Panasonic GH4 vs Sony A7S compared - who wins the 4K battle on paper?

[Joel]

The Lens Turbo (.72x Speedbooster clone (.71x)) works with vignetting: 

I spoke with the guys at Metabones last year and they assured me that a speed booster with MF lenses is possible and they are looking into it. You got vignetting because of the adapter. 

[Brian W. Allan]

I spoke with the guys at Metabones last year and they assured me that a speed booster with MF lenses is possible and they are looking into it. You got vignetting because of the adapter. 

Don't forget the 0.7x gain in focal ratio, regardless of vignetting and a wider FOV...  This is very important to me for astro/nightscape photography.

[yiomo]

Unless I missed something on the various posts that compare the two (including this one), no one seems to mention that IN camera the A7s does 4:2:2 , whereas the GH4 does 4:2:0. 

 

Isn't that enough to expect a much better colour rendition?

[jcs]

A7S does 420 internally: 422 externally.

[Nikkor]

Unless I missed something on the various posts that compare the two (including this one), no one seems to mention that IN camera the A7s does 4:2:2 , whereas the GH4 does 4:2:0. 

 

Isn't that enough to expect a much better colour rendition?

But the G4 does it in 4K, the A7s only in 1080p. The 4K 420 will have more color resolution than the 422 1080p.

Oh and it's not even true...

[jcs]

http://pro.sony-asia.com/pressrelease/asset/570730/section/broadcastreleases (states 8-bit XAVC-S is 420; 10-bit is 422).

http://***URL removed***/news/2014/04/06/sony-announces-alpha-7-series-full-frame-mirrorless-with-4-2-2-4k-video-output (420 for internal 8-bit 1080p recording)

[yiomo]

Thanks jcs, i got confused with all this numbers. I guess there goes that advantage. But there are still a few things more..

 

First time in my life I am so eager about a product and Sony won't give this camera to few people to show us some footage. No wonder why so many people hate Sony. It seems it doesn't care so much about being customer friendly. Besides 2 clips, everything is still on paper. 

[jcs]

yiomo- I was going to wait for the A7S, but after realizing that the "FF advantage" is a myth, I purchased a GH4. Time will tell if the A7S is a better camera, however it will be because of the sensor technology, image processing, and color science and not the sensor size (more info here: '?do=embed' frameborder='0' data-embedContent>> ).

[sunyata]

This is from sony's specs pdf:

 

Clean HDMI output:

 

1080 60i compatible device:

3840 × 2160(30p/24p) / 1920 × 1080(60p/24p) / 1920 × 1080(60i),YCbCr 4:2:2 8bit/ RGB 8bit

 

1080 50i compatible device:

3840 × 2160(25p) / 1920 × 1080(50p) / 1920 × 1080(50i),YCbCr 4:2:2 8bit/ RGB 8bit

 

and this is from an article on "photopop" about the A7s:

 

 http://www.popphoto.com/gear/2014/04/atomos-announces-first-4k-recorder-sony-a7s

 

"Like the Samurai and Ninja Blade, Shogun allows the recording of pristine, 422 10-bit images straight from the camera sensor captured using 4K/HD ProRes, Uncompressed RAW Cinema DNG or Avid DNxHD codecs."

 

which is a little misleading to say the least, since they also don't mention in that same article that the A7s is outputting 4k 8bit 4:2:2.

 

4:2:2 is better than 4:2:0, but believe it or not, it's not a lot better. I'm curious about the RGB option though.

 

I did this to show bit depth and sampling differences in grading a while back. Pause when you get to the 8bit 4:2:2 4k, in particular when it goes red, to see the artifacts. This also shows a "reformat" in full 32bit float space from 4k 8bit 4:2:0 to 2k float.

 

 

but bottom line, if you get the shogun, you can then get actual 10bit 4k 4:2:2 from the GH4 and not from the A7s and that makes a huge difference in being able to actually utilize all that faux cine-like gamma in post.

[yiomo]

There are two things that the Sony sensor does better for me. First it gives me a couple more usable iso stops and second the DR seems superb.
Regarding the 10 422 from the GH4, I saw a short film made using yagh and even though on specs it looks better, it still cannot match the FullHd 8bit or 4k 8bit from Sony's clips.

I am very tempted with the GH4 because it looks like a better conceived & made camera overall, but strictly on image quality I think that even with a limited 8bit Sony wins. At least for now. I check everyday for new footage from GH4 but nothing comes close. It is only people who experiment with grading a lot who give decent results that try to mimick (using software) what Sony does better using a better sensor.

In my humble opinion of course.

[sunyata]

I've seen those clips too and I know what you mean.. it's just that I work in an environment where 8bit will get noticed, I tried sliding it in once before on a "D" title because I was slammed on time and drive space (and i thought the uncompressed looked fine).. a production person in QC flagged it by running a 4 or 5 stop curve on my job in a screening room. It's like synonymous with 1) not knowing what you're doing or 2) oops, a mistake. I went with #2. I wish the A7s did 10bit log though, not cine-like integer but actual log. Seems to be the ideal camera for that.

