Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
01-17-2013, 08:10 AM   #31
Loyal Site Supporter
drougge's Avatar

Join Date: Jan 2010
Location: Malmö
Photos: Gallery
Posts: 787
QuoteOriginally posted by GibbyTheMole Quote
From what I've read elsewhere, it looks like a rolling shutter works like this: Let's say you pick 1/1000 for a shutter speed. It exposes the first row of pixels at 1/1000th, then after a certain amount of time, exposes the next row at 1/1000th, and so on. If you choose 1/8000 for a shutter speed, it exposes the first row at 1/8000, but still waits that same predetermined time period before exposing the next row at 1/8000. The time it takes to write the entire exposure is the same either way. (Somewhere between 1/48 & 1/60 of a sec.) So that's where you get the jello.
I agree with this (don't know about the specific numbers, or if it's whole rows at a time), and I believe it agrees with my preceding post. But since this is the internet I don't feel quite sure, did you mean to disagree with something in my post?

01-17-2013, 08:50 AM   #32
Veteran Member

Join Date: Nov 2009
Location: Iowa
Photos: Albums
Posts: 2,269
Original Poster
QuoteOriginally posted by drougge Quote
did you mean to disagree with something in my post?
Nope. Just popping in with my understanding of the way a rolling shutter works based on stuff I've read on the topic. I know far from everything though, so I could very well be wrong. ;-)
01-17-2013, 12:01 PM   #33

Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by GibbyTheMole Quote
As far as I know it is pretty much is impossible to freeze fast motion with a rolling shutter and no wobble (jello effect). With a mechanical shutter that exposes the entire frame at once, it's a different story. The native non-toy lenses (01 prime, 02 zoom, 06 zoom) and the genuine Pentax Q to K adapter have a leaf shutter built into the lens with speeds up to 1/1000 of a sec. Jello isn't a problem with those because you're not using the electronic shutter unless you go over 1/1000. Faster than 1/1000 with those, and you're using the electronic shutter which is susceptible to the jello effect.

More info here.
Just to add to your explanation, the reason why the mechanical shutter can freeze motion is that the mechanical shutter essentially turns the whole sensor off all at the same time and allows the sequential write of the sensor to take place in the dark (with the shutter closed). With the electronic shutter, the whole sensor cannot turn "off" all at the same time, and has to go through the sequential row/column dump cycle while the sensor is still being exposed to light since there is no physical light barrier.

The point in my first post was to suggest that we try to make this a more practical than theoretical thread and illustrate how this effects our photography in a real sense and discuss what we need to do (if anything) from a technique standpoint to make it less of a concern.

Personally, my brain starts to turn to jello when tech aspects are beaten to death in theory without any practical implications.

For example, if you go way back to the period where the Q was introduced, but nobody had one, there were countless threads where theoretically-derived opinions were posed that the Q could never be used as a digital TC because diffraction would prevent any usable IQ past f2.5 because of diffraction, and all shots from the Q would have essentially unlimited DOF. With some creativity from our members, we've shown that neither of these has to be true, and we continue to break new ground to what is possible and how things can get done with the Q.


  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, effect, jello, jello effect, length, lengths, lenses, mirrorless, pentax q, pentax q10, pentax q7, q10, q7
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax lens of similar focal length: vs faceoff comparisons required! JayR Pentax SLR Lens Discussion 12 10-31-2011 10:24 PM
focal length on crop sensor question? littledrawe Troubleshooting and Beginner Help 14 09-28-2011 03:06 AM
FFF question - fisheye, focal length and FOV d.bradley Pentax SLR Lens Discussion 10 09-11-2011 11:21 PM
focal length prime vs zooms sany Pentax SLR Lens Discussion 7 05-15-2011 01:14 PM
fish eye effect + focal length Gooshin Pentax SLR Lens Discussion 2 12-05-2007 03:17 PM

All times are GMT -7. The time now is 05:26 PM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]