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IntroductionLooking Through a LensLet the games begin with another FDTimes NAB edition. Articlesare arranged partly by theme but mostly in order of diligently metor missed deadlines.Caution: this article may raise a few eyebrows. Do not attempt:the picture above is the element of a very expensive lens droppedaccidentally. Curiously, continued shooting with the damagedlens resulted in images that weren’t unusable.NAB 2013 buzz will be anamorphic lenses, more K and 4K, waysto shape the image with new lenses, filters and effects. Ways toconnect cameras, recorders, rigs and accessories, ways to movecameras, to illuminate, and ways to stand out.Standing out was what the AFC Micro Salon was all about lastmonth. This annual expo and gathering of the Association ofFrench Cinematographers in the former Pathé Film Studios inMontmartre is a favorite show. Imagine Cine Gear with fine wineand finer food. Rental house owners and technicians were peeringintently into lenses with high powered Maglites and magnifyingglasses. Scrutinizing lenses on projectors. Counting lines, looking for distortion, searching for color aberrations. Looking “into”lenses or looking “through” lenses? All fine but why?While some at Micro Salon were looking into places offering thebest production incentives, cinematographers were engaged in passionate discussions on how best to customize the digital image, using vintage lenses, trying any deliberate or desperate measure togive their work a unique character in the face of digital cameraswhose sensors they felt were all similar. It’s not just France. We hearit worldwide: apprehension that digital cinematography sometimesseems like shooting with one film stock and using the same lab.Some have said that film was unique as a capture medium becauseof its random permutations of many different film emulsions, exposed with a panoply of different cameras, lenses, and filters, processed by many different labs, using different chemicals and evendifferent water, timed and printed in various ways. The concernlately has been with homogenized digital sensors, inside the samecameras, auguring a perceived reduction in creative possibilitiesthat a cinematographer might have.Cinematographers always had love-hate relationships with cameras. A camera was never built that didn’t suffer drilling, grindingand the ministrations of retrofit syndrome to make it unique. Butnot everyone has a Philippe Ros, Olivier Garcia, Nicolas Pollacchi,Hervé Theys or a company like HD Systems ready to redesign custom gamma curves for their digital cameras. So, it’s back to whatcinematographers always knew: lighting and lenses.Carey Duffy continues the theme with his “Chamber of Secrets”filters tutorial. The adjacent piece “Looking Through a Lens” is anopening salvo in this discussion.For years, I thought that dust, digs and little scratches inside anew lens or on the front element were the equivalent of a sloppysurgeon leaving a sponge inside the patient. How often did I torment lens manufacturers by asking for a dozen new lenses to bepresented, each of which I would painstakingly inspect and reject until I found the most pristine of the pristine. Ironically, allthis persnickety prep went out the window after the first day onlocation (EXT. SANDY, SALTY WINDSWEPT BEACH - DAY).Lenses are not hermetically sealed. Dust, dirt, smoke, and sootfind their way inside lenses the moment they leave the factory.Scratches on lens elements may cause a tiny part of the image to bea little less sharp. In most cases, we won’t notice the difference unless it occurs along an edge that’s supposed to be razor sharp, liketext or a straight line, or part of a flare. For faces, fashion and beauty, there could be a benefit—although using a filter to soften theimage is a much less costly and eminently more reversible methodthan attacking your 25,000 Summilux-C with sandpaper. At widerapertures, much less of the scene is in focus, so a scratch is morelikely to blend in with everything else. When you stop down to T16,you may notice the effects of a scratch because everything is muchsharper by comparison. In other words, scratches are less apparent at wider apertures. Nevertheless, camera rental houses will holdyou responsible if you scratch a front lens element. You’ll have topay for the replacement cost, just as Hertz and Avis will hold youresponsible for a dented bumper.It turns out that scratches, digs, sleeks, and other tiny marks fromthe polishing and manufacturing process, as well as scratches encountered in the real world, are not the end of the world.In his paper for the 2010 International Optical Design Conferencein Jackson Hole, WY, Cody B. Kreischer wrote that surface qualityspecification with most optical components is for cosmetic purposesonly. Cody is President of Kreischer Optics Ltd (www.kreischer.com).He explains, “It would take 26 optical elements with 2 pits of 0.5 mmdiameter and one scratch 0.008 mm wide by 10.0 mm long to producea 1% drop in contrast at the image plane. Although this is a simplifiedexample, for the majority of optical systems, surface quality has negligible effect on optical performance.” (The Adversarial Relationshipbetween Optical Performance and Scratch-Dig; opticsinfobase.org)Issue 53 Apr 20135

