15fps PDX10 footage?

[Boyd Ostroff]

I haven't tried shooting this way, but just grabbed my VX-2000 and set it for 16:9 wide mode using the "camera set" menu. Now I go to the "manual set" menu and it allows me to turn progressive scan on. But as I'm not much of a fan of the VX-2000's widescreen mode this doesn't particularly excite me....

[Ignacio Rodriguez]

I detected something strange today when checking the photo mode on my PDX10. I was in my room, with not much light. I switched from video to photo, expecting the image to get even darker due to proscan. Surprisingly, the image got BRIGHTER! I don't have a clue as to what might be going on. But as I understand it, most cams that do proscan lose 6dB of sensitivity over interlaced mode. It is very unexpected that the image get's brighter instead of darker. Could it mean that even in photo mode the camera is not really doing proscan either? That would outraging! Any thoughts?

[Andre De Clercq]

Boyd, did you then turn wide on or just verified it...because if you set "progressive" in the menue, the "16:9" turns back to 4:3.(see also pg 36 in the manual)

[Boyd Ostroff]

AHA, you're right. When I actually activate prog scan the viewfinder switches back to 4:3. Strange. Oh well, like I said, I am not a fan of either widescreen or 15fps progressive on the VX-2000 so none of this makes a lot of difference to me....

[Mike Sanchez]

Ignacio,

The still exposure settings are setup to generate an sRGB image on a computer monitor. The video exposure settings are directed at NTSC tone reproduction.

Hence, the appearance of a brighter image through the NTSC output to your LCD.....

At least that is what I think is going on. I noticed the same thing with my TRV950.

It may also be that in your custom presets you have adjusted the exposure compensation upwards and forgotten......that happened to me a couple times too.

Question: I saw your comment about 1/30 shutter speed "losing resolution" and have literally observed this myself relative to 1/60. But, I do not understand why? Can you explain? I thought the 1/60 shutter speed still ended up displayed at 1/30 but interlaced? Resolution in video is still one area I am fuzzy on my understanding.

As a guess....is the resolution in 1/30 half what the resolution in 1/60??

[Boyd Ostroff]

This topic has come up before and if you search you'll find more information. It is a little hard to conceptualize, I agree. Normally, when you shoot a 1/60 sec the camera writes it's data to successive odd/even interlaced fields and these pairs are combined to make 30 frames per second. However, if you set exposure to 1/30 sec the shutter stays open during the capture of both the odd and even fields. The result is that both fields have the same data written to them.

So if you shoot at 1/30 second you can get sort of a quick and dirty "film look" since the motion blur will be closer to film's 24 fps and the frames won't appear interlaced. However, as you note, the vertical resolution is halved since both the odd and even fields were sampled at the same time, instead of being offset by 1/60 sec.

Try it, and look closely on a good monitor. You'll notice that the image looks softer than footage shot at 1/60. Now in reality I'm guessing that it probably isn't quite as simple as all this, because I think most cameras do some vertical blending of the scan lines even at 1/60 sec in order to help avoid stair-stepping. But I still find the resolution difference quite noticeable.

[Ignacio Rodriguez]

> It may also be that in your custom presets you have adjusted
> the exposure compensation upwards and forgotten......that
> happened to me a couple times too.

Yes Mike. That's exactly what happened. Once I equalled the custom presets the low light response looked quite the same.

> Question: I saw your comment about 1/30 shutter
> speed "losing resolution" and have literally observed this
> myself relative to 1/60. But, I do not understand why? Can
> you explain?

Well it seems to me that the cost of an image sensor depends on several factors, mostly the size of the chip and amount of circuitry they put into it. In order to keep the price down, most CCD panels don't have enough circuitry to output 60 full frame images per second. Possibly odd and even lines are physically wired to the output circuits in a certain way, this makes the CCD simple to manufacture. When you drop to 1/30 (or 1/25 PAL) the camera just closes the circuits for adjacent lines and sums their output (thus the sensitivity increase). Now this explains the resolution loss with standard video resolution sensors, like the PD170, but in the case of the PDX10 we have two other factors to account for: (1) The CCDs have much higher than SD resolution, and (2) the sensors are progressive capable. So what's going on then? Well, essentially the same thing only the problem is not the CCD itself but the video processing circuitry. My guess is that Sony thinks the target market doesn't care much about proscan, so they just use the same video processing circuitry and firmware to convert the CCD output to video, and thus keep the cost as low as possible. It's so frustrating, because the PDX10 actually does proscan in photo mode, which proves the capability is there.

