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01-07-2011, 08:03 PM   #1
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Down on K5 Audio / Video

While my photographic experience with the K5 has been rewarding, video field work has been frustrating lately.

Acknowledging that K5 audio sucks (32KHz) and is not, nor never claimed to be, a video tool on equal footing with, say, a 7D or GH2, here are some issues:

Audio:
(1) Overly aggressive automatic gain control. This is true with all DSLRs but it seems more problematic on the K5.

(2) Body noise: as soon as the mirror flips, any external mic touching the camera body, metal or rubber mounted, picks up this incessant rumble that defies even the low pass filter. Have tried this 3 different ways:
(a.) Rode Videomic mounted directly to the hotshoe
(b.) Rode NTG-2 floating in a shockmount connected to either the hotshoe or on a flash bracket
(c.) Zoom H1 mounted to a flash bracket with metal screw and rubber pad.

I'm well aware of camera noise - I've done this before - but again this seems to be far more of an issue on the K5.

Video:
Crazy, sudden exposure shifts - often in the beginning - for example, video flashes near white and/or gets dark. Happens every once in a while with newer lenses but consistently (i.e., every time) using older manual lenses (M50/1.4 and M28/2.8).
Can someone try this out with theirs? This is driving me absolutely nuts. Unless one is stationary and recording a pre-focused static object, manual focus is the only way to go with this camera.

01-07-2011, 08:49 PM   #2
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QuoteOriginally posted by MrPetkus Quote
(2) Body noise: as soon as the mirror flips, any external mic touching the camera body, metal or rubber mounted, picks up this incessant rumble that defies even the low pass filter. Have tried this 3 different ways:
(b.) Rode NTG-2 floating in a shockmount connected to either the hotshoe or on a flash bracket
Guessing this is from SR. Try turning it off?
The shockmount should have isolated it enough.

Any idea what the bit rate of the video is?
The D7000 is lower than the 5D. Looks like lots of jello shutter in this example too...
Review: Nikon D7000's Video Capabilities (Professional Photographer Magazine Web Exclusives)
01-07-2011, 09:06 PM   #3
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Bit rate ~ 40mb/s

Yep - have SR disabled...

QuoteOriginally posted by kenyee Quote
Guessing this is from SR. Try turning it off?
The shockmount should have isolated it enough.

Any idea what the bit rate of the video is?
The D7000 is lower than the 5D. Looks like lots of jello shutter in this example too...
Review: Nikon D7000's Video Capabilities (Professional Photographer Magazine Web Exclusives)

Last edited by MrPetkus; 01-07-2011 at 09:22 PM. Reason: Correct bit rate
01-07-2011, 10:35 PM   #4
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Also want to state that I have movie aperture control set to fixed.

I've been experimenting tonight with video. I HATE that the K5 decides the ISO sensitivity w/out any user control whatsoever. My theory is that the K5 is incorrectly calculating exposure on older manual lenses using aperture ring and hence adjusts ISO needlessly in realtime. Deconstructing a video sequence frame by frame in Premiere reveals more image noise following exposure flashes. But there's no way to tell because what the K5 is doing in video mode is completely opaque to the user.

Testing newer lenses like the DA 15/4 with manual focus selected doesn't yield the same exposure shifts. And so my guess is that aperture values are being communicated to the K5 via one of the electrical contacts absent on the older K mount lenses. (Note to self: read up on K mount specs).

I'm going to test my Tammy 28-75 having the aperture ring set to auto then manual and will report back.

01-07-2011, 11:09 PM   #5
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OK - ran my test and confirmed my suspicion.
Pentax K5 + Tamron 28-75/2.8 - 1080p movie mode & movie aperture control set to "Fixed"
Results:
- Tamron w/aperture ring set to Auto - no exposure jumps in video
- Tamron w/aperture ring set Manually - exposure jumps everywhere

Great. At least I know how to avoid the video problem - use newer lenses w/out an aperture ring or set to auto. Of course that means old lenses are out.

Did the K7 behave this way? Unfortunately, I sold mine and really didn't record video much with it.
01-08-2011, 01:16 AM   #6
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you wouldn't think you'd have to but record audio to a separate device.

lock exposure also.
01-08-2011, 02:57 AM   #7
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Minusta kamera on kamera ja videokamera on videolkamera, näitä ei pidä sotkea toisiinsa. Minun videokamerallakin saa tilttikuvia silti en ota niitä, enkä K-5 digikameralla videoita. Ovat rakenteeltaan ja laadultaan ihan eri mailmasta. Nämä risteytykset on vain huonolla maulla myyntikikkoja vain.
01-08-2011, 04:06 AM   #8
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That's bad to hear. The K-7 had no such issues. My Rode Stereo Videomic didn't pick up noise and audio had constant gain. Expsure with manual lenses was ok too. I'll really have to do my video tests for the K-5. Would be a pity because overall video quality from the K-5 is very good.

QuoteOriginally posted by MrPetkus Quote
While my photographic experience with the K5 has been rewarding, video field work has been frustrating lately.

Acknowledging that K5 audio sucks (32KHz) and is not, nor never claimed to be, a video tool on equal footing with, say, a 7D or GH2, here are some issues:

Audio:
(1) Overly aggressive automatic gain control. This is true with all DSLRs but it seems more problematic on the K5.

