Low light conditions with Z1U

[joshpickering]

Has anybody experienced the Z1U in low light situations? Or have you shot with it with controlled lighting? My company owns 2 of them and we interview alot of people. We have a SONY 500 as well that handles light very good. We set them up side by side and the HDV just seems alot darker, even though we were watching our zebra stripes on both cameras. The subject was properly lit. We had are zebra stripes on 70% on both of the cameras. Does the Z1U just not handle lighting conditions very well at all? Or during the down conversions process going from HDV to DV, do you lose brightness? Any help would be appreciated. Thank you.

[Philipp]

According to what I see on my Z1 it seems to be the downconversion. If I film HDV the picture comes out just fine. Did you turn on the cinegamma? That might be a reason. I experienced very low noise even in hyper gain. So from my point of view the Z1 is quite OK in this concern.

[joshpickering]

Well, we shoot in HDV then we downconvert in camera to DV going into Final Cut Pro 4. But we shoot for HDV. The menu is at default. Cinegamma is not turned on.

[Philipp]

Hm, capture using DVHScap and convert using MPEGstreamclip. Then convert to SD an FCP. You should get some better lights doing that. The camera does some strange job to the pictures, I don't know...

[Barry_Green]

The Z1 is quite a bit slower than the DSR500. A DSR500 is probably equivalent to an exposure index of around 500; the Z1 (without electronic gain) is more like 120. The DSR500 should be at least two full stops faster than the Z1.

Additionally, the Z1 has lower latitude, so if you're exposing for the highlights you'll find that the dark areas crush to black much quicker on the Z1 than on the DSR500. To be fair, you're comparing a 2/3" $15,000 camera against a 1/3" $5,000 camera, so you have to expect some compromises.

If you use the CinemaTone gamma, that will cause the dark areas to crush even quicker.

[Wesley_Wong]

Hey Barry,

so what do you suggest? Should I expose for 70% zebra and get my bright spots over ?

I'm new to company's Z1 too and its so different to the Pd 150 + 170 as well as my own DVX.

[Barry_Green]

70% zebras are used for exposing faces. 100% zebras are used for checking to make sure your highlights aren't blowing out. If you're using 70% zebras and never letting them show, then you're almost definitely underexposing. I'd say set your zebras to 100% and make sure they don't show, and see if that delivers exposures more like what you're used to.

100% is a lot more useful, in more situations, than 70%. 70% should be used when shooting caucasian faces, and they should trigger on the hot spots on a face (forehead, tip of nose, etc). In other words, you *do* want to see 70% zebras, just not too much of 'em, and only on the brightest parts of the face. Then you swap to 100% zebras to see if anything really bright is "blowing out" in the scene. If there's nothing blowing out, then you're good to shoot. If there are blown out spots, then you have to either adjust your lighting (if possible), adjust your exposure (if lighting adjustments aren't possible), or compromise -- choose whether blown-out highlights are more important than proper face exposure.

[Wesley_Wong]

Thank you once again, guru Barry.

You're a life saver.


p.s. I'm still bemoaning the fact that a light/spot meter is pretty useless in digital filmmaking...

[Simon Wyndham]

Not necceserily. I find 75 zebras more useful for overall exposure than 100 even without faces. For example I know that concrete on a sidewalk is generally around 75ire so I can expose for that and get a better idea of a balanced exposure to work from.

I usually have my white clip set to 109. I have my two zebras set to 75 and 100, I'll expose to balance things out as best I can (although with faces I will expose for those and let the rest take care of itself assuming I'm in an uncontrolled run and gun situ). On very bright objects such as reflections you can expect to see the 100 stripes. But because my white clip is set to 109 I know that I still have headroom in those highlights that I can work with in post to bring back down to legal levels. BTW the reason I set my white clip to 109 is that it reduces the chance of banding at those higher levels. I want as much range as possible to work with.

Dunno if the Z1 allows those settings to be adjusted however.