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Quality of HVX / HPX in 24p vs HMC150 in 1080
Hi,
I’m deciding between the Panasonic HMC150 (which is AVCHD and uses SD cards) and the HPX170 (which is DVCProHD and uses P2 cards). What is holding me back from getting the HPX is the cost of P2 cards.
But I am wondering, if I were to save on card costs by shooting in 720p on the HPX (which uses about half the space as 1080 when shooting in 24p?) would that still result in better quality than shooting in 1080 on the HMC150?
I didn’t see any other posts on this comparison, aside from the one I posted in the HMC150 forum as well, but if you know of any, please point me towards them
Thanks!
Isaac
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19 Replies
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AVC CAM or AVCHD codecs can look pretty good at 24Mbps, they are full sample codecs in highest quality mode, however, that advantage is not as useful for a pixel shifted CCD camera like the 150. The other issue is 4:2:0 color space vs. 4:2:2 for DVCPRO HD and the HPX170, which is the exact same front end as the 150. If doing a lot of green screen, 4:2:2 can be advantageous.
The 170 has the advantage of the simplicity of editing with DVCPRO HD,
which isn’t as processor intensive, variable frame rates for off-speed shots, Native frame rate modes so that a 32Gb card can record for over 80 minutes in 720/24PN. HD SDI is also useful for professional monitors, which the 150 lacks.Jeff Regan
Shooting Star Video
http://www.ssv.com -
Thanks Jeff, for the helpful info. I hadn’t thought too much about the back-end issue of output and editing. I had assumed I’d transcode the AVCHD to something FCP can work with, but that may be a pain.
So, as far as image quality goes, do you think that having 4:2:2 color space, and having a higher data rate of 50mb/s vs 24 mb/s contributes more to the quality of the image than the extra resolution?
I wonder if you took a 720 x 960 HVX image and enlarged to 1080 x 1920 and compared it side by side with HMC150’s 1080, what it would look like. I’ve looked for comparison pics online, but these images are already compressed for the web so it doesn’t help much.
Also, regarding the HMC150 “pixel shift” you mentioned, does that mean than 1080 x 1920 on the HMC isn’t “really” 1080?
I don’t totally understand how the resolution works with these cameras, but I read somewhere that each chip on HMC150 is 960 x 540 pix, and that this “amounts to a resolution of about 1440 x 810.”
This sort of confused me. Because then it seems like I’m really comparing 960 x 720 vs 1440 x 810, rather than 1920 x 1080, which is a much smaller difference.
Thanks very much
IsaacPS – While we’re talking resolution, why are some of these cameras 1080 x 1440 (like my Canon XHA1s) and some are 1080 x 1920 (like the HMC150)? They both look like the same aspect ratio so how does that work out? Thanks again Jeff
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I can answer that last question. 1440×1080 doesn’t use square pixels. It’s pixels are wider than square, so each pixel is covering more ground. What that means is that you’re not really getting 1920 lines of resolution. The codec compensates for this and does some math so that it doesn’t have to record as much information. So, if you’re image is in the shape of a football field, both resolutions are recording the length of the football field. The 1920 records 1920 small slices of the field. The 1440 records 1440 slightly bigger slices of the field.
The HPX 500 and HVX 200 do this.
Overall, all these cameras are going to have a great image when looking at a well lit image. I’ve seen the local news channels shooting with 150’s. Where they start to separate from each other is in optics and latitude. The smaller chip cameras will not give you as big of a range going from highlights to blacks. They are noticeable different. Also, the optics for the bigger cameras are much better and give you a better depth of field and cleaner image.
I own a 150 and it has a super wide lens and the images look great. However, I’m a bit disappointed with the depth of field that I’m able to get.
-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl -
Isaac,
Don’t use bit rate as a quality comparison because DVCPRO HD is a DCT based codec that is much older and less efficient than an h.264 AVC codec. DVCPRO HD at 720/24PN runs at 40Mbps, not 100Mbps anyway.
