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View Full Version : please help: 25p - pulsates



ib84
2007 May 18th, 06:01
hi out there,
today i got my PAL-HV20, and i am not convinced at all:
Aside rolling shutter / wobble (what a disturb!), but when i record in 25p which is very important to me, there is some strange pulsating effect.
here is a sample (http://hv20.info/yopu/25p_pulsating.mpeg)

I applied linear blend deinterlacing, but no effect.

please help me! Until tomorrow I have to decide if i bring it back or not

thanks for fast answers

Mal
2007 May 18th, 07:55
The clip is very small (short) and I'm having a hard time seeing what it is you want us to see.
Okay, I've taken it into Quicktime, and looked at it closer.
Yes, I see it now.

From what I can tell, this is not coming from the cam though, unless the cam had difficulties in focusing for some reason or another.
But the pulsing is definitely coming from the footage going in and out of focus.
Since this is happening with such smooth frequency, it would be very possible that this is a result of some deinterlacing or other format conversion.

What's your process from getting it from the MiniDV tape to a MPEG file?

Worley
2007 May 18th, 11:40
I see the pulsating, and agree that this is down to the focusing. Bright images are difficult for cameras to focus on - and look at the reflection from the photos!

Try moving the camera slightly to the right, so the camera is focused more on the wall.

Worley

aneubert
2007 May 18th, 17:38
The pulsating ist clearly an AF-Issue - simply try the following:

- Zoom onto a target with AF = on
- Wait till the cam has focused
- Switch to MF
- Press record
- Zoom out at any desired speed

Using this workaround the picture will be rock solid anytime.

With AF = on i can see the pulsating in nearly all shots with sharp objects in front of an unsharp background.

I guess Canon could fix this issue by a firmware update if they wanted to, however this would depend on the level of complaint about this missbehaviour.

I love the picture quality of the cam, but this bug ruins a third of the shots that im doing.

Regards, Andreas

Mal
2007 May 18th, 17:54
I love the picture quality of the cam, but this bug ruins a third of the shots that im doing.

Not if you follow your own advice. :hv20-smilie81:

(good advice, by the way....)

ib84
2007 May 18th, 19:16
thanks aneubert et al, that was helpful. tomorrow i give it some more testing, to decide if i keep it

Emanuel
2007 May 18th, 23:03
I love the picture quality of the cam, but this bug ruins a third of the shots that im doing.

Not if you follow your own advice. :hv20-smilie81:

(good advice, by the way....):hv20-smilie09:

aneubert
2007 May 24th, 17:12
Not if you follow your own advice. :hv20-smilie81:
(good advice, by the way....)

Thanks! But the AF-Button is badly placed resulting in camera shake everytime i try to correct for this firmware bug.

AND: This workaround only works when you zoom out, when you zoom in the AF often needs to be active to adjust focus from the old to the new target....

So a fix would very appreciated!

Andreas