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Sony TRV950 / PDX10 Companion
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Old October 25th, 2004, 09:06 AM   #1
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Let me see if I have this correct...

With several shortcomings of the PDX10's manual controls, one should work around them in the follwing fashion.

1. Lock shutter speed

2. Never go wide open or gain will be applied (is there a way to back down the gain to 0db and still shoot wide open)

3. Never stop down lens to much because the auto ND's will kick in...if shooting in bright daylight, simply overexpose and put your own ND's on...I would assume if you are in manual and outside and you set exposure to f2.8 or f4, the ND's will not kick in unless you stop down the lens?

Any comments or corrections to my points would be appreciated...thanks.

PS: Anyone know if the GS400 has these Gain and ND issues?
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Old October 27th, 2004, 07:17 AM   #2
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Re: Let me see if I have this correct...

1. Lock shutter speed

You should stick with 1/50th (PAL) or 1/60th (NTSC) unless you either need a lower speed because of low light levels, or to achieve a special effect.

2. Never go wide open or gain will be applied (is there a way to back down the gain to 0db and still shoot wide open)

You can limit gain to either 6dB or 12dB but not 0dB for some reason (this is from memory, I don't have the camera with me). The gain is calibrated in 3dB steps, with 18dB at the far right of the exposure scale. So, starting with the exposure indicator at the right hand side of the scale, six clicks to the left gets you to the 0dB position. If the image is too dark at that point then you either need to use gain or reduce the shutter speed.

Whilst gain is best to avoid in principle, I don't find that using a little causes any significant image deterioration.

Also "wide open" refers to the aperture, which is already wide open at the point gain starts to be applied. The reason for applying gain is because the aperture won't open any wider to allow more light in.

3. Never stop down lens to much because the auto ND's will kick in...if shooting in bright daylight, simply overexpose and put your own ND's on...I would assume if you are in manual and outside and you set exposure to f2.8 or f4, the ND's will not kick in unless you stop down the lens?

You seem to have this back to front. Stopping down the lens does exactly the same as applying ND filters - both reduce the exposure level, and are therefore alternatives (although they can of course be combined). ND filters are a better bet than an aperture stopped down as far as it will go as the latter degrades the image far more.
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Old October 27th, 2004, 09:19 AM   #3
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pdx10 Limitation

Thanks for your response Pat. I don't think I worded my questions is the best way. They are not to be taken as general technical questions, but instead, directed at the PDX10's manual limitations. I am just trying to confirm that I have the correct procedures in managing it's limitations. For example:

From what I have read, if you set the PDX10's aperature to it's wide open setting, the gain automatically kicks in to either 3db or 6db (if limiter is set, otherwise up to 18db).

Also, I have read if you stop the lens down to much, ND's start to kick in so the exposure can return to the sweet spot of the lens...Hence, a way to defeat this would be to have the exposure set at 2.4 or 4 (theoretically of course - i know the PDX has a bar) and have your picture overexposed until you put your own ND on.
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Old October 27th, 2004, 10:35 AM   #4
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Re: pdx10 Limitation

From what I have read, if you set the PDX10's aperature to it's wide open setting, the gain automatically kicks in to either 3db or 6db (if limiter is set, otherwise up to 18db).

What I was trying to explain is that the exposure scale in the viewfinder effectively shows the aperture opening - except for the last 6 clicks to the right where the aperture is fully open and gain is being applied in 3dB increments. Unless of course you have limited gain to 6dB or 12dB.

Also, I have read if you stop the lens down to much, ND's start to kick in so the exposure can return to the sweet spot of the lens...Hence, a way to defeat this would be to have the exposure set at 2.4 or 4 (theoretically of course - i know the PDX has a bar) and have your picture overexposed until you put your own ND on.

I think I see what you mean. Yes, the camera will apply ND filters as an alternative to having to stop the lens down too far to get the correct exposure setting. And yes, fitting an ND filter on the lens is a more controlled alternative to having the camera apply internal ND filters. I have a 0.9ND fitted almost all of the time. Sorry if my previous reply was confusing but I misunderstood you.
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Old October 28th, 2004, 05:03 AM   #5
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You've hit upon one of the PDX10's greatest failings in my view - and one that stops it being loved by professionals who like to be informed as to what's going on when they twiddle those dials.

As the maximum aperture of the lens varies uniformly between full wide-angle and full telephoto (losing 1.5 stops on the way), it gets very difficult to tell (from the half-wit exposure bar) exactly when it is you reach maximum aperture. There's no fixed point of course as it depends on what focal length you happen to be shooting at.

Pat speaks a lot of sense on this matter, but counting the clicks from the right hand side isn't strictly accurate because of this varying maximum aperture. And it's no good turning on the 'Display' later, as this tells silly lies about what aperture was used, ignoring the fact that beyond f4.8 the three NDs are brought invisibly into play. The display shows these as apertures whereas in fact they're not.

So using maximum aperture is good except for the fact that you may well stray into gain-up mode and you'll have more vignetting of course. But better this than using f8 with such tiny chips, and much better than upping the shutter speed and getting that CCD smear. Stick to 1/50th as Pat says.

Using front-mounted NDs doesn't really help much with this camera simply because you're working in the dark aperture wise. The built in NDs are fine as they stop the lens stopping down beyond f4.8, but your .9ND won't harm unless you go into gain-up of course. As Pat says the gain-up mode is pretty good on this camera, but you're suffering the softness and flare and vignetting of using maximum aperture as well as making the picture slightly noisier. Not things I'd recommend for ultimate picture quality, as I'm sure you'd agree.

