Do I have whack color bars?

[Josh Bass]

This is sort of an offshoot of the thread I previously spawned about waveform monitors.

I took my XL1s down to a rental house, where I have some friends. They allowed me to plug into a waveform monitor, and then calibrated the waveform monitor to a $2000 external color bar generator. Then I turned on MY camera's bars, and they're totally off! I thought one of the new features of the XL1s is that it was supposed to have true SEMPTE bars?

Just to make sure it wasn't some miniDV problem, I then took the cable from my camera, and plugged it into a DVX100 they had on hand. I pulled up its bars, and they're spot on! Same setup and everything, I just moved the cable that was hooked into my camera to the DVX, didn't change another thing.

So what's up? Is it my particular camera? I thought I was generally pretty careful, but who knows? Anyone else experienced this? Is it the same on all XL1s'? That doesn't make sense, because wouldn't almost all of them have been returned by pissed off buyers who were expecting real color bars? What's the point of even calibrating a monitor to bars that are way off?

Am I missing something real simple? These guys at the rental house aren't dummies--they deal almost exclusively in HD related work, and may soon be using that new fancy Viper camera dealie. . .so they're not morons who don't know what they're doing or anything.

[Josh Bass]

Another weird thing is that in Vegas 4's waveform monitor (however reliable that is . . .supposed to be any good?), they're spot on, as far as I can tell, on both luminance and chromanance are concerned. As long as I leave the "studio RGB" box checked, that is.


Is it possible it's a connector issue? My camera was hooked up to the hardware waveform monitor via the audio 1 in/out on the back. They had a a BnC to RCA adapter, and then a BnC cable hooked up to the waveform monitor. Could that have anything to do with it? Could my RCA jack be funky?

[Jeff Donald]

How were the bars off? The cable shouldn't make a difference as you found out. BNC/RCA adapters probably aren't the cause.

[Josh Bass]

I don't remember exactly in what way they were off, just that none of the pluge bars were falling on the values they were supposed to be at (blacks were crushed), and on the vectorscope, the colors were way outside the values they were supposed to be (they are were at like 80%).

[Don Palomaki]

What were the values you measured on the XL1s?

Might it relate to IRE 7.5 vs. IRE 0 black levels?

[Josh Bass]

I'm going to go back and check today. I just remember that they were off, and not in any reasonable way.

[Jeff Donald]

I'm inclined to think along the same lines that Don is. I also wonder if they had the signal terminated.

[Josh Bass]

Ok so, here's the deal: I did the test today at the rental house. Switching between the $2000 color bar generator, and the bars from my camera (recorded onto a tape, and that tape played through a miniDV deck), there is still a severe discrepancy between the true bars of the generator, and mine. The whites are slightly over 100% (maybe just cause it's a miniDV camera, not a super duper pro cam?) and the colors are slightly off, as judged by the vector scope (same reason?), but the real difference is in the pluge bars. The ratios BETWEEN the bars look to be correct, that is, that they're about 4 IRE units apart, but the actual NUMBERS are way off-- from left to right, they read, approximately, guestimating by their positions between the marked lines on the waveform monitor: -17, -12, -7.5. Does this make any sense?

I did a test someone on DV.com suggested, that is, calibrating my monitor to the XL1s' bars, seeing how the picture looks straight from the camera, then calibrating the monitor to Vegas 4's bars, and doing the same. As far as I can tell, the settings (the positions of the contrast, brightness etc. knobs on the monitor) were exactly the same, and the picture as viewed through the camera looked identical to my eye. Furthermore, I imported my bars into Vegas, and looked at them on Vegas' waveform, and they're spot on. . .just where they should be. The test I mentioned in the above paragraph, recording bars to a tape and playing back that tape through a different deck was also suggested by someone on DV.com.

Sorry if I'm reiterating some stuff.

[Rob Lohman]

Could it be that the analog outputs are doing something very
weird then? That's a thing that might be interesting to test by
someone with the approriate equipment.

[Don Palomaki]

Expected pluge values are 5, 7.5, and 10. The 12 and 17 you report are off by about the nominal NTSC setup of 7.5. The 7.5 is the exception. What MiniDV deck did you use? What were its settings?

Has anyone else tried the test with an XL1s?

I did some test a while ago on an XL1 undocumented bars, but they were never advertised as standard levels (and they are not).

[Josh Bass]

Yeah, I was going to politely request that anyone else with (or easy access to) an XL1s and waveform monitor simply hook the camera up to the WF, and see if the bars are where they should be.

As for the deck, I'm sorry, don't remember the brand name or anything. I know it did both miniDV and DVCAM, and was longish, that is, shaped kind of like a waveform monitor or one of the smaller video monitors. I just put the tape in and played it, didn't set anything. I did look for knobs with which you could adjust chroma, hue, etc, and didn't see anything like that.

[Jeff Donald]

Josh, I am still leaning towards a problem with set-up. The deck used for playback of your tape may have been adding set-up to the signal. Is it possible to just hook the camera up to the scope?

The adjustments for the deck may include the ability to adjust set-up via internal menus displayed on an on board LCD display or an external monitor.

[Josh Bass]

Just hook the waveform monitor straight up to the camera? Yes, I've done that. That's when the problem was first noticed, the crushed blacks. Or did you mean something else?

[Andre De Clercq]

If the sync backporch on the WM is set at 0 IRE, does this mean that the pluge signals are at lower than zero IRE levels?

[Josh Bass]

Sorry, guess I should have asked this before: when you say "analog out", do you mean a specific port on the camera? The RCA jacks? Or do you mean a function of the camera's hardware?