For over a century, cinematographers have enjoyed almost complete control over their images. They could choose focal length, frame rate, shutter speed, and depth of field -- what and how much is in focus -- whether super deep, or razor thin to pop a subject cleanly from its background.
Video gave shooters advantages of ease, speed and flexibility. We still have manual modes that let us tweak exposures, focal lengths, shutter speeds and such, but much of our control over depth of field has been stripped away..
Affordable 24p cameras and more sophisticated in-camera and post tools have done a better job mimicking film stocks, but until recently the almost-infinite depth of field gave the images away as video.
It's a fairly simple problem of optics and physics. The smaller the "target area" of the image captured by the lens, the deeper the depth of field. The sensor area in your 1/3" DV or HDV camera is so tiny compared to a 35mm film frame that the depth of field (DoF) is incredibly deep. Even with a wide-open iris, almost everything in frame is relatively sharp.
Enter the Depth of Field Converter.
Converters come in lots of flavors, styles, brands, and with wildly varying price tags. But they generally work the same way, starting with allowing you to connect a 35mm-format lens to your video camera. Various models work with everything from Panavision film lenses to consumer still camera lenses. The lens projects the image onto a groundglass, where the camera records it.
The result is a video image, but with the DoF characteristics of film. Combine that with a 24p frame rate and the results can be very filmic indeed.
One popular misconception is that converters are there just to give you super-shallow depth of field. Not true. They give you CONTROLLABLE depth of field, whether that’s shallow, deep, or somewhere in between.
Shot with the Canon XL-H1 with the stock lens. Note that the gnomes in the foreground and background are fairly sharp.
Shot with the Canon XL-H1 with the P+S Technik Mini35 lens adapter, and a Leitz-Panavision 50mm prime at f1.3. Notice how soft foreground and background allow us to achieve PGS (Proper Gnome Separation).
Simple in theory, yes, but challenges abound.
The biggest challenges that must be overcome are light loss, grain, and image orientation. The developers of different DoF converters have addressed these problems in different ways.
All DoF converters eat up some light, ranging from a half-stop or so, to as much as two stops of light loss. This makes lens choice critical, although the subject deep of lens selection is deep enough that we shall save it for another day.
Visible grain on the groundglass is another issue. Just as you can see grain when you look through the viewfinder on your 35mm SLR, the same goes for DoF adapters.
Along the way, engineers figured out that if you rapidly move the groundglass, the grain will blur out and become invisible. On the first converters, the solution was to create a disc-shaped groundglass, which a tiny motor would spin just like a compact disc.
Early problems with this setup included grain "swirls" which sometimes became visible. The solution was a groundglass that rapidly oscillates rather than spinning. The engineering is much more complicated and the power requirements greater, but no more swirls.
Some converters (which are generally called "static" converters) do not move the groundglass at all or have any power requirements, but use a glass with ultra-fine grain that is not photographed. Hot spots within the image are the biggest challenge with these devices.
Image orientation is the third challenge. A basic DoF converter results in an image that is actually recorded upside down, which must be re-oriented in post.
The higher-end units contain a built-in prism block which re-orients the image, but it comes at the price of a bit of light loss. Some mid-range units offer "flip module" accessories that correct the picture orientation. A few cameras (such as the JVC HD-200 and HD-250) actually allow you to invert the recorded image to take advantage of these lower-priced converters.
Location shooting is dealt with by turning monitors upside down, or even using magnets to flip the picture on the camera's LCD screen. Some people even mount their CAMERAS upside down.
In the rest of this article we will take a look at a few, although certainly not all, converters in different price ranges. This is not a direct comparison, review, or side-by-side "shootout" in any way, just an overview of various features available on some models.
THE HIGH END
The Mini35 is the granddaddy, created by German cinema powerhouse P+S Technik. This is the converter most used by the highest-end shooters, and the one so many others lust after. It has been used for everything from low-budget indie productions, to network television pilots, feature films, even that great Jerry Seinfeld "Superman" campaign for American Express.
The first models of the Mini35 had a rotating groundglass, but later models incorporated the oscillating system, a method which has since been adopted by most other DoF adapter manufacturers as well.
P+S Technik Mini35 with the Panasonic HVX200 DVCPRO HD
Earlier units only had "high" and "low" speeds, but in the current 400 Series units, the speed is continuously variable. A simple tweak of a thumb wheel can increase or decrease the oscillation rate should the grain become visible (most usually under higher-than-normal shutter speeds). The unit is completely silent, even when running at its highest speed.
Compared to other units, the Mini35's most obvious first-blush difference is "attachability." Most DoF converters are devices attached to the front of your camera, including your camera's built-in zoom lens. The Mini35 is more like a cradle that your camera body fits into. If your camera has a removable lens, the P+S Technik attaches directly to your camera body via a small relay, eliminating the bulky (and light hungry) video zoom lens that came with your camera altogether.
Lens mounts are available for all the popular flavors. PL mounts are usually used for high-end cine lenses, but mounts for consumer SLR lenses are also available. They even have Panavision and BNCR mounts.
