Lenses and Lights

Review of Instructional books and DVDs for 3D film productions

2010-10-25T15:09:00.000-07:00

It's sort of surprising that with all the attention (and theatrical business) 3D cinema has been receiving for the last several years, there aren't more instructional materials available for the professional cinematographer or editor to get up to speed quickly. There are a lot of websites, particularly of the DIY with two cameras strapped to a rail variety, but precious little hard info that couples theory to practice and is applicable to professional 3D rigs.

The classic book is Lenny Lipton's Foundations of the Stereoscopic Cinema. (out of print, but available for free download here) It's very heavy on theory, but you won't find much on the current state of equipment, as it was published in 1982.

Last year saw the publication of 3D Movie Making: Stereoscopic Digital Cinema from Script to Screen, by Bernard Mendiburu. This is a very up to date volume. Not only is it accessible and easy to read by anyone already familiar with the basics of cinematography, it contains many exercises and experiments you can try, including some that don't require access to a dedicated 3D camera rig.

It includes links to websites and a DVD with many useful examples. I recommend this book to anyone starting out in stereoscopic 3D film production (or even fairly far along the way). For producers and directors new to 3D, the first 3 chapters are particularly helpful. I think this book will become a standard and I wouldn't be surprised if it's picked up as a textbook.

Now there is also a very cool course available as a multi DVD set: Stereo 3D Filmmaking: The Complete Interactive Course. I've been viewing the five discs, and I'm very impressed.
First, this obviously wasn't just thrown together quickly to take advantage of the 3D boom. The creators have put real effort into it. They didn't just shoot a lecturer in 3D either. Scenes are selected to specifically show off the technique or effect, and includes interiors with near backgrounds, and exteriors with far backgrounds.

The media files on the disc are all in side by side Quicktimes, and are played using the included Frame Forge StereoPlayer. I was viewing on a MacBook, and it was very easy to view, and some of the least amount of ghosting in color anaglyph I've seen on a computer. (partly because they reduced the color saturation a lot). If you have a 3D monitor that can interpret the side by side files directly then you can view the DVD with the glasses that fit your monitor type, polarized or shutter glasses.
It includes not just good examples, but bad examples too, so you can see exactly how screen plane violations and too much divergence get you into trouble. More to the point, there is so much about 3D that is difficult to explain well in a book, without clear visuals from multiple viewpoints, such as "dynamic floating windows". Each chapter illuminates each instructional point with not just samples shots, but also diagrams from the side or above and graphic schematics of the scene. I particularly liked the section on the importance of higher resolution for good stereo photography--it made it very clear how compression can lose the small detail that is so important for creating depth that goes beyond making layers, to depth that appears rounded and life like.

I've almost forgotten one of the best features of the package, the Stereo 3D Lab, which uses the Frame Forge Pre Visualization program. This lab comes complete with it's own set of audio guided lessons, only here, you can manipulate the controls on a virtual camera rig, either a side by side rig or a beamsplitter mirror rig. The view from the camera is simulated and updated instantly, so you can experiment with differing interaxials and convergences, angles of view, distances, etc. Very cool.

At this point, I'm supposed to say, but wait there's more-- 3 DVDs that are just interviews with leading people in stereoscopic production. At first I thought these would be filler, but I got a lot out of them.

At US$350, this is not cheap, nor an impulse buy for most people. But I think it's worth it. Not only is it less expensive than an actual hands on course, it is 950 minutes, or almost 17 hours of material! Plus you don't have to travel to where a course is being given. For someone who has been asked to plunge into 3D filmmaking for the first time, or for someone who is already on their way with a 3D project, and still knows they have a lot catch up on, this will be a great help. The best combination would be if one could view this DVD course simultaneous with having accessing to a 3D camera or rig or monitor, so you could try out the examples on your own right away. This combined with a hands on course, or combined with access to a 3D rig for a couple of days, would be ideal. Of course you could try out many of the examples here by using side by side video cameras, if you also have a way to capture and view the images you create in 3d. It's not ideal, but it would be great at really experiencing all the steps in the process.

Video Camera History

2009-02-16T13:10:00.000-08:00

A capsule history of video cameras, that focuses on their operation, I also posted to wikipedia. http://en.wikipedia.org/wiki/Professional_video_camera#History

Professional television camera history has two main lines: the gradual shrinking of the camera as it became more versatile and self contained; and a progression of sensors from large insensitive tubes to smaller, much more sensitive tubes and finally to very small, very sensitive solid state chip imagers. Cameras that contained their own recording mechanisms did not appear until the early 1980s.

