Photovision Digital Calibration Target

how does this work if you set it up then change lighting conditions?

You're using knowledge and experience to make up for the shortcomings of the tool. The target isn't doing the work its claimed to do, you're doing it.

The target gives you a blank, detail-free white section. Blank, detail-free "white" is not supposed to be Zone VII. Zone VII is light gray. You know that and you compensate (using your knowledge and experience) for the fact that the target is not accurately representing what it claims to represent.

The most necessary bit of information for a digital exposure is the intensity (location on the histogram) of the brightest tone that must retain detail. Zone V is actually irrelevant. What you need to know is which part of the scene is Zone VII, and you need to make sure you place that tone at the top of the sensor's range. The tri-toned target does not give you a bright tone with detail (you must have detail to see the point you start to lose it)--it gives you white without detail.

Further, in normal use facing the camera (illuminated by the fill light), that white isn't really white and you have to use your knowledge and experience to determine where on the histogram it needs to fall to render it properly. It doesn't tell you what you really need to know, and to use it all you have to juggle what it does tell you.

RDKirk wrote in post #9432047
The target gives you a blank, detail-free white section. Blank, detail-free "white" is not supposed to be Zone VII. Zone VII is light gray. You know that and you compensate (using your knowledge and experience) for the fact that the target is not accurately representing what it claims to represent.

The most necessary bit of information for a digital exposure is the intensity (location on the histogram) of the brightest tone that must retain detail. Zone V is actually irrelevant. What you need to know is which part of the scene is Zone VII, and you need to make sure you place that tone at the top of the sensor's range. The tri-toned target does not give you a bright tone with detail (you must have detail to see the point you start to lose it)--it gives you white without detail.

Further, in normal use facing the camera (illuminated by the fill light), that white isn't really white and you have to use your knowledge and experience to determine where on the histogram it needs to fall to render it properly. It doesn't tell you what you really need to know, and to use it all you have to juggle what it does tell you.

But the problem is that digital is like shooting slides and the dynamic range of transparency film is widely acknowledged to be only 5EV...five Zones! Wouldn't it be necessary to have Zone VII and a half brightness area on the target for digital ETTR practioners?

Color neg has about 7EV of dynamic range. And black and white negative film has about 8-9EV of dynamic range, which is what the Zone System was conceived to help with.

The Zone System's Zone VIII really only gets applied at a practical level with color neg and black and white film, but we're talking about digital here. And HDR was invented as a technique to address the limitations of dynamic range, but ETTR itself is inherently not as applicable under that technique.

And having a spike at Zone VII still is useful, you simply don't snug it up against the right edge of the histogram as tightly as a spike in Zone VIII. Why do you need a bright tone with detail (Zone VIII), if fundamentally you know that the target spike is placed in Zone VII?! After all, the Zone System is all about 'placement', and scenes do not always have the same dynamic range to be captured.

Wilt wrote in post #9433174
But the problem is that digital is like shooting slides and the dynamic range of transparency film is widely acknowledged to be only 5EV...five Zones! Wouldn't it be necessary to have Zone VII and a half brightness area on the target for digital ETTR practioners?

[QUOTE]

Remember that the range of the digital sensor is "anchored" at the top end (unlike film, the range endpoints of which flop in the breeze, coming to land at many possible points depending on development).

The very top end of the digital range is Zone X and can be nothing else. But remember that the Zones describe tonality of the scene as it has been reduced to a reproductive medium, so although to the eye a bright white is less bright than a bright light, in the reproductive medium, that might not be so. It's still true with the digital sensor--255 is as high as it goes, whether depicting a white sheet of paper in sunlight or the sun itself.

So we can't safely use a blank white tone as the anchor point because we can't know how white blank white really is--blown is blown is blown.

You can look at a white tone in shadow (the white tone of the tri-toned target facing the fill light) and accurately place its spike where it should be (reproduced as a light gray) because you already know that it should be a light gray instead of white. You're using the knowledge and expertise you already have to make up for the shortcomings of the tool. But for that matter, you could have gone through the same exercise with a gray card because you know what you're doing anyway--you didn't need no steenkeeng tri-toned target.

The immovable object that is the top end of the digital range actually makes exposure rather simple: Correctly place "the brightest tone that must retain detail" at the top of the range and that's the best single exposure you can set on the camera. You can then, if you desire, add more light to the shadows, but that's the best you can get out of the sensor itself in a single exposure.

[QUOTE=RDKirk;9434221]

I might know what I am doing, but the PhotoVision comes with an instruction DVD to educate the uninformed, so the knowledge is not that unique even to a novice.

It doesnt really look good to me. Clinically perfect white balance when there is a color cast in lighting just looks fake and unnatural.

I agree with thepiecesfit. But I'd prefer to get everything WB-wise under control, then in post, add or subtract temperature from shots to taste rather than shoot ending up with multiple temperatures, and having to deal with each one separately. It's a pain.

hmmmm green roads...
i think sometimes the best thing to do is to shoot b/w and call it art/old fashioned/etc.

Re: shooting at weddings - i don't, but when event shooting i'm be more inclined too shot raw and expose for the environment, and then adjust en masse using the best 'temp' appropriate in post on a 'per-lighting-conditions/location' basis.

re: the OP - there's not much difference between unifing the entire scene in a golden/yellow tones OR shooting in black and white and then appling a gold/yellow colour cast/overlay to the whole scene.IMO