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-   -   best shutter-angle disaccord (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/121439-best-shutter-angle-disaccord.html)

Dominik Seibold May 12th, 2008 08:38 AM

best shutter-angle disaccord
 
Let's call 24/25fps normal playback-frame-rates, 30fps the medium rate and 50/60fps high rates. For me it seems absolutely clear, that for normal rates a shutter-angle of 180° is most natural. Smaller ones we call the "saving private ryan-stress"-effect. But a shutter-angle of 360° is way to blurry, so it gets hard to aim your eyes at/discover moving objects resolving in headache, and also it has a more video-like and less film-like-look compared to 180°. But for high-rates a shutter-angle of 360° is most natural.
So if you shoot at 25p you should not use any longer exposure-times than 1/50s. And when you shoot at 60p for slomo-playback at 25fps (overcrank) you should not use any longer exposure-times than 1/120s.
The cause I'm writing this is, that I think most of you don't agree with my shutter-angle-opinion: I'm interested in the EX1 and now going to buy one. So I watched a lot of footage of it posted by people of communities like this dvinfo-one. And what I discovered was, that about 90% of the 24/25p-ones have shutter-angles of 360°. So I'm confused, because I think people buying/using a 7000$-cam are at least intermediate-experienced and so using shutter-angles consciously instead of accidentally. So those people disagree with my 180°-shutter-angle-is-the-best-opinion. But it's not only me, who likes 180°, but also 100% of all major-movies are shot with 180°-shutter-angles. So I'm confused.
What do you think?

Piotr Wozniacki May 12th, 2008 08:50 AM

I think you're wrong is assessing most of us 24/25p shooters use 360deg shutter as the "speed of choice". To the contrary - the 180deg is used by default, and we only switch shutter off (=set it to 360deg) in low light situations, in order to gain this full one stop of exposure.

Dominik Seibold May 12th, 2008 09:11 AM

For me the 180°-look has a much higher priority than picture-noise. So I would only use a longer exposure-time, when 18db-gain don't suffice or there isn't much movement. Here are examples of clips with 360°-shutter-angles, but with obvious headroom for extra-gain:
http://web.mac.com/chupap/Films/tablemanners.html
http://www.kamrat.tv/video/Slussen1080p.wmv
http://www.kamrat.tv/video/Hammarpilot1080p.wmv
http://skifilm.info/oyvind/nature_test_1080p-H.264.mov
http://www.archive.org/download/EX1_...486_01.mxf.mpg

At the same time I only found two with 180°:
http://www.archive.org/download/PMW_...368_01.mxf.mpg
http://www.aerialsfilm.com/stevet/Ren_AZ_EX1_SAMPLE.m2t (very loveley one :) )

Another example: Take a look at vimeo: it's hard to find ex1-footage with 180°, because most do have 360°.
Additionally I didn't even find ONE overcrank-example without 360°.

Dennis Joseph May 12th, 2008 09:25 AM

How did you figure this out?

Dominik Seibold May 12th, 2008 09:37 AM

With my eyes. When I see a fast enough motion I can immediately recognize the typical 180°/360°-characteristic. Is that skill exceptional?

Sami Sanpakkila May 12th, 2008 09:38 AM

I use 180 degrees mostly. In low light situations I much rather use 360 shutter than add any gain. In a situation that requires 18db I'd use a good flashlight instead.

Dominik Seibold May 12th, 2008 10:10 AM

Quote:

Originally Posted by Sami Sanpakkila (Post 875860)
In low light situations I much rather use 360 shutter than add any gain.

So you find 6db more annoying than 360°-shutter? 6db should be one stop, because 6db could mean doubling the output-voltage of a sensor-pixel, but I'm not sure. Then I would absolutely prefer 6db, because 6db-noise on the ex1 isn't much, but 360° is much headache.

Piotr Wozniacki May 12th, 2008 10:15 AM

Dominik, I see you're being very dogmatic about the whole thing - while in fact it's all very relative:)

Even with 360deg, there are situations where motion blur or stuttering can be avoided completely.

On the other hand, sometimes engaging gain is preferrable - but you cannot make a simple hard rule about it!

Dominik Seibold May 12th, 2008 10:33 AM

Quote:

Originally Posted by Piotr Wozniacki (Post 875888)
Even with 360deg, there are situations where motion blur or stuttering can be avoided completely.

Of course, if there isn't much movement, there won't be much blur even with 360°. Then I also would use 360° when it gets dark. But as soon as the 360°-blur gets conspicuous, it's a bad and I try not to use it.

Sami Sanpakkila May 12th, 2008 04:48 PM

Quote:

Originally Posted by Dominik Seibold (Post 875887)
So you find 6db more annoying than 360°-shutter? 6db should be one stop, because 6db could mean doubling the output-voltage of a sensor-pixel, but I'm not sure. Then I would absolutely prefer 6db, because 6db-noise on the ex1 isn't much, but 360° is much headache.

Personally I would choose shutter speed over gain even when there is movement. I like that kinda Wong Kar-wai look. Or maybe I should say Christopher Doyle look actually :)

Steve Mullen May 12th, 2008 06:04 PM

Quote:

Originally Posted by Piotr Wozniacki (Post 875888)
Dominik, I see you're being very dogmatic about the whole thing - while in fact it's all very relative:)

Even with 360deg, there are situations where motion blur or stuttering can be avoided completely.

On the other hand, sometimes engaging gain is preferrable - but you cannot make a simple hard rule about it!

I think Dominik is saying that the setting of the shutter-speed is of primary importance because it changes the LOOK of the video being shot. I claim anything other than ABOUT 180-degrees is an in-camera FX.

I too would not change the LOOK of a scene just to get a more noise free image. I watch tons of Discovery and Nat Geo HD -- and it is VERY common to see a slight -- or even a huge -- increase in noise in very dark situations. The same has always been true in film until the last decade. I think folks don't even notice noise because they kind of expect it.

HOWEVER -- in a great discussion I had with Larry Thorp at NAB -- he did the CiineAlta at Sony -- I got expert confirmation about "judder" on inexpensive cameras. The appearance of judder is very much greater on the low cost cameras. (I won't go into details now.) One way of minimizing the judder is greater blur from slower shutter-speeds. SO:

180 may not be "normal" for the EX1.

Folks shooting 360 may inadvertntly be trying to solve the judder issues they see.

Dominik Seibold May 12th, 2008 07:24 PM

What exactly do you mean with "judder"? I never noticed any judder with any cam. Inaccurate "frame-timing" of video-cameras seemed for me to be always beyond any perception.


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