Early studio television camera -- Gray box on right is the lens, gray box on top is the Viewfinder, sides are lowered to show internal electronics.

At the beginning, these cameras were very large devices, almost always in two sections. The camera section held the lens and tube pre-amps and other necessary electronics, and was connected with a large diameter multi-core cable to the rest of the camera electronics, usually mounted in a rack. The rack would be in a separate room in the studio, or in a remote truck. The camera head alone could not generate a video picture signal on its own. The video signal was output from the rack unit to the rest of the studio for switching and transmission. By the fifties, electronic miniaturization had progressed to the point where some monochrome cameras could operate stand alone and even be handheld. But the studio configuration remained, with the large cable bundle transmitting the signals back to the CCU (Camera Control Unit). The CCU in turn was used to align and operate the camera's functions, such as exposure, system timing, and video and black levels.

The first color cameras (1950s in America, early sixties in Europe), notably the RCA TK-40/41 series, were much more complex with their three (and in some models even four) pickup tubes, and the size and weight drastically increased. Handheld color cameras did not come into general use until the early 1970s, and the first ones were two pieces, a camera head shoulder unit that held the lens and tube section, and a backpack unit. The Ikegami HL-33 was the first of this type, but was followed a up by one piece cameras. These one piece cameras, (The HL-77 from Ikegami and the TK76 from RCA) made possible, in combination with portable 3/4" U-matic VCRs, the introduction of Electronic News Gathering (ENG), which very rapidly replaced the 16mm film cameras that had been the dominant method for capturing news events. This established the standard operation in the field of a two person news crew, one operating the camera, and one carrying the shoulder strapped U-matic recorder and a boom microphone. The control layout for the camera's most important functions was also established with these cameras, and continues to define an ENG camera to this day.

In the early 80s, the first cameras with on board cameras were brought to the market. The far more successful of these used the Betacam recording system. At first these cameras used pickup tubes, and the recorders were of the removable type. Models with CCD imagers came on the scene in the mid-80s. These brought multiple benefits. They were much more stable and less prone to drift than tube cameras, and didn't require a warm up or calibration time at the beginning of the day. They also were not prone to image burn in or streaking caused by bright lights. The early models did not have the resolution or color quality of their tube counterparts, but successive models quickly pulled ahead of tube technology. Eventually, cameras with the recorder permanently mated to the camera head became the norm for ENG.

Studio camera technology did not stand still during this period. The camera electronics shrunk, and CCD imagers replaced the pickup tubes. The thick multi-core cables connecting the camera head to the CCU were replaced in the late seventies with triax connections, a slender video cable that carried multiple video signals, intercom audio, and control circuits, and could be run for a mile or more. As the camera innards shrunk, the electronics no longer dictated the size of the enclosure. But the box shape remained, as it was necessary to hold the large studio lenses, teleprompters, studio viewfinder, and other paraphernalia needed for studio and sports production. Electronic Field Production cameras were often mounted in studio configurations inside a mounting cage. This cage supported the additional studio accessories.

In the late 90s, as HDTV broadcasting commenced, HDTV cameras suitable for news and general purpose work were introduced. Though they delivered much better image quality, their overall operation was identical to their standard def predecessors. New methods of recording for ENG cameras were introduced to supplant tape. Ikegami and Avid introduced EditCam in 1996, based on interchangeable hard drives. Panasonic introduced P2 cameras. These recorded a DVCPro signal on interchangeable flash card media. Several other databased recording systems were introduced, notably XDCam from Sony, and as of 2009, it remains to be seen what will become the predominant method of camera media for professional use in the 2010s.

ENG Video Camera Definition

2009-02-16T13:07:00.000-08:00

What's the difference between the big shoulder cameras pros use, and small handheld camcorders? Here's a piece I edited on Wikipedia that I liked so much, I thought I'd reprint it here.

