Shane Hurlburt in ASC Magazine: Primo Lenses INCREASE Latitude by 1 1/2 stops???

K

Kholi

Section Moderator
It's strange, but right out of this months ASC Magazine (An Article Written by Shane)...

Shooting with Stilll Lenses, I was seeing about 5 1/2 stops under key and 3 1/2 stops over. When we went to the Primos, the Latitude increased by about 1 1/2 stops in both directions. After seeing the Primo glass combined with the 5Ds sensor, we've decided to shoot the remainder of Easy Day -- even the sequences we'd planned to shoot with 35mm -- with a combination of the 5D and 7D.

...

That's quite a claim. If it holds merit, which it probably does in some respects, then it really shows why you still need excellent glass in front of the sensor.

I had just been ready to take order of two 7D PL mount cameras, I'm waiting for Iilya Friedman's solution to show up but from now on, I really need a PL mount DSLR. A pair, ideally.

Makes me want to go and pick up some GH-1's until then.
 
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This makes me want to do an article called "Contrast and Video Slrs - What we need to know."

reminds me of our discussion on noise in shadows shooting with zeiss contax vs. Canon lenses...is it an electronics issue, an optical issue or a combination.

Questions I want to address and discuss with top opticians, sensor technicians, and world renowned cinematographers involve the role of contrast and microcontrast in dynamic range and perceived dynamic range.

How does filtration play a role?

This is where artists and engineers meet.

In this day and age I believe that a minimum of 1part science to two parts art is necessary in order to achieve what we seek as visual artists.

If maximum dynamic range is what we want then we should start examining
how our cameras create it. Read up on what arri is doing with the d21, red is doing with the mysterium x, and do all the tests we can with what we have now.

Definitely a hot topic!
 
Kholi said:
I had just been ready to take order of two 7D PL mount cameras, I'm waiting for Iilya Friedman's solution to show up but from now on, I really need a PL mount DSLR. A pair, ideally.
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You know that Primos aren't PL-mount, right? Which is the whole reason they can even work on the 7D/5D. But you also know that you can't get them anymore, for use with an SLR, that was the whole policy shift where Panavision's decided that they don't want their lenses going out unless it's with one of their bodies too.

Shane also said that the ZF/ZE lenses were the closest to the Primos.

As for his claim that Primos added three stops (THREE STOPS) of dynamic range... I would love to see some examples of that. He said it increased latitude by 1 1/2 stops "in both directions" -- am I to understand he's saying it added 1.5 stops on the top, and 1.5 on the bottom, for a total of three stops?

How is that possible? How is 1.5 stops possible?

Kholi, can you find some time to go over to Panavision and ask them to mount a Primo on one of your 7Ds, just so you can do a comparison shot?
 
Barry_Green said:
You know that Primos aren't PL-mount, right? Which is the whole reason they can even work on the 7D/5D. But you also know that you can't get them anymore, for use with an SLR, that was the whole policy shift where Panavision's decided that they don't want their lenses going out unless it's with one of their bodies too.
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That I do know. I was speaking more in-line with using Cinema Glass in general. Particularly Cooke S4s. Definitely aware of the modification and or sacrifice needed to make a Pl mount work.

Shane also said that the ZF/ZE lenses were the closest to the Primos.

As for his claim that Primos added three stops (THREE STOPS) of dynamic range... I would love to see some examples of that. He said it increased latitude by 1 1/2 stops "in both directions" -- am I to understand he's saying it added 1.5 stops on the top, and 1.5 on the bottom, for a total of three stops?

How is that possible? How is 1.5 stops possible?
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I have NO idea how it's possible and it doesn't even sound right. But, I assume he would make sure that his claims held salt before being printed in a magazine.

Kholi, can you find some time to go over to Panavision and ask them to mount a Primo on one of your 7Ds, just so you can do a comparison shot?
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I wish I could. I may, however, be able to get together with Dan up there and do some testing if I can find the time.
 
RedUser just did a MASSIVE lens test with all sorts of lenses, including Compact Primes (essentially ZFs) against Red Pro Primes, SuperSpeeds, UltraSpeeds, etc. I don't recall anyone saying anything about substantially enhanced latitude on any particular lens set...
 
I Need to talk to some real experts...

But...perceived latitude as a function of contrast may have something to do with it.

Some experts have claimed that the canon lenses may have lower microcontrast when compared to zeiss (multicoatings,barrel internals, and
glass being factors)

one thing I have to agree with Mr. Hurlbut on is, better lenses will always yield a
better picture.

I can imagine the conversation at panavision...

Panavision boardmember:
"You want me to trash your Eos adapters? Do you? Shooting with canon cameras in the background instead of a genesis... Dah dah dah dah dah! For gods sakes those slrs are amateur."


note: the above fantasy is meant as a lighthearted attempt at humor, and is by no means a serious representation of any people or events, real or imaginary.
 
We're talking about the range of brightness values that the camera can resolve. How dark is dark, how bright is bright. The wider the latitude, the more information it can process. A normal video camera, shooting indoors with a window in the shot, might have black shadows and a blown-out white window, because the shadows are too dark and the window is too bright for the camera to handle it all. The traditional way to handle this would be to shine additional light indoors (bringing up the shadows) and darkening the window (bringing down the highlights) so that you compress the dynamic range of the scene so that it can fit into the camera's available latitude.

