Image on LCD flipouts and viewfinders doesn't go all the way down to black?

[Ignacio Rodriguez]

I was wondering if anybody else has noticed: on my Sony PDX10, 0% luma or black is not really displayed as black but as something a little brighter, both through the flipout LCD and the viewfinder. It's like some kind of 'setup'. You can tell if your camera does this by setting it to 16:9 and taking note of the difference between the black in the active image area (try full black like lowering exposure to minimum and/or keeping the lens cap on) versus the black letterboxing bars that appear above and below the image.

Does anybody have a clue as to what is going on? Could it be a way of compensating for the reduced dynamic range of the LCD?

[Boyd Ostroff]

I think this is just an inherent problem with LCD's... they have a limited contrast ratio. The newer ones are better... I have a Sony 16:9 LCD monitor with 500:1 contrast ratio. A couple years ago I got a Samsung LCD that bragged about its 350:1 ratio. But on any of these screens you can still see some light on a totally black image. Same for the screen on my Powerbook G4.

So basically that's all you're looking at IMO. Now this is all very dependent on ambient light also (at least in terms of the flip out screen). And it is very much influenced by the viewing angle of the screen. I find it's a natural reflex to position your eyes such that they view the brightest possible image on an LCD panel. Almost always this will not be the optimum angle for contrast however. This is always an issue on my laptop, and I have gotten into the habit of intentionally tilting the screen back a bit until the blacks are as black as possible. I found this out the hard way after editing still images in photoshop and posting them on the web, then looking later on a CRT and finding they were all too dark.

On my camcorders I like to take them into a dark room and compare the image on the LCD screen to a monitor, then set the brightness accordingly. Again, I learned this the hard way after shooting some performance video that was all too dark. When I do this I also take note of the correct angle to view the LCD for maximum contrast. This works well for me when shooting in a darkened theatre, but outdoors in the open I mainly rely on experience to set the correct exposure. Even with an LCD hood you don't get a very accurate idea on the little screen in bright conditions.

But FWIW, I just pulled out my PDX-10 and looked with the lens cap on. I don't see any difference between the 16:9 frame and the surrounding area like you describe (although the room is moderately lit). Where is the screen brightness set on yours? Mine is just below the middle on the bargraph. Hit the touchscreen buttons FN > PAGE2 > LCD BRT

[Ignacio Rodriguez]

> But FWIW, I just pulled out my PDX-10 and looked with the lens
> cap on. I don't see any difference between the 16:9 frame and the
> surrounding area like you describe (although the room is
> moderately lit). Where is the screen brightness set on yours?
> Mine is just below the middle on the bargraph.

Hmm. Yes, changing the brightness got black down to black, just one step below the default value. However, the problem persists in the BW viewfinder and there seems to bo no way around it.

I have also noted that there seems to be a dynamic limit in the highlights which is not the same as the recorded video. When the image appears as full white on the LCD, it is still not burnt white in the DV image viewed on an attached NTSC monitor or on a computer through firewire.

One could assume this as a safety feature, since it makes you think you will be save if you underexpose the highlights because you will surely not be underexposing the 'real' video. However, if this is the case it tends to defeat the purpose because I started getting used to it and cought myself several times saying to myself "don't worry, it's not really overexposing, it's just the LCD , and later discovering I *was* actually overexposing. Lousy, eh? Guess it's a better idea to use zebra as a reference for overexposure.

On another thread we had consensus about it being better to underexpose DV... and that get's us back to the real black thing... I need to have clear idea of how dark I am going :-(

Yeah yeah I know... get a real monitor :S

[Boyd Ostroff]

<<<-- Originally posted by Ignacio Rodriguez : Guess it's a better idea to use zebra as a reference for overexposure.-->>>

I think that's the best way to go, and it's how I personally gauge exposure. But after you get used to the camera and have viewed a lot of footage on a monitor, I think you'll have a pretty good idea of what the final results will be when you view the scene on the LCD screen. Or at least that's what I have found. There's no substitute for experience....

[Ignacio Rodriguez]

I totally agree Boyd, in time you get the feel of the camera and it's LCD and so on. But the point is, I still don't know *why* the image is never 0% in the BW viewfinder, although it does go down to 0% on the tape. It's just one of those stupid litlle things that bug you all day when you don't understand them :-)

The logical conclusion, looking at the results of turning down the brightness one step on the the flipout color LCD, is that for some reason Sony turns the viewfinder brightness up a few dB (which might also explain while the image burns to white sooner than on tape)... but why would they do such a thing... I guess there must be a reason. Does this also happen in the BWVF of other Sony miniDV cams?

Now that I think of it, this might not be such a bad thing. An 'overexposed' monitor would naturally make the operator have a tendency to underexpose. Because DV has more latitude in underexposure than in overexposure, this is what we should all be doing to get more natural pictures, right?