a7s II Rolling Shutter

I have a sneaking suspicion that 194 views and 0 replies translates to what is known in layman's terms as a "dumb question"
 
Rolling shutter is going to be a problem with large sensor cameras of this size for a while. Maybe over the next few years with advancements in processoring power/efficiency we will see some improvements, but getting the sensor to read-out that fast is going to take more muscle/heat dissipation. Given the sacrifice in low light performance with global shutters, I don't see them going that route either.
 
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The A7rII has a better rolling shutter performance than the A7s no?

I think there's latitude for a small improvement over the A7s, but nothing major. There's been a few nods to improvements but nothing concrete yet. Maybe they're still tweaking it.

I don't see what the difference is between a full frame A7s and a APS-C FS7 in terms of data to scan, the number of lines is roughly the same so i don't think heat is the limiting issue. I can't see any reason why a FF sensor with larger pixels would take longer to scan...?

cheers
Paul
 
paulcurtis said:
I don't see what the difference is between a full frame A7s and a APS-C FS7 in terms of data to scan, the number of lines is roughly the same so i don't think heat is the limiting issue. I can't see any reason why a FF sensor with larger pixels would take longer to scan...?
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Sony's foremost priority with mirrorless has been to maintain a compact size, which seems to directly contradict any notion of increasing the horsepower/form factor size. I think the A7 family is pushing the envelope in terms of their thermal threshold, thus they chose to stick with the same battery solution as the nex 5. Think its safer to assume they will be saving those improvements for next-gen tech.

Even Canon has stated the only issue preventing them from putting 4k in a smaller form factor has been power & heat dissipation. Kind of impressive that their 1dc was doing 4k internally(with a massive 500mbps) without any overheating back in 2012.
 
Samuel H said:
Not really: it's fast in FF mode but in APS-C, which is the mode with no line skipping, it's actually even slower. Link.
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I was looking at https://www.cinema5d.com/sony-a7rii-rolling-shutter/

Which implies that UHD Full Frame scan is 16ms. Is that not the case then? You've got 34ms for FF S35 (but they have 29ms for that) and 20ms for FF. Compared to 30ms for the A7s. Well i'd take 20ms over 30? (unless i'm reading this wrong?)

cheers
Paul
 
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LeoGrey said:
Sony's foremost priority with mirrorless has been to maintain a compact size, which seems to directly contradict any notion of increasing the horsepower/form factor size. I think the A7 family is pushing the envelope in terms of their thermal threshold, thus they chose to stick with the same battery solution as the nex 5. Think its safer to assume they will be saving those improvements for next-gen tech.

Even Canon has stated the only issue preventing them from putting 4k in a smaller form factor has been power & heat dissipation. Kind of impressive that their 1dc was doing 4k internally(with a massive 500mbps) without any overheating back in 2012.
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Sure but look what they've achieved in such a short space of time. And i really *don't* think the increase is read out speed is really that much of a difference.

If the A7rII can scan UHD from full frame in 16ms i'd take that. It would be roughly the same amount of data on an A7sII, but it wouldn't be skipping lines.

I doubt that is the case (otherwise i'm sure sony would be marketing that), but i don't believe it's quite as impossible as you make out.

chers
Paul
 
paulcurtis said:
I was looking at https://www.cinema5d.com/sony-a7rii-rolling-shutter/

Which implies that UHD Full Frame scan is 16ms. Is that not the case then? You've got 34ms for FF S35 (but they have 29ms for that) and 20ms for FF. Compared to 30ms for the A7s. Well i'd take 20ms over 30? (unless i'm reading this wrong?)

cheers
Paul
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it might be faster, but the little improvement is pretty much useless imho... it's still bad.
i've been shooting a show this week (5th day in right now) on 2 a7r2s, one internal 4k and one going out to the shogun. the rolling shutter improvement isnt anything to write home about.
side note: the one recording internally has over-heated 4 times during takes now (these are max 7 minute takes) and the low light performance is worse than i expected.
 
paulcurtis said:
Sure but look what they've achieved in such a short space of time. And i really *don't* think the increase is read out speed is really that much of a difference.

