Quick review of A7S vs GH4

J

jcs

Veteran
Quick Review A7S vs GH4

Where the GH4 is better:

  • Build quality
  • Viewfinder
  • Flip out screen
  • User interface (by a mile)
  • Battery life (by a mile)
  • Color science
  • Skin tones
  • Rolling shutter (by quite a bit)
  • Detail (internal 4K and 4K to HD)
  • Noise grain (mostly pleasing monochromatic)
  • Built-in flash for stills
  • When lens size is included, a much smaller package
  • Can shoot best quality on < 64GB Class 10 UHS-1 cards (A7S requires >=64GB cards for XAVC-S)
  • Price
Where the A7S is better:


  • Low light (it's very good however the noise grain is colored and multi-spectral; not as pleasing as GH4's mostly monochromatic fine-grain noise)
  • Shallow DOF (add a SpeedBooster/focal-reducer to the GH4 and this isn't much of an advantage)
  • Audio (no buzz; not tested thoroughly yet though)
  • If a 5D3/full-frame owner: can use existing lenses with a non-focal-reducer adapter (with similar DOF)
  • Super 35 mode allows use of many NEX lenses (some aliasing)
  • Auto ISO
After having worked with 5D3 14-bit RAW and RED RAW, where the unmodified RAW looks pretty good straight from the camera, Slog2, Cinegammas, Cine-D/V, etc., start looking like gimmicks. None of those gamma curves are providing a real increase in dynamic range. In certain cases they may provide more information for 8-bit compression, however they can be tricky to use and must be exposed carefully. I've had the best luck shooting Natural with the GH4 (and no crazy curves), though iDynamic is helpful sometimes (appears to be local pixel group based processing vs. a simple curve. The A7S has a similar feature (disabled if any picture profile or effect is active, though)).

Rolling shutter is very challenging on the A7S in full frame mode (worse than the 5D3): not very usable for handheld without a lens with IS and/or a solid rig. The A7S menu and button system is a mess. The FS700 has a better design! (many folks find the FS700 non-intuitive to use).

Both cameras have aliasing and moire in slow motion. Perhaps similar to the FS700 in 240fps mode (not as bad as FS700 480+fps modes). I haven't done a direct comparison, however the FS700 120fps and less slow motion is better than the GH4 and A7S (all slow motion modes).

While the A7S isn't quite a one-trick-pony (low light), the GH4 is a much better all around camera. I haven't had the A7S as long as the GH4, so there may be other elements that make the A7S more compelling, yet to be discovered.
 
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* "Shallow DOF (add a SpeedBooster/focal-reducer to the GH4 and this isn't much of an advantage)" --> not true, GH4 in 4K with speedbooster is still 1.63x crop (1080p is soft and muddy, and still 1.42x)
* "None of those gamma curves are providing a real increase in dynamic range" --> slog2 on the a7s definitely does. All other modes clip a lot of stuff that is still alive using slog2.

Apart from that, I appreciate your comments. I wouldn't have guessed the build quality seems better on GH4 than on a7s, for example.

Could you shoot something like this, comparing DR of a7s+slog2 with GH4 with whichever profile you think is best?
 
squig said:
So do you think the MK3 raw files have more dynamic range than the A7s?
Click to expand...

More absolute sensor dynamic range, no. I believe other folks have shown the A7S has about 2 stops more DR vs the 5D3. That said, the FS700 also has about 2 more stops vs. the 5D3, however 5D3 RAW is far superior to the FS700 (AVCHD) and to my eyes has much better color science vs the FS7Q. The FS700/FS7Q rock for slomo.

Regarding the A7S color science: when doing a 'standard' test at my desk, which has many different color temperature lights (incandescent, fluorescent, and LED (monitors)), I found that when using Slog2 there were greenish/yellow patches in skin at certain luma levels: not easy to correct in PPro (need qualifiers, etc.; not fixable with WB or curves (without some sort of masking)). This tells me that something funky is going on with perhaps some kind of 3D transform in the camera. The FS700 also had problems in this situation (and many other similar ones). The 5D3 and GH4 do much better.

