a7s II dynamic range - 12 stops, or 14?

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filmguy123

Veteran
I read conflicting things online. Cinema5D made a chart that the A7s cameras are achieving around 14 stops dynamic range. Yet elsewhere I read 12 usable stops.

The GH4 with vlog on an external 10-bit 4:2:2 recorder, I read 12 stops of dynamic range.

What are the actual numbers here and how do the two compare in practice? Is the A7s DR with slog3 about on par with a GH4 *properly* tuned in with vlogL and external 10-bit 4:2:2 recording?
 
Results from different testers may vary because one group may deem a certain point on either end of the range to be usable while another group may not.

I don't know about the A7S, but I think the A6300 and A7SII have more DR than the GH4.
 
^This

For DR you just can't follow numeric measurements, unless they come from the same source and were taking the same day with the same methodology. I have done several shootouts in the past few years, and my measurements for the same camera would change by as much as 3 or 4 stops depending on how I measured it (which initially was a "just don't know better" thing but more recently was dictated by what I was going to use that shootout for: will I care for fine textures in the shadows -which makes uncompressed RAW look much better- or will I be fine with seeing big shapes in shadow areas -which means compressed codecs have a chance).

Before V-log, which is when I tested this, the a7S had an advantage of 3 stops against the GH4. How much DR does V-log add?
 
filmguy123 said:
I read conflicting things online. Cinema5D made a chart that the A7s cameras are achieving around 14 stops dynamic range. Yet elsewhere I read 12 usable stops.
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I'd say the answer may lie in your post somewhat. FWIW I have no idea what it is. But 14 stops DR and 14 usable stops DR aren't exactly the same thing. Usable tends to mean with acceptable highlights and noise levels. The problem with "usable" is that it is subjective. What noise someone will accept might differ from one person to the next.
 
Seems to be that the GH5 will hit a solid 12 stops usable DR with 10-bit 422 internal with vlog. I'm wondering how this will size up against the A7s. If the DR characteristics end up being somewhat similar, with only a slight edge to the A7s, I'd be inclined to stick with the GH5.

I don't need the extreme lowlight of the A7s and the GH5 is much improved. I don't need the wider FOV of the A7s as I'm happy with the crop factor solutions on GH5.

I do admit there is something about the "look" of the larger sensor on the A7s that is appealing but I feel much of that has to do with the DR, and if that ends up being a very close call on GH5 vlog vs A7s there are a number of features I prefer on the GH5 (from useability, menus, gear compatibility, and VFR 36, 48, 72, fps modes all the way up to 180fps).
 
There's a good chance A7SIII (or at least A7RIII) will be announced at NAB. A7S I was announced at the show in 2014.
 
Really depends how you count. In reality it's hard to sum up noise performance in one number or set a threshold for where you stop counting DR stops.

I've seen A7SII xyla charts that show 16 steps visible, but then how you decide that translates to stops of DR varies widely depending who you ask. In reality Dragon/Alexa/A7S2 all show around 16-17 stops visible, but how the noise shows up in the last couple stops is what sets them apart. By comparison, a GH4 on a similar chart can't seem to discern more than 12-13stops.
 
NorBro said:
There's a good chance A7SIII (or at least A7RIII) will be announced at NAB. A7S I was announced at the show in 2014.
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Perhaps it's possible they'd announce an A7RIII way in advance but the A7 update usually comes out first and that's not rumored to be released until the summer. Seems unlikely to me an A7RIII would show up before Dec 2017, and extremely unlikely an A7SIII would show up in 2017...
 
But the cameras are way overdue? A lot of people thought the A7III and even the A7RIII were going to show up in Fall 2016...and were allegedly supposed to but the earthquake delayed the plans/roadmap.

Each year brings a bunch of new cameras, so if Sony didn't update the big ones in 2016, we should definitely see a new A7RIII AND A7SIII in 2017.

It would be crazy if not, haha.
 
Sony has said the time of one camera announcement every few months is over: they declared 2017 the year of lenses. Which doesn't mean there won't be any new cameras, but maybe it won't be those that people are expecting.

The GH5 definitely warrants an answer, it's making too big a splash to be ignored.
 
Samuel H said:
Sony has said the time of one camera announcement every few months is over: they declared 2017 the year of lenses. Which doesn't mean there won't be any new cameras, but maybe it won't be those that people are expecting.

The GH5 definitely warrants an answer, it's making too big a splash to be ignored.
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It must have been said after the FS7II announcement in November because in October we saw the A6500!
 
The only thing I'll say about the A7/A7R/A7S III cameras is that they were all held up by the earthquake. I do not understand Sony's pipeline, whether the staggered A7 series release schedule is dictated more by manufacturing or R&D. If it's by R&D, though, I think it may be conceivable that since the release has been delayed by a bottleneck in the factories, R&D would have carried on, and all 3 models may be ready to launch simultaneously this year. If it's more a production pipeline issue as to why Sony delays/staggers releasing the models, though, than perhaps the staggered release will continue out of production pipeline necessity.

But as I understand from the rumors, A7 refresh was originally due in fall and then delayed due to the earthquake, so anything may go come NAB 2017.
 
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One question I have on Dynamic Range is that of the difference between 12 stops and 13 stops. When we speak of stops, I understand that one stop better light intake equates to TWICE the light absorption. That's huge!

But how does this relate to latitude? Is an extra 1 stop of dynamic range equate to TWICE the latitude? Or is it more of a percentage increase in overall tonal range that can be achieved? It seems crazy to me that 14 stops of DR would equate to 4 times greater latitude range than 12 stops.
 
It's one stop more latitude, which means "twice" but feels like "just a bit" becasue our perception of light is logarithmic. You can overexpose by one more stop and then correct it in post without losing quality. Or underexpose, or half a stop each way: it depends on the case.

NorBro said:
It must have been said after the FS7II announcement in November because in October we saw the A6500!
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It was just this week, and it wasn't so much a Sony statement as a SAR post summarizing (I guess) what their sources are telling them.
 
If one looks at their product map -

APS-C 4K for $1,000
APS-C 4K for $1,400

Then there's room for full frame 4K at ~ $2,000 but they're probably ceding this price point in 4K video it to GH5, OMD EM1 MKII and Fuji XT2 (Sony manufactures sensors for all of the above).

Then they have A7RII, SII and A99II at ~ $3,000. Hypothetically, they could have muscled up on processing on A99MKII but decided not to cannibalize the A7RII/SII sales.

And for the entry level 4K, they have RX10 and RX100 compact series.

So, the $2,000 tier remains a 4K gap for them but they can live with that for the time being.

At the "pro" line, the anticipated A7RII/A7SII in a camcorder body, 10-bit codec, etc. never materialized. A7RII was announced roughly 15 months after the GH4 first shipments. IMO, this will hold for RIII and SIII. Look for them in the summer of 2018.

2017 should be for the Cine Alta (F-5-55-65) replacements.
 
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