A7s APS-C Video quality äs good äs FF.?

B

benn

Well-known member
I have the motorized E-Mount 18200 and would like to know if the video quality is in the APS-c Mode on the A7s as good as in the fullframe mode? Anybody using this combination?
thanks Benn
 
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It's supposed to be a touch less resolution (James Miller says it produces less aliasing when doing 60p though). In my tests I don't really see the difference tbh... It's nice that if you use a fast 35mm 1.4 and switch to APS-C it's like having a ~52mm f2 on full frame. One prime lens does the job of two!
 
An important point with the 60p thing: 50/60p in APSC mode is supposed to be better than 50/60p in full frame mode only. It is presumably the same as 24/25/30p in apsc mode, which is a little bit softer than 24/25/30p full frame mode. Also there is less rolling shutter in APSC mode.
 
I have used the PZ 18-200 with the A7s now for about 10 weddings. Love it. The 60p thing is totally true in that it's almost free of moire and aliasing when in APS-C mode whereas 60p in FF mode has a ton. For that reason alone I returned my FE 70-200 lens because we shoot everything at 60p. Not 100% sure about sharpness difference when shooting at 24/30p in FF vs APS-C mode, but others here probably can give you more info on that.
 
Crop mode will use more of the center of the lens so it will appear to be sharper. HOWEVER.....Be aware that the noise floor is not as low in crop mode and the noise and any blocking artifacts will appear LARGER. As well. I've seen it first hand and it was the same with the GH4. Crop mode is great in decent conditions but you've been warned :) FF mode is THE mode for best overall quality.
 
This is what I've been going by:

Daylight 24/25p, tripod or not much movement: FF or APS-C, not much difference.
Daylight 24/25p, lots of camera movement/whip pans: APS-C only, reduces RS
Daylight 50/60p: APS-C only. No moire or aliasing that I can see, as opposed to FF mode.

Lowlight 24/25p: FF mode primarily, APS-C mode if ISO is below 12800 and its not too dark.
EXTREME Lowlight 24/25p: FF mode only. APS-C is noise city when it gets too dark.
Lowlight 50/60p: Make the choice between noise (APS-C) or moire (FF). Up to you.

I'm sure everyone will have their own way of doing things, but this has worked out well enough for me so far.
 
ok, so that means FF for 24p/30p and APS-C plus speedbooster for 60p/120p
thanks
(my camera is finally arriving in a few days)
 
morgan_moore said:
That image is magnified! Seems like a total non test. Surely test would be to move the camera back (or re lens) and equalise the FOV?

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The point is not to match the FOV but to show the difference in both modes. If I matched the FOV the results would be the same. Go ahead and try this for yourself if you like.

Using two different lenses just changes the variables.

In order to see the difference I had to enlarge the image to 400% at normal viewing the difference is very hard to see if at all and really isn't an issue. I would rather have the option to shoot in APS-C than not have the feature. My favorite Sigma 18-35 and Tokina 11-16 are fantastic in APS-C mode.

As for noise. I have been shooting in 4K with the GH4 and reframing in a HD timeline shows the noise a lot more. It's basically enlarging the noise in the image. A little Denoiser helps a lot. Something to think about if you intend to do this later with the Shogun and A7s.
 
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I shot a short on the a7s yesterday in a dimly lit room to try it out, just to do whatever and see what works or not. Started with FF but switched to APS-C when I realized my 24-70 zoom wasn't quite enough tele for me. Mostly close-ups of faces, but I couldn't really see any difference. Maybe a bit more noise, but I was in SLOG2 (Kholi's PP) and ISO 3200 the whole time, between +0.0 - +2.0 EV. Let's see what happens in grading.
 
Samuel H said:
ok, so that means FF for 24p/30p and APS-C plus speedbooster for 60p/120p
thanks
(my camera is finally arriving in a few days)
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Congrats man (I know you've been wanting it) can't wait to see what you crank out.

I'm sort of resolved to shoot everything in APS-C mode as my fave glass is Sigma 18-35 but as I have a single coated 35 F/2 + 55 1.2 nippon/nocktor I'm considering doing some testing to see if I like the more vintage/flare susceptible/softer lenses on the FF better. Any thoughts or speculation on this?
 
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