Req: Alternating Shutter Speed

[Mark B.]

I'd like a feature where I can set two shutter speeds, to allow the camera to alternate between the two speeds on each frame. Put closely together, the exposure variations could be (in post) merged into single frames with high dynamic range. It obviously would not be perfect, due to scene variations with objects moving quickly, but for most situations involving slow or still scenes it would be close enough to satisfactory (or would at least provide interesting FX). Even better, if the two shutter frames could follow one another back to back as closely as possible, treating the frames as grouped pairs. If this works really well for two frames, the concept could be expanded to three (or more) frame groupings for even greater dynamics. But, two frames is good enough for now.

Frame Number : Shutter Speed
-------------------------
Frame #1: 1/100
Frame #2: 1/500
<Wait>
Frame #3: 1/100
Frame #4: 1/500
<Wait>
Frame #5: 1/100
Frame #6: 1/500
<Wait>
Frame #7: 1/100
Frame #8: 1/500
<Wait>
ETC...

It would also allow a choice, in post, between two exposure levels for a given scene. So you could expose for windows on one speed, expose for the interior lights on the other speed. Then in post you could say "I think this will work better using the window exposure", then you'd just pull out the even or odd frames to accommodate. Shooting at 48fps would give 24fps on each shutter speed.

 

[Dan Hudgins]

May need 96fps.

May need 96fps.

I'd like a feature where I can set two shutter speeds, to allow the camera to alternate between the two speeds on each frame. Put closely together, the exposure variations could be (in post) merged into single frames with high dynamic range. It obviously would not be perfect, due to scene variations with objects moving quickly, but for most situations involving slow or still scenes it would be close enough to satisfactory (or would at least provide interesting FX). Even better, if the two shutter frames could follow one another back to back as closely as possible, treating the frames as grouped pairs. If this works really well for two frames, the concept could be expanded to three (or more) frame groupings for even greater dynamics. But, two frames is good enough for now.

Frame Number : Shutter Speed
-------------------------
Frame #1: 1/100
Frame #2: 1/500
<Wait>
Frame #3: 1/100
Frame #4: 1/500
<Wait>
Frame #5: 1/100
Frame #6: 1/500
<Wait>
Frame #7: 1/100
Frame #8: 1/500
<Wait>
ETC...

It would also allow a choice, in post, between two exposure levels for a given scene. So you could expose for windows on one speed, expose for the interior lights on the other speed. Then in post you could say "I think this will work better using the window exposure", then you'd just pull out the even or odd frames to accommodate. Shooting at 48fps would give 24fps on each shutter speed.

To do that you may need 96fps since the sensor may need to be cleared after each change to the shutter time. It is easer to use two cameras and a semi-silver beem splitter, read my other posts on this subject.

You can shoot HDR with 48fps equal shutter time, if you rig a flip flop to the VHz of the camera, then put a LC shutter in front of the lens, it will act as a ND filter on every other frame. You can also sync a servo motor and drive a 1/2 or 1/4 ND filter wheel to get the same effect.

So far, none of the RED team have answered the question about if the shutter time can be changed in the RED ONE (tm) sensor on every other frame, or have they?

This 37M/pixel Panavision (tm) sensor seems to offer HDR through high speed multi-frame or somthing?

http://www.panavisionsvi.com/imagers_DMAX.htm

 

[Mark B.]

To do that you may need 96fps since the sensor may need to be cleared after each change to the shutter time. It is easer to use two cameras and a semi-silver beem splitter, read my other posts on this subject.

You can shoot HDR with 48fps equal shutter time, if you rig a flip flop to the VHz of the camera, then put a LC shutter in front of the lens, it will act as a ND filter on every other frame. You can also sync a servo motor and drive a 1/2 or 1/4 ND filter wheel to get the same effect.

So far, none of the RED team have answered the question about if the shutter time can be changed in the RED ONE (tm) sensor on every other frame, or have they?

This 37M/pixel Panavision (tm) sensor seems to offer HDR through high speed multi-frame or somthing?

http://www.panavisionsvi.com/imagers_DMAX.htm

I'm already broke from the first camera, can't afford the second. Also, a two camera system would be too bulky for a lot of situations. The LC shutter might be an option, except aren't those shutters optically inferior?

 

[Thom Steinhoff]

Interesting idea. How about 3 frames (sure you would have to lower it to a lower res to accommodate)

1/120
1/96
1/120

I think you might have a better time with motion estimation with a shot on either side.

In this HDR mode, I would think you'd set the shutter speed and the camera would decide for itself what speed it should do on either side of the desired shutter speed based on what it could do and what works best.

Of course, I would think the rest of the workflow would be a bit tricky. Maybe the Proxies could just skip these HDR frames so you could play directly at only the desired shutter speed ignoring the others. If you wanted to make use of the HDR frames you would have to process them in Red Alert or Red Cine.

Seems like a lot of work. Red already rocks and does magic--lets focus on stability for now!

 

[Dan Hudgins]

LC vs. PLZT

LC vs. PLZT

I'm already broke from the first camera, can't afford the second. Also, a two camera system would be too bulky for a lot of situations. The LC shutter might be an option, except aren't those shutters optically inferior?

If the glass LC shutter is inside the lens then some of the evenness issues might not be as large a issue. PLZT have conductor lines on them and may cause diffraction.

The spinning disk could have good optical quality.

I wish someone would answer the question about if the sensor needs to be cleared before the next readout (requiring 96fps for double exposures per frame at 24fps) if the shutter time is changed from one frame to the next, it would reduce the amount of speculation about things that may just not work, is there an answer to this question posted already?