A77 Question: How much of sensor is used for video?

Started Sep 19, 2011 | Discussions thread
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A77 Question: How much of sensor is used for video?
Sep 19, 2011

This may sound like a silly question, but I can't seem to find the answer anywhere I look. Technically, this question can apply to majority of the DSLRs that shoot video:

Does anyone know how much (percentage or resolution) of the sensor is used for video?

I know the max video resolution is 1920x1080 and that it uses an electronic stabilization for video, thus eating some pixel height and width there. But does that mean that out of 6000x4000 pixels, when video is shot it is only using 1920x1080 of them on the sensor? Or is it using a larger amount of surface of the sensor (say 5760x3240 or 3840x2160) and scaling it down to 1920x1080?

The reason I am curious is for a few reasons:

One of those reasons is how it would effect your view through the lens. If it is "cropped" down to just 1920x1080, then wouldn't your crop factor on the lens multiply greatly? So a 50mm is no longer a 75mm equivalent, but maybe closer a 125mm or greater (just guessing here)? Also, if this is the case then it would be harder to get a wide angle view.

The other reason is pixel size. If it is using the same pixel count as say a 16MP APS-C sensor, then the 16MP sensor would have a larger surface area being used for video and the potential for better video quality.

I'm not trying to bash or knock one camera or the other for how the video is being done. This is just simply something I am curious to know how it works. I haven't had the opportunity to get my hands on a A35/55 or even the NEX cameras to experience myself. I do have an A77 on pre-order that will be replacing my A700 and I look forward to using the video capabilities on my little one that is due in January. But until then, any input or knowledge is great appreciated.



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