Though by definition, ENG (Electronic News Gathering) video cameras were originally designed for use by news camera operators, these have become the dominant style of professional video camera for most uses, from shooting dramas to documentaries, from music videos to corporate training. While they have some similarities to the smaller consumer camcorder, the following differences should be noted:

* ENG cameras are larger and heavier, and usually supported by a shoulder stock on the cameraman's shoulder, taking the weight off of the hand, which is freed to operate the lens zoom control. The weight of the cameras also helps dampen small movements.
* 3 CCDs are used instead of one, one for each primary color
* They have interchangeable lenses.
* All settings, white balance, focus, and iris can be manually adjusted, and automatics can be completely disabled.
* The lens is focused manually and directly, without intermediate servo controls. However the lens zoom and focus can be operated with remote controls in a studio configuration.
* Professional connectors - BNC for video and XLR for audio. There are at least two XLR audio inputs.
* A complete timecode section is available, allowing time code presets; and multiple cameras can be timecode-synchronized with a cable.
* "Bars and tone" will be available in-camera (the color bars are SMPTE (Society of Motion Picture and Television Engineers) Bars, a reference signal that simplifies calibration of monitors and setting levels when duplicating and transmitting the picture.
* Recording is to a professional medium like some variant of Betacam or DVCPRO or Direct to disk recording or flash memory. If as in the latter two, it's a data recording, much higher data rates (or less compression) are used than in consumer devices.
* The camera is mounted on tripods and other supports with a quick release plate.
* A rotating behind the lens filter wheel, for selecting an 85A and neutral density filters.
* Controls that need quick access are on hard physical switches, not in menu selections.
* Gain Select, White/Black balance, color bar select, and record start controls are all in the same general place on the camera, irregardless of the camera manufacturer.
* Audio is adjusted manually, with easily accessed physical knobs.

Ten Tips for Better Web Videos

2008-09-12T11:49:00.000-07:00

The great thing about all the new camcorders out there is you don't have to be expert in the underlying tech to get a great result. Here are some simple tips to maximize the performance out of these small wonders.

First—Get Close - Television isn't quite the close-up medium it used to be, what with the popularity of big screens everywhere. But web video sure is. Get Close! Not chin to forehead close, but upper torso or head and shoulders close. People want to see you, not the junk in the background. If your camera has a zoom, backing the camera up and zooming in, is much more flattering to your features than placing the lens close to your face.

Second — Avoid Backlighting - Windows make horrible backgrounds. Daylight can be 800 times brighter than indoor light, and your camera can't cope. So your subject won't look like a silhouette set your camera so the daylight is coming from the side or behind the camera, but the window isn't visible in the picture.

Third — Minimize Noise - Good sound makes video look better! Web videos sound echo-ey and noisy, because the microphone is on the camera, and not close to the person's mouth. Check to see if your camcorder has an external microphone input. An inexpensive microphone from a Radio Shack or an electronics store that has a good camcorder dept. will work much better than the mike on the camera. A lapel mike like the one shown here is perfect.

Fourth—Use a Tripod - Steady does it! When using a camcorder, avoid hand-holding. Web compression software works better on a steady image, and a stable shot looks more professional all around. You can use a tripod, or even place the camera on a steady flat surface. On top of a box on a table works fine. The camera should be at the same height as your face. If cameras seem to make people look ten pounds heavier, shooting from below doubles that effect!

Fifth—Brighten Up! - The low light ability of modern cameras is astonishing. But if the picture looks grainy or blurry you may need more light. Or you may have plenty of light, say from overhead fluorescents, but everything looks flat. Indirect soft light coming in from a window to the side and to the front of the face, almost always gives a very pleasing look. (But not direct sunlight falling on the face -- and with care not to let the window itself show in the picture!)

Sixth—Move With Caution - The zoom lens is not a garden hose. Moving the camera around and zooming in and out will just give the audience motion sickness and be very hard to edit later. Hold -- roll tape -- pause tape, frame the next shot. If you’re not able to use a tripod, hand-held can work, thanks to cameras with anti-shake features. It's easier to handhold if you stick with a wide angle, brace against a wall or doorjamb.

Seventh—Lots of Variety - Insert shots! Close-ups and cut-aways are the meaty bites of the video stew. Get lots of detail shots of whatever you are describing verbally. Not only are they informative, insert shots break up the monotony of the single talking head shot. They’re invaluable as cut-aways when you need to shorten the video, and cover over the jarring jump in the edit. Hold each shot for ten seconds. It’s a lot easier to edit a shot shorter, than it is to make it longer.

