HMC150 vs HPX170 for compositing/green screen

J

jamesc

Well-known member
I know that the HPX170's 4:2:2 vs HMC150's 4:2:0 makes the HPX170 better for for compositing/greenscreen/heavy grading (though I guess it's somewhat debatable). Are there any other major reasons beside better/smoother edge definition? What happens to 4:2:0 vs. 4:2:2 during extreme grading?

Can anyone pseudo-quantify how much worse HMC150 4:2:0 with chroma smoothing vs. HPX170 4:2:2 is for green screen? Aka, will the HMC150 get me 95% of the way there, but leave me no way to get a clean key when blown up? Does anyone have any horror stories about how difficult 4:2:0 made their lives for greenscreen/grading but how 4:2:2 saved the day?

My assumption is that HMC150 is "ok" for compositing/greenscreen/heavy grading, while the HPX170 is "pretty good".

Some of my projects will invovle some high motion greenscreen sequences, however, delivery will primarily be HD web streams and DVD. For me, cost is a factor, so I'm still heavily debating between the HMC150 and the HPX170.
 
I've shot alot of both. I'd say that the 170 is just a bit more forgiving if your key isn't perfect.. That's all. If you nailed it.. then there's very little difference.. but you do have to get something within reason... One major advantage over the older cams is the WFM. That makes lighting a greenscreen a lot easier for seeing hot spots and such.


I don't think it's enough of a different to outweight its many positives. You'll be fine.. and if you ever keyed DV then this is lightyears better.
 
I've not used the 150 but I just recently shot green screen with the 170. The waveform monitor was a huge help.
 
I believe the HDMI port on the HMC150 outputs a 4:2:2 signal. The SDHC cards can't record with a high enough bit rate to store all the data. I am sure some one will correct me if I am wrong.
 
KKeller said:
I believe the HDMI port on the HMC150 outputs a 4:2:2 signal. The SDHC cards can't record with a high enough bit rate to store all the data. I am sure some one will correct me if I am wrong.
Click to expand...

That's correct, the HMC150 HDMI outputs 4:2:2 since it bypasses the compression. In a studio environment, the HMC150 through HDMI should match the HPX170 through HD-SDI.

I'll be buying the Black Magic Intensity (possibly Pro) so that I can get 4:2:2 when my Mac Pro is around. I've considered the portable solutions (Intensity in MacBook Pro / Intesity Capture Station / Wearable Intensity in Backpack), but the convenience of 4:2:2 directly on HPX170 is still enticing.

@Justyn: Thanks for sharing your experiences. It's definitely reassuring and I've decided to stick the the HMC150 and spend the price difference getting other gear :).
 
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