Thanks Bill.

afaik.....

sony has always made cameras for the masses....like the metaphor for a Chevy Nova. Sony finally stepped out of their box and made a Cinealta available for the masses...albeit a wee bit expensive. OK, so, their marketing gurus told them most people would never deal well with the myriad of controls. And, I suppose, in a way the marketting folks were right. Nevertheless, I'm very happy with what i bought. OK, vignetting, backfocus, labels that wear off, etc., etc., I got a pretty decent camera for the $$$ I spent. I'm not exactly ready to believe Sony the next time around, but, who knows?

...and how does this matter in the grander scheme of things? well, not worth a shyte.

Vegas does produce the plots of gamma curves. So no need to go through OnLOcation (DVRack).

Except that with HDRack you get real time viewing of the curve, thereby seeing the immediate effect of changes to the camera settings. It's inconvenient, if not totally unworkable(at least, for myself), to make changes, then export the recorded result to Vegas to see the result of those changes. Using vegas is a good workaround, I suppose, if you can trust those somewhat untrustworthy Vegas scopes.

Agree. I was just wanting to investigate gamma curves, so that lends itself to going offline. Hopeless for the variables you were looking at.

I just finished all 20 pages of this thread. Many thanks to all the contributors.

If you wanted to use Std3 gamma, is there a reason why this would not work?

1.) Choose a high contrast outdoor scene.
2.) Expose on a neutral gray card, centering the graph on the x-axis of the histogram.
3.) Remove the card and compose the scene.
4.) Turn on Zebra 2 (100%) , adjust knee downward until zebra stripes go away.
5.) Adjust black so that it's not crushed on the histogram.

It needs to be an 18% reflectance gray card. Kodak makes them, others may too. Available at any pro photo store. An 18% card is made to fall in the center of the scale.

At a Nikon photo school I was taught that the palm of a human hand, regardless of race, is 36%. You can hold your palm up, meter and open up one stop. If your own palm is in front of the lens, your thumb will remind you to open up 1. Make sure the light level and angle matches you subject. In direct sunlight, no problem. In artificial light, the palm has to be in subject position.

In my tests this has always been correct, as improbably as it seems.

a grey card will work. S0, in fact, will any card whose reflectance in perfectly neutral....RGB255 to RGB0. I believe the convention is a pure white 255:255:255

Not if you are setting exposure. A 255:255:255/90% card set to the middle of the histogram will give a major exposure error. Great for white balance though.

An 18% card will, in essence, tell the camera the amount of light falling on the subject. It's an alternative to directly measuring the light with an incident meter. If everything is calibrated correctly, both will give the same exposure value.

I have done that for years, the palm trick + 1 f-stop with 35mm SLR, but I wouldn't have dared admit it here.

lots of people seem to use zebra set at 70% for skin tones. I've found 60% to give me a much better exposure. Anyone else notice this?

Same here, at least if I use STD4 or Cine4 I will get too bright picture when zebra is set at 70%...


Dennis

Zebra level
 

Hi Bill,
first of all - thanks to all your investigations concerning the EX1 profiles. Great work and even more important - great results. I am very frequently using your profile with Cine 4 ...

Concerning Zebra level:
I am actually using 90% zebra for the low level. The reason is, that I use Zebra only as a white clipping indicator. So seeing zebra marks would warn me, that I am almost over exposing. The setting of Zebra very much depends for what indication exactly you are using it. As "the last warning before clipping white", I prefer to set zebra low just very little below actual clipping and Zebra high just above clipping level. So when I see Zebra low, I can react - if I would ever see Zebra high... it is too late ...:-(
But Zebra high setting makes sense, as sometimes I even want pictures to clip in some very selected highlight peaks...

My goal is, to make maximum use of the camera's dynamic range seeing as much detail in white and black parts of the picture. Of coarse there are scenes, which have much higher dynamic than any camera can handle - that's why we compress parts of the shades not to loose details by crashing blacks or whites (or worst case both...)
It is up to the DoP to decide the best compromise and target the film/video to the right expression using all technical possibilities.

That's why I appreciate your work Bill - as it targets to squeeze maximum usable dynamic range out of the EX1 with natural colours...

Recently I found, that very often auto Iris works very well to keep the image well exposed. Of coarse this is only useful in shots where depth of field is not critical. At least my tests confirmed, that in auto IRIS mode using Bill's Cine4 profile comes very close to optimum exposure (no clipping of white).
As long as I minimize clipping of white without crushing blacks, I can do everything else in post production...

regards,

Ulli

Ulli...

Indeed, using zebra for highlight exposure control is what zebra is designed for. I think the conventional wisdom is to use zebra for monitoring highlights, either on white objects, as you describe, or by monitoring highlights on skin. On interior shots, such as a stage production, where there are no true white objects to meter, what is important is to not blow out the specular reflections on human faces. This is where a 60% (or 70%)zebra setting is invaluable.

Can you actually trust HDrack with the EX1? I mean the only way to see the scopes is to go in with firewire right? Will it give an accurate representation of the signal? Or HDrack works now with HD-SDI too?