Replies to This Discussion

Permalink Reply by Gregger Jones on April 23, 2009 at 10:05pm

Nice blog... It may be a little hard to understand if you don't really know what a rolling shutter is... Here is an article from Mitch that might shine some light on it...

http://blog.abelcine.com/2009/04/15/the-difference-between-a-global...

I also heard that the new Panny 300 just got an upgrade that will take that split field thing out of the CMOS its toting.

Short story is I need to see this movie... ah... the list.

Permalink Reply by Dante Fignolo on April 25, 2009 at 6:45am

You are missing out! Jai ho!

Permalink Reply by Dante Fignolo on April 25, 2009 at 6:46am

The site with the Screen Captures also has a decent explanation of the rolling shutter / CMOS

http://jackcabbage.blogspot.com/2008/06/sony-ex1-cmos-and-rolling-s...

Permalink Reply by Moderator on April 25, 2009 at 9:18am

yeah, that is the same link from the top, it seems that you can't be shooting pappa razzi type scenes with cmos/rolling shutter. gregger and i had the hpx300 out a few weeks ago and shot scenes with a lot of flash bulbs and you could see the color banding in real time...... i wonder if into the future, pappa razzi will not have as many flash bulbs because more of them will be shooting video out of dslrs and will be wanting more consistent light...... maybe it won't turn out to be the same problem if flashes become less common with photo media as high quality video is more portable and attainable to the same crowd that is shooting stills now......

Permalink Reply by Gregger Jones on April 25, 2009 at 9:43am

Frame grabs from cameras that use constant light... Hmm interesting.

Permalink Reply by Moderator on April 26, 2009 at 3:16pm

i think it has constant light sensing, right? but there are still discreet frames being recorded? so if you are shooting at low frame rates it could be sensing flashes bulbs from flash cameras beginning and ending in the space of time between the recording of discreet frames to be making calculations on contrast in the image recorded..........?

Permalink Reply by Gregger Jones on April 26, 2009 at 8:52pm

well I guess there are a couple of ways to skin a cat... I noticed that the wiki description makes it seem as if its one line at a time but most of them are a cascading event. As far as I can tell the discreet frame is a description that is opposed to alternate lines. Paul Grunke has a cool rolling shutter grab from his cell phone that is vertical... Here

Permalink Reply by Dante Fignolo on April 25, 2009 at 10:44pm

And of course:

http://en.wikipedia.org/wiki/Rolling_shutter

Permalink Reply by Moderator on April 28, 2009 at 8:04am

Grunke's shot is perfect. i think the si2k still has frames, as the rolling shutter turns, the angle is such that the first shafts of light break through the opening initially, and then as the opening gets wider, more light. the chip reads the first shafts first, and so the cascade effect is created by delays in the time it takes for light to hit the next line of pixels. at 24 fps, each frame is being captured over approx 4% of one second. i think the cascade is inside that .04s time, scanning a quarter of the chip in .01 seconds time for example......