broadcast viewfinder and color bars

[Michael Bendixen]

I've switched from using a mini-dv camera to using digibetas and a F900 broadcast style camera. One fuzzy area I've had is with the viewfinders. With mini-dv cameras I never seemed to have a problem reconciling my viewfinder exposure with the exposure that I'm recording on tape. If I have the brightness on the viewfinder set too low, then I'm overexposing the image. There's the same issue with contrast as well.

I have to rely on color bars a lot. But this raises other questions....I was always taught that the pluge bar (7.5) needs to blend in with the (3.5) superblack bar just too it's left. If, I make the bars blend together, then my luminance seems too dark. Is there something I'm missing here?

I'm just trying to get to a spot where I know exactly what I'm putting on tape. I've done tests in the field, but when we switch cameras, this is not always an option.

Thanks!

Michael

[Brian Drysdale]

You basically set up the viewfinder the same way as you'd set up a monitor, except with a B & W CTR viewfinder you don't have to worry about the chroma. It sounds like you're not setting the contrast correctly - you should adjust to where the white box at the bottom left begins to glow at the edges and then take it back just enough to remove the glow. The white should just be changing brightness at this point, your level should then be correctly set up at 100 IRE.

[Michael Bendixen]

Thanks Bryan. I'll try that. But just to double-check. With the pluge bars in the lower right corner, the 7.5 bar needs to blend with the 3.5 bar so the border becomes invisible right?

Michael

[David Heath]

Originally Posted by Michael Bendixen

I'm just trying to get to a spot where I know exactly what I'm putting on tape. I've done tests in the field, but when we switch cameras, this is not always an option.

In a word, my answer would be - zebras.

For all the reasons you describe the problem is knowing what to adjust - the viewfinder or the camera - and the viewfinder will need readjustment for differing lighting conditions. With most being b/w CRT, it's not really possible to accurately judge correct exposure just by looking at a simple image alone.

Hence zebras, and most modern 2/3" cameras have two patterns which come and go at different levels. (The EX are the only sub-$10,000 cameras I know of which have a sophisticated arrangement.) Typically, one pattern may be set at 100%, and another to start at 85%, stop at 90%. The patterns are easily distinguished, and easily let you know what areas of the picture are bright, and what burnt out - even with a badly mis set viewfinder.

[Brian Drysdale]

Originally Posted by David Heath

In a word, my answer would be - zebras.

For all the reasons you describe the problem is knowing what to adjust - the viewfinder or the camera - and the viewfinder will need readjustment for differing lighting conditions. With most being b/w CRT, it's not really possible to accurately judge correct exposure just by looking at a simple image alone..

Having said that, a correctly set up B & W CRT V/F on a 2/3" high end broadcast camera will allow you to set a pretty good exposure. However, unusual coloured lighting situations like night clubs can cause problems.

With your eye against the viewfinder eyepiece, it's very consistent, however, if you work with your eye away from the eyepiece it will be inconsistent.

Zebras are great just so long you have something in shot that you know matches the zebra level, otherwise you tend to just look at the picture and either you like it or you don't.

Here's a link for setting up bars
Video Production Support - How to calibrate a NTSC monitor