Rolling shutter and lightning footage

[Mikko Lopponen]

Originally Posted by Jack Kelly

Not only does is say factually incorrect statements like "Image Device: Progressive" but it doesn't make any mention of the framerate for SSR or the read-speed of the rolling shutter.

The ccd itself is progressive on the hc7. It just doesn't output anything in progressive.

I though you were going to do camera tracking with the hc7? Well...I've done small tracking work with the hc1 and they've worked ok, but I don't know how the hc7 would work with a complete camera tracking environment. Probably well enough. You could always correct the errors afterwards anyway.

[Jack Zhang]

Originally Posted by John Mitchell

Hi Jack - just interested in this statement. AFAIK the only way to capture DnxHD is with an Avid DnxHD board with exclusively HD-SDI input. Have you had success capturing with a Blackmagic Intensity card, because that would be interesting indeed?

Actually, I was just referring to what formats would work for post-production and not take up the bandwidth of uncompressed HD.

I, myself, currently uses a laptop without any uncompressed capture yet.

[Sorin Vassa]

someone here said that if there are no artifacts there is no rolling shutter effect, or that the HC7 has a CCD.

it is wrong, first it has a CMOS, very big difference.
second there is no relation between artifacts and rolling shutter. rolling shutter is caused by the way cmos saves each line (instead of the whole image) so if you move it fast, the lower lines are saved later, the image has wobble.

the samples seen here, except "Stanley Park Sunset and Nighttime" show nothing useful. they had too little shake and very low shutter speed (<100).
the "Stanley Park Sunset and Nighttime" shows lot less wobble than canon's hv20 (http://www.socalspeedzone.com/incartest/incartest.html).

it would be great if someone would film a pan video, just left-right-left handheld, at 100 shutter speed looking at some vertical lines like doors. we could determine the level of the rolling shutter effect.

[Dave Blackhurst]

Just FWIW...

Shot a wedding reception the other day, nighttime, outside, DJ had a strobe light... you get the idea. I saw this and took some video as a "worst case" scenario.

First, the view in the LCD was so bad I didn't think I'd get anything usable... the strobe light pretty much wigged out the display. I pointed in the general direction anyway...

I've looked at the actual footage shot, and you can see that depending on the timing various parts of the picture are lit, and it's all over the place, middle, up , down, you name it. Obviously the timing of the strobe and the timing of the lens are going to result in some "interesting" results!

OK, so what's the verdict? Well, the footage looks rough, but you can still tell it's video of people dancing... and it doesn't look completely awful... I wouldn't use it offhand, but it was better than I expected. I've seen worse on TV... not that that says much.


SO, yes, rolling shutter is there, saw it on some FX7 footage I shot that day with every idjit with a disposable cam shooting wildly (forget the slingshot, personally I'm going to bring a tranquilizer gun next shoot... go ahead, stand up and block my shot, punk...<doing my best Eastwood impersonation>).

I can work around it, the cameras shot amazing looking video, PERIOD! I've got a couple camera angles in most cases, and I can honestly say that as I downloaded the raw video, I noticed how incredibly clean and color "correct" the video looked (thinking how EASY this will be to edit!!! YEAH!), NOT the annoying flash/rolling shutter issues.

I looked back at some SD video, and what flash did to THAT, and really I think I'll take the HDV from these CMOS cams any day of the week, rolling shutter or not. Frankly I think it's the quality that makes these little annoyances stick out more - sure it's not "perfect", but DANG, look at what you DO get!

DB>)

[Sorin Vassa]

that case is way to extreme, with strobes and all.

how about a more normal video, the hv20 has wobble on pretty normal, rather slow panning footage.

[Dave Blackhurst]

Didn't have my HV20 with me or I probably would have tested... I'm finding I use the HC7 over the HV20 - at least until I get more testing time with the Canon. I'm sure the Canon would have had similar issues at the least with the difficult shooting situation.

[Ian G. Thompson]

Originally Posted by Sorin Vassa

....the hv20 has wobble on pretty normal, rather slow panning footage.

Not on my HV20. Slow normal panning looks rather...um....normal. You only see that type of effect when you have quick jerky movements side to side...in that case...you wouldn't use the footage anyways....no matter WHAT type of cam you have.

