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For creators who wants to make videos for platforms like IGTV and youtube as examples you have two totally different formats. Portrait and landscape. You could obviously crop a video or photo from either orientation to the other. But lately I keep thinking that having a camera with a square sensor would make sense to be able to support both formats from the beginning then use the footage for either orientation without loosing out on quality on one of them.

Does this exist?

just_user
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    Better yet, why not a circular sensor that covers (almost) the entire image circle, and you can crop to rectangular, square, or any other shape you want in post...? – twalberg Jul 10 '19 at 14:04
  • Does a circular sensor exist? – just_user Jul 10 '19 at 14:18
  • This is what I found wonderful about the Hasselblad 2¼ x 2¼ square format. – Stan Jul 10 '19 at 15:33
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    Circular sensors would be a wasteful manufacturing nightmare, unless you made them whole-wafer sized. – rackandboneman Jul 10 '19 at 16:03
  • @rackandboneman It could be a patchwork sensor in a cross shape. – xiota Jul 10 '19 at 16:42
  • @xiota but really, isn't a "circular" sensor just a patchwork sensor of lots of cross shapes? That is, the discretization of the sensor area into pixels causes several step-changes to each rectangular area. – scottbb Jul 10 '19 at 20:12
  • See Would it be possible to make a 36×36 mm “full frame” sensor?, which concentrates on full-frame but I think fundamentally covers the issues in the answers. – mattdm Jul 10 '19 at 20:58
  • But why not make them whole-wafer-sized? A 25.4mm wafer would only about 10% smaller than APS-C, as long as you etch the rest of the support electronics on the back side of the wafer. And a 51mm wafer would give you a 4mm border all the way around an APS sensor, so you could potentially put the other circuitry on the front side, or put it on the back side and capture more of the fall-off region (potentially usable to get wider shots under the right circumstances). It would be a little wasteful, but not exorbitantly so. – dgatwood Jul 11 '19 at 20:01
  • @dgatwood To do what you suggest, would you get a medium format camera to use with a full-frame lens? Or use an APS-C lens with a full-frame camera? Such a camera probably wouldn't be marketable. People would see the unused sensor area as a defect. – xiota Jul 11 '19 at 20:53
  • It would be a slightly-more-than-full-frame sensor. I guess pedantically, that's "medium format" in that it's larger than full-frame, but nobody would call it that. The idea is that the photosensitive area of the sensor would cover the entire usable image circle of a full-frame lens (though there would likely be some wiggle room in defining "usable"), and any additional wafer space would be used for support electronics, reducing noise by putting amplifiers, etc. on the same die as the sensor. And ostensibly, if you wanted a round photo for some reason, you could use the whole sensor. – dgatwood Jul 12 '19 at 17:44
  • No idea if modern steppers etc can even handle 1 inch wafers anymore, or whether 1 inch wafers are still produced. Also, no idea if you can manage two live sides on standard equipment... – rackandboneman Jul 12 '19 at 20:07
  • @rackandboneman I don't about "standard" semiconductor manufacturing equipment, but back-side illuminated sensors are becoming fairly common in both small (mobile) sensors, and larger (APS-C, 35mm full frame) sensors. Sony's mirrorless, and Nikon's D850 & z6 / z7 bodies all have BSI CMOS sensors. – scottbb Jul 12 '19 at 21:16

3 Answers3

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Even if you had a square sensor, composing for landscape and portrait simultaneously would require leaving a lot of room around the edges for cropping, which would cause you to "lose quality" for both formats.

Use the format most suitable for the target platform. If you really need multiple, incompatible formats, consider using a multi-camera setup.

Apparently square sensors are made and used in the aerospace industry, and many cameras do provide a 1:1 crop setting. However, I am unaware of any consumer camera that contains a native 1:1 sensor.

  • There are medium format cameras with a 5:4 aspect ratio.

  • The closest, commonly available format is 4:3, found in micro-four-thirds cameras, many medium-format cameras, compact cameras, and cell phones.

When the desired aspect ratio is known ahead of time, it's "best" to make a sensor directly in that aspect ratio to fit within the imaging circle. The problem with square sensors, when non-square, rectangular aspect ratios are desired, is...

