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06-03-2013, 08:04 AM   #31
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QuoteOriginally posted by PiDicus Rex Quote
This simplest explanation I can give, is that it can cause the playback to strobe or flicker. In film cameras, this was because some frames would be exposed for longer then others, and some would be exposed while the film was in motion.
I don't intend to be simply contrary, but I think there are some assumptions here as to film camera standards, and perhaps how the k-01 is operating.

I've never shot with a 'pro 35 mm' motion picture camera, but I use smaller format 16 / 8 mm cameras, Bolexes and Beaulieus mostly. With these cameras, there is pretty much never a mutiple ratio between the shutter speed and the frame rate. For example, for one of my cameras these are the correlations:
12 fps 1/30 s shutter
18 fps 1/50
24 fps 1/70
48 fps 1/140
64 fps 1/180

and it's possible to partially close the shutter to get finer control over exposure.

Films flicker noticeably below 18 fps (the rate at which the continuity of motion illusion kicks in), but otherwise there is not jerky motion. I don't ever get 'half frames' from miss aligned shutter/frames. The clockwork in the camera regulates the shutter speed and frame advance in tandem.


QuoteOriginally posted by PiDicus Rex Quote
I electronic cameras, it was because some had one clock running the fps, and a separate clock running the shutter, so frames could begin part way during, at the start, or near the end, of the sensor charge cycles.
I think there may be some presumptions as to how the K01 handles it's frame buffer. I do understand how a CMOS sensor is read, however I don't know the proprietary methods that Pentax uses to make each frame. The K01 can certainly read the sensor at rates much faster than the electronic shutter speed. Perhaps you are approaching the limit when you get to 1/4000s . Might the shutter speed rather rate how much time is allowed for the sensor to collect data before being read? As I said I do not know how Pentax implements its electronic shutter, but it would seem like the very least sophisticated way to do it would be to read the sensor at a slower rate for slower shutter speeds.

I have noticed however that there seems to be significantly less 'jello' happening with my K-01 than on my friends Fuji XE-1. I suspect there is some significant processing going on to the image on the way to being written. Certainly, there is the crop and electronic shake reduction.

Anyhow, 1/30th of a second is the slowest shutter that I'm used to using with film, and it gives a motion blur that is familiar, and I generally leave it at that rate for most video work. If I want less blur, I'll use a faster shutter, knowing that the movement will look more strobelike -- but this is due to less motion blur rather than some kind of misalignment between shutter and frame rate, so far as I understand. This can be smoothed out a bit in PP.


Last edited by verdigris; 06-06-2013 at 11:18 AM.
06-04-2013, 06:15 AM   #32
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Okie, first up, the flicker I'm referring to, is not the motion flicker of slow running film - in TV terms that flicker is called Stutter.

Flicker for TV is changes in brightness.

Probs need to make sure we're all on the same page - I'm coming from a broadcast background and moving in to film, there are plenty of terms that are used in both with separate meanings.

So the flicker I'm referring to is where one frame will be brighter or darker then the ones surrounding it, usually because of the difference in exposure time. In film cameras this will be from where the opening of the rotating shutter does not fully line up with the film, if the speeds are not matched.
Thankfully it's a issue that was solved a long time ago in film cameras, with the shutter drive being slaved off the film transport motor, so they remain in sync. With them fixed to each other, 180 degrees opening for any film speed, has the shutter open for half of one frame's time duration, and the film moving during the other half.

Broadcast TV camera's will usually only do shutter speeds that represent the same sort of openings as in film cameras. Again using the PAL numbers, for shooting at 25fps, 180degrees is 1/50th. 90degrees open is 1/100th, ( quarter the time = 4 times the fps), and so on.
This also stops the shutter speed and the local lighting ( PAL countries generally use 240volts at 50Hz AC Supply ) from causing more flickering.
-> Point here, having the shutter speed NOT matching, is far more of a problem with vision shot using artificial lighting then it is with Natural lighting.

This sort of flicker has been noted in many DSLR productions, personally seen it more on 'Brand C' cameras being used on student films, music videos and adverts.

Yes, I'm very much hoping that the K-01 doesn't show the same behavior, but it is still better practice to stick to accepted shutter speeds where the problem can not occur.
06-04-2013, 06:26 AM   #33
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On 'Jello'...

Most of what I've shot so far has been on tripod, with higher shutter speeds for the car racing, and 1/50th for dramatic stuff, behind scenes video, and wrestling, and with the SR turned off.

I've been pleasantly suprised at how little rolling shutter there has been in the footage so far, with fast moving wrestlers crossing the frame, or the camera panning to follow the sportscars.

That said, I was taking photos at a Roller Derby event on Sunday, hand held at the long end of the 28-80 zoom. The SR for photo's does a pretty good job, but when switching to video I noticed there were times the SR didn't keep up with the pans as the skaters swept past.

So it's a matter of keeping the camera mounted appropriately, with any user based shake damped before it gets to the camera. I've got an old set of rails to mock up into a matte box and shoulder rig, and will see how well that goes for hand held usage.
06-05-2013, 06:38 PM - 1 Like   #34
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QuoteOriginally posted by PiDicus Rex Quote
On 'Jello'...

Most of what I've shot so far has been on tripod, with higher shutter speeds for the car racing, and 1/50th for dramatic stuff, behind scenes video, and wrestling, and with the SR turned off.

I've been pleasantly suprised at how little rolling shutter there has been in the footage so far, with fast moving wrestlers crossing the frame, or the camera panning to follow the sportscars.
The key here is that SR is turned off. That's the source of 90%+ of the rolling shutter problem. The morons who claim to know what they are doing in testing the camera for video all left the SR on, and then panned things like speed boats and reported on the terrible results. Well, if you use the camera in ways that basic instructions (and common sense) tells you not to do, you get degraded results. They might as well have reported that the camera is not capable of providing an image when shot in total darkness...