What you get with a full sample codec is better resolution if the front end of the camera can actually produce a full raster image. The CCD’s in an HVX200/A, HPX170, HMC150 are pixel shifted, doubling the pixel count from 540X960 to 1080X1920, in theory. However, this does not have the true resolution as a full raster sensor. But, you are recording more samples horizontally with square pixels with AVC HD vs. rectangular pixels that sub-sample 1080X1920 down to 1080X1280 in the case of DVCPRO HD, just as HDCAM sub-samples to 1440.
Some of the lack of color space in a 4:2:0 codec can be replaced by a full sample codec, but the real detail has to exist in the first place.
I haven’t done side by side testing of the 150 and 170 because the 150 doesn’t do enough of what I want, and I already had 2/3″ DVCPRO HD cameras, so the 170 made more sense as a B-camera.
Ultimately you need to decide on which workflow works best for you, whether you want to spend $600 per 32Gb P2 card, if the off-speed capabilities of the 170 are important and what kind of monitoring you have.
If you want the most possible resolution, then an HPX300 is the best choice, and twice the dollars, of course!
Jeff Regan
Shooting Star Video
http://www.ssv.com -
Thank you both.
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Aha, yes. The 300 is nice, is a shoulder mount camera and has interchangeable lenses. But the 300 has smaller chips AND it’s CMOS, which many people object to.
-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl -
What about the GY-HM700U ?
With some sort of attachment, that can shoot in XDCamEX at 35mbps. Or is that bit rate also not comparable because its a different codec?
I posted this question somewhere else, but since you’re here : ) ….
How would you order these codecs in order of image quality, storage space aside, and all other things being equal:
– XDCamEX – 35mbps
– XDCamHD (same?)
– HDV (mpeg2) – 25 mbps
– AVCHD (mpeg4) – 24 mbps
– DVCProHD – 35 mbps
– Whatever codec JVC uses when recording to SD cards, when not using XDCam. HDV? -
Honestly I’m not a codec expert. I went crazy this year in comparing cameras and whatnot. It’s really hard to say “All else being equal.” because it’s not. It’s completely irrelevant to compare just codecs because there’s so much more that goes into the quality of the image.
About the best you can do is look at still images from different cameras and see the differences.
I will say, in my limited research, the HDV image is probably the lowest quality image you’ll see. However, HDV cameras are consistently being used as b-cameras and even a-cameras for broadcast television.
I’d look at budget and workflow and specific needs above all else.
-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl -
HPX300 has 1/3″ sensors, as does HMC150/HPX170, only CMOS full raster vs. CCD pixel shifted. HPX500 has 2/3″ CCD’s, pixel shifted, DVCPRO HD only, no AVC-Intra 50 or 100.
JVC 700 is HDV based, so MPEG2 Quicktime files or optional XDCAM EX, both are Long GOP 4:2:0, same as AVC CAM(AVC HD). DVCPRO HD offers Native frame rates, 4:2:2, I-Frame frame structure, but is sub-sampled to 960 and 1280 horizontal for 720 and 1080 resolutions.
JVC 700 uses 1/3″ CCD’s, pixel shifted vs. native HD sensors.
I would rather buy an EX1(well, actually I do have an EX1) than a 700 because it has 1/2″ full raster CMOS sensors, SxS card XDCAM EX is built-in. It is quieter and better in low light than any of the other cameras, but has CMOS artifacts, lousy ergonomics.
If Panasonic came out with a large sensor(1/2″ or bigger)camera with AVC-Intra 100 for under $10K, it would be a giant killer. HPX300 is not as good in low light, noisy, deep depth of field compared to EX1 or other larger sensor cameras.
Jeff Regan
Shooting Star Video
http://www.ssv.com -
Hi Jeff
What do you mean by “Native frame rates” for the HPX? What does it mean if it’s not native (as is the case with the other 2 cameras?) ?
When you say that JVC 700 uses 1/3″ CCD’s, pixel shifted vs. native HD sensors…
that’s the same with the HPX and HMC150 right?Thanks again
Isaac
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