understanding 4:3, 16:9, 3:2

[ThirtyWest]

Hello,

Does 3:2 imply the same horizontal field of vision (or angle of vision depending on how we're talking) is maintained and the vertical is adjusted?

I know 16:9 is just 4:3 with the top and bottom missing data.

What I'm asking is if the sensor area, horizontally, is reduced in 3:2?

I don't think the mavic air 2 can do anything but 4:3, 16:9, but I'm doing some math and I see others can.

 

[zocalo]

It depends on the sensor, but if 3:2 is available than it is generally the full resolution of the sensor and is mostly used for stills as it equates to aspect ratio of the 35mm film format. Both 4:3 and 16:9 are more usually used for video (analogous to PAL/NTSC/VGA and widescreen respectively), and tend to be cropped down from the full resolution of the sensor in at least one direction, although there are video optimised sensors that have native 4:3 or 16:9 resolutions as well.

As an example, on the M2P the sensor is native 3:2 with a max stills resolution of 5472×3648 (~20MP), with the various video resolutions being cropped and/or interpolated out of that depending on precise resolution and options selected. The M2Z however has a native 4:3 sensor with a resolution of 4,000x3,000 (12MP), and crops/interpolates video from that.

 

[ThirtyWest]

but the physical sensor usage. is the left to right visible area the same on all three (4:3, 16:9, 3:2) and it's the vertical the is adjusted? Or, when in 3:2, does some of the horizontal get clipped?

 

[EsaT]

but the physical sensor usage. is the left to right visible area the same on all three (4:3, 16:9, 3:2) and it's the vertical the is adjusted? Or, when in 3:2, does some of the horizontal get clipped?

Depends on camera/sensor.
If sensor is the "most rectangular", all other aspect ratio images come for cropping bottom and top.
If sensor is "less rectangular", more rectangular aspect ratio images come from cropping left and right.

Though 3:2 is usually the widest/least rectangular sensor in cameras used for still images and hence 16:9 is cropped.

 

[ThirtyWest]

Thanks.

 

[zocalo]

As EsaT said, it depends on the sensor again. Most sensors are now made with video in mind, so the horizontal resolution is usually selected as an exact multiple of a video aspect ratio, e.g. for 1080p (1080x1920) it might be 3840 or 5760 pixels giving 2x or 3x ratio. Each square of pixels can then be sampled to provide a single pixel of the output video much easier than they might if any interpolation were needed.

Even so, it's not at all uncommon to find either a slight crop in the horizontal axis as well as a much larger crop in the vertical, or some additional pixels in the horizontal axis that are not used by stills but are used to avoid a larger number of photosites going unused in video mode. The former approach is usually to make downsampling from the higher resolution sensor to the chosen output video resolution much easier by having a round, or reasonably round, ratio of photosites to output pixels. Which cropping approach is best really depends on what your primary usage case will be, stills or video - if it's video then having a slightly more panoramic sensor than a typical still resolution like 3:2 will mean a lower stills resolution, but still provide an optimised resolution for video with fewer photosites overall.