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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Rolling shutter different for Scarlet?

FYI here are the two sequential frames. I scaled them to 10% size so that I could post them here.
 

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The thing with panning is that you can't control the speed variations between two different pans. A fan should give you a constant speed.

Uli Plank said:
The RS is working in vertical direction, so the blades get larger when moving down and smaller when going up.
Click to expand...

Oh, yes, true that. I still think it would be better to test with straight blades to make it easy to read. Also, I would compare frames with identical blade positioning, to account for the directionality of the shutter. That would provide a clear comparison, as long as you lock down tripod, use the same lens and the same crop/resolution setting (4k).
 
Roberto Lequeux said:
The thing with panning is that you can't control the speed variations between two different pans. A fan should give you a constant speed.
Click to expand...

There's no need to match pan speed if you can calculate the read-reset time in milliseconds for both cameras using the above method.

There's no question that EPIC is capable of faster times than 14ms. It needs to be capable of at least 8.3 milliseconds for 120fps.
 
Les C. said:
If you ever get into motion tracking (for the money we are paying, hopefully you will not want to limit yourself to all jobs except those that need motion tracking), here's an explanation of rolling shutter on CMOS cameras affecting SynthEyes (used in many small movies like Avatar, Mission Impossible: Ghost Protocol, etc.)
http://www.ssontech.com/phpBB2/viewtopic.php?t=478
Click to expand...

Lots of BS in that thread, like: "Just for info, the RED one camera will use a CMOS global shutter sensor."

But one hint later in the thread is correct: you can use 2K to reduce the effect massively, and I was able to see that clearly with out "test fan". So, in case you run into trouble when motion tracking, it might be worth a try.
 
Uli Plank said:
Lots of BS in that thread: "Just for info, the RED one camera will use a CMOS global shutter sensor."
Click to expand...
Keep reading the thread. It has lots of useful info, but I'd pay attention to the author more than the comments.

The author (ssontech who wrote the software) specifically mentions the RED ONE as having less issues.

But, CMOS will inherently have some Rolling Shutter delay.

The question is .... how much. And that's determined by how fast it can read from the sensor.
 
I agree 100%. And, anyway, the thread started with a Canon HV20, and even the R1 is so much superior…
 
Eric Pascarelli said:
FYI here are the two sequential frames. I scaled them to 10% size so that I could post them here.
Click to expand...
God, it looks like a cellphone.

When I first got my Scaret I was incredibly dissapointed by a normal-speed pan being rife with skew on a 50mm lens. I think we need to get to the bottom of this, because I would be blown away if the EPIC had as much rolling shutter as I'm seeing on the Scarlet.
 
Fan tests are a common way to test for rolling shutter. Since all three blades should be universal in shape, the amount of distortion will show off the significance of the rolling shutter. the blades on the left side will be distorted to be narrower than they actually are and the ones on the right will be longer than they are. In the example here the Scarlet shows that it is about 33% worse on rolling shutter, which surprises me because I would expect them to be the same. Another thing that could account for what we are seeing is that the fan speed could be different. I'd like to see a more controlled example where both cameras were filming the fan at the same time and synced. Also I'd like to know if the cameras were set to the same shutter speed and resolution.
 
Of course both cameras were set to identical values, including shutter and resolution – I think I mentioned that.

That fan is quite stable in speed (I have a pretty good ear for music) and the shots were done minutes apart. The results from that fan are quite reproduceable, I double-checked with an EX-1 and a Canon 5D, which I tested a while ago and I still had the images. Judging from this, the Scarlet is a tad better than the R1, both are not too far from the EX-1 (which doesn't even have half the resolution) and the 5D – as you may expect – is awful. The blade on the right is covering more than 180 degrees with it…
 
Sorry I missed that the setting were identical. It sounds like the Scarlet does have a slightly worse rolling shutter than the Epic. The only possible variable is fan speed, but as you mentioned, its consistent.
 
Thank you so much for that! You just added one more reason to our list for paying extra and getting an Epic, not to mention charging a little more to clients.

