View Full Version : Need help with ND filter versus shutter speed (angle) question
Andrew M.
02-11-2008, 06:24 AM
Most cine lenses are optimized for wide open or for 5.6 max.
Also on some of them going above 11 stops will produce bad refraction.
Sure very easy put ND filter when there is too much light and all will be perfect.
Well in situations where light is changing and you can’t stop to change the ND filter can we change exposure (shutter angle) ?
On RED would be easy to program user batons in such a way that you could have ability to change the shutter speed in real time.
The main question is, what is your experience in shooting 1/1000 to 1/2000 (4 to 8 deg)?
Will such shutter speed influence the moving picture quality or produce unwanted effects?
Andrew
Paris Remillard
02-11-2008, 07:30 AM
The main question is, what is your experience in shooting 1/1000 to 1/2000 (4 to 8 deg)?
Will such shutter speed influence the moving picture quality or produce unwanted effects?
Andrew
It will influence the moving picture quality. Whether or not it's unwanted I guess is dependent on whether or not you knew the effect it would have. The faster the shutter speed, the less motion blur. So the motion will look more stuttery. If you are choosing that look for effect, it can be great. Think Saving Private Ryan. If you are just shooting a "normal" scene and want it to look like "normal" film motion, it won't.
Andrew M.
02-11-2008, 07:38 AM
Thanks for the answer parisrem
Yes, no blur could be desired or not depends from the shot. I wonder though if fast shutter speed will influence the shutter skew that there is so many posts about here. Theoretically it should reduce the skew but it depends how Misterium is reading the sensor.
I see few footage posts with diffraction and remark next to it that I didn’t have proper ND filter so I had to shoot at f16.
Well why then not to increase shutter speed if there is not much paning or movement.
Unless even a slow pan will produce stroboscopic effect, will it?
David Mullen ASC
02-11-2008, 07:55 AM
If all you want to do is control exposure, use ND filters, not the shutter. There always ends up being some movement in a sequence of shots in a scene, so you can't count on everything being static for you not to notice the strobing from the shortened shutter speed.
Andrew M.
02-11-2008, 08:11 AM
Dave, do you have any experience with 30 or 60fps? I guess at 60 there is no problem with strobe effect.
ND filter change doesn’t take long time but if you pan from dark no sun place, to full blast of noon sun, it could be problematic.
On MP lenses you have maybe 3 stops before infractions shows up and 3 stops is probably not enough from shade to sun, is it? On top of it these shoots are usually high contrast shots
Paris Remillard
02-11-2008, 08:22 AM
Thanks for the answer parisrem
Yes, no blur could be desired or not depends from the shot. I wonder though if fast shutter speed will influence the shutter skew that there is so many posts about here. Theoretically it should reduce the skew but it depends how Misterium is reading the sensor.
I see few footage posts with diffraction and remark next to it that I didn’t have proper ND filter so I had to shoot at f16.
Well why then not to increase shutter speed if there is not much paning or movement.
Unless even a slow pan will produce stroboscopic effect, will it?
It would have to be a veeeery slow pan. I've seen a formula for how fast a pan should be based on FOV and shutter angle but I don't remember what it was. I just rely on my personal taste in most situations.
I think that shutter angle has no effect on the sensor read/reset speed. At least that's what I remember the Red team posting at some point. And faster shutter speeds actually make the skew MORE noticeable, since there is no motion blur to help mask the effect.
If you have a matte box and filters ready, it only takes a few seconds to throw in or pull out some NDs. They really are essential with the Red or any motion picture style camera.
Andrew M.
02-11-2008, 08:43 AM
Thank you both for the help, I guess I will go the well tried route you suggested.