Ryan Patrick O'Hara
Veteran
The Future of Super-Fast Lenses
Making a professional S35mm cinema lens at a T/1 is almost unfathomable in design and manufacturing difficulty. The resulting cost of such a lens would likely be unprecedented. Perhaps more importantly, the demand for such a lens is hard to grasp. In 35mm and S35mm cameras shooting at T/1, the depth of field would be considerably shallow compared to the already super-shallow T/1.4. Very few cinematographers would desire the aesthetic look such depth of field offers. Additionally, cinematographers would not want to put their 1st camera assistants through incredible strain while constantly putting the shot at risk of focus error. T/1 is simply too expensive and shallow for mainstream use.
Which T-stop is ideal? It is a safe generalization to state most cinematographers cautiously avoid the use of T/stops wider than T/4 or T/2.8. These two stops still offer shallow depth of field qualities, but allow more reasonable depth of field for the subject. Stops wider exhibit more extreme shallow depth of field that may not satisfy the desired look of the picture. As mentioned, wider stops tax the focus puller and increase the potential risk for error and reshoots. Therefore, unless extremely shallow depth of field is the intended look for the picture, the only reason to desire a super fast aperture lens is if the cinematographer knows or fears not having sufficient lighting to properly expose.
Eliminating the need for super-fast lenses for aesthetic use, the only remaining factor is one of exposure. If the cinematographer simply does not have the natural or artificial means of lighting to proper exposure, faster lenses are the answer. Camera technology, however, is relentlessly irradiating this need as this article is being printed. With the arrival of the newest generation of digital cinema cameras, the progression of camera sensitivity has taken giant leaps forward. In fact, digital camera sensitivity is advancing at such a rate; it is argued that T/2.8 is the new T/1.4.
The following are manufacturer issued or commonly rated ISO/ASA ratings for recent (2009/2010) professional digital cinema camera models:
Make/Model
ISO/ASA ratings
200 – 400
Arri D-21
200 – 400
RedOne Mysterium
320
Phantom 35/HD
320
Sony Cinealta F900
320
Panavision Genesis
400
Available in 2010- 2011, the following cameras or upgrades represent a hint of what is to come. As of this writing, common ratings or preferences are:
Make/Model
ISO/ASA rating
800
RedOne Mysterium X
400 – 800
Phantom Flex
1000
Sony F-35
650-1000
Notice Arri, RedOne, Phantom, and Sony have at least doubled in sensitivity between camera models or upgrades. Sensitivity coupled with cleaner signals, allows the possibility of stretching these numbers further.
Why T/2.8 On the New Cooke Panchros Work.
All facts considered, it becomes increasingly difficult to understand why anyone who could achieve a desired shooting stop of at least T/2.8, would justify spending more money for a set of equal quality super-fast lenses. This especially rings true when budgeting lenses for the 2nd unit or multiple camera production. If a stop under T/2.8 is not needed, renting multiple sets of more expensive lenses adds up quickly. Thus, the question remains; “ does one need a T-stop wider than T/2.8?” The answer is increasingly ‘no’.
The newest wave of digital cinema camera is now one or even two stops more sensitive than their previous generations or models. Of course, most cinematographers are well versed in shooting digital cinema cameras around 320-400iso/asa, at reasonable T-stops; as that has been the ballpark sensitivity for almost all professional digital cinema cameras in the past few years. However, there are productions that shoot in extremely low light and otherwise need to shoot wide open at T/1.4 for exposure. Previously marooned at T/1.4 wide open, these same filmmakers, with the same light levels, may now achieve similar exposure but with a T/2 or T/2.8 lens using one of the many higher sensitive cinema cameras.
Perhaps the only other reason to desire a super-fast lens is a direct result of another historical precedence regarding optics. It is the classic tale of the knowledgeable cinematographer wishing to stop the lens down a couple of stops in order to ‘center the lens’, a term for finding the sweet spot on a lens; where the image is at optimal performance in relation to sharpness. Historically, this isn’t a false practice. Many super-fast lenses from yesteryear, sacrificed a degree of sharpness when wide open. If using an older T/1.3 lens, stopping down to a T/2.8 or T/4 would typically exhibit optimal sharpness in the image. This practice still holds true regarding older primes and zoom lenses. However, the new Panchros are designed and built to work at optimal sharpness from wide-open and down the aperture. They do not need to be stopped down in order to find the ‘sweet spot’.
What does the future hold?
Since cinematographers typically desire a decent stop around T/2.8 –T/4, the new camera chips are making that goal more and more accessible. These cameras allow those who previously worked at such stops more room for experimentation, while those who were forced to shoot at open stops just to expose, an opportunity to shoot at their desired stop. With camera sensitivity currently in an arms race with no end in sight, the need of super fast prime lenses, which cost more to produce and rent, will dwindle to that of specialty lenses for most productions.
The future of super-fast lenses appears to be slowing.
-Ryan Patrick O’Hara, cinematographer
(All numbers assigned as ISO/ASA are either found by the author from experience, as a realistic base sensitivity or are number taken from a manufacturer recommendation. Test cameras and find what works.)
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