Looking Through a Lens, cont’dAs J. L. Plummer said, “Optics are made to look through, not at.”(SPIE, 1979, vol. 181, pp. 90-92.)Eureka. I had always wondered how still photographers managedwith multiple cameras dangling and optics clanking together,with lenses dusty and scratched. To paraphrase the Clint Eastwood line in Magnum Force, “You’ve got to know your limitations.” To learn more about limitations, I spoke with manufacturers, rental houses and lens gurus.Iain Neil, Optical Designer of the Leica Summilux-C and manyother cine lenses, said, “When we talk about scratches and digs weare really talking about very small cosmetic defects. For example,residual polishing marks called sleeks appear as fine scratches andsometimes they are only a fraction of a wavelength in width butsometimes appear like other scratches which may be much coarser. Unfortunately, sleeks are common to see on exotic glass types,which virtually all lens companies use to achieve high performanceimages. In addition, they are hard to see unless the lens is lookedinto with a high power projector. Lenses with large exit pupils andextra edge blacking may also tend to magnify these sleeks. Almostall high performance lenses will exhibit some small cosmetic blemishes, primarily due to high technology glass, coatings and fabrication. These will tend to be more noticeable in lenses where theblacks and skin tones are best. When you look into these lenses ona powerful (say 400 watt) projector, the cosmetic defects may standout more. It should be noted that this would probably not be visiblewhen holding the lens by hand and looking through it by eye at ablue sky, because chances are that the cosmetic defects would bealmost invisible in that viewing situation.”Jon Maxwell, Optical Designer, said, “We are all using more ‘exotic’glasses that are necessary to deliver the increased speed and performance that the industry now expects. The difficulty is that untilthese glasses are anti-reflection coated they are more susceptibleto cosmetic marks, environmental attack and polishing artifacts.These cosmetic defects are no more ‘dangerous’ than they ever havebeen, but they can be more numerous.”Les Zellan, Chairman of Cooke Optics said, “Most of these artifacts are not visible under our 60 watt light bulb test; but put a lenson a lens projector or shine a bright point-source LED flashlightthrough the lens and all sorts of ‘things’ can become visible. Noneof these ‘things’ affect the performance of the lens and to some extent it is the trade-off that has to be made to get lenses that performto today's expectations. In the end, it is important to remember thatthere are no images of any kind formed in the lens; the light raysgo through the optics of the lens to produce a focused image on thedetector (film or digital), and cosmetic defects, by definition, don’taffect the quality of that final image. At Cooke we strive to give ourcustomers the best possible lenses both optically and cosmetically.”Jean-Marc Bouchut, Angénieux Technical Support Manager said,“Cosmetic defects have no impact on the image quality; unfortunately, for some customers who do not have sophisticated testequipment, it is an important acceptance criteria.”Dominique Rouchon, Angénieux International Marketing andSales Director said, “At Angénieux, we always target perfection,including the cosmetics aspect, particularly on our high end rangeof lenses. It is a fact that such an approach has a cost, ultimatelyincreases the production costs, and makes the price of the lenses6Apr 2013 Issue 53higher. We do our best to train our customers on the subject inorder to make this approach change. We hope this article will contribute to this understanding and help people recognize that thereare many more important criteria to evaluate in a lens.”Larry Thorpe, Senior Fellow of Canon’s Professional Engineering& Solutions Division, said, “All of the major lens manufacturershave mastered multiple aspects of optical design and manufacturing over many decades. The science of optical design is tightlybound up with the science of tolerancing. Lens elements are madeto tight tolerances that