Is an SD Lens on an HPX-502 acceptable if shooting in SD mode?

[Tim Polster]

This is a bit surpising to me.

When you mention downconvert mode, I think of external software.

I would have thought since the imaging sensors were closer to SD resolutions that they could pull an actual SD image from them rather than pull it through the HD-SD up and down cycle.

[David Cleverly]

Even though all information on these forums is certainly appreciated, I will really have to have a look at one with an SD lens on it to see how it goes.

And then there are those who actually use the camera with an SD lens:

I asked a colleague with 20 years experience in news who owns a 502 with an SD lens, about his camera setup and he says he LOVES it and says the SD lens in HD mode is fine. No complaints with the camera's pics in SD mode, either. Perfect camera and pictures for news, he says, and he is very particular - everything has to be perfect, so he wouldn't keep the cam if it was crap. He said that, if you put it side-by-side with a PDW-700 XDCAM, you would be able to see the difference, but that difference, in his opinion, was not enough to warrant the price difference to him.

I guess the proof is in the pudding - not the on-paper specifications.

[David Heath]

Originally Posted by Tim Polster

This is a bit surpising to me.

When you mention downconvert mode, I think of external software.

I would have thought since the imaging sensors were closer to SD resolutions that they could pull an actual SD image from them rather than pull it through the HD-SD up and down cycle.

My understanding is that although the sensors are 960x540, all the image processing happens in a 1920x1080 matrix, frame by frame, and that's how the pixel-shift magic does it's trick as well. In fact, that's why the sensors are 960x540 - having them half of the full raster processing matrix makes for easier processing. You don't get full raster resolution - rather about 1200x650 for luminance, but that makes for pretty good 720p pictures.

All the other modes are then derived via scaling from this. Horizontal scaling gives DVCProHD (1280x1080), and H&V scaling gives 720p and 576i (in 50 Hz countries). The 720p conversion is reckoned to be pretty clean, as the chips and processing don't give much detail above the 720 resolution - there's nothing to give rise to aliases!

Forming the SD output is different, because there is detail between about 1200 and 720 horizontally, and about 650 and 576 vertically - that's what makes it an HD camera! And that's what gives rise to the aliases that can be seen in the 576i zone plate image.

[David Heath]

Originally Posted by David Cleverly

I guess the proof is in the pudding - not the on-paper specifications.

Most definately, but I'd define the eating of the pudding as the end to end chain - camera via transmitter etc to viewer - whereas the direct camera output is a bit like the uncooked mix!

In the early days of ENG (Ikegami 79s and early U-matic) cameras were lined up simply according to their direct output. The better the camera output looked, the better the final result, obviously? As it turned out, no. Cameramen were seeing their pictures transmitted, didn't think they looked good, and would come to get the camera checked, only to find it was fine - so what was going on? Eventually it dawned that the optimum amount of aperture correction for straight out of the camera viewing was causing "ringing" in some of the U-matic electronics. A white-black edge would cause "rippling" after it, and this was the cause of most of the problems.

The cure was pretty easy. The output was recorded, and the aperture correction slowly turned up whilst recording a commentary on the audio track what it was set to. Then playback, look for optimum quality, note the setting from the commentary, and leave the camera set to that.

Of course, what then happened was a lot of cameramen were complaining that their camera then looked soft, which on the direct output and in the viewfinder it indeed did. Eventually, it got accepted that it was a worthwhile price to pay for a better OVERALL result.

Roll on 25 years and digits, and the same principles hold true. Aliases may be hardly visible on a direct output, but can really screw up compression systems, especially broadcast ones which may be running at an absolute minimum bitrate. You can't tell what final output will look like from a simple viewing of the camera, that's why aliases are so dangerous.

None of this is to say the 500 is crap. Just to say that it's *SD* output won't be as good as from such as a DSR570. Same applies to pretty well any HD camera you're likely to try.

[David Cleverly]

Thanks David,

I am wondering then:

Is it better for me to future-proof myself here taking advantage (so to speak) of the insurance claim by replacing the 570 with an HD cam but shooting in SD until we need to go HD? Will SD be THAT bad on an HD cam??? And we are talking NEWS here, not production.

Or am I better getting the 570 replaced with, say, a DSR-450 SD? The trouble is, SD Sony's are a long wait.

The thing is, that if I go to SD now, I will have to actually PAY for HD in, say, 18 months. God forbid!! :-)

Incidentally, I saw a colleague's story go to air tonight that was shot on a 502 in SD and sent via FTP to the network. Looked great!

[David Heath]

Originally Posted by David Cleverly

Will SD be THAT bad on an HD cam??? And we are talking NEWS here, not production.

I don't think it's a case of "cor, look at THAT!" bad by any means. It's just that the best SD comes from an SD camera, but the general belief is that if a camera is capable of HD, it's SD output must be great - better than an SD camera. And that assumption is wrong.

What you do depends on how much money you have to spend, and where you see your career going in the next few years. If I was biased, I could make a very good case for any of the options, and a very good case against.

As far as the 500 goes, it's pluses are it's available now, low power consumption, no extra money from you (all off insurance), use existing lens, and it has an in-camera DV 25Mbs mode.

Against that, it's the bottom of the P2 HD range and lacks some features that you might have got to take for granted in a DSR570 - double zebras, radio mic integration etc - and it's a different system to that used by your main client. That may not matter too much to you at the moment, but what if in a couple of years time you start to work more closely with their operation? If they are going on to PDW700s, I also think it will look soft against them come the move to HD, especially as full 1080 displays are becoming more prevalent.

[Kit Hannah]

Originally Posted by David Cleverly

Is anyone here actually shooting on a HPX 500/502 in SD? Are the pics acceptable for news gathering? Is there any difference between the said 502 and the 500 you guys are talking about here?

I am. I do it every day. Looks wonderful.

I have 2x HPX500's, and use them mostly with Canon J 15x9.5 SD, external focus lenses. The lenses cost me $125 each. I literally use them everyday for shooting HD commercials for our Digital Signage Network. We have done extensive testing on this very subject. I think that you would be foolish to get anything less at this point. Most SD Cameras these days cost as much or more than the HD counterparts. Even the SDX900 I believe costs more than the HPX500. Many clients request HD footage now, because they'll be able to use it in the future. Typically I record everything in HD and render out to SD if I need to, which looks awesome. Go poke around in the hpx500 forum and I think you'll find many more answers there.

Kit

[Matt Gottshalk]

Yup as Kit said, a GOOD SD lens on the HPX works just fine.

Here is a comparison between my Canon J series SD lens and my Angeniuex HD lens,

HPX-500 SD vs HD lens comparison on Vimeo