Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-22-2013, 01:22 PM   #16
Veteran Member




Join Date: Jul 2010
Photos: Gallery | Albums
Posts: 573
If you want the ability to use different lenses etc and the potential for the highest quality video, then a dslr makes sense.

Now I know why I liked my Canon G12 so much for video, it had a CCD sensor



07-22-2013, 01:33 PM   #17
Forum Member




Join Date: Jul 2013
Posts: 93
Original Poster
Thanks for the video ryan, although rolling shutter problem that appears on the right side is almost gone in the last models. Even in the pentax K30 is better than average (apparently), and it's barely noticeable, maybe only when you move it really fast.

But I want to confirm first hand that the jello effect is due to the SR and not the rolling shutter.
07-22-2013, 02:05 PM   #18
Ole
Administrator
Ole's Avatar

Join Date: Sep 2006
Location: Copenhagen, Denmark
Photos: Gallery | Albums
Posts: 3,783
QuoteOriginally posted by Anvh Quote
The SR in video mode is very different with the K30 and K-01

With the K5 they use the actual mechnical SR you also use when photographing, however with the K30 and K-01 they don't.
The SR used in video with those camera is software based, they record "full sensor" and the crop it a bit to and move the crop around the sensor. Just put the camera on a tripod if you don't believe me and compare the image you see with live-view when photographing or when you are in movie mode.
Anyway this the cause of the jelly effect with SR.
dpreview's reviews of the K-30 claim that the SR mechanism occasionally can be heard on the audio track during recording. This would indicate that the K-30 SR is sensor shift and not software based.

Do you have a K-30 and can verify that the SR is software based?
07-22-2013, 05:26 PM   #19
Site Supporter
Kozlok's Avatar

Join Date: Jun 2012
Location: Albuquerque
Photos: Gallery
Posts: 1,667
Johnny, Buy the K30 from a vendor with a 30 day return policy, try it out, decide for yourself. The K30 is a great stills camera, but it is the wrong choice for serious video. It will take video, but it's definitely for family memories, not for anything serious.

07-23-2013, 02:15 AM   #20
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by Ole Quote
dpreview's reviews of the K-30 claim that the SR mechanism occasionally can be heard on the audio track during recording. This would indicate that the K-30 SR is sensor shift and not software based.

Do you have a K-30 and can verify that the SR is software based?
QuoteQuote:
Although the Pentax K-30's incorporates a sensor shift-type image stabilization system, this is disabled during video recording, in favor of what Pentax calls 'Movie SR'; in essence, digital image stabilization. Unlike a mechanical system, this allows completely silent operation, but there's no such thing as a free lunch. The system works by creating the video feed from a 'window' of pixels in one particular location on the sensor, with the location of the window moved around the sensor as needed to correct for motion. For this system to function, you need to leave a band of "spare" pixels around the periphery of the sensor, and in the process, the K-30 effectively increases the effective focal length crop significantly. While for telephoto videos this may in fact be desirable, it means that if you want the widest possible field of view, you'll want to disable image stabilization.

Likely due to the manner in which it operates, the K-30's Movie SR sometimes induced a slight "wobbling" in captured videos, visible as a slight squashing / stretching along the vertical axis. This is distinct from the "jello" effect caused by rolling shutter, although the two effects can be present in a single clip, making the distortion even more pronounced. We also noted that as you reach the limits of the corrective area available by panning the sensor window, the K-30 shows "hiccups" in video playback where your subject moves significantly further than it should in a single frame. On the plus side, the system is very stable, able to correct reasonably well even for motion from walking.

Note that even if you disable Movie SR, you don't recoup the wide-angle capabilities. The crop is increased at all times when in movie mode.
Pentax K-30 Review - Video

Would like to see your claim about the audio.

