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ZONE SYSTEM WITH 14+ STOPS (Alexa/Red/etc)

zone system hdr alexa red

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#1 Ignacio J. Durruty

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Posted 17 March 2016 - 07:22 AM

Hi everyone!

 

Here's a question that I've read a lot on but still haven't gotten my mind 100% around:

 

I've just been gifted a Sekonic L-758Cine (yeah, it's awesome! haha) and am going to work on a couple of projects where I'll be able to get a profile from the cameras (Alexa, RED, Canon C300, etc).

 

Now, I've never worked with Ansel Adam's Zone System before, but I know the basics of it's 11 stage (0 to X) tonal system and how between each value (V to VI) there is a 1-Stop difference.

 

My question is: with a camera that has 14+ Stops of dynamic range, how would one go about fitting those 3 - 4 extra stops in calculating what falls on what part of the system. If we fit those 14+ stops into the Zone System, the difference between V and VI wouldn't necessarily be a full Stop, would it?

 

Cheers!

Iggy


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#2 Mark Dunn

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Posted 17 March 2016 - 07:30 AM

The zone system was devised in the 1930s for b/w film printed on fibre-based photographic paper. It doesn't readily translate to colour film, never mind digital imaging.

In short, film has a non-linear response to light which the zone system is intended to exploit, as opposed to the raw signal from a sensor, which is linear.


Edited by Mark Dunn, 17 March 2016 - 07:35 AM.

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#3 Mark Kenfield

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Posted 17 March 2016 - 07:51 AM

Actually, I think you basically want to stick within the conventional, 11-stop zone anyway. Modern sensors might technically get you more range than that. But at Zone X, five stops over middle grey - you're burning hot anyway, and there's very little left above it. And at Zone 0? Well you might as well grade it down to pure black, because you're right into the noise floor of even the cleanest cameras these days.

 

Sticking to the conventional system is a good way to (after your grade) net yourself deep, rich blacks, and clean highlights with very little clipping out.


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#4 Adrian Sierkowski

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Posted 17 March 2016 - 12:02 PM

Zone has more to do; also with DISPLAY, not CAPTURE. so you may be capturing x stops; but let's not kid ourselves, at present, we're all winding up in REC which is substantially less than 14+ stops.


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#5 John E Clark

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Posted 17 March 2016 - 04:40 PM

Zone has more to do; also with DISPLAY, not CAPTURE. so you may be capturing x stops; but let's not kid ourselves, at present, we're all winding up in REC which is substantially less than 14+ stops.

 

This is really important... the Zone System is a system of 'previsualizing the final print (display/projected image/ whatever...)' and a method of testing the image capture and 'printing' processes to achieve that previsualized image. (in so far as possible...).

 

One can of course perform a calibration process on meter, camera and resulting image captured, which is part of the zone system, and may involve a camera that has 14 stops worth of what is now called 'dynamic range'...

 

But ultimately it is about the output displayed image.


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#6 Ari Michael Leeds

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Posted 17 March 2016 - 05:04 PM

LOL he "has too much latitude."


I think I have read all there is to read on the internet, now.  Gee we have that same "problem" with film!  What do we do with all this latitude?

Further, we have to use that much bigger color space.  An ordeal and a hassle, I know!  You shoulda waited two weeks to post this.


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#7 Carl Looper

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Posted 19 March 2016 - 07:54 PM

The zone system is for pre-visualisation (in one's imagination) of what a particular scene might look like when printed.

 

Ansel Adams was very much into using reflected light meter readings - which makes sense when you see his work. It's predominantly landscape and natural light. By surveying an environment in terms of reflected light readings one can convert the readings into greyscale values - in one's mind (after some practice) - and see what a given scene is going to look like as a final print - and make decisions on that basis. One can answer questions such as: does a given scene, in the way one might frame it, produce a distribution of tones that one might appreciate as a print. How balanced are all the various tones. Should I look for a better scene. Perhaps if I change the angle a little it might be a better result.

 

It's a way of learning how to translate a given scene in terms of how that will otherwise translate into a print. And on that basis, take a photograph.

 

With a well calibrated digital screen you effectively don't need to learn the zone system. The screen can be regarded as already a glorified reflected light meter reading where it's already converted such into a distribution of grey tones. The "print" is already being visualised for you.

 

But even still, learning the zone system means you don't have to rely so much on a given screen, other than for framing purposes.

 

C


Edited by Carl Looper, 19 March 2016 - 08:08 PM.

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#8 Stuart Brereton

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Posted 19 March 2016 - 08:24 PM

As always, it's worth pointing out that the Zone system for exposure was only half of Adams's system. The other half was a technique of pull or push processing which allowed him to arrive at a desired negative density.

 

Pre-visualisation is a valuable skill, but the zone system itself is of only limited use when dealing with digital cinema.


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#9 Carl Looper

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Posted 19 March 2016 - 08:36 PM

I should just add that what is important is the distribution of tones in the result. For example, my computer screen has a range of 9 stops so if I'm previsualising a scene for display on this screen I'll be wanting to previs that scene in terms of a 9 stop range. If the camera has a 14 stop range, either 5 stops of tonal info get lost in translation (out of range: turns to either black or white), or the 14 stop range gets "compressed" into the 9 stop range of the display, or some variation between. Depending on what you intend to do you'd need to factor that into your previs.

 

So lets say the display has a 9 stop range. Then you can prepare a chart in which there are 9 steps, from black to white in which step represents a stop. But if intending to compress a 14 stop scene to these 9 stops then each of these steps of the chart (in your imagination) represents 1.5 stops on your light meter, on location. 

 

C


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