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Andrew Reid

Canon 1D C vs Sony A7S 4K - dynamic range - preview

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A7S + Shogun 4K in S-LOG exposed for highlights.

1D C the same, but 4K internal (Canon LOG).

1D C seems to have a dynamic range advantage. Maybe of 2 stops more usable information.

I don't understand why the A7S is dumping so much data in the shadows. Big holes in it and lots of noise.

Blacks should not be crushed like that in a LOG profile!

When you have a shot without a really hot area (like a window or light you want to expose for) you MUST bring S-LOG 2 up away from those lows to get a good image, even if it means putting the ISO to crazy levels.

The 1D C is different. It's applying ISO at an analogue level, and ISO 200 seems to have the same dynamic range as the other ISOs.

A7S needs to be at ISO 3200 as we know.

Not trying to justify my purchase here, just giving you some of my research early ahead of the blog post for commenting on. Will add depth to the final article to hear your thoughts.

But it seems 1D C is looking like a real bargain if the price keeps dropping...

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EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

I'm not sure if the focus is slightly of on the 1DC but the sharpness and detail the A7S is picking up is really good compared to the 1DC.

1dc-vs-a7s-dynamic-range-zoomed.jpg

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Focus is off a hair and different lens used so ignore that. Was purely concentrating on the spread of light from the highlight to the shadows.

But that blow-up reveals something else interesting...

The contrast of the A7S shot is much higher. You seem to have dark dots and the sellotape tab doesn't look right, kinda muddy and same colour as the rest of the board.

The 1D C looks like it contains 10x the colour and shades to the A7S shot.

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It appears there's an issue with the A7S's Slog2 via HDMI:

http://forum.atomos.com/showthread.php?53033-Sony-A7s-quot-breaks-quot-SLOG-2-on-it-s-HDMI-output!

My understanding is it's not really Slog2 via HDMI (try the same scene recorded internally). Someone mentioned something about messing with 0-255/16-235 ranges in post (not clear if for a fix or workaround).

vas- I would expect both the GH4 and A7S to provide more detail than the 1DC. Narrative work and people tend to look better softer, so many DPs use filters and other tricks to reduce detail. The 1DC's softness and color science are what give it a more filmic look vs. the other two cameras (which can also look filmic with filters and the right settings/post work).

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Guest Ebrahim Saadawi

I would think the a7s has more dynamic range due to cleaner shadows AND better highlight recovery, I mean Sony marketed it as 15 stops of DR at some point... so seeing it that far behind the 1dc/1dx sensor is quite shocking. Why are the shadows so noisy? I think there's something wrong here

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The 1D C looks like it contains 10x the colour and shades to the A7S shot.

​Exactly, more color but with out the light looking harsh.  Blown highlights is what makes for amateurish video which is why I can see professionals paying to get that image.

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A quick test in PS with ACR appears to show more DR with the A7S. More detail in the shadows and more recovery possible in the highlights. The A7S had more color noise, and is more magenta in the shadows (trying to correct overall color including shadows changed the board color too much (too much work to fix for this quick test)):

1DC_A7S.thumb.jpg.9e8bd869eaa42f2a42a283

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The A7s have significantly more shadow detail, albeit it with more noise. With Neat Video the A7s should comfortably match or exceed the the usable dynamic range of the 1dc. The lack of detail in the 1dc shadows might be an indication of aggressive internal noise reduction. 

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Either the 1dc's sensor has taken steroids or the a7s is not delivering its advertised dynamic range.  what was the a7s ev meter saying in spot mode on the highlight?  I recon you could have slammed the a7s harder on the highlight without the information breaking up.  maybe by as much as 1-2 stops harder.  I'm finding my s-log footage is looking the best it has done after ragging it by +1 to +2 stops on the highlights.  the zebras are useless on the a7s as is the metering when in s-log mode i am finding     

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Either the 1dc's sensor has taken steroids or the a7s is not delivering its advertised dynamic range.  what was the a7s ev meter saying in spot mode on the highlight?  I recon you could have slammed the a7s harder on the highlight without the information breaking up.  maybe by as much as 1-2 stops harder.  I'm finding my s-log footage is looking the best it has done after ragging it by +1 to +2 stops on the highlights.  the zebras are useless on the a7s as is the metering when in s-log mode i am finding     

​I'm pretty sure the A7S S-LOG is better internally. In 4K there's something not right.

