Hpx 170/500 dynamic range question

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DanHD

Well-known member
Both the hpx170 and hpx500 record in 8bit dvcpro HD with 422 chroma, but the 500's chips are larger, equaling larger pixels.


Does this translate to an increase in dynamic range, particularly at the bottom end, ie shadows?


I ask because I'm filming a B&W Noir short, and I need all the tonal range I can get. I can afford to rent a 500 for a week.

or is the different negligible?
 
I know there are.

But my question still stands, does it offer a larger dynamic range and if so, why? is it the larger chips?
 
I have a camera comparison chart from Fletcher camera that shows the ASA and latitude to be the same for the 200 and 500, ASA 320 and 7 stops. Interestingly, an HDX900 and HPX2000 are rated at ASA 500 and 9 stops. When using AVC Intra with the 2000, due to the 10 bit vs. 8 bit advantage, latitude goes up to 10 stops.

I know that when I shoot with my 170, I don't have the latitude I'm used to with my 900. The 500 should have the advantage in noise and resolving detail in wide shots compared to a 1/3" Panasonic HD camera.
 
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I shot a comparison video with and without DRS mode on the 170. It's about 1min 45sec into this video: http://vimeo.com/1873623

It's not a thorough testing of DRS, but you can notice differences in latitude. Look at how DRS handles the highlights of the sun and the clouds, while keeping the shadow areas of the apartment building at a good exposure.

You can only use DRS on the 170 in 60i modes or 60p if using 720p. It would have been great to have this in 24p and 24pn modes, but we can't on this camera. Can this be changed with firmware?
 
Hi,

Dan, The 500 will give you more latitude and the tonal gradations are better.

Dino, The chart from Fletcher is full of erroneous information, starting with that 7 stops for the 500, I have seen 9. 7 seems right for the 200 but not the 200A/170. And you are right the 900 is even more gorgeous.

David, Don't use DRS on everything. It is a good tool for run and gun in extreme lighting but will stab you oin the back on normal lighting with noise. The good news is that youcan't use it in other modes beyonf the 60i/60p but the big the 900 can, and just want ot point out that you do not want it when it is not needed.

Best,

Jan
 
Thanks for the info Jan. I thought it odd that a 2/3" sensor wouldn't have more latitude than a 1/3" sensor.

I am a fan of the DRS circuit and use it a lot on exteriors. I haven't been bothered by noise, and have even used it in interiors a few times. I have noticed that DRS can be a problem on very saturated chroma, actually causing a phase change in the color of the objects.

I certainly would have preferred that DRS be available on my HPX170 at 24 and 30p, as it is on my HDX900. I would probably use it more with the 170 due to its lack of latitude compared to my 900.

I thought I had read somewhere that an SDX900 had more latitude than an HDX900, but that would potentially mean an HPX500, which uses the same sensors as the SDX900, would have more latitude than an HDX900, which I don't think is the case.
 
DanHD said:
but what GIVES the 500 more latitude??????
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Large sensors utilize larger pixels, larger pixels collect more photons, allowing for more dynamic range. Theoretically, a full raster, native HD sensor will have less dynamic range due to having more pixels for a given sensor size. This also has a lot to do with why larger sensors are faster and therefore require less preamp gain vs. small sensors, yielding less noise.
 
Wait so you're saying if the 500 was full raster it would have LESS dynamic range because there are more pixels?

So why does the 50,000 dollar hpx3000 have so much more dynamic range than my HPX170 (besides 10 bit vs 8 bit)

Because there are so many more pixels (full raster) wouldnt they be unable to collect as much light, thus lowering DR?



So my cam less pixels but bigger ones, and more expensive cams have more pixels but smaller ones?
 
It comes down to pixel size. Even though an HPX3000 or F900R have more pixels, they aren't smaller than the pixels of a 1/3" chip, but they are definitely smaller than a 2/3" SD chip, this is why HD cameras are noisier than SD cameras.
 
Dino said:
I am a fan of the DRS circuit and use it a lot on exteriors. I haven't been bothered by noise, and have even used it in interiors a few times. I have noticed that DRS can be a problem on very saturated chroma, actually causing a phase change in the color of the objects.
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We have had a customer ruin his entire shoot as he thought to leave it on, think it would get in the way. But it did. Made some shots borderline unusable.


I certainly would have preferred that DRS be available on my HPX170 at 24 and 30p, as it is on my HDX900. I would probably use it more with the 170 due to its lack of latitude compared to my 900.
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There isn't enough memory in the little guy to do that.


I thought I had read somewhere that an SDX900 had more latitude than an HDX900, but that would potentially mean an HPX500, which uses the same sensors as the SDX900, would have more latitude than an HDX900, which I don't think is the case.
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It does have a little more than the HDX but that is simpley due to the bigger pixrls. And BTW it is not the SDX chips in the HPX500. Thos chips could not output 60 frames, and they were only 520,000. The HPX is 620,000.

Best,

Jan
 
Jan_Crittenden said:
We have had a customer ruin his entire shoot as he thought to leave it on, think it would get in the way. But it did. Made some shots borderline unusable.
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With the HDX900, DRS defaults to off upon powering up. In fact, when shooting high contrast exteriors, I've sometimes put a piece of camera tape on the camera with a reminder to turn DRS on. I keep DRS on a User button. I've been happy with the results for most exteriors, knowing I would be grading in post to get back some contrast.


There isn't enough memory in the little guy to do that.
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Interesting, I would have thought 24p would require less memory than 60p.


It does have a little more than the HDX but that is simpley due to the bigger pixrls. And BTW it is not the SDX chips in the HPX500. Thos chips could not output 60 frames, and they were only 520,000. The HPX is 620,000.

Best,

Jan
Click to expand...

Thank you for correcting my error. I had heard the 500 used the same chips as the SDX900. So it is possible for SD cameras to have more dynamic range than HD cameras, given the same sensor size?
 
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