontal without turning the camera, or cropped to any aspect ratio without wasting sensor area?

I think a lot of the reason we have rectangular sensors today is because of practical considerations regarding the size of the shutter, mirror and viewfinder, but we're not far off getting a solid state camera - basically something like the Panasonoc GF1 with sensor switching instead of a shutter.
 
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