Guy Mcloughlin
Forum Replies Created
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Yes, ideally the data rate should be 2.5x the standard rate, but from what I’ve read it’s only a 50 percent increase.
The few samples I’ve seen appear to be OK, though I don’t know what would happen if you were trying to record a detailed high-speed event.
Vitaliy Kiselev ( creator of the GH-1 Hack ) recently posted on the DVXUSER site that the firmware to the AF-100 appears to be completely open, and thus he should have little trouble hacking the AF-100 firmware once he modifies the programming in his processor model. So there is the chance that down the road an AF-100 Hack could increase the data-rate for regular filming and overcranking.
Vitaliy Kiselev: Good-news-about-AF100-firmware
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One area where the DVX100 is still useful is live video streaming, which is one area where SD resolution and Firewire output is very useful.
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…Not trying to be a “shirt” disturber, but I have read that the AF-100 records at a 50 percent higher data-rate when shooting 60 FPS over-crank video, which roughly puts it at about 35 Mbps.
This means that a 16 GB SDHC card would only record about 60 minutes of 60 FPS over-crank footage, that would play back as 150 minutes of slow-motion 24P.
Over-crank also requires Class 10 memory cards, and does NOT record any sound while shooting.
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The AF-100 is a whole new ball-game in that we’ve finally got a professional video camera that can shoot shallow DOF images at a very affordable price.
CONS of Using a DOF Adatper Rig
– 1.5 – 2 stops of light loss
– Not as sharp an image as a large-sensor camera
– Huge difference in size and weight makes a DOF adapter much more awkward to use
– You have to be careful to make sure the back-focus is set correctly or sharpness suffers
– P2 Cards cost a lot more than good quality SDHC cardsCONS of Using the AF-100
– It costs more than many DOF adapters
– You have to get used to a new work-flow to process AVCCAM video shot on SDHC cards ( especially if you edit with the Mac )…I would keep in mind that the AF-100 is NOT an ENG camera, so you will likely want to hang on to your HPX-170 for quick “run’n’gun” style shoots. ( I own a HMC-150 with uses the same memory cards and batteries )
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16×9 Inc makes a very strong J-Clamp that clamps to the handle of most prosumer cameras including the HMC-150. It’s not cheap, but it’s very well made.
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I am pretty sure that the new Panasonic GH-2 DSLR does not have any time limit to the length of video take, as long as your memory card still has room.
The GH-2 should be in stores by the end of the year ( or sooner ), and early reviews indicate that it just might be the best DSLR camera for video work. ( Yes, better image quality than the Canon cameras. I own a Canon 60D, and may end up switching to the GH-2 in 2011. )
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What’s the firmware of your camera?
The current firmware is 1.21, and I think it was firmware 1.19 or 1.20 that added SDHC Class 10 compatability.
I use only Patriot brand SDHC cards, both Class 6 and Class 10 with no problems at all over the past 18 months.
NewEgg: Patriot LX 32GB SDHC Class 10 Flash Card : $70
https://www.newegg.com/Product/Product.aspx?Item=N82E16820220452&cm_re=patriot_sdhc-_-20-220-452-_-ProductNewEgg: Patriot IRIS 32GB SDHC Class 6 Flash Card : $75
https://www.newegg.com/Product/Product.aspx?Item=N82E16820220444&cm_re=patriot_sdhc-_-20-220-444-_-Product*** Canadians can buy the same cards from NewEgg.ca
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COMMENT re: 1080 60P cameras
The only consumer cameras that I know of that can shoot 1080 60P are the Panasonic TM700 and HS700, and you may have some issues when trying to edit this footage on a Mac.
…As far as your 1080 60i footage goes, you can convert this to 1080 30P fairly easily, though the image may not be as sharp as footage actually shot at 1080 30P. ( de-interlacing will fuzz anything that is moving )
If you are still after your slow-motion effect, you might want to take a look at the Twixtor software which does a great job of creating pseudo slow-motion from standard footage.
RevisionFX Twixtor
https://www.revisionfx.com/products/twixtor/overview/ -
I did some quick tests of audio noise last night that I will publish next week once I’ve had a chance to test more cameras and recorders. Here’s how I test for audio noise:
1- Connect a Sound Devices mixer to camera/recorder ( I use a BeachTek passive adapter for devices that do not have XLR inputs ) using LINE level outputs.
2- Turn on the 1 Khz tone on the Sound Devices mixer, and adjust the recording level on the device ( camera or recorder ) so that the 1 Khz tone registers at -12 dB. ( -12 or -20 dB recording levels are standard when using digital devices because these devices do not have any headroom beyond 0 dB, so you are creating 12 / 20 dB headroom by recording at -12 or -20 dB )
3- Record the 1 Khz tone for 5 seconds, then turn off the tone while still recording for another 5 seconds.
4- Open the recorded audio file with a sound editor, and measure the sound level when the -12 dB tone is both on and off. You may need to adjust the volume of the audio file to ensure that the recorded tone is playing back at exactly -12 dB. The audio level measured when the tone is off should represent the actual noise-floor of the recording device under theoretically ideal conditions. ( in reality every mic has it’s own noise-floor, thus measuring in real-world conditions will vary greatly on how quiet the attached microphone is )
5- To test the mic pre-amps of the device, repeat the same steps but this time set the audio mixer to output a MIC level 1 Khz audio tone ( I use a -50 dB in-line PAD with the Sound Devices MixPre mixer ), and then use the built-in mic pre-amps of the device being tested to set the 1 Khz tone to -12 dB. With high quality mic pre-amps the noise-floor will be the same for both LINE level and MIC level tests.
…With my quick tests last night, both my Olympus LS-10 and HMC-150 showed a noise-floor around -60 dB for a LINE level signal, my Canon HG21 showed a noise-floor around -73 dB for a LINE level signal, and the Panasonic HS700 camera showed a noise-floor around -82 dB ( 22 dB lower than my HMC-150 )
I will publish all the results next week ( along with sample WAV files ) once I’ve had a chance to test more recorders. ( I want to add both Sony digital recorders and the Sony EX-1 camera )
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>>>But I did see a drop in noise when I simply added the Mixpre to the chain, taking the mics that I was feeding in to the mixpre first.
What was the change in dB ?
I used Sony Sound Forge 9 to measure the audio levels, and did not see much difference. ( I’m using AudioTechnica 4053B and 3031 condenser pencil mics along with Sanken COS-11x lav mics and Sound Devices mixers: MixPre and 302 )