I'm sometimes accused of being a cheerleader for P+S Technik, but it's because their product really does work flawlessly. The ease of use, fit, finish, design, and optical quality is as high as any equipment that I have ever owned. I used to shoot a great deal of 35mm film, but haven't cracked the cases on my film cameras since I began using the Mini35. It really does look that good.
Of course this all comes with a price. The Mini35 is not cheap. Together, the basic unit, connecting kit, and a lens mount is going to come in at just a bit over $10,000, probably more than your camera. Add expensive prime lenses and you’re well into "real money" territory.
For some shooters, the usability and results are worth it. At our little company, Fantastic Plastic, even our GM who does all the bean counting (and always looks askance at me when I talk of new "toys") considers it the best investment we have ever made.
While price tends to limit Mini35 ownership, many are still winding up in the hands of indie shooters. "A lot of them go to rental houses," says Barbara Lowry of ZGC, Inc., the company that distributes P+S Technik products in the United States. "People are using them for just about everything: independent filmmakers, television spots, pilots, and TV shows."
Lowry concedes the unit carries a high-end price tag, but says "If you're going to go out in the field and shoot a major project, it’s well worth it."
As a daily Mini35 user myself, I have to agree. If you are a full-time professional cinematographer, out there in the trenches shooting projects with decent budgets most every day, I personally think the Mini35 is the way to go. For those more on indie-sized budgets though, or the "weekend warriors" who just want more filmic video, there are more affordable options.
P+S Technik may have figuratively invented the wheel, but it's Redrock Microsystems that's putting a lot of people in the driver's seat.
It's not quite a Mini35 clone, but it does work on exactly the same principles. Redrock has traded some of the Mini35's higher-end features for a very workable but less-costly unit in an effort to bring DoF conversion to more users.
"It's keeping in line with the indie spirit," says Redrock partner Brian Valente, who says it's important to put ownership within the reach of indie filmmakers. "The challenge is, to get really good results you have to have some experience with it," Valente says, contending that full-time ownership of an M2 rather than occasional rental of a Mini35 allows more users to be able to learn it, get used to it, and get the most out of it.
Unlike most adapters, Redrock still uses a spinning groundglass rather than one that oscillates. In their particular design, the company says this is an advantage and allows the M2 to operate at higher f-stops without revealing the grain, and makes the unit less power-hungry.
Like the Mini35, Redrock M2 owners come from a variety of types of production, doing a wide range of work. "I use it a lot for commercials, both local and national, and some image pieces for corporations," says Houston-based freelancer Larry McKee of Eagle Productions. "I've even used it on feature-length films."
As others have, McKee chose Redrock after a bit of Mini35 sticker shock, and has been pleased with the results. "It does add a bit to production time,” McKee says, "but the clients all seem to feel like it's worth the look."
While the P+S Technik Mini35 is basically all-in-one, the M2 system contains a fair number of mix-n-match pieces: the adapter itself, rods, support system, external power supply, mounting kits, connecting lens, etc. The microX accessory upgrade kit includes an add-on module to re-orient the picture.
Redrock Micro is also making a name for itself with accessories that, while they were designed for use with the M2, can be used with other brands of adapters, video cameras, or even film cameras.
For example, the microFollowFocus is a traditional cine-styled follow focus unit that can be used with cine, SLR or video lenses. It's a lower-priced unit, but without lacking the features or workability of high-end FF systems. During a recent all-day test drive on a real shoot, the unit performed like a champ.
As for the M2 lens adapters themselves, prices start at $750 for the base adapter itself. Bundles range up to about $3000 which include the adapter, carrying case, lens mount, rods, support system, and follow focus unit.
If the P+S Technik is just a dream, and Redrock is still outside your indie budget, options still abound. There's a whole crop of ultra-low-budget adapters that should be within reach even for the most frugal budgets. Many are in the sub-$1000 category, with some people even cobbling together homemade units for as little as $200.
It's a long list of either available or soon-promised adapters: the Brevis35, the Letus35, SGpro, Indie35, the Cinemek G35, the WDR35 Plus, the i-35HD, the MagiCine Z-Box, and quite a few more.
Some are better than others, and there's a great deal of the "you get what you pay for" factor among the adapters in this category. Some have a decidely “home science-project” look to them, complete with taped-together or hot-glued parts, and PVC plumbing fittings instead of machined metalwork. A couple of other models look suspiciously similar to the Redrock.
Poor results from some of these products have scared off some who might otherwise be doing more DoF conversion. "The first one I bought wasn't that great, with a lot of vignetting and image warping," says Adam Frey of Maryland-based Crimson Chain Productions. "It was not anything you could use on a professional shoot -- it was a flimsy contraption, with lots of plastic parts inside it."
Frey also had issues with noise. DoF converters should operate silently, but his early-model Letus35 was noisy enough to cause sound-recording problems. An upgrade to a newer-model converter solved some, but not all, of Frey's problems and he's still gun-shy to shoot with it. "I just don't know that it's worth the trouble," he says.