> Now in reality I'm guessing that it probably isn't quite as
> simple as all this, because I think most cameras do some
> vertical blending of the scan lines even at 1/60 sec in order
> to help avoid stair-stepping.

I think you are correct Boyd. And it is so frustrating to not be able to turn it off. You can turn that filter off in the Panasonic DVX100A, and the difference is so big that even though the DVX100A is not a native 16:9 camera, it's 16:9 image in proscan is as good as the PDX10's deinterlaced output because there is no loss due to the vertical LPF, whereas we lose some resolution when deinterlacing in post.

Wouldn't it be really really cool if Sony gave us a firmware update for proscan? Dream dream dream.

[Boyd Ostroff]

Ignacio, do you really think this could be as simple as a firmware issue? Doesn't also have something to do with cpu power and bandwidth? I always assumed that's why the VX-2000 et al limit progressive mode to 1/15 sec.

Well, I guess we'll just have to wait and see if Sony comes up with an updated PDX-10 to match the HC-1000 replacement for TRV-950 they've introduced in Japan....

[Ignacio Rodriguez]

> Ignacio, do you really think this could be as simple as a
> firmware issue? Doesn't also have something to do with cpu
> power and bandwidth?

Most likely it's more than just a firmware issue... but who knows... 30p is actually the same bandwidth as 60i.

> Well, I guess we'll just have to wait and see if Sony comes
> up with an updated PDX-10 to match the HC-1000 replacement
> for TRV-950 they've introduced in Japan....

Does the HC-1000 have proscan?

[Boyd Ostroff]

I don't know if it offers proscan, but sort of doubt it. The only info I've seen in English is at camcorderinfo.com. I don't find anything too exciting about the HC-1000 other than the price (which they guess will be around $500 less than the 950), although there is conjecture that it offers the same high quality 16:9 as the PDX-10. The LCD screen has actually shrunk to 2.5". The camera has a pivoting body style (not sure how that would work on a pro model with XLR box). The article says the CCD's are the same.

No info on this camera is available on Sony's US website, they still list the TRV-950 and a search for HC1000 does not yield any results.

[Mike Sanchez]

Gents,

Thanks for the replies.....

coming from the still photography world where resolution is relatively simple ... I can see that video resolution is much more complex.

I too am a bit puzzled why 3 1MP sensors cannot create the same resolutions during shutter speed of 1/30. But, Boyd, there is no question that the apparent resolution is substantially less at that shutter speed.

Sadly, the1/30 shutter speed provides very good indoor video when the gain is limited to 12dB. Much lower noise. Too bad it has to be lower res.

Ah...well....I have decided that the video holy grail is almost as hard to find as the real holy grail.

High res, low noise when taken indoors, audio that sounds like you were there.....what camera is that?

[Boyd Ostroff]

Ha,... but unlike the real holy grail I think the video grail can be had.... for a price (which is more than most of us are able to pay however).

Mike - I thought Sony was going to buy back your defective TRV-950 and you were going to get a GL-2. What happened with that?

[Ignacio Rodriguez]

Stephen, by september there will be a new Sony, the PC350, which will have 24fps. It might also do progressive 15fps. I suggest you take a look: http://www.camcorderinfo.com/content...der-$1,300.htm

[Stephen van Vuuren]

Funny you mentioned that - I was just reading the article literally a few seconds ago. Interesting though strange it does not appear on a camera with very useful manual controls.

Though progressive scan with full 16:9 could provide a nice widescreen image - the camera appears to do 30 fps and throw away every 6th frame, though until it appears, who knows.

But September is a long time to wait as I have several projects to do before then.

[Mike Sanchez]

Boyd,

Sony has indeed offered me a complete buyback ... paperwork they sent me is remains good for a bit more time. I just send it in with the receipt.

But.....I went and thoroughly examined the GL2. Gorgeous. But, big, and, much more expensive.

I am extremely aggravated that I have to set the LCD display to bright to eliminate the audio hum. But, once I do that, combined with my recent acquistion of an Azden SGM-X, the audio sounds great.

The video is OK....and.....there is the hassle factor.

So....am sitting tight.....and.....probably will just keep the TRV-950 and work around the audio hum.

PS - I read a great deal about microphones but then just took a risk on the Azden SGM-X because it has mini to mini plug.

When I handhold the mic pointed toward the area of interest the sound is really very, very good. So much better than the built in mics its no contest. Good bass sound, good high freq.

Not as focussed on the target area as I expected (picks up side and a good deal back) but much better than the built in for directionality.