So far the 5D3 RAW is still by far the best color experience in terms if accuracy and nothing dramatically weird happening to colors as exposure changes. So far I prefer the A7S with no color profiles or other effects: looking to get an accurate representation of the scene compared to what the eye can see and no strange surprises (as with Cine-D on the GH4).
 
Samuel H said:
* "Shallow DOF (add a SpeedBooster/focal-reducer to the GH4 and this isn't much of an advantage)" --> not true, GH4 in 4K with speedbooster is still 1.63x crop (1080p is soft and muddy, and still 1.42x)
* "None of those gamma curves are providing a real increase in dynamic range" --> slog2 on the a7s definitely does. All other modes clip a lot of stuff that is still alive using slog2.

Apart from that, I appreciate your comments. I wouldn't have guessed the build quality seems better on GH4 than on a7s, for example.

Could you shoot something like this, comparing DR of a7s+slog2 with GH4 with whichever profile you think is best?
Click to expand...

Thanks Samuel. I don't have time for technical video tests to shoot, edit, and post, however I will get the A7S into one of our upcoming model shoots (ideally getting the same footage with the GH4).

The point about shallow DOF wasn't meant to mean the GH4 will have the same DOF as FF: Super 35 (1.42 and 1.63 are close) is plenty for decent shallow DOF. FF is cool, however Super 35 / 1.5-ish crop is a pretty good functional sweet spot.

I think we all agree that sensor dynamic range cannot be extended with any gamma curves (from the noise floor to sensor clip). All the gamma curves can possible do is re-distribute the steps and perhaps if exposed correctly get more useful information stored once truncated to 8-bit and compressed. Slog2 on the FS700 wasn't (isn't) very useful for 8-bit AVCHD.
 
^ Nothing can beat the DBolex in that front (edit: jcs beat me to it, it was so obvious...)

True, no curve will ever increase the DR captured by the sensor. But some curves crush a very big part of it, slog2 keeps it mostly alive. But yes, 8-bit, trade-offs everywhere.
And of course first things first, don't worry about the test. Though I would volunteer to process the footage if anybody is willing to give it a go.
 
jcs said:
Where the GH4 is better:

  • ...
  • Color science
  • Skin tones
  • ...
  • Noise grain (mostly pleasing monochromatic)
Click to expand...
You're kidding, right? That's not been my experience... The GH4 color science is unnatural at best, and downright ugly at worst... Shadows are far too saturated (grass and leaves on overcast days still looks neon), skin-tones are often dull and plasticy, and the highlight rolloff is way too sudden.

And the last word I would use to describe the grain on the GH4 is "pleasing"... It's chunky macro-block city! It looks much finer when recorded externally, but personally, I was pretty disappointed by how much the noise levels in internally recorded footage interfered with my attempts to grade it to make it feel a little less like a $400 consumer camcorder was trying to have sex with my eyes.

I'm being a little harsh, but I've been frustrated by the GH4's lack of predictable results (some shots look fine and some look yuck!) and the fact it makes me feel stupid because I can never find the button or menu-option I'm looking for (not a problem I've had with Canon or Sony cameras...). Personally I'm longing for a more subtle expressive image – particularly more dynamic range and gentler highlight rolloff (A7S on it's way!).

There I've said it! I'm breaking up with my GH4!
 
jcs said:
More absolute sensor dynamic range, no. I believe other folks have shown the A7S has about 2 stops more DR vs the 5D3. That said, the FS700 also has about 2 more stops vs. the 5D3, however 5D3 RAW is far superior to the FS700 (AVCHD) and to my eyes has much better color science vs the FS7Q. The FS700/FS7Q rock for slomo.
Click to expand...

You're not the first person to mention the yellow blotches in the skin, it's a scary one.

I was just chatting to my cinematographer about whether we should give the A7s a miss on my feature but we came to the conclusion that it would be good to still have it on hand. I don't want to go any higher than 3200 ISO with the MK3 and we're going to be forced to go higher than that on a few shots since we're not rolling with any white trucks so the A7s could save our arses in those instances. The MK3 is fine for me for slo-mo because I have a couple of 1.5x Iscoramas.