One group trying to overcome the "if it's cheap, it doesn't work" mentality is Canadian company Cinevate. Their Brevis35 converter is tiny in size compared to the big boys, but developers claim it packs a punch.
Although usable on any camera, the Brevis35 is especially well-suited to the wide range of small palmcorder-type HDV cameras, promising great filmic images out of something as small as the tiny and affordable Canon HV20 and HV30.
Brevis35 with the Sony XDCAM EX1 CineAlta
"It's the only microprocessor-managed adapter in the world," says Cinevate president Dennis Wood, citing the proprietary power monitoring and management circuitry in the unit. Internal batteries run the adapter for about 30 hours, with a recharge taking only 20 minutes.
Unlike most manufacturers, the Brevis35 is customizable with a number of different groundglass options, which the company calls CINEFUSE diffuser screens. By selecting the most appropriate groundglass for your particular camera, it helps optimize image quality and solve the vignetting problems that have plagued many of the lower-priced converters.
Cinevate's goal is to put adapters into the hands of any shooter who needs one, without sticker shock. "It's for everybody from wedding videographers, corporate shooters, filmmakers of all types and budgets," Wood says. "It's quite a diverse group."
The basic Brevis35 unit comes in at around $1100. Like Redrock, the company does offer a "flip module" to correct the upside-down image. It's available in a bundle that brings the full package to about $1500.
IT'S NOT MAGIC
One thing to keep in mind is that DoF adapters are no magic pill or wonder gadget that you simply throw on to make your next video look like Lawrence of Arabia. They take skill, practice, and time to learn.
Cinematographers used to shooting 35mm will take to the adapters like a duck to water. For those with a video-only background, there's a steeper learning curve. Focus, often practically just an afterthought with video, now becomes critical. Shoot with a 50mm or longer lens wide open and you can get a DoF literally only an inch deep.
That can make for dramatic images, but also for some stressful focus pulling that takes practice (and a good follow focus unit, which is a must).
Viewfinders on most smaller cameras now become even less useful for focusing than ever, and can't be relied on to ensure sharp images. A full-blown HD monitor is most helpful during shooting, but I find the old-fashioned "Hollywood" method of focusing is the most reliable: a tape measure.
The DoF adapters can be mastered easily enough. Just don't plan to buy or rent one the day before a big shoot if you have no (or even just limited) experience with them.
But if you want your video to REALLY look like film, shoot as if you were shooting film. Time to put on your film pants, people.
Be sure to check out Looking for Film Look? Shoot Like Film! by Kim Segel, in the Cow Magazine's Film Values Issue.
Film-look software will never offer the same impact on your work that film-style shooting will. Software will also always take longer than shooting right the first time. Learn the tools and techniques to maximize film looks, even on paupers budgets.
Today many people (even some of those still shooting 35mm) block and light a scene first, then let the DoF fall where it may. But old-school cinematographers know that creating the desired DoF begins with the very first discussions about where to place the camera and where to move it in a shot. Only after making making those decisions do they then light the scene (and even choose the filmstock) accordingly.
In other words, DoF conversion is no substitute for great lighting, inventive direction, clever blocking, good sound, inspired acting, or a compelling story. But, used well, they can give good video the extra push to make it great.
Just remember to keep things in focus.
Oh, and keep in mind the most common mistake that newbies make with these gadgets: forgetting to turn the darn thing on.
To hear more from Todd on cinematography, depth of field converters, and much more, be sure to join him as a guest on the Creative Cow News Round-up Podcast.
Also in that episode, the latest news from Boris FX, LaCie, Amazon, Microsoft, and more.
Director and Cinematographer Todd Terry serves as Creative Director of Fantastic Plastic Entertainment, Inc., a small but full-service production house he and a partner founded in Huntsville, Alabama. The company is both a creative agency and a production company, having conceived and created thousands of industrial films and television commercials over the last decade.
In addition to Fantastic Plastic's room full of ADDYs, Todd has won his region's AdFed "Best of Show" honors as "Cinematographer of the Year" and "Director of the Year" five times. He is a recipient of the American Advertising Federation's highest honor, the Silver Medal.
An admitted sufferer of technophobia, Todd is an old-school film guy who still likes to shoot celluloid when he can, and is fond of foregoing CGI for practical effects whenever possible.
Todd started his career on the other side of the camera as a wanna-be actor. A string of bad films and made-for-TV movies ("Tonight on a powerful Lifetime Original Movie, Meredith Baxter-Birney gets beaten yet again...") prompted a jump to the other side of the camera, but he still gives plenty of credit to those acting days of his youth. "I learned more on my first day on a real set than I did in four years of film school," he says. "Instead of concentrating on hitting marks and remembering blocking, I was always too busy watching the cinematographer and trying to figure out why he was doing this or that."
When not glued to a camera, Todd has displayed a penchant for expensive hobbies that he can't remotely afford, such as flying, sailing, and motorcycles. He claims to own no socks.
You can find Todd Terry hosting in Creative COW's Business & Marketing , Canon camcorders , Cinematography , HDV Format , Indie Film & Documentary , and Lighting Design Pros forums.