If the A7rII can scan UHD from full frame in 16ms i'd take that. It would be roughly the same amount of data on an A7sII, but it wouldn't be skipping lines.

I doubt that is the case (otherwise i'm sure sony would be marketing that), but i don't believe it's quite as impossible as you make out.

chers
Paul
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We are talking about two different things I guess. What I was referring to was the performance level in most s35 prosumer/professional cinema cameras that have "tolerable" levels of rolling shutter(c100/c300/fs7/fs700/f5/etc). Using those as a benchmark, I would say mirrorless is 1-2 generations away from having the necessary processing power to remedy the situation. This is of course is assuming its something that Sony is even capable of/or wants to remedy. As I've said before, I think there will always be certain bugs/sacrifices prevalent in the consumer/prosumer cameras that oem manufacturers are willing to live with because there is no alternative.
 
caseywilsondp said:
it might be faster, but the little improvement is pretty much useless imho... it's still bad.
i've been shooting a show this week (5th day in right now) on 2 a7r2s, one internal 4k and one going out to the shogun. the rolling shutter improvement isnt anything to write home about.
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I'll take anything! There seems to be a sweet spot though, on Samuels list the FS700 is down as 15ms and for 99% of cases that's been fine for me. It's just that the A7s is now twice that speed.

That hint of 19ms coming off the A7rII isn't that far away from the FS700, i would have thought that was a noticeable improvement? Cinema5d claim 16ms for UHD.

What are you're seeing, are you running 4K FF UHD (which is the mode they say gave that speed)? Maybe they're wrong?

LeoGrey said:
We are talking about two different things I guess. What I was referring to was the performance level in most s35 prosumer/professional cinema cameras that have "tolerable" levels of rolling shutter(c100/c300/fs7/fs700/f5/etc). Using those as a benchmark, I would say mirrorless is 1-2 generations away from having the necessary processing power to remedy the situation. This is of course is assuming its something that Sony is even capable of/or wants to remedy. As I've said before, I think there will always be certain bugs/sacrifices prevalent in the consumer/prosumer cameras that oem manufacturers are willing to live with because there is no alternative.
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I understand what you're saying but those tests indicate A7rII UHD FF 4K at 16ms, which is 2ms shy of the FS700.

Now i can't test or confirm any of that. Samuels lists shows A7rII 4K FF at 19ms.

So i'm just saying that if these figures are correct, then the capability is there now.

And not wanting to go too far OT. All these cameras need to do is to dump a RAW stream of data, that's it. On the other thread i really don't think there is any technical reason why not, it's just marketing and product positioning and also that the customer base (the majority) just wouldn't get it.

cheers
Paul
 
* Recording RAW would be great for projects that require the best possible IQ you can get, but it doesn't affect RS at all (RS depends on how fast the data is read out of the sensor, how you process it doesn't have any effect in this sense).

* I think my method is better than the one cinema5D uses, but in any case we're in the same ballpark: a7R II in APS-C mode is slow as hell, but in FF mode it is kind-of-usable, close to "actual videocamera" performance but not quite.

If the a7R II could record RAW or even slog3, there would be no point in going for the a7S II, except if you absolutely need the best possible lowlight performance.
 
Samuel H said:
* Recording RAW would be great for projects that require the best possible IQ you can get, but it doesn't affect RS at all (RS depends on how fast the data is read out of the sensor, how you process it doesn't have any effect in this sense).
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Unless the processing is a factor in when the next frame can be read out (but probably not)

Samuel H said:
* I think my method is better than the one cinema5D uses, but in any case we're in the same ballpark: a7R II in APS-C mode is slow as hell, but in FF mode it is kind-of-usable, close to "actual videocamera" performance but not quite.
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If the A7sII could do a scan at that rate, i'd be happy. But i would have thought Sony would be pushing that if it was true.

Samuel H said:
If the a7R II could record RAW or even slog3, there would be no point in going for the a7S II, except if you absolutely need the best possible lowlight performance.
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But it doesn't read all the pixels does it? It skips across the sensor, or do you think it's binning them? I thought only the A7s reads every pixel for 4K.

I've not looking in detail but are their any aliasing issues?

cheers
Paul
 
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