encompass their shape, thickness, and surface accuracy. The required polishing to achieve that surface accuracy takes time —and that time is expensive. Tolerancing of theinevitable tiny imperfections to those surfaces known as digs andsleeks that remain has been stringently optimized to strike the requisite balance between the tolerances necessary to meet the lenssystem performance specs and the manufacturing costs entailedin meetings those tolerances. Attempts to significantly better thoseimperfections can quickly lead to soaring manufacturing costs.”Otto Nemenz, President of Otto Nemenz International said,“Sometimes camera assistants come to check out lenses and rejectthem if there are little specks, dust or digs inside. There are moreimportant things to look at, like backlash and tracking.”All this might seem to be good news for over-worked camera assistants and rental house floor technicians. But not so fast. Sleaksor dust inside the lens may not affect performance, but they maystill be viewed with the same degree of horror as the owner whohas just purchased a new Lamborghini Gallardo and discovers ascratch on the mirror. Performance may not suffer, but pride does.Cody Kreischer added, “The fact is that the better the opticalquality, the harder it is to make a lens look ‘pretty.’ The glassesneeded for the best color correction tend to be more difficult towork with, in addition to being expensive. Also, the higher the‘as built’ performance needs to be, the tighter all the tolerances ofthe lens need to be, which includes surfaces which may need tobe literally within a millionth of an inch (0.000001") shape accuracy and very tight center thickness tolerances. Kreischer Opticsmakes high-end optics for commercial, medical and military applications, often in small quantities, which often require skilledhand polishing to achieve these tolerances. If a surface has to berepaired for a scratch, you are basically starting over, and lesslikely to finish it to as good an optical quality as it was before. Inmost cases, cosmetic quality is ‘just for pretty’ (as my wife says)and does not equal optical quality (performance).”Iain Neil wrapped up, “Having pointed all these things out aboutlenses, there is another kind of contamination to worry about.Potentially much more significant than stuff inside or on the lensis dust lurking on the sensor itself, on the cover-glass surfaces, oron the sensor filter surfaces. Because it is so much closer to theimage plane, sensor dust could cause a greater problem with image quality than most lens scratches or digs.”As we scratch the surface of NAB 2013 proclamations and dig ourheels into the expo’s endless carpets, we’ll seek out new tools andtechniques that tempt with aspirations of creating images thatstand out. As we move to more immersive and higher resolutioncinema, I expect our lenses will become even more exotic andeven more important. The adventure continues.

Tiffen and the Chamber of Secretsapart from those in the know. I am, of course, referring to theuse of camera filters. It seems that these highly sensitive opticaltools are rarely discussed in major cinematographic publicationsapart from broad, sweeping references. I hope to enlighten with adiscussion about the different technical and aesthetic advantagesthey provide. Their diverse use and intricate ways can help resolvethe anxiety of today: that my camera looks so very much like yourcamera, but I want to find a way to make my images look differentfrom yours.By Carey DuffyAs digital technology attempts to replace origination on film, longthe bastion of many cinematographers, a collective anxiety questions whether new image capture paradigms have led to a reduction of creative possibilities. This has fundamentally challengedthe cinematographer’s ability to work, poetically speaking, “in thedark.” What remains to enable a cinematographer to stand out?With the proliferation of on-set monitors and LUTs, the abilityto craft moving images without interruption from the video village is a thing of the past for many. Only too often do we hear thephrase “shoot it clean and fix it in post,” challenging the cinematographer’s pursuit to fulfill the creative brief.But, as this new digital broom sweeps film away, it introduces newand wonderful tools whose potential seem endless. With so muchto learn about these new technologies and workflows, the moderncinematographer (whether schooled in film or fresh to the industry)embarks on a new quest. However, the one remaining factor that hasbeen ever-present in this transition is the primary objective to process focused light on reaching a recording format. How the imageis crafted onto that format is now one of the hottest topics of debateabout