JimAndersson wrote in post #13213667
I know a square sensor would be mer expensive to build because it would need to be "higher" than a "normal" one, but what the hell, medium format isn't exactly cheap anyway.
A 1.618:1 APS-C (yes I know it wouldn't really be APS-C) and full frame shouldn't be more expensive to make, and a 1:1 "APS-C" should be cheaper than a standard 3:2 full frame.
JimAndersson wrote in post #13213902My thought about square frames originates in the theory of using the most of the image circle of lenses, and cropping to rectangular shapes would still use the image circle optimally. There are already the 5:4 format, so why not?
The problem with a square sensor, is that you not only have to make it higher, but narrower as well. The corners of the frame have to fit within the image circle and simply extending the image area upwards will put the corners outside the image circle. The actual area of the sensor would be about the same, but a FF bodies 36x24 would have to become around 30x30. The problem there is that subjects suiting square images are very much in the minority, most being either long and low (cars, aircraft, many animals, typical landscapes etc., ) or tall and thin (people for instance). The rectangular image format is by far the most pleasing the majority of the time. I had a 6x6cm medium format outfit for a while, but got fed up cropping so much expensive real estate away. I ended up selling it and got a 6x4.5cm set up instead, less cropping and I got 15 shots on a roll instead of just 12.
If you are going to end up cropping to a rectangular format, then you lose the extra height of the square sensor, but you have also lost the width too, with the sensor being narrower. So effectively, you have ended up shooting on 30x20mm of sensor instead of 36x24mm. That is inefficient. Granted, on those few occasions where a perfectly square image works, you can now have a 30x30 image instead of 24x24, but that isn't worth the trade off of losing 36x24 FF sensors.
As for moving to 1.618:1 sensors, that is simply removing a sliver along one long edge. It would mean you could eke out another couple of mm sensor width to have a 38 or 39mm wide sensor, as it is shallower. Again, though, wider and lower images are less wanted than the current ratio (although certainly more usable than a square format). However, anybody wanting that ratio can simply use the current sensors and simply crop a little off the top or bottom. In fact, I do that quite a lot myself. However, I wouldn't want to be committed to that lower and wider sensor as I would often end up cropping the ends off when I need a touch more height.
The current sensor ratio is a good one for most people, most of the time. When you need something different, it is a good ratio to crop from without losing too much.
Add in that any camera being put on the market with an unusual shaped sensor would make it harder for it's owner to get prints made without radical cropping to fit traditional print shop sizes and frames. Of course, if a new ratio became popular and taken up by more manufacturers, then the printers and frame manufacturers would likely set up to accomodate it, but in the meantime camera buyers would likely shy away due to the potential problems. You only have to look at how many people don't like having to lose a little at the ends, when making a 10x8 print, now. Make the image even longer, so they have to cut a lot more off, and they won't be happy.
This has been debated over and over on here, but the current sensor ratio is probably the most practical shape most of the time.
. Like most 120 cameras (not all), mine shot in the 6x6 format. 
