[Solved] Full HD Picture sharper than Video

[Letni]

Hey people 

I've got a question.
Why is a picture in Full HD (1920x1080) resolution, sharper than a video in Full HD (1920x1080)?

(add Infos)
Canon Eos 650D
Sigma F1.4 30mm DC A

Settings: 1/60 f1.4 ISO 400

  Full HD Picture
Full HD Video

thank you before you in advance. 

[dmilligan]

Lossy video compression and the fact that 1080p video is upscaled from a slightly lower resolution.

[Letni]

ok, thanks for the information.
Maybe Do you know from which resolution 1080P is extrapolated?

[Audionut]

There is no interpolation for video either.

[dmilligan]

1728x972 if memory severs me correctly. The reason is that to get to a resolution close to 1080p Canon does line skipping on the sensor, rather than a crop so that you get the full FOV of your lens. I think it would be too processing intensive to try and do a downscale from full resolution (i.e. to difficult to read and process that many pixels in realtime). You camera is 5184 pixels wide so the best they can do is take 5184 / 3 = 1782 (with the corresponding height) and then upscale that to 1920x1080 so they can call it '1080p'. Higher megapixel cameras like 5d3 have enough pixels to do true 1080p by line skipping.

[Letni]

My questions are therefore answered and I thank you for that.

THX