[yiomo]

 

4:2:2 is better than 4:2:0, but believe it or not, it's not a lot better. I'm curious about the RGB option though.

 

 

I find it so confusing that there are people who say that 8bit vs 10bit is not a really noticeably big difference vs the others who claim the opposite. And now I read that 4:2:2 is not really different than 4:2:0.  But then you have other professionals who claim the opposite. Who to believe ! I trust my eyes for now.

 

In any case both the in camera GH4 and A7S footage looks very usable to me. I am not a broadcasting technician, but then again my doc that went to festivals and found distribution to be broadcasted on TV was shot on a 5d with a horrible DR and h.264 codec. Now we are laughing at it, but 4-5 years ago it was king and very well usable and very much used. 

 

Perhaps some have reasons to pixel peep so much. Personally, I just can't bother anymore.  Both cameras at 8 /420 seem to provide great results. I just prefer the sony image.

 

 

Den praises the slog2. So who knows. Perhaps it is true, perhaps it is just the salary talking. If this excuse of a marketing department they have in Sony would give the camera to more people to play with, we'd have a better idea.

 

Now, if a bunch of people come in the open and start claiming that the A7s produces an unusable image, in any terms, I will probably pass. We know it's not the case with the GH4, I doubt it will be with A7s. 

 

I guess we'll have to wait a couple more months and see. Hell, the can't even post a price for us Europeans. How incompetent are they??  I've never had any Sony stuff and I guess if I get this camera, I will join the herds of people who hate that company but love its products.

 

[noone]

 

I find it so confusing that there are people who say that 8bit vs 10bit is not a really noticeably big difference vs the others who claim the opposite. And now I read that 4:2:2 is not really different than 4:2:0.  But then you have other professionals who claim the opposite. Who to believe ! I trust my eyes for now.

 

 

I think it might be that people can not really tell the difference but those who's job it is to look and use computer equipment to do so can.

[Birk Kromann]

I think people tend to forgot DR. We can discuss this forever, but resolution and but depth isn't everything. IMHO the most difficult thing to correct/change is DR ergo is should be the highest priority. To me that gives the nicest images and is why the A7s looks so much nicer.
And that's talking from a professional point of view.

[sunyata]

 

I find it so confusing that there are people who say that 8bit vs 10bit is not a really noticeably big difference vs the others who claim the opposite. And now I read that 4:2:2 is not really different than 4:2:0.  But then you have other professionals who claim the opposite. Who to believe ! I trust my eyes for now.

 

 

 

 

If you pause the test I posted when it gets to 4:2:2 and 4:2:0 you can compare..

 

It also covers the reformatting of 4k 8bit to 2k 10bit myth (I'm taking it into float space actually but it's got all the overhead you need to test the theory). You won't see a noticeable difference in "workability" of the 4k after it has been reformatted to 2k HD in float space. 

 

I think a lot of the confusion is really coming from the camera companies that sometimes give you the pertinent info, and other times they leave it out while hyping things like pixel count. I've noticed they also are guilty of mixing terms, like "log" and "dynamic range" in their specs.

 

i.e. You can't have "log" gamma in integer 8bit space, so calling your gamma profile sLog is a little confusing. Another good one, they seem to have propagated the belief that dynamic range is the "min" and "max" luma values, at least I've heard it described that way on blogs.. which would mean 0 black to 3 (which would be pure white) in a 2bit file is wide dynamic range.

 

I got one more! They also have convinced people that low contrast is the "film look", whatever that means. This is the most confusing one. Movies don't look low contrast when projected (movies like Transformers, LOTR are over saturated and high contrast).. it's a pipeline issue only to preserve film gamma and it really requires 10bit log to equal film print density, everything else is just low contrast, so they should call it that.

[Nikkor]

DR is worthless if you have to put it into 255 values (8bit), if you shoot flat = banding, if you shoot with a normal tone curve=low DR. Anyway, that doesn't mean the a7s will be terrible.

[sunyata]

DR is worthless if you have to put it into 255 values (bit), if you shoot flat = banding, if you shoot with a normal tone curve=low DR. Anyway, that doesn't mean the a7s will be terrible.

 

Yea, I agree, the A7s is certainly not terrible. I don't think the DR your sensor can capture is worthless if it's crammed into 8bits either, but it's not nearly as workable in post.

[Birk Kromann]

Depends how good your colour grader is and how bad you light things.

[Nikkor]

Anyway, if the picture style engine is good enogh you can always pick a good one for everyshot.

[hmcindie]

DR is worthless if you have to put it into 255 values (8bit),

 

Say that to GH2 owners.