Uli Plank said:
So, I tested both cameras, and there is a difference. Even the Scarlet is better than most other cameras, but the Epic is visibly better:

RS_Compare.jpg
Click to expand...
 
Glen Powell said:
Pretty much what I was thinking - certainly not a HUGE or TERRIBLE difference based on this example. None of my clients (or end viewers for that matter) would ever notice or question this level of rolling shutter.
Click to expand...

They might, it depends on the shot. Whip pans in cities (which we sometimes want to do) can really be a problem with ANY amount of skew present.
 
Glen Powell said:
Pretty much what I was thinking - certainly not a HUGE or TERRIBLE difference based on this example. None of my clients (or end viewers for that matter) would ever notice or question this level of rolling shutter.
Click to expand...
Remember that the fan blades, if not turning, are rather large to begin with. So a small change in the fan blade size can indicate a very LARGE change in rolling shutter delay.

If it is 14ms, as Eric Pascarelli calculated earlier, that is a HUGE amount that can interfere with image stabilization (which a lot of people use) and certainly motion tracking (which less people use).

And it's almost 3 times the 5ms that I ?thought? the Epic exhibited.
 
Anderson Boyd said:
I'm beating a dead horse here but imprecise tests like this are what spawn the unfounded rumors about RED.
Click to expand...
Could you indicate how Eric Pascarelli's result of 14ms was imprecise?

I would love for that to be an error, but the math looks simple?
 
Eric Pascarelli said:
There's no need to match pan speed if you can calculate the read-reset time in milliseconds for both cameras using the above method.

There's no question that EPIC is capable of faster times than 14ms. It needs to be capable of at least 8.3 milliseconds for 120fps.
Click to expand...

Oh, so those were two frames from the same clip? Sorry if a prior post alluded to that effect, I haven't read the whole thread. I assumed they were an Epic-Scarlet comparison... In which case pan speed would need to match to compare the angle of a vertical subject. One way would be to set both cameras up side by side on the same head using identical lenses and shoot a distant object.
 
Eric Pascarelli said:
So I did a rough timing of the Scarlet at 23.976 4KHD and was very disappointed to find a read time of about 14ms or about 1/72 second.

This is no better than the original RED One - maybe a bit worse.

If anyone has gotten a different result or anyone from RED knows the exact spec, please let us know. I would love to be wrong here. But I am quite confident about my methodology.
Click to expand...

What firmware version? Maybe like the LHC (Large Hadron Collider), they are taking their time to ramp the Scarlet up to full speed?

Uli Plank said:
Sorry, was quite dark all day through. Shot at 1/400th, both 4K HD, same lens, the fan is quite constant, I use it for other cam tests too.
Of course this is not scientific, but a relative comparison. I don't think it will by anything noticed by our clients, but it may cause problems when you need 3D camera tracking.

BTW, the blades are same shape, same size, of course – or the fan would destroy itself in seconds…
Click to expand...

What firmware version? I'm really hoping RED are tuning the speeds - as the differences that you show (testing in basically the same method as one of the Zacuto tests), and Eric's calculations, show a very large difference that will affect image stabilization and motion tracking - and even normal-speed panning with a 50mm as noticed by Monte Casey : http://www.reduser.net/forum/showth...nt-for-Scarlet&p=955630&viewfull=1#post955630
 
Monte Casey said:
God, it looks like a cellphone.

When I first got my Scaret I was incredibly dissapointed by a normal-speed pan being rife with skew on a 50mm lens. I think we need to get to the bottom of this, because I would be blown away if the EPIC had as much rolling shutter as I'm seeing on the Scarlet.
Click to expand...
Could you post a 1080p example of a normal-speed pan that is getting skewed?

BTW - one of the Zacuto tests for rolling shutter uses what is essentially a fan (their 'wheel test at 6:30 shown below), so the original 'fan test' comparison of the Epic and Scarlet seems quite valid.

If I combine the 14ms delay for 4K computed in an earlier post with your 'skewed' normal-speed pan, I don't exactly know what to think?

http://www.zacuto.com/the-great-camera-shootout-2011/episode-three
 
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