Slow Shutter on HPX 250 / 160 ?

R

Reflex Films

Active member
Just wondering if the interval record mode/ or frame rate hack lets you do longer exposures than the HVX200 did.

it would be great to be able to leave that shutter open in interval mode and get some extra lowlight timelapse gold.
 
Reflex Films said:
Just wondering if the interval record mode/ or frame rate hack lets you do longer exposures than the HVX200 did.

it would be great to be able to leave that shutter open in interval mode and get some extra lowlight timelapse gold.
Click to expand...
Well, the HVX didn't allow slow shutters in interval mode at all. So the way we got the wonderful smeary streaky headlights type of shots was to use the 2-frame-per-second hack, and use a 360-degree shutter; that combination gave us 2fps with 1/2-second exposure time.

You can do the exact same thing with the HPX250 and the AC160; they have variable frame rates that go all the way down to 2fps, so set it on 2fps with 360-degree shutter to get 1/2-second exposure.
 
Hi guys, I'm reading from official specs that the Hpx250 VFR can go down to 1 fps, meaning that you can gather up to one second of light, with shutter angle set to 360.0d (actually 359.5d, as they say)...
That's amazing!
It was shown in the first Hpx250 Demo video, there'a a low framerate Over-60i with a noticeable long exposure blur... :cheesy:


Unlike, the AC-160 has an undercrank limit at 2 fps (while it rocks in 1080 overcrank!).
 
Yep, I should have pointed that out but I blew it. The HPX250 does indeed go down to 1fps in VFR mode, and can do that in 1080 or 720 mode. It can't overcrank faster than 30p in 1080, but can go up to 60p in 720. But it has VFR from 1 to 30 in 1080, and 1 to 60 in 720 (in certain discrete steps, of course).
 
great to know that i can get nearly 1 sec exposures - with the new low light sensitivity improvements i should be able to get some nice dusk / sunrise stuff with the sun over the horizon.

so the cheaper 160 actually does 1080p overcrank to 60 frames - while the HPX 250 is limited to 720p overcrank - thats counter intuitive - must be a data rate / codec limitation of DVCPRO / AVCintro.
 
Yes, the 160 does 1080p overcranking up to 60fps, and the 250 can do up to 30fps in 1080. But the 250 does a few things the 160 doesn't as well, including 10-bit 4:2:2 recording and 10-bit output on the SDI and HDMI, so it earns its price difference in different ways.
 
Hi Barry,

I would appreciate if you could post the relevant scene files for HPX250 to allow extremely slow shutter ... I am not certain if the HPX172 frame rate hack is identical for HPX250. Thank you.
 
There's no need of framerate hacking on the Hpx250.
You simply go and set the slowest framerate available in VFR mode (720 or 1080 mode), down to 1 fps.
This leads to up to one second of light exposure per frame, if you set your shutter at 359.5d.
 
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Faust said:
There's no need of framerate hacking on the Hpx250.
You simply go and set the slowest framerate available in VFR mode (720 or 1080 mode), down to 1 fps.
This leads to up to one second of light exposure per frame, if you set your shutter at 359.5d.
Click to expand...

Can this be done on a 160 as well?
 
Noel Evans said:
Can this be done on a 160 as well?
Click to expand...
Nope, VFR on the AC160 allows the slowest framerate at 2 fps only, with half a second of maximum exposure time.
However, on the AC160 the INTERVAL REC function can be set to catch actually one or less frame-per-second (down to one frame recorded each 2 minutes) but I don't think it is possible to set a shutter speed slower than 1/6th of a second on PH 1080/24P@59,94Hz mode or on PH 1080/25P@50Hz mode...
 
Cheers faust. Bit out of the loop on the 250/160 - still thinking one or the other for some of the jobs I get.
 
Noel Evans said:
Cheers faust. Bit out of the loop on the 250/160 - still thinking one or the other for some of the jobs I get.
Click to expand...
Hi Noel, choosing between the two camcorders can be such a hard dilemma...
Especially considering that they seem to complete each other regarding some specifications (e.g. over/undercranking, encoding quality, card reliability, etc).

Differences aside, my main complaint goes to the temporary focus loss (manual focus) during zooming that affects both camcorders, since they share the same lens block.
How could Panasonic engineers allow issues of this kind on these new jewels?
Previous models like Hvx200 or Hpx171 (I work with both) were affected too, but the zoom limited to 13x only was able to mask the loss of manual focus in a smaller margin for error...
 
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