HVR-A1E Shooting Tip!

[Max Hertz]

One problem oft discussed with the A1E is the fast zoom.
Alas, I have found a solution!
I was playing around with the camera the other day and noticed this useful quirk.
Go to Shot Transition in the menu.
Now, without programming any shots in, use the zoom.
You will now find that you can get a really nice slow zoom! :D
Has anyone noticed any other useful quirks in the camera?

[Alan Roberts]

Another one is the gamma selection. If you use standard gamma (i.e. not Cinetone) and switch Black Stretch on, you get a surprisingly accurate ITU.709 curve (maximum slope 4.5) with a knee at 86% compressing highlights up to 250% exposure. That's only a stop short of the HDW750, and it's noise peformance is a little better, so you get to capture around 11.3 stops. That's not bad for a tiddler.

[steelej]

Come on Alan, get your hands on a Z1 and give us some tips :-)

John.

[Alan Roberts]

I'm reporting on the A1 because I've got one. I've paid for it. All the settings documents I've done for the BBC have been on cameras loaned to the BBC for that purpose. So far, nobody's asked for settings for the Z1 (it costs money to do it). Are you offering? :D

[steelej]

If you'd do it for a cup of tea and a jaffa cake then you're on :D

John.

[Alan Roberts]

I'm just a wee bit more expensive than that :D

[Max Hertz]

Hi Alan,
How about a retrospective review on the A1 now that you have had to the chance to get to know it?
Would you be tempted by Ferrero Rocher? ;)

[Alan Roberts]

I'll probably do a full setup for it, and add it to the BBC list. I haven't finished the tests yet (having problems connecting it to my Vaio, discussed in another thread), but I've fully rummaged colorimetry and gamma. What's left to do is to explore it's spatial frequency response (mtf) and how gain and detail affect it. I need HDV connectivity to the Vaio to do that. About another week if all goes well.

And this one's for free.

[mooblie]

OK - So which one of us is going to give Alan a Z1? :)

[JOHN . A.V.]

It`s that tumbleweed moment !

[Alan Roberts]

Gift isn't needed, just a loan for about 3 days. But not until I've managed to get th A1 to talk to my Vaio. Still no progress on that. Edius works in HDV just fine, but won't talk to the A1 in HDV mode (DV mode's fine).

See here (http://forums.dvdoctor.net/showthread.php?p=248506#post248506).

[Max Hertz]

...that would be fantastic :)
where would I find the BBC list?
Have you ever noticed a wobble in the picture?
It has happened when shooting hand held,
Could this be because of the mpeg2 compression or could it be the image stabiliser?

[Alan Roberts]

http://www.bbc.co.uk/rd/pubs/whp/whp034.shtml gets you the R&D White Paper that covers the science, and a list of all the addenda (one per camera or variant of camera).

Wobble in picture when hand-held is almost certainly down to the image stabiliser (electronic, not optical) running out of range and letting go. Tip for getting more stable pictures is to drink just enough alcohol, but not too much. Many moons ago I used to take 35mm stills in folk clubs, often candle-lit, with an F/1.4 lens. I found I could get steady exposures down to 1/4 second after the first pint of Guinness, but after the second, I couldn't cope with slower than 1/15th. After the third, I couldn't find the shutter button.

[Max Hertz]

Ah, Guinness - the Irish answer to the glidecam!
A tried (if not trusted) technique! :)

[Max Hertz]

Alan,
Thanks for the link.
I heard the wobble might also be caused by the way the cmos chip processes the image using a "rolling Shutter"
Have you heard of this?

[Alan Roberts]

The principle of a shutter in an electronic camera is interesting and can be solved in several ways. The simplest approach is to raise the substrate potential in a single pulse. This is like having water in a canvas bucket, and suddenly pushing the bottom of it upwards until it turns inside out, all the charge is dumped into the drain. So, at the start of a field period, light starts to accumulate in the pixels, and at some later point, all the cells are discharged at the same time. Light then accumulates until the time the sensor is read out, and this interval is the "shutter-open" time. In cmos sensors, it's possible to have a "rolling" shutter, where cells are cleaned out one at a time, or a line at a time, instead of junking the lot. In the simplest of cameras, this is the only way to do it because there's no other storgae, so video's read cout directly from the chip. But tv cameras generally don't work that way, they shift the charge from the light sensitive part to another part as temporary storage from which the video signal's read out. So it's generally not do this way.

I still reckon the stabiliser runs out of range and lets go.

[Max Hertz]

I hope so
Any luck with connecting your viao by the way?

[Alan Roberts]

The story unfolds; it's not over yet. I found that the SP2 download isn't complete, it didn't install the AV/C driver, but it's on the cd version. Now, the Dell works fine (capture/edit HDV on a 1.86GHz Centrino) but the Vaio (2.8GHz full P4) insists on trying to decode the MPEG during capture and makes a pig's ear of it.

Richard Payne of DVC's making helpful suggestions, but I'm still puzzled why a slow machine can do it but a fast one can't.

[Max Hertz]

...strange.
I have n't edited full HDV yet, I'm downconverting in Avid on my old Dell with no problems.
Going to switch over to Mac and Final Cut HD soon.
just waiting on the new intel version, hope it's a smooth transition!
best of luck!

[steelej]

Alan, if you're capturing using edius then it'll try and re-encode the MPEG into the canopus HQ intermediate and a 2.8 machine will struggle to do that, if you want to make sure you get a clean capture then you can capture the MPEG transport stream by using MPEG capture and in the settings select the transport stream option as opposed to the canopus HQ option, editing the m2t file is more painful than canops HQ but you can convert afterwards instead of trying to do it in realtime.

Don't know if that's your problem but I find on my machine I can capture a few minutes at canopus HQ before it starts to break up, a number of people on the canopus forum had the same problem and most say you need a bit more ooomph to be able to do the encode to HQ on the fly.

John.

[Alan Roberts]

Yes, I k now about the options. With identical settings in the MPEG capture dialog, the Dell captures the transport stream and shows no picture in the window, but the Vaio flails about trying to show the picture and wrecks the captre as a result. I'm well aware than neither machine is up to conversion to HQ on the fly, I can't afford a machine to do that until well into the next tax year. My problem is that a 1.86GHz Centrino captures MPEG fine, but a 2.8GHz P4 can't. The Vaio shouldn't be trying to decode and display the video, that's the problem, I think.