what being a cinematographer is in this new digital age.For many the concept of “burning in the image” at the point oforigination has been a long-held doctrine. This is where the visualinterpretation of imagery begins its journey. The tools used arethe cinematographer’s primary instruments of control over thequality and character of light encountered on a production.Lens choice is the primary tool to advance the visual storytellingprocess, determining angle of view, point of view, focus, sharpness or softness, and “speed of light.” The cinematographer’s secondary tool kit is one that still often remains a guarded secret, anarsenal of “dark arts.” To the uninitiated, a clean image is all that isrequired for digital acquisition. The world of Post image manipulation is open to all who can turn on a computer.We do not forget that Post Production and effects work for cinematographers has always been an inherent part of the job. So,what is this guarded secret of dark arts that I refer to as a secondary tool kit? I am talking about all the other pieces of glassthat illuminate, craft and conjure up images and feelings thatenter our consciousness without ever being openly discussedCamera filters have been used since the beginning of photography. It is easy to simply split filters into two major categories:chromatic and non-chromatic (or think of it as color and effect,or filters you need and filters you like). This helps classify filtersbut it does not tell the full story. Filters are used to solve technicalproblems or add aesthetic mood and sensations. Nevertheless, anaesthetic effect can be achieved by using a technical filter and atechnical effect can be achieved by using an aesthetic filter. Useis open to an individual’s interpretation. The laws of physics govern capturing of moving images regardless of acquisition format,however these laws may also be tested and broken.False color or pollution - where it starts or endsOne of the biggest changes with the move to digital is the advantage of higher ISOs. This, in turn, has created a challenge forstandard neutral density transmission reduction filters (NDs).NDs are considered to be a vital tool for cinematography. Butthe problem with standard NDs is that they do not cut the wavelengths that adversely affect the sensor’s color reproduction. Inshort, they allow pollutant wavelengths and false color (Far Red680 nm to 700 nm, Near I. R. 700 nm to 750 nm, and sometimesFar I. R. 750 nm and beyond) onto the sensor. This new problemmeans that filter manufacturers have had to rethink NDs. Theiranswer has been to produce a new type of Neutral Density filter,the “IRND” to replace standard NDs for digital cameras. Everycamera model has a different sensor and algorithm designed toproduce their own color space. The goal of producing a specificanswer to reduce neutral light transmission across individual sensors reading and cutting wavelengths at different nanometers iscurrently not available. That’s why a one-size fits all answer hasbeen formulated by the filter manufacturers. Each different camera model also uses a different internal IR blocking filter and adifferent Optical Low Pass Filter. To complicate things more,Neutral Density translucent dyes used in the manufacture of filters from all manufacturers vary from batch to batch. Only noware camera manufacturers introducing internal IRND filters, buteven then they do not cover all stop eventualities.It is easy to understand why this issue causes so much confusion.One constant phenomenon is that digital sensors need to readlight into the Far Red end of the spectrum to produce great looking skin tones. And this is where pollution starts.There are other ways to cut polluting wavelengths with filters.These are specifically-designed band cut filters using coatings tocut at a given wavelength. The issue with these types of filters isthat they do not cover all focal lengths. The coatings used introduce chromatic vignetting on wider focal lengths.Filters that reduce Far Red and Near IR pollution on digital cameras need to start working within the visible spectrum. For someIssue 53 Apr 20137

Tiffen and the Chamber of Secrets, cont’dcameras, this issue appears under normal lighting conditionssuch as Daylight or Tungsten, even without the use of an NDfilter. Understanding your camera sensor’s response in variouslighting environments has never been so important.Therefore, reducing visible l

ADORAMA RENTAL CO Weiden Berlin Prague Paris creamsource. Sponsors and Educational . tors, Grips, Gaffers, Crews, Rental Houses, and Manufacturers. It’s written, edited, and published by Jon Fauer, ASC, an award-winning Cinematographer and Director. He is the author of 14 . Looking Through a Le