Do you think it's advantageous to convert the 5D DNGs to LOG in ACR?
 
S-log color is definitely funky on the A7S. Skin is easy fix in my experience though (which is playing with Roman's dpx files).
5dm3 RAW doesn't look like that much DR, but the image is nice and fat after postprocess, nowhere near the thin results of processed A7S s-log. Too bad there is no 10-bit recording in the A7S.

It would be interesting to see a number on the rolling shutter.
 
squig said:
Do you think it's advantageous to convert the 5D DNGs to LOG in ACR?
Click to expand...

You can do this if you like the available log-ish profiles (visionlog and cine-something, are there others?), but with Resolve 11 now featuring more raw controls than Resolve 10 it might be pointless. ACR is still maddeningly sluggish. You will also lose some precision even if you bake to 12-bit files, you will also lose the ability to tweak raw options during grading. Nothing beats grading from the raw files, imo.
 
I keep hoping something more practical than log comes out. One thing i do not understand is why highlights have to get up and die in standard color profiles. If i could just have a log profile with slightly darker black point.

Much love for the methodology of the f35, as it seems to be more about looking right than being a digital negative. Varicam was sort of like that too, but with less to work with. So many of the cameras now require post. Post should be about finesse and for specifics, not a needed step. Yet there is no middle ground between a standard picture style and log. C100 has wide dr, but i haven't used that yet.


As for the color reproduction between the gh4 and the A7s, from what i have seen, they both exhibit some weird skintone in wild light. A7s has a range from beautiful subtle tan to magenta and yellow bias, user error may have been at play(edit, looks like it was a cheap variND type of filter causing the color shift, see vimeo link below...) But, i could imagine the gh4 doing well in a studio situation, or where a sharp and popping image were needed. The A7s looks far more subdued and nuanced. But factor in rolling shutter and the gh4 seems way more pro/broadcast friendly.

The next/current battle is on display tech. The subtle shift in highlights on any camera with more than 11stops latitude is going to be difficult to display with current products and compression methods.
http://vimeo.com/m/99584477
 
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To the OP: Obviously some of this stuff is subjective, but I disagree with some of your opinions.

Build quality - the A7s is a pretty solid chunk of metal, much less plastic than the GH4, the A7 body is smaller too
Viewfinder - the GH4 still smears the edges like the GH3 - IMO the A7s VF is much better
I do prefer the versatility of flip out LCD, but Sony's LCD is easier to see in bright light - I do wish is was touch screen though
User interface is a personal thing, but Sony's is great, it now resembles Canon's with tabs on top and its logically organized
Skin tones - another personal thing - but this is one reason why I sold my GH4, I just didn't like the way they looked, especially in the sun which is where I shoot a lot
So far 1080p in the A7s is looking really sharp and detailed, the superior DR and highlight recovery is much more valuable for me than a little more more sharpness, the A7s 1080p looks better than any other DSLR 1080p
The GH4 gets pretty noisy at 1600, 3200 was unusable for me - another reason why I sold my GH4 - it flat out sucks in low light, the A7s is nice at 12,800, the GH4 is rubbish at 6400
Even with a speedbooster, the GH4 doesn't do wide and standard legacy glass FL's justice, my cheap OM 21/3.5 loses all its magic on M43, again depends on preferences, but this was the final nail in the coffin for my GH4, all my lenses were bought with FF in mind and it would be expensive to replicate what I have in M43

The GH4 is faster when shooting stills, but again noise at moderate ISO's demonstrates the limits of the M43 sensor, it loses detail and gets pretty noisy above 1600, 6400 looks better on my A7 and the A7s is even better in that regard. There's a lot more highlight and shadow recovery in raw's from my A7 and the files are much cleaner, and I'm sure it'll be better once the A7s raws are supported.