Would have done my usual trick of 2 stops to the right but the highlight was already burning out.

Looks like Doug was right.

Anyone know a good restaurant that serves words?

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The Gh4 was't invited either;)

​It is in the upcoming 4K shootout I'm working on.

D750 sensor is actually bloody amazing. The stills are the best I've ever seen. The video is good for 1080p but obviously times move on

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As per the thread jcs linked to, I applied the levels fix to the a7s portion of the image. I also pushed the a7s white balance closer to that of the 1dc. The 1dc image remains untouched. The comparison would be better if the levels fix was applied to the prores and the WB applied in camera, but even just working with the jpg I think the a7s is the better image (more detail, better DR, less banding). Colours could be better but I'm guessing a7s was using s-gamut as opposed to cinema or pro colour.

Black level on the 1dc image seems to be 32(?)

The apperance of noise on the a7s image is reduced somewhat after the levels and WB fixes. And regarding noise, a comment from the same thread jcs linked:

One of the things I have noticed about all the Sony cameras I have had in recent years, (AX100, RX10, FS100 and FS700) is that they apply noise reduction into the CODEC processing circuit. HDMI does not have this noise reduction because it's not passing through the H.264 encoder (and noise reducer)

This is a good thing. You can apply your amount of noise reduction to your liking in post. The less processed my HDMI is, the happier I am. (In most cases)

1dc-vs-a7s-dynamic-range-a7slevelswbfixe

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The purpose really was to look at the source file and see the differences.

You can certainly grade it that's what you're meant to do with LOG.

Though even after grading I'm not happy with what's going on over HDMI with S-LOG. Needs a fix!

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The purpose really was to look at the source file and see the differences.

You can certainly grade it that's what you're meant to do with LOG.

Though even after grading I'm not happy with what's going on over HDMI with S-LOG. Needs a fix!

​Sony colors are indeed challenging, however don't you agree that for this test the A7S has more usable DR? It appears the A7S doesn't apply NR over HDMI, so unlike the internal NR of the 1DC, the A7S will need NR in post.

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I'm not seeing that. Very fine noise grain on the 1D C files and NR is off in the menus. The A7S shadows just look worse. Muddy unfortunately. Like Doug said earlier. He was right.

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Hey Andrew, I'm not seeing a 1DC DR advantage in your test image:

1DCvA7S.thumb.jpg.da95a1374f04dd288aaa12

I've marked a few areas where to my eye there's a lot more detail/SNR in the A7S shot vs. the 1DC. There's also purple chromatic aberration on the edge of the light and on the specular edge of the silver camera ring for the 1DC but not the A7S. I'm sure the 1DC is a better overall camera, especially skin tones, however it appears the A7S has more usable DR. 

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I'm not sure how you've graded that, it doesn't look like what I get. Might not be your fault, you are grading a heavily web compressed JPEG after all.

I get a stop more detail in the highlight and at least 1-2 stops cleaner shadows...

Top A7S 4K S-LOG and bottom 1D C MJPEG.

(Click to enlarge to see the noise grain in the shadows and on table surface)

That's what I mean by 'usable'. You have to crush the blacks on the A7S to get rid of the noise in the shadows. On the 1D C you can leave the shadows 'as-is'.

They both have a 0% curve in Film Convert on to try and exceed the maximum dynamic range that's usable... to show as an example. No artistic merit :) I know it looks awful on both!

S-LOG 2 needs fixing for 4K it isn't working right.

And how is purple chromatic aberration the fault of the camera? It's a lens thing anyway.

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