Beside the review, the manual of the K30 also calls it "movie SR", enough hints i think.
07-23-2013, 08:33 AM   #21
Pentaxian
ScooterMaxi Jim's Avatar

Join Date: Jul 2009
Location: Minnesota
Posts: 1,463
The jello effect is nearly totally gone with SR off. All video devices that utilize electronic scan off of large CMOS sensors will have some jello effect when panned aggressively - as the sensor is scanned in segments. The effect will be similar with any large sensor camera you buy - and effectively the same as the competing NEX models utilizing the same sensor. I would estimate that about 80% effect is nullified by turning off SR. I think people leave SR on because that's just what they are accustomed to doing. If you are shooting an interview, or normal scene with people moving around (not a sports activity), you won't get jello effect. For panning or sports, turn off SR.

The crop factor comes in at roughly 1.7x (as compared to 1.5x for stills) depending on how you make the calculation - as video is more extremely horizontal at 16:9 ratio as opposed to 3:2 for stills. You definitely notice it - but far more is coming off of the top and bottom than the sides. Given that 2k is the capture for video, the crop has no effective impact on image quality. However, the extent of h.264 video compression is quite significant.

Bottom line, the K-30/K-01 is the best Pentax has to offer for video, but if video is a huge factor I think there are better brand options out there. The K-01 is a better overall video device than the K-30, related to dedicated live view and the better audio.
07-23-2013, 10:49 AM   #22
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Quality of the video seem to be better with the K5 though but no manual controls.
07-23-2013, 12:25 PM   #23
Pentaxian
ScooterMaxi Jim's Avatar

Join Date: Jul 2009
Location: Minnesota
Posts: 1,463
Hard to say. Compression makes a difference in favor of the K-5. Overall, you have a lot more flexibility being able to shoot at 30 or 60 fps with the K-30, and I suspect that the auto exposure control is better. The manual controls are so much better (especially on the K-01), I would have to go with the K-01. Shooting faster quality lenses seem to make a huge difference. It just helps to focus more sharply with a 2.8 or faster, and the imaging isolation seems to negate some of the compression effect.

07-24-2013, 05:36 AM   #24
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Well you can still adjust the aperture with the K5 and EV values so you "can" atleast influence the ISO and shutterspeed somewhat.
60FPS can be nice but isn't essential most of the time and the k5 has a working SR with video...

It's choosing the lesser worst however you look at it.

Maybe it's time to buy a black magic pocket...
07-24-2013, 01:50 PM   #25
Forum Member




Join Date: Jul 2013
Posts: 93
Original Poster
QuoteOriginally posted by ScooterMaxi Jim Quote
The jello effect is nearly totally gone with SR off. All video devices that utilize electronic scan off of large CMOS sensors will have some jello effect when panned aggressively - as the sensor is scanned in segments. The effect will be similar with any large sensor camera you buy - and effectively the same as the competing NEX models utilizing the same sensor. I would estimate that about 80% effect is nullified by turning off SR. I think people leave SR on because that's just what they are accustomed to doing. If you are shooting an interview, or normal scene with people moving around (not a sports activity), you won't get jello effect. For panning or sports, turn off SR.

The crop factor comes in at roughly 1.7x (as compared to 1.5x for stills) depending on how you make the calculation - as video is more extremely horizontal at 16:9 ratio as opposed to 3:2 for stills. You definitely notice it - but far more is coming off of the top and bottom than the sides. Given that 2k is the capture for video, the crop has no effective impact on image quality. However, the extent of h.264 video compression is quite significant.

Bottom line, the K-30/K-01 is the best Pentax has to offer for video, but if video is a huge factor I think there are better brand options out there. The K-01 is a better overall video device than the K-30, related to dedicated live view and the better audio.
Wow, this is a very clear answer. I know the jello effect is caused by the CMOS technology, but with the SONY sensor pentax has the effect is nearly non-existent. The strange anti shake effect is caused exclusively by the SR. I still don't understand why pentax decided to use this effect, didn't they have camera testers? It's unacceptable in this level of quality. And they had the experience with the K5... No comments.