Cost is an advantage for the GH4 body, but depending on your lens lineup, it can get pretty spendy - and in many cases impossible - if you try to match FF FOV and DOF. Something like the CV 21/1.8 or OM 21/2 is basically impossible in M43 land, same goes for a 24/1.4, 35/1.2, 50/1.2, 85/1.4 and so on. Even something like a cheap FD 20/2.8, or any $50 50/1.4 will cost you much more to match in M43. The CV 0.95 lenses are soft WO. EF lenses are cheap to adapt to e-mount, only needing a $85 generic adapter with electronics instead of a $600 booster. Obviously native M43 lens selection is better, but I prefer MF when shooting video and focus by wire lenses just don't do it for me. 4k crop on the GH4 kills the wide end even more.

Lens size is a given when the sensor is 4x larger, the lenses will be bigger too, that's unavoidable.

YMMV
 
I would really love to see some good side-by-side comparisons.

Especially:

- dynamic range
- skin tones
- 96fps (GH4) vs 120fps (a7s)

What I have seen so far the a7s doesn´t look any better than the GH4 regarding the noise - maybe even worse...
 
What ever happened to Den Lennie's GH4 A7s comparison that he announced? He said he got a paying job that prevented him from completing the edit, but that was weeks ago.
 
AlexLeith said:
[/LIST]You're kidding, right? That's not been my experience... The GH4 color science is unnatural at best, and downright ugly at worst... Shadows are far too saturated (grass and leaves on overcast days still looks neon), skin-tones are often dull and plasticy, and the highlight rolloff is way too sudden.

And the last word I would use to describe the grain on the GH4 is "pleasing"... It's chunky macro-block city! It looks much finer when recorded externally, but personally, I was pretty disappointed by how much the noise levels in internally recorded footage interfered with my attempts to grade it to make it feel a little less like a $400 consumer camcorder was trying to have sex with my eyes.

I'm being a little harsh, but I've been frustrated by the GH4's lack of predictable results (some shots look fine and some look yuck!) and the fact it makes me feel stupid because I can never find the button or menu-option I'm looking for (not a problem I've had with Canon or Sony cameras...). Personally I'm longing for a more subtle expressive image – particularly more dynamic range and gentler highlight rolloff (A7S on it's way!).

There I've said it! I'm breaking up with my GH4!
Click to expand...


I would agree with this - I haven't owned a GH4 but I've poured over footage from it and I really find it quite odd in it's colors in a very unpleasing way - personally. So far, from my 1 day with the A7S it's much closer to what I consider natural realistic color rendition than anything I've seen from the GH4 - including skin tones.

But like I said I haven't owned or actually shot with a GH4 - I gave that up after seeing the first few videos that came out.
 
I'll weigh in more as soon as the A7s arrives but from the early (best shot) material I've seen, both cameras can be coaxed into producing a very similar image overall. The biggest choice I had to make was how much I valued low light performance and in the event world, that's a BIG ONE. I got some gorgeous wedding footage with the GH4 and the shooting experience was incredible. 4k takes up no more space than 1080p (100mbps) and the ability to have that detail on demand in such a compact form factor is amazing. The battery life on the GH4 was also mindblowing. 10hr wedding and I was barely halfway through the second battery. No record limit (in case you have a long ceremony and use it as a safety angle).

The Sony? I figure the subtle differences in color science and the low light is the enough to justify giving up the rest of the GH4's perks (not to mention MUCH more affordable price tag and glass flexibility). Heck, if it doesn't offer that much better of an image, I'll gladly return it, buy a speedbooster and take the savings. It's not a canyon of image quality that separates them from what I can see so far. Not nearly the divide some people are making it out to be anyway. See some of the better examples out there and you'll see what the GH4 can produce but still, early posts seem to always disappoint so I'm expecting the Sony to deliver a great image.

My advice for the budget conscience, bang for buck crowd that doesn't need crazy low light and who may be considering changing their glass based on this decision.....buy the GH4 and use Implulz or FilmConvert. Instant magical footage. Color science goes right out the window, practically. Non issue.
 
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