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Fast Lenses vs. Fast Stock


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#1 barryagilbert

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Posted 21 November 2005 - 09:46 AM

Sorry if this is a newbi-ish question - I've shot a few 35mm projects (as a director) and I have a clear idea of the trade-offs and characteristics of different speed stocks, but I'm wondering what the general relationship of a fast lens to a fast stock is.

I know it's an incredibly general question, but my point I suppose is, when you're employing a "fast" lens is it more often in mind to push a fast stock even further, or say to keep with a 200 stock when normal lighting conditions would just be pushing the edge...do you guys employ it as a long term strategy on a shoot were there may not be enough of a budget for a proper lighting package, etc. Any responses read with great interest.
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#2 Max Jacoby

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Posted 21 November 2005 - 11:03 AM

Most people select their lenses based on their look, not on the speed. Most cine-lenses are around T2 anyway (Ultra Primes, Primos, Cooke S4s, Zeiss Standards), so the speed is not really a deciding factor. But the Master Primes and the Super Speeds are T1.3 on the other hand, so they have a one stop advantage over the above lenses. Modern spherical lenses are designed to work well wide open, so the difference between different stops (i.e wide-open and one stop down) is not as apparent.

With anmorphic lenses on the other hand the combination of stock and stop is more important. There is a noticeable difference in anamorphic lenses between wide-open and 1 stop down, respectively between 1 stop down and 2 stops down. So if one had the choice between shooting 200 ASA at T2.8 and shooting 500 ASA at T4, the improvement in the optical quality of the lens between T4 and T2.8 would far outweigh any improvement in grain/sharpness of the filmstock between 500/200.
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#3 barryagilbert

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Posted 21 November 2005 - 12:43 PM

Most people select their lenses based on their look, not on the speed. Most cine-lenses are around T2 anyway (Ultra Primes, Primos, Cooke S4s, Zeiss Standards), so the speed is not really a deciding factor. But the Master Primes and the Super Speeds are T1.3 on the other hand, so they have a one stop advantage over the above lenses. Modern spherical lenses are designed to work well wide open, so the difference between different stops (i.e wide-open and one stop down) is not as apparent.

With anmorphic lenses on the other hand the combination of stock and stop is more important. There is a noticeable difference in anamorphic lenses between wide-open and 1 stop down, respectively between 1 stop down and 2 stops down. So if one had the choice between shooting 200 ASA at T2.8 and shooting 500 ASA at T4, the improvement in the optical quality of the lens between T4 and T2.8 would far outweigh any improvement in grain/sharpness of the filmstock between 500/200.


Thanks, that's very interesting. Which leads to a follow-up question regarding your comment on choosing a set of lenses based on their "look". I have heard in an off-hand way of certain characteristics of certain makes of lenses (i.e. that Zeiss is very "sharp") and I wonder how you would characterise the different looks of the brands you menton above. Thanks -
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#4 Max Jacoby

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Posted 21 November 2005 - 01:39 PM

I haven't tested the new Master Primes yet, but they are the sharpest lenses out there, bar none. Arri say that they are sharper at T1.3 than other lenses at T2. They are the only set of lenses where the breathing and flaring is negligeable.

Of the remaining lenses, what I've found is that of the big 3, the Ultra Primes are the sharpest, followed by the Primos. The Cooke S4s are not very sharp, but on the other hand they have the most pleasing contrast, making for a very three-dimensional look. The Ultra Primes have the least good contrast, and once again the Primos fall in the middle, contrast-wise.

The Superspeeds are less sharp but have better contrast than the Ultra Primes. They are sharper, but with less pleasing contrast than the Cooke S4s. From what I've heard, the look of the Zeiss Standards is closer to that of the Cookes.

Just comparing the Zeiss lenses to the Cookes, they are the result of different design philosphies. Zeiss have always tried to make the technically most perfect lens and have pushed new boundaries with the Master Primes. Cooke on the other hand have a more old-school approach to lensmaking. For instance the focal plane on Zeiss lenses is flat (i.e. if you point the camera at a wall, the whole wall will be sharp), while that of the Cookes is slightly curved, which approximates how the human eye sees. That is one of the reasons people find that the Cookes look more organic than Zeiss lenses. But on the other hand with Zeiss lenses the focus falls of quicker, so you can really see which part of the picture is sharp and which is soft. With the Cookes the focus falls off more gradually, so the difference between sharp and soft becomes less noticeable. Since these lenses are less sharp to begin with, the Cookes sometimes look simply soft, with no part of the image clearly sharp.

All that being said, no lens is 'better' than any other. They all offer different looks, different personalities to suit the different tastes and needs of the people who use them.
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