[Jack Zhang]

The only case you might be concerned about a rolling shutter is in compositing, What Jack Kelly was gonna do with one of the cameras. With geometric correction it might work out.

By the way, I saw a video a while ago where someone composited a 3D purple teaspout into a HV10 sample. The perspective matching failed miserably. Could it be because of a rolling shutter?

[Sorin Vassa]

Originally Posted by Jack Zhang

By the way, I saw a video a while ago where someone composited a 3D purple teaspout into a HV10 sample. The perspective matching failed miserably. Could it be because of a rolling shutter?

only if the camera was moving

also geometric correction should be available in each software used to generate the 3D. that won't be possible. once the footage is taken, if it has wobble, it's ruined forever. even though some tracking software could fix the errors, that would remain a solution only inside that software and won't be shared thru the production pipeline.

[Sorin Vassa]

Originally Posted by Ian G. Thompson

Not on my HV20. Slow normal panning looks rather...um....normal. You only see that type of effect when you have quick jerky movements side to side...in that case...you wouldn't use the footage anyways....no matter WHAT type of cam you have.

that's not the idea, the idea was to evaluate the shutter effect on hc7 vs hv20.

[Keith Moreau]

Hi All

I have a Sony HC1, great little camera, a backup to my newer Sony V1U. I'm doing some shots from a moving platform with the HC1 that have exhibited what I believe is the rolling shutter effect, lines get bent and buildings look like 'jello' when the camera is jiggling a lot. The HC1's built in stabilization doesn't seem to help that part, and fast shutter speeds emphasize it. Putting the video through a stabalizer effect like Final Cut Pro 6 Smoothcam makes it smoother but it's still jiggly like jello. Unacceptable.

I'm about to purchase a HC7 as it 'seems' to exhibit less of this effect, but in all the searching I've done I don't have a definitive statement. Does anybody know if the rolling shutter effect is reduced with this camcorder?

If not any other options for a small, lightweight HDV camcorder that doesn't have this effect?

Thanks all for your advice.

-Keith

[Jack Kelly]

Hi Keith,

Overall, I'm very happy with my HC7e. The image quality is fantastic. I recently did a shoot with a Z1e as the "A" camera and the HC7e as the "B" camera. In some shots, the HC7e produced *better* results than the Z1. Very impressive. The slow-mo feature is nice too.

Unfortunately, the HC7 certainly does suffer from a rolling-shutter. If you're looking for the rolling-shutter artefacts, you can see them in a lot of the footage recorded from the camera. There are people who claim that rolling shutter wont be an issue for the majority of shooters because - they ask - "who would pan that fast?" But you don't need to pan fast to see rolling shutter issues. Just doing a hand-held shot on a long lens shows the rolling shutter as the camera jiggles.

I phoned both Canon and Sony to ask about the rolling shutter issues with their cameras but neither company could give me a satisfactory answer.

If you absolutely have to have a camera which doesn't have a rolling shutter then opt for a CCD camera rather than a CMOS camera (e.g. the Z1).

Thanks,
Jack

[Douglas Spotted Eagle]

It's not just panning that exhibits rolling shutter issues; high shutter speeds will virtually always out the rolling shutter problems. However, slow pans, slow shutter, thsi shouldn't be a problem. It rarely is for me.

[Marcus Marchesseault]

Since this thread veered pretty far from V1/FX7 posts, I thought that I would clarify that the HC cameras don't have the CMOS polling speed of the V1/FX7 as Sony put 4 pixel reader unitss in the V1/FX7. I haven't seen nearly the rolling shutter effect on the V1 as the HC cameras. Also, in situations with vibration, it may be preferable to turn off image stabilization on CMOS cameras. The fast motion of the image stabilizer itself may make rolling shutter seem worse since the stabilizer may actually move during the exposure/read. This is something you should try so you can know which you prefer.

[Ian G. Thompson]

Originally Posted by Sorin Vassa

that's not the idea, the idea was to evaluate the shutter effect on hc7 vs hv20.

Sorin...I know what you are saying and what this thread's topic is..but I wasonly addressing this statement "....the hv20 has wobble on pretty normal, rather slow panning footage'...
But if you want to talk higher shutter speeds then yes...not necessarily wobbles...but panning in full or even semi zoom produces those rolling shutter artifacts. I found that the higher I go...the more pronounced it is.