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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 :)

Motion blur Vs shutter

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Irri

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My experience with film tells me a shorter shutter time equals less blur. I assumed this would be true with RED. A compositor told me that the shutter didn't help with RED because it just sharpened the blur. I just did a quick test and there seemed to be a huge difference with faster shutters. Has anyone else tested this?
 
The compositor is wrong -- just as on a film camera, the shorter shutter speeds reduce the amount of motion blur. I'm not sure what he means by "sharpening the blur" anyway. Less blur tends to mean more sharpness whether with a film camera or a digital camera.
 
Video cameras usually default to each field being recorded for the full amount of time available, so at 60 fields per second, each field is open for 1/60th second.

Motion blur = shutter speed though.

Graeme
 
So I saw that the shutter is on high contrast scenes (specially if the actor is in front of white or white parts in picture) most visible. For me stronger than on film. Moving the camera (pan) specially on white vertical parts in the picture show that. What I saw is, that on the DCI Projections the RED Material has a stronger shutter as on a filmprint. Is there any way to get a little bit less shutter feeling on high contrast scenes?
To change the shutter a little bit longer exp time makes it softer but not better....

thx
rainer
 
rainer,

are you saying the you saw the same RED material projected twice - one time Digital and one printed to film - and the digital had more shutter?

best wishes,
martin
 
Motion stutter is highly contrast dependent. It would be interesting to measure the contrast ratio of the dark and light between film and digital and see if there's any correlation.

Graeme
 
Stutter is usually thought of as being a factor of speed of pan. But if you are panning over contrasty objects, it will look worse than if you're panning over a low contrast scene. DOF also effects stutter, and shallow DOF will help because the background will be blurry, and there is therefore low edge contrast on those blurry objects.

Graeme
 
That's really interesting. I'm sure I have read specific rules on pan speeds to avoid stutter. I've never seen edge contrast mentioned before though. I guess it is similar to the way contrast and resolution are related. Does this affect how a computer would interpret the information as well how a human would?
 
martinnoweck said:
rainer,

are you saying the you saw the same RED material projected twice - one time Digital and one printed to film - and the digital had more shutter?

best wishes,
martin
Click to expand...

Hi Martin !

Yes, you can see it at the digitale cinematographie in munich next week. I will show an example the big screen....

So Greame... you are absolutly right.... but what do we do with the wide shots with high sharpness and high contrast? outdoors you are often in this situation.... do you think there is any chance to get a little bit more aware of that ??? a film like stutter would be also a great improvement.....

regards
rainer
 
Well, film has the very same issue. I've seen many a film film with the very same issues on high contrast edges. I think you need to "modify" the panning rules when you see high contrast, or otherwise reduce the contrast somehow, or send the contrasting edges out of focus somehow.

Where I found this from was from Alan Roberts' BBC R&D paper on making video look like film: http://www.bbc.co.uk/rd/pubs/whp/whp053.shtml

Graeme
 
Yeah! fillage is very easy to see in film/Red at 180º (1/48 or 1/50) when panning and I´m with Rainer and Graeme high contrast does not help.

The solution is to go shorter in shutter but then loose this "filmic look".

but Rainer are you asking for a mecanic shutter for the Red??
 
For sure film has the same issue... and the RED stutter is ok... but in heavy contrast scenes the stutter is quite more visible as on film..... and it looks different than on film....
 
The "fillage" is cooler on film, isn´t it?

but now Greame has more free time... who knows? :)
 
What's free time? I'm always working on "stuff".

Graeme
 
i know this topic has been discussed to death:

if i understood it right there a many parameters like sensor size, panning speed, contrast and focal lenght, etc. but film is "recorded" 24 fps and each frame is projected "twice" or "double" versus electronic images being recorded 24 fps and projected 24 fps resulting in more stutter.

i have been told that there a electronic projectors or at least monitors which emulate the behaviour of a filmprojector by inserting a short black frame.

any thoughts?

@ rainer: i hope i can attend your screening if my little son allows it! what time will it take place?

best wishes,
martin
 
The 24fps acquisition is what directly influences stutter. Playback fps and the mechanics or display influence image flicker. Some displays effectively show 24p video with either 2 or 3 displays of each frame, but with other displays, each frame is shown once for the duration of the frame with no dead space.

Graeme
 
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