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Old January 14th, 2007, 03:46 AM   #1
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Low light esp. 480p60 mode

As a long time user of the HD10, I was always glad to have the 480p60 mode as it gave me a full stop of sensitivity or more for those times when it was just to dark for HD. And of course gorgeous 60fps that upscales nicely to 720p.
Now I was considering the HVX200(briefly), mostly for multiple frame rates, and P2 (I do short film and it would work well for that) and SD modes that I assumed would have excellent low light ability much like the SD DVX100. But when I asked on the HVX200 forum I was told that the SD modes offer no low light advantage over the HD modes. I don't understand why this is so, but it is.
Now my question for HD100/200 series cams is, does the 480p60 mode give you a big jump in sensitivity like the older HD10 does?
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Old January 14th, 2007, 10:15 PM   #2
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The HVX200 doesn't get that much of a boost because the sensors are pretty close to standard def in the first place, it uses pixel shifting and upconversion to get 720p.
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Old January 14th, 2007, 11:11 PM   #3
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Originally Posted by Stephan Ahonen
The HVX200 doesn't get that much of a boost because the sensors are pretty close to standard def in the first place, it uses pixel shifting and upconversion to get 720p.
...and in the case of the HD100/200, when used in the SD mode, you are still using the same sensor and therefore, there is no difference between SD and HD modes either. All HD cameras are less light sensitive than their SD counterparts. A fact of life at this point of evolution. You can get a little extra by modifying you shutter speed and frame rate (which you can do with all cameras). Just accept it and adjust your lighting and other production variants.
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Old January 15th, 2007, 01:16 AM   #4
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So why do I get a full stop or more when going from 720p30 1/30th to 480p60 1/60th(even more if I go 1/30th) on the HD10? Doubling the frame rate and double the shutter and I still get a big jump. Sensor resolution is close to the HD100's. So what give's.
Secondly I would have to ask, has this been tried or is it just educated guessing? Does the HD100/200 really do nothing when you switch from 720p to 480p?
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Old January 16th, 2007, 03:59 PM   #5
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***BUMP****

Can someone please help me out with this. It would only take a minute.
A simple shot out the window would do. Lock the shutter and exposure. Take 10 seconds of footage. Switch to 480p keep the same lacked shutter and exposure. Take 10 seconds of footage. Play back.
Thanks in advance.
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Old January 16th, 2007, 05:27 PM   #6
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Ken,

I tried what you suggested with my HD100 and can tell no difference in light between 720p/30 and 480p/60. Shutter was 1/60 and iris was locked at 5.6 in all modes. I verified this in Vegas by comparing the waveform monitor between the sequences.
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Old January 16th, 2007, 11:02 PM   #7
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Originally Posted by William Hess
Ken,

I tried what you suggested with my HD100 and can tell no difference in light between 720p/30 and 480p/60. Shutter was 1/60 and iris was locked at 5.6 in all modes. I verified this in Vegas by comparing the waveform monitor between the sequences.
the HD100 uses a defualt of 1/60th in 30p, so there is no difference since you are shuttering at 1/60th by defualt in both modes. going from 1/30th to 1/60th is a full stop loss, and can be a big deal for some. its the equivalent of 6db of gain. the HD100 is on par with other HD cameras for light sensitivity. you can also improve it by working with gamma and black stretch to get darker shots to be much more acceptable. having shot lots of other cameras, I have no complaints about the HD100 vs anything else. comparisions to 1chip consumer cameras are simple not right because they make images that are not any where near the HD100. 1chip cameras also lack an optical block that splits the light to the chips as well.


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Old January 17th, 2007, 04:15 AM   #8
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The fact wether or not you'll improve in low light capability is a question on how the DSP in-camera works. This can be either way: the signal (photon-count) of several small HD pixels (within the spot of 1 'SD-pixel') might be added to each other to result in a new (and brighter) 'SD-pixel' and thus improved low light capability. Also, the camera's DSP can process the image in HD and then transfer it to SD to put it to tape. What happens then (effectively) is that an average is taken of the signal of all HD-pixels that constitute 1 SD-pixel. Low light capability doesn't improve this way, but overall image quality is somewhat better because the image processing (DSP has been done before the down-rezzing...
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Old January 22nd, 2007, 07:11 PM   #9
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None of the explanations seem to cut it for me. Especially the its a one chip, argument. I am shocked that there is no sensitivity increase for the HD100/200 series. It was something I could always count on when using the HD10.
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Old January 22nd, 2007, 09:38 PM   #10
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Quote:
Originally Posted by Ken Hodson
None of the explanations seem to cut it for me. Especially the its a one chip, argument. I am shocked that there is no sensitivity increase for the HD100/200 series. It was something I could always count on when using the HD10.
There is far superior gamma control and black stretch control in the HD-100 and yes you can use it to increase sensitivity in dark scenarios. I've created a "dark interior" scene file that makes the camera extra sensitive in very low light scenarios. The HD-250 benefit's from the super encoder which is much better with noise in this scenario. What this means is you can boost gamma and gain with useable footage. I had an example clip put up last year depicting the advantages of gamma settings in a very dark alley scenario. I think the files are down now and long gone.

The sensors in the camera are more sensitive in SD mode as you'd expect from your HD10 experience but not quite as sensitive. We used to pull the old 30 shutter speed trick in order to get more light to the CCD's in order to keep from gaining up. In the case of the ProHD camera's you can bypass those tricks by using your gamma setting as well as black stretch and black compress in the menu.

take care,

S.Noe
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Old January 23rd, 2007, 11:56 PM   #11
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Originally Posted by Stephen L. Noe
There is far superior gamma control and black stretch control in the HD-100 and yes you can use it to increase sensitivity in dark scenarios. I've created a "dark interior" scene file that makes the camera extra sensitive in very low light scenarios. The HD-250 benefit's from the super encoder which is much better with noise in this scenario. What this means is you can boost gamma and gain with useable footage.
S.Noe
The question still is, if you apply such "tweaks" or setting while shooting in the 480p60 mode, is there even more improvement over doing the same thing in 720p mode? It isn't a matter of gain or black stretch but the native sensitivity. The jump is big going from 720p to 480p in the HD10. From what has been reported back to me in regards to the HD-100/200 or HVX200 there is NO boost what so ever.
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Old January 24th, 2007, 07:52 AM   #12
 
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Just read this thread....
in my experience with DV and now with the HD110, it's pretty clear to me that the HD110 has about 1-2 stops more latitude than my XL2. Improved latitude is quite different from low light sensitivity. I 've had the occasion to shoot several venues in very dim incandescent light. I was surprised at the quality of the recorded video, even at 9dB gain.
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