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-   -   Exposure Issue in Manual (https://www.dvinfo.net/forum/sony-trv950-pdx10-companion/25022-exposure-issue-manual.html)

Steve Tapping April 24th, 2004 02:05 AM

Exposure Issue in Manual
 
If ya could take a look at this link---
http://a.domaindlx.com/eightamps/OverExpo.jpg
Obviously it's over exposed.
This was how I shot it--
Full Manual
I had no filters or wide angle lenses on.
Shutter speed at 100.
White balance outdoor.
Custom Presets not sure on.
and exposure 1 click up from total black.
This last point is an issue.
Parts of the wave are quite dark but the spray reached it's limit.
The only way I can combat this problem is shooting in auto where the exposure jumps around quite a bit. It was a very bright day but these are really dissapointing results, so disapointing that many of these shots are not usable. I had zebra set on & I could see it was overexposed but what could I do. If I clicked the exposure down it would be pure black.
ND Filters would solve this problem I'm guessing but sometimes I would like alot less contrast.
How do I stop these extreme exposures in the white wash without darkening the rest of the wave too much?

thanks

Boyd Ostroff April 24th, 2004 07:47 AM

When I try to open your link my browser just hangs for awhile, then I get a message that a connection failure has occured....

Tom Hardwick April 24th, 2004 01:43 PM

What you need is a good deep (three stop) neutral density filter, Steve. You don't say in your post whether you have a 900 or a 950, but in the situation you describe an ND8 would get you well clear of those tiny apertures just before the diaphragm blades close completely. I'm glad to see that when in auto it disturbs you. It should.

I see you'd set 1/100th sec and that's also one way to soak the light, but for movies it's generally not a good idea. If you go too far - to 1/300th sec say, the film will take on a stacatto look and you'll see 'shuttter-stutter'.

Get well away from f8 and f11 and your image resolution will improve remarkably too. The ND filter is an answer to many a prayer in DV filming, and although the 950/PDX10 has three built in, you're not in control of them as you are with the VX2100, say.

tom.

Steve Tapping April 24th, 2004 07:27 PM

Boyd here is another link that will work:
http://home.iprimus.com.au/tappings/OverExpo.jpg

Tom I have a PDX10P and I had a feeling I was going to have to buy some ND filters very soon.
With the shutter speed issue I get conflicting answers. Many surf videographers say shoot at a high shutter speed it gives clear results in slow motion and in normal picture, however the people that know this camera say don't shoot at high shutter speeds.
What would you classify as the sweet spot of this camera as in f./ for my intended use.
The photo shown is my favourite spot to film and I have not had good results there once, when I say good I mean perfect.
I will stick behind the PDX because I don't think there is a better DV camera out there for my requirements, I would just like consistent results & it looks like ND filters will help that.
Thanks heaps for your help Tom.

regards
steve

Tom Hardwick April 25th, 2004 12:52 AM

In testing this PDX10 many things have come to light. Unlike the PD100 this camcorder has no manually operated neutral density (ND) filter. Instead the PDX10 uses three automatic NDs – small slivers of uncoated filter that slide into position one after another behind the two aperture blades. Because the camcorder uses such tiny chips (effectively 1/5”), diffraction losses – especially at very short focal lengths – causes real degradation of the image.

This is why Sony has limited the apertures that are available for use, both in the manual and automatic modes. I feel that blanking off all apertures smaller than f4.8 seems to us to be curtailing the camera’s photographic potential, and furthermore, to be somewhat patronising. It certainly curtails the depth of field control as exposure is manipulated not by varying the aperture but by applying more or less ND. The camera will shoot at an aperture of f4.8 in bright sunlight, whatever focal length you choose.

If you're filming at full telephoto in the manual exposure mode the camera has all of one and a half stops to play with. What this means is that (contrary to the 'Display' information that's effectively useless) the camera will open to full aperture of f2.8. If it gets brighter - or you want to film at a smaller aperture - you can film at f4.8. If it gets brighter still the camera has no more apertures up its sleeve - it now resorts to using the first of the three ND filters. If it gets brighter still the second and then the third ND are moved into the optical path.

When even these aren't enough to control the exposure, the camera will either stop down further or raise the shutter speed to compensate, but the former loses resolution and the latter takes you towards CCD smear.

The Sony designers have insisted, to the point of forbidding access to any apertures smaller than f4.8, that you shoot using the 'sweet spot', where vignetting has disappeared and diffraction hasn’t taken hold. At this aperture the PDX10 can give fabulous results, really breathy-taking quality.

As regards slo-mo, the camera only takes 25 (30) fps, so any manipulation of the speed is going to have to work with the available fields, and interpolate between them. I find that the 1/50th sec (in which the camcorder records everything that happens in front of it) gives the best slo-mo, but others like the more stacato look of higher shutter sppeds. It's not sharper, it's just that there's less motion blur. But higher shutter speeds - as I've said - are a no-no on the PDX10, so another ND it is, Steve,

tom.

Shawn Mielke April 25th, 2004 02:28 AM

Higher shutter speeds in less than controlled situations, or any situation with hot spots, may be a no no, but there are situations in which they are quite usable and interesting...Just felt I had to say that.

Tom Hardwick April 25th, 2004 02:45 AM

Absolutely agree Shawn. Switch the camera to 1/10,000 sec and use a flash gun set to 100Hz. At this speed it appears to act just like a flash light, and at these exceedingly high shutter speeds there are some amazing things to be frozen by video.

tom.


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