(2) Body noise: as soon as the mirror flips, any external mic touching the camera body, metal or rubber mounted, picks up this incessant rumble that defies even the low pass filter. Have tried this 3 different ways:
(a.) Rode Videomic mounted directly to the hotshoe
(b.) Rode NTG-2 floating in a shockmount connected to either the hotshoe or on a flash bracket
(c.) Zoom H1 mounted to a flash bracket with metal screw and rubber pad.

I'm well aware of camera noise - I've done this before - but again this seems to be far more of an issue on the K5.

Video:
Crazy, sudden exposure shifts - often in the beginning - for example, video flashes near white and/or gets dark. Happens every once in a while with newer lenses but consistently (i.e., every time) using older manual lenses (M50/1.4 and M28/2.8).
Can someone try this out with theirs? This is driving me absolutely nuts. Unless one is stationary and recording a pre-focused static object, manual focus is the only way to go with this camera.


01-08-2011, 07:42 AM   #9
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If you really care about audio quality then you're going to record to a separate device anyway. Audio on the K5 is pitiful - attach the most expensive mic and you're still subject to a 32KHz sample and ACG.

I record sound off-camera and use the on-camera audio as scratch sync. I'm annoyed by the strange body humming (not using SR) - even if I'm recording audio elsewhere I'd still like to mount the mic on-camera for convenience.


QuoteOriginally posted by WerTicus Quote
you wouldn't think you'd have to but record audio to a separate device.

lock exposure also.
01-08-2011, 08:08 AM - 1 Like   #10
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I was expecting this response sooner or later => a camera is for photos and a videorecorder is for videos; use the right tool for the job.

Unfortunately this statement doesn't reflect where the market has gone.

QuoteOriginally posted by 30v iPentax Quote
Minusta kamera on kamera ja videokamera on videolkamera, näitä ei pidä sotkea toisiinsa. Minun videokamerallakin saa tilttikuvia silti en ota niitä, enkä K-5 digikameralla videoita. Ovat rakenteeltaan ja laadultaan ihan eri mailmasta. Nämä risteytykset on vain huonolla maulla myyntikikkoja vain.
01-08-2011, 05:25 PM   #11
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Haven't don much video, but for the K-7 a bracket was enough to separate incamera noise with the Rode mic.
01-08-2011, 05:42 PM   #12
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QuoteOriginally posted by MrPetkus Quote
I record sound off-camera and use the on-camera audio as scratch sync. I'm annoyed by the strange body humming (not using SR) - even if I'm recording audio elsewhere I'd still like to mount the mic on-camera for convenience.
How do you do that? I very curious in doing this or using say Flip Hd and K-5 synching
01-09-2011, 11:36 AM   #13
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QuoteOriginally posted by vievetrick Quote
How do you do that? I very curious in doing this or using say Flip Hd and K-5 synching
I use a portable digital audio recorder (like here) to capture audio while I'm recording video on the K5. I have both the Zoom H4n and H1 (the H1 is garbage).

Depending on the circumstance, I'll use the Zoom's on-board mics exclusively. Other times I'll attach external mics - either XLR or 3.5mm (Rode Videomic). If the audio recorder's on-board mics are good enough & money is tight then you can forgo the Rode Videomic completely. IMHO, recorders with killer on-board mics are the Olympus LS-11 and Sony D50 followed by the Zoom H4n. Note that the Zoom H4n is the only sub-$500 audio recorder that will allow one to simultaneously record audio using both the on-board and separate mics.

If you want good audio to go along with the K5 HD video then record 44KHz WAV at a minimum. Then back at home, I import both K5 AVI and audio WAV into Adobe Premiere Pro. I split the AVI audio from the video and sync the WAV to AVI looking for an audio peak corresponding with an action such as a person clapping or using a clapper. Or you can skip the hard work and purchase PluralEyes which will automatically sync both audio-video. Then I delete the AVI audio, export the finished file to whatever format I like, and import into Lightroom (my catalog).

Another option is to simply attach an external 3.5mm mic (e.g., Videomic) to the K5 audio-in and not worry about syncing. But then the K5 will degrade the audio signal with its automatic gain control (ACG) and 32KHz sample rate. To counter the ACG and have the ability to add more mics then one could purchase a preamp with ACG suppression like the JuicedLink DT454.
01-09-2011, 11:44 AM   #14
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I've just started with video but have used a similar process recently. I record a lot of audio for my band. Another procedure you can use is take the audio file from your video in Premier (I use elements) then edit the audio using software such as sony acid or Cubase and then add the edited audio back to the video. Did this recently for another band with a flip video. the video was terrible but the audio excellent.

Shu
01-09-2011, 12:10 PM   #15
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For those wanting to try this method - I recommend Audacity as well which is feature-rich, cross-platform, and free.

QuoteOriginally posted by shuie Quote
I've just started with video but have used a similar process recently. I record a lot of audio for my band. Another procedure you can use is take the audio file from your video in Premier (I use elements) then edit the audio using software such as sony acid or Cubase and then add the edited audio back to the video. Did this recently for another band with a flip video. the video was terrible but the audio excellent.

Shu
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