  • A non-square crop from a square sensor that fits within the imaging circle would leave large portions of the imaging circle unused.

  • A square sensor that completely covers the imaging circle would have unusable corners. It would also have to be larger than necessary, which would increase manufacturing costs and defects.

    A camera with such a sensor would likely also be unmarketable. Consider what would happen if a manufacturer put a medium-format sensor in a full-frame body, or a full-frame sensor in an APS-C body. Consumers would consider the unused sensor area and lack of lenses capable of using the full sensor to be defects.

image

xiota
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  • Regarding the first point - the largest rectangle that can be inscribed in a circle is a square. So in that sense, a square sensor would actually maximize the portion of the image circle in use. You're right, though, that any rectangle will leave quite a bit of the circle unused... – twalberg Jul 10 '19 at 15:35
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    @twalberg - "if a non-square, rectangular aspect ratio is desired" - so you'd have to crop within the square, reducing the used area compared with if a rectangle with the proper aspect ratio were used in the first place. – xiota Jul 10 '19 at 16:34
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    The only case where a square is the maximally-useful area is when the result you want is also that same square. – mattdm Jul 10 '19 at 22:01
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    It is trivial that, if you want to make arbitrary crops and are constrained to use a rectangular sensor, then a square is indeed the best choice in terms of losing the least sensor area. –  Jul 11 '19 at 09:51
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    @tbs That's manifestly not true. Look at the diagram in this answer. For any given non-square aspect ratio, you can fit a larger rectangle in the image circle than you can fit into just the square. And consider that cameras can be easily designed so that 90° rotation is a simple matter. And additionally, excepting the special case where shift is wanted, a center-aligned rectangle is preferred. – mattdm Jul 11 '19 at 11:51
  • Note "Arbitrary crop" vs framing, as in after capture: Worst case arbitrary edge-to-edge 2:3 crop from a square sensor uses 42.5% of the effective image circle. Worst case arbitrary edge-to-edge 2:3 crop from a 2:3 sensor [Taking a portrait crop from a landscape image] is using 26.1% of the image circle. - Square is flexible in post, and the less square the sensor is the less flexibility you get in post without losing out on capture area. – TheLuckless Jul 11 '19 at 18:40
  • @TheLuckless On average, when cropping for both landscape and portrait simultaneously, the loss of imaging area will be the same. However, when the desired aspect ratio is known, using a sensor that is already in that format is superior to cropping from a square. In the 3:2 example, 58.8% of the imaging circle is used, compared with 42.4% when cropping from a square. – xiota Jul 11 '19 at 20:49
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There are cameras with sensors that are much closer to square, namely medium format cameras, though they’re admittedly not perfectly square. (See https://www.adorama.com/alc/5-best-medium-format-digital-cameras). But the shape of the sensor turns out to be largely of academic interest as medium format cameras are overkill for your need, they’re not cost-effective, and they entail all sorts of practical limitations with respect to video capture.

It’s going to be best to just use a standard digital camera and crop. Some cameras offer in-body cropping, but but likely not in video. More likely, you’ll just crop in post. But to facilitate composition during capture, some cameras offer square grids on the monitor while shooting. Even this is, admittedly, a bit hit and miss. (E.g. the “square” gridlines on Sony a7Rii are fine for stills, but are a bit off in video).

Regarding how to perform square crop in post, it just depends upon your video processing software. For example, in Premiere Pro, you can just go into “Sequence” » “Sequence Settings” » “Video” » “Frame Size”.

Robert Ryan
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The Panasonic DMC-LX100 does not just provide for several different aspect ratios ("Multi Aspect Ratio") covering the image circle with about 12MP in more or less all aspect ratios except 1:1, it also offers "aspect ratio bracketing" which produces several images in different aspect ratios at once.

Panasonic has a few cameras with that feature. It doesn't, though, provide for landscape and portrait at the same time. Haven't heard from others doing the same, but then I haven't actually looked.

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    OP asks about a camera with a square sensor. Your answer describes a camera that doesn't even allow for 1:1 crops. – xiota Jul 11 '19 at 00:54