06-06-2013, 07:42 AM   #35
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Yuuuuup.

"Put it on a tripod" is the standard rule among the crowd of guys I work with regularly, in regards to ALL cameras with Rolling Shutter sensors.

I'm looking forward to seeing what I get with the K-01 on a rails/shoulder rig with a matte box, with the SR on and off.

My hand held tests are showing that at the wide end of a zoom, filming behind scenes so far, that the SR does work, so long as there is no fast movement of the camera. Tight end of the lens and SR on or off is the usual sucky mess without some sort of brace.
I mastered an XL-1 's form factor, and am used to having a full sized camera on my shoulder, so a DSLR rig should be just the same as it is with a 5D or the ilk.

Last edited by PiDicus Rex; 06-06-2013 at 07:53 AM.
06-06-2013, 10:45 AM   #36
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Of course, another option is dialing in a low level of SR on lenses that allow for it. You can get a happy compromise that way.

My biggest problem with the video implementation is entirely on the audio end. They give you a lot of decent audio features, but then the AGC is so heavy handed - forcing the noise floor up to unacceptable levels in the silent passages. It doesn't clean up properly even in Audacity.

Serious work requires going to a separate recording device. I guess that's the right thing to do in the first place.
06-06-2013, 10:08 PM   #37
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Yes, the K-01's audio is a mixed bag - Manual Level control (admittedly buried in a menu), but then 32kHz sample rate and AGC,..

I'm looking at a Tascam external recorder, there are the H1, H2 and H4n from Zoom that are almost a defacto standard, along with a Sony equivalent, and all record at 44.1kHz or 48kHz, and some at 96kHz

And then you get things like a mates Sound Devices 788, with 8 separate tracks recorded at ( IIRC ) 192kHz sample rate.
06-07-2013, 09:31 PM   #38
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Yes, the 32kHz is a real problem, especially if you are recording music. I'm not sure anything over 48kHz is worth worrying about, but I do believe PCM is worthwhile even though the sample rate is overkill.

All of the units you mention will work quite well (some of the cheaper Tascam units are claimed to have some noise floor problems, though). I researched the options pretty thoroughly and went with the Olympus LS-7 - and find it fantastic, especially considering the comparatively low price. Use it a lot for work - very versatile that way. Its only downside is the lack of an input in, but I really don't need anything more than a mic in and phone jack. The small size is a huge advantage - as I'm taking it with me most of the time.

06-07-2013, 10:48 PM   #39
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This is the one I'm looking at - it has a feed to the camera and from the camera, so you can send Tone and set levels and monitor the return feed to check for clipping.

Tascam DR-60D 4-Channel Linear PCM Recorder / Mixer for DSLR - TAS-DR-60D | Videoguys Australia

It's a little more complex then most, but reminds me a lot of the features available in ENG cameras, and will still suit when I add a BMD Cine Cam with MFT mount to my kit, or if I'm working with the usual crews PMW-F3, Red, etc.
Having top and bottom mounts should also make this form factor easy to add to a Rails/Matte Box kit, as a weight on or behind the shoulder, where any mic or video feed cables can hang down out of the way during hand-held operation.
06-07-2013, 11:52 PM   #40
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Googled that Olympus unit - looks good for a lot of things, the voice activation could be a good idea, so long as someone doesn't say the words to stop it recording during a take,..

Only down point for me is the lack of Balanced inputs.
06-08-2013, 01:38 PM   #41
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Video success

My girlfriends sister got married and I brought the k-01 with 35mm 2.4. Shot at 24fps 1080p

Cut clips in final cut pro x that to a bob marley song that was used for her dance w the groom. Burned the video to DVDs and it was a hit.

I used this stabilizer

Amazon.com: Glide Gear DNA 1000 Small Camera Action Video Stabilizer: Camera & Photo

Wish youtube would let me upload it!
06-09-2013, 02:21 AM   #42
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There's a couple of those available locally, but I'm loathe to buy one - when I've used them before, I could never get the cameras to stop rolling.
I spent too much time doing Weddings professionally, and built up the muscle memory to hold a large SVHS camera stable using my Tripod and the Sun Gun's lead acid gel-cell as a counterweight, with no gimbal, so when I go to use SteadiCam style rigs, I end up over controlling them.

35mm on a K-01 would be like a 50mm FF, perfect for portraits and wedding videos. 24fps will help give it a nice 'film' look.
06-09-2013, 02:54 AM   #43
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Hello everyone. I was wondering if any of you can tell me about the audio quality recorded from the K-01 and your set ups.

I was interested in using the K-01 for videos because of focus peaking and being a bit lighter, but I would also like to hear about your thoughts about the audio gain control and if you can hear any hissing, etc.

Thanks
06-09-2013, 12:44 PM   #44
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The onboard audio is good enough to record a good 'guide track' for syncing to a better audio recording, such as the external recorders listed above, for Corporate & Event videos, and short film production.

The onboard audio samples at 32kHz, which is not of high enough quality for any sort of music reproduction. With an external microphone, it is okay for voice recordings, but not great.

If it can be bumped up to 44.1kHz or 48kHz sample rate, with the AGC switched off, and level meter display added in the firmware updates, then it will be absolutely fantastic.
06-14-2013, 12:43 AM   #45
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Just a quick sample shot,... to show what happens when you film under LED lights, which cycle on and off many hundreds of times per second.

Count the number of drumsticks,..

Also works as an example of Rolling Shutter, showing where the lines were scanned and lit at the same time for the brighter sections of the blurred drumstick, and with the darker sections being lines scanned while the LED was cycled off.
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