IQ of a6300 4K -> 1080p Versus a7s 1080p ?

[Mark Romero]

Has anyone done much comparisons between the 4K footage of an a6300 AFTER it has been transcoded down to 1080p with that of the original a7s shot in 1080p?

Is there really that much of a difference in terms of details and other image quality aspects?

And I asking specifically for footage recorded in camera, not to an external recorder.

Thanks in advance.

(Still wishing that the D750 video had more detail... and that I didn't have to send it in to Nikon for a recall from the latest service advisory released yesterday.)

[PannySVHS]

Hey Mark! A7s has pretty much pixel perfect 1080p and should compare very well to downscaled 4K.

[ade towell]

I think the colour is much nicer with the a6300, the 4k is pretty spectacular, but rolling shutter is really bad 

[hmcindie]

I have this weird memory of the A7s looking better in some aspects (slog had more information, less rs than a6300 in 4k) and worse in others (a7s mark I had this interesting halo/black line effect with strong highlights. I hated that with a passion). A7s was fullframe and that gave it a more interesting look than the a6300.

If I'd have to choose, I'd still use the A7s mark I over the a6300.

[maxotics]

19 hours ago, Mark Romero said:

Has anyone done much comparisons between the 4K footage of an a6300 AFTER it has been transcoded down to 1080p with that of the original a7s shot in 1080p?

Is there really that much of a difference in terms of details and other image quality aspects?

Yes and it is significant.  The A7S has 12 million pixels over a 24x26mm sensor, the A6300 has 24 million pixels over a 16x24mm (smaller) sensor.  

You want the best 1920 x 1080 pixels in your video frame.  You'd want the largest camera sensor pixels filling that frame, because the larger they are, the more they're sensitive to light.  The A6300 will need something like 2 pixels to capture the light one pixel can in the A7S.  Because there is space between pixels, you lose sensitivity there, plus all the electronic work you need to combine those values. 

In really good light, the A6300 will probably match the A7S.  HOWEVER, as soon as you start moving away from 400 ISO exposure the A7S will begin to crush the A6300.  

As others have pointed out, if one was going to only use the camera for video (or 12 megapixel photograph) there really is no competition.  I have an A6300 and A6000.  If it wasn't for the external mic and USB powering of the A6300 I'm not sure I'd keep it.  Yes, the 4K is really nice in the right situation, but my wife wouldn't notice the difference between the A6000 and A6300 4K downscaled video.  For YouTube stuff, the A6000 is still a monster (especially when the new firmware gives you XAVC-S at 50mbs.  If I could trade the A6300 for the A7S 1 I would in a heartbeat   

[mercer]

Sorry this is slightly off topic, but not really... I am, or will be, in the market for a second camera for casual shooting. I've narrowed it down to a few choices, some 1080p, some 4K, and some things I've been noticing while watching a bunch of videos on Vimeo, is that cameras with 12mp sensors have some serious, for lack of better word, mojo to them.

I've noticed it with the a7s, the LX100, the AF100, and most recently with my slight interest in the A7ii.

So, is there something technically relevant to this anecdotal mojo I'm noticing?

[Mark Romero]

19 hours ago, ade towell said:

I think the colour is much nicer with the a6300, the 4k is pretty spectacular, but rolling shutter is really bad 

Thanks for the note.

When you say the 4K is spectacular, do you feel that way once it is transcoded / exported as 1080p ?

5 hours ago, maxotics said:

In really good light, the A6300 will probably match the A7S.  HOWEVER, as soon as you start moving away from 400 ISO exposure the A7S will begin to crush the A6300. 

I would be using it primarily at Higher ISOs (1,200 to 6,400). 

[ade towell]

the a6300 4k exported as 1080 to me looks nicer than the a7s but then I really didn't like the colour science of the a7s and sold it pretty quickly. The colour is much improved I think with the a6300 and it is great in low light up until about iso 6400 - then the a7s pulls ahead.