A Canon 7D has about 8 stops of latitude, in general; maybe 8.5. That means that the range from the very darkest item it can resolve, to the very brightest item it can resolve, is a factor of 8^2, or 256 times as bright. In terms of footcandles, if you set exposure so wide-open that it could see something that was lit with one footcandle (i.e., it could just barely distinguish that item from pure blackness), then the brightest possible element it could see would be something lit with 256 footcandles of light. Any brighter than that and it would blow entirely out to white. And if you closed down the iris so that you could properly record the brighter object, then you'd find that the darker object has now disappeared; it's too dark off the bottom of the latitude.

So what's being discussed here is that using a Primo lens is somehow supposed to make the camera able to resolve up to three additional stops of latitude. Widening the camera's range by effectively eight times. So to go back to our one-footcandle comparison, the contention is now that if you used a Primo lens instead of an SLR lens, you would now be able to properly resolve that one-footcandle dark object, and not only could you properly easily be able to resolve the 256-footcandle bright object, but also an object that was 2,048 footcandles!

I simply don't see how it's possible.
 
I wonder what their cheapest body rents for...If they would rent an older platinum or Gold body for fairly cheap, and the 7D adapter because you are going to use your 7D as your "B"camera. I'm just sayin'.

Not that I believe you get additional dynamic range out Primos, they are just the cleanest and best lenses on the market. Dynamic range is a function of the sensor, short of tapping into the raw stream of the camera in still mode, you aren't going to increase the dynamic range by 3 stops.

Update:

To answer my own question, I called Panavision in Woodland Hills. They have definitely pulled the 7D adapters. They don't want to rent just lenses without bodies, which is odd because when I was doing miniature work, some of the Mitchell cameras had panavision mounts just for that purpose. The Primos were much cleaner than the Nikon lenses that had been traditionally used by VFX houses.

The least expensive Panavision camera rents for $1200 per day for a 3 day week...plus the lenses. Ouch, I can buy a nice set of Zeiss primes for the cost of that package.

Oh well...
 
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umuima said:
What does a PL mount do?
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It lets you attach PL-mount lenses. PL is the Arri Positive Lock lens mount, which is pretty much the de-facto standard for all cinema lenses, except Panavision lenses. Panavision has their own PV mount for their lenses.

So if you're looking at Zeiss Ultra Speeds or Ultra Primes or Compact Primes, or Cooke S4s, or Angenieux Optimo zooms, or Red Pro Primes, those are all going to be PL mount.

A 7D can't take a PL mount, as the mirror gets in the way of the lens; the only way to get PL lenses on a 7D would be to modify the camera to get rid of the mirror.
 
Barry_Green said:
It lets you attach PL-mount lenses. PL is the Arri Positive Lock lens mount, which is pretty much the de-facto standard for all cinema lenses, except Panavision lenses. Panavision has their own PV mount for their lenses.

So if you're looking at Zeiss Ultra Speeds or Ultra Primes or Compact Primes, or Cooke S4s, or Angenieux Optimo zooms, or Red Pro Primes, those are all going to be PL mount.

A 7D can't take a PL mount, as the mirror gets in the way of the lens; the only way to get PL lenses on a 7D would be to modify the camera to get rid of the mirror.
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Like this:

http://7dcinema.blogspot.com/2010/01/canon-7d-with-pl-aka-pl7d-aka-7dpl.html
 
Interesting. Skeptical, but maybe someday possible.

One possible theory could be the way the lens handles and redirects light. Here's an interesting thing Ira Tiffen, of Tiffen filters, had to say about a concept to increase the "appearance" of range via glass:
(from: http://www.cinematography.net/edited-pages/Hi-ConFilters.htm)

"The concept centres around wanting to render highlights darker than they would otherwise appear, to show more highlight detail, and to specifically do so in a manner that fits in with the often-used practice of maintaining a particular T-stop to better maintain lens sharpness and depth-of-field characteristics. Used the way we suggest, not compensating for exposure, the filter will darken highlights by one stop, which, if it were just an ND filter, in darkening everything by one stop you would not see a real change in contrast.

The difference is that the low contrast component will still lighten shadows. The net result is that you have raised shadow luminance AND reduced highlight luminance simultaneously. You could accomplish this by closing down a stop and using a Low Contrast filter, but you would have to make the stop adjustment, which may be undesirable. When you compensate for the one stop of the Soft Con filter, you are effectively taking advantage of it as an ND filter to allow for a larger lens opening while retaining its ability to lighten shadows and reduce contrast.

Think of exposure adjustments as able to either raise or lower luminance levels of everything. Highlights up, shadows up; highlights down, shadows down. The only time this results in an apparent increase in contrast is in parts of the scene that are either black from underexposure or white from overexposure; in either instance, adjusting exposure will bring out more detail and thus more apparent contrast. But contrast is still the difference between the luminance levels of highlights and shadows, and to effectively increase this you may need to be able to treat both differently, as I have written earlier.

Grads and attenuators will allow overly bright areas to come closer to being properly exposed at the same exposure that you would use for getting good detail in otherwise darker areas, such as with an overly bright sky- a ND 0.6 grad will usually be enough to allow good detail in the average bright sky as well as in the darker foreground. However, these filters will not have an increasing or decreasing effect on actual contrast apart from the particular circumstances of apparent contrast changes I refer to above."
 
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