In any case, it's still usable with the SR off and using a tripod it should be able to take nice video shoots (despite the bitrate).

Am I correct? I can't wait to have it in my hands next month!

Another question, is by any chance this effect gone in the new K50 and K500?? Has anybody tried them for video?
07-24-2013, 04:28 PM   #26
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Well the SR works a lot better with the K5 because they use the mechnical version.
I think they went and used software based SR because it is soundless, you can hear the SR with the K5 when using the build-in mics.


About the K50 and K500, by the looks of it the internals and software is so good as the same as with the K30 so expect no changes.
07-25-2013, 10:19 AM   #27
Veteran Member




Join Date: May 2012
Posts: 698
I had never realised that the K-30 used digital SR in video rather than sensor shift - came as quite a surprise to me. That prompted me to check what the K-r does and interestingly that uses the mechanical sensor shift mechanism.

I also shot some video with both cameras with SR on and the K-r the SR seems to work fine whereas on the K-30 the SR seems to make the video more wobbly rather than more steady.

I can understand them opting for the digital vs mechanical SR on the basis of the noise it makes as on the K-r it really does make the soundtrack useless unless you're filming a rock concert or an F16 taking off. However they should have made it an option to choose, especially since there are many cases where you don't even need to record the sound.

As regards the effectiveness of the video SR on the K-30 I think there must be a bug of some sort in the firmware as it really only makes things worse.
07-25-2013, 10:44 AM   #28
Veteran Member




Join Date: Mar 2007
Location: U.K.
Posts: 685
QuoteOriginally posted by lister6520 Quote
As regards the effectiveness of the video SR on the K-30 I think there must be a bug of some sort in the firmware as it really only makes things worse.
I don't think you can say that 100%. Video SR seems to make videos much smoother for me, no idea why it wouldn't really - perhaps it's all down to how much handshake you have as to whether SR can cope or not. If it can't cope it's bound to lurch around trying to find a new stable position with each jump.
07-25-2013, 12:10 PM   #29
Forum Member




Join Date: Jul 2013
Posts: 93
Original Poster
QuoteOriginally posted by SteveB Quote
I don't think you can say that 100%. Video SR seems to make videos much smoother for me, no idea why it wouldn't really - perhaps it's all down to how much handshake you have as to whether SR can cope or not. If it can't cope it's bound to lurch around trying to find a new stable position with each jump.

Please watch the video

I think anyone in the Quality department in pentax wouldn't let a camera be available in stores with this "bug".

It's not normal and someone should be blamed.

Last edited by JohnnyXD; 07-25-2013 at 12:20 PM.
07-25-2013, 08:24 PM   #30
Banned




Join Date: Feb 2013
Posts: 390
QuoteOriginally posted by JohnnyXD Quote
PENTAX K30 16.2 MP with 18-135mm WR Lens - YouTube

Please watch the video

I think anyone in the Quality department in pentax wouldn't let a camera be available in stores with this "bug".

It's not normal and someone should be blamed.
I think you're beating a dead horse here. Video is not the primary function of the K30. If you don't like it, don't buy it! Perhaps you'd be better served by something made by other manufacturers.
Reply

Bookmarks
  • 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, forum, jello, k-30, k-50, k30, pentax, pentax k30, pentax k50, stabilization, thanks, video
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Jello lenshoarder Pentax Q 4 05-15-2013 03:36 PM
Jello effect vs. focal length question GibbyTheMole Pentax Q 32 01-17-2013 12:01 PM
new K-5 owners: jello video test? kenyee Video and Pentax HDSLRs 3 11-03-2010 06:04 AM
Before I buy a K-x about the "jello" effect lovemehate Video and Pentax HDSLRs 38 10-19-2010 04:56 AM
K-7 Video - Jello Effect? jct us101 Video and Pentax HDSLRs 14 10-31-2009 08:27 AM



All times are GMT -7. The time now is 01:27 PM. | See also: NikonForums.com, 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?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top