The GS400 (and virtually all camcorders that don't have an external ND switch) use the same principle, and have done for many years. It's just a disappointment that Sony should feel the need to do this on one of their DVCAM models.

tom.
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Old October 28th, 2004, 10:01 AM   #6
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Just to clarify one common misconception about the PDX-10, TRV-950, VX-2000 and VX-2100. The AGC LIMIT custom preset parameter is only effective when you shoot in one of the auto modes. In other words, it limits how much gain the camera will automatically apply in a dark scene but has no effect in manual mode. See page 62 of the PDX-10 manual
Quote:
About the AGC Limit
When adjusting the exposure manually, the level of the gain is up to 18dB (OFF).
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Old October 29th, 2004, 03:35 AM   #7
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Tom - I take your point about the varying maximum aperture. However, is it not the case that the gain is applied in 3dB steps, and the full gain range would always be 6 clicks from the right hand side of the exposure bar (and therefore determine the widest available aperture, whatever that may be)? You clearly have a lot of knowledge in this area and I want to make sure I've understood it.

Sony really should have displayed the aperture (and gain) in the viewfinder in what they define as a pro model.

Boyd - thanks for clarifying, I'd forgotton about that.
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Old October 29th, 2004, 06:19 AM   #8
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You're correct Pat - the gain is indeed applied in 3dB steps, and that would suggest that (as you say) 6 clicks down and you're at 'open' (max aperture) with no gain up applied. What's strange though is that this point can be anything fron f1.6 to 2.8 (say f 1.92). so what's the next click down? A half stop from that?

Now look at this. If you're filming at wideangle 'open' is f1.6, so all the available half stop clicks will take you down to f8 presumably. I don't have my PDX10 any more so I can't check this out. Now you go to full telephoto and do the same number of clicks. Is the camera now filming at f14? It's not likely of course, because all those clicks just bring in more and more ND.

This camera is fine for those who neither know or care how it gets such good results - they simply accept that it does so. I've nothing against this, but like you I feel it a retrograde step from the PD100. Trouble is with the PD100 and VX2100 you can get caught out - if you don't flick in the ND when asked to do so in the v/finder, the camera will film at ever smaller apertures, with dire consequences due to diffraction. At least with the auto ND filtration it's one less thing to worry about in the stress of the shoot.

tom.
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Old October 29th, 2004, 12:56 PM   #9
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I suppose in the absence of aperture/gain information the key thing to know is when the gain is and isn't applied, and therefore when the aperture is at its'widest with minimal DoF. However, although I haven't done any comparison testing on this I suspect that the DoF is always going to more than you would want to throw the background out of focus, with CCDs that size.

And yes, I'm fine with the auto ND filters. In fact I'm fine with just about anything being automated, provided it (a) tells me what it's doing and (b) allows me to override it.
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Old October 30th, 2004, 07:10 AM   #10
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The thing I really liked about the PDX10 was the manual focus confirmation in the v/finder for a second or two after I'd turned the focus ring. This was invaluable when shooting stage plays, when you're in the dark just before the curtain rises. With the VX2k if I've had the last shot on auto focus I'm quaking, as I can't switch to manual (unless I accept the 'infinity' position), and if I leave it to the automation the scene always come in as a pull focus. By act 4 this can start to look intentional (I hope).

Like you Pat - I want to be kept informed of when I'm at or near maximum aperture and it's not asking much, is it? I mean - a pointer moving along a bar must be just as difficult and expensive to engineer as an aperture display. The bar takes up even more v/f real estate which is a pity, but maybe Sony thought they didn't want to have f8 up there when in reality it was f3.5 + a lot of ND. I even thought about putting a sticky tape index mark on my side-screen to indicarte the point.

I'll bet there were a lot of heated R & D discussions at Sony HQ about this camera. It's USP was indeed its 16:9 performance, but the low light performance must've been making a lot of the engineers squirm with embarrassment.

tom.
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Old October 30th, 2004, 09:31 AM   #11
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Yes, I find the focus distance display helpful too, but don't assume that it's based in any reality either. When shooting performances I do the same thing as Tom, but depending on how far out you've zoomed it may tell me that sharp focus is anyway from 1.8 to 22 meters when in reality I'm 32 meters from the stage. This is due to the huge DOF in part, but I'm also suspicious as to where those numbers come from. I'm also always curious as to whether setting the focus to the same number will always give the same results. Regardless, if you note the distance displayed by "push auto" for a given zoom level, you can match it manually in the dark and have a fair chance of being close.

Just last night I shot a performance of Don Pasquale which is a comedy that's very brightly lit, including footlights. Under these conditions I continue to marvel at how nice a 16:9 image this little camera can produce. I don't think we will find anything else to match this quality for quite some time, unless we are willing to pay quite a bit more. There are a number of annoying quirks to the PDX-10, but if you can learn to work around them it will not disappoint you.
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Old November 3rd, 2004, 05:25 PM   #12
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> At least with the auto ND filtration it's one less thing to
> worry about in the stress of the shoot.

Yes. Since most of my work is documentary, I use auto a lot. What I do is play with the AE point in the CP menu, I usually set it way down, always keep zebra on to make sure I don't overexpose (this camera tends to overexpose, it seems) and I only press the EXPOSURE button to "freeze" exposure when I like what I see.
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