Eighth—The Camera Sees Differently Than You Do - Don’t get the blues. Watch out for your scene looking overly red or too blue. It’s the result of mixing different kinds of light, such as sunlight with tungsten or fluorescent bulbs. Stick to one light source, so your camera's automatic function can balance to that. If you’re still having trouble, check your camera manual, looking for the section on how to set the white balance. Usually it’s a menu item, with Sun, cloudy, bulb or fluorescent tube icons representing different color casts.

Ninth—Not Everyone Can Be Woody Allen - If you're the one in front of the camera it's hard to do a good job behind the camera. Work with an associate who can both operate the camera, and give you feedback on your performance. Rehearse on tape, watch the result together, see what works, drop what doesn't.

Tenth—The Word Comes First - Write out what you plan to say, even if you're not going to read it word-for-word on camera. Writing it out organizes your thoughts, and helps maintain focus on the subject. Rehearse-out all those distracting "uhms" and "you-knows."

How many lights can I plug into this circuit?

2008-03-15T10:42:00.000-07:00

You're on location, in a house built in the 1940s. But you're worried about blowing fuses or popping a circuit breaker with the bright and hot lights from the nice Arrilite kit you brought.

You need a way to tell in advance, how to know when the next light you plug in will blow the circuit. You're not an electrician, you heard there was a formula, by some Ohm guy, but you have no idea what it is.

No matter -- There is a simple way to figure this out, and keep out of hot water (and in the light) with the homeowner.

It seems confusing, because the electrical draw of your light fixtures is expressed in Watts, while circuit capacity is marked in Amps. Ohm's Law is an electrical formula that electricians use to make this conversion, but in practical application, you don't really need to use a calculator for this sort of simple situation.

Let's start by looking at the situation in the house. A circuit is a single line of electrical supply, that is usually shared by several outlets or lights in the home. Each outlet is NOT a circuit! Instead, multiple outlets are shared by one circuit. Also, normally, all the outlets or lights in a room are not dedicated to a single circuit. They are usually spread across several rooms. In a two story house, the lights will usually be on circuits shared between floors. This seems illogical, until you realize what happens if the circuits were divided by floor. If that circuit blows, all the lights on that floor go out, and no one can see, until they can find the a flashlight, and get to the circuit breaker.

Fortunately, discovering the capacity of a circuit in a home is easy. First, find the circuit breaker panel. (The following refers solely to 120 Volt electrical service as commonly found in North America.) It might be in a utility closet or it might be on the back porch. If the home has a garage, it is often found there. Upon opening the panel, you'll normally find two rows of black switches, the circuit breakers. These have two digit numbers printed on them, normally a a 15 or a 20. That number is the number of Amps the circuit can safe handle, before the breaker trips off, cutting off the power. If the circuit breaker didn't do this, the wiring in the walls would overheat, and start a fire. This is a special effect we normally want to discourage -- and there are better ways to meet firemen.

If the house is older, built before the 1960s, and never been re-wired, it may have fuses. These are very often only 10 amps. NEVER replace a 10 amp fuse with a higher number fuse, this is very unsafe! If you're blowing fuses, it's for a reason. More current is being drawn than the circuit can safely handle without overheating.

The next puzzle is to figure out which outlets in the house are assigned to which circuits. If you're very fortunate, sometime in the past, someone else already figured this out for you, and filled in the blanks in the circuit description on the circuit breaker panel door. Sadly, we often find that we're the first persons to bother filling in this card. If that's the case, you have little choice but to experiment, and turn breakers off and on to determine which plugs they control. Before you start, make sure there is nothing plugged in or turned on that might be harmed by the loss, or sudden resumption of power. Home electronics, computers etc. Now you could have another crew member walk around the house with a light, plugging it in to every outlet, yelling out when the light is extinguished, as you flip breakers in turn. A slightly more elegant solution is to use a cheap AC outlet powered radio instead of a light. That'll preserve your vocal cords. It also works well if you don't have an assistant--although with a lot more steps as you walk back each time to move the radio's plug. But you needed some exercise anyways, right?

You'll notice too that in addition to the breakers marked 15 and 20, there are other breakers, with higher numbers, and ganged together as one switch. You don't need to test those, they're for high power items that are hardwired, or not plugged into standard outlets, such as clothes dryers, ovens and heaters. If you're lucky, all the outlet breakers will be 20 amp circuits, and the 15 amp breakers are just assigned to ceiling lights. As it is, you may discover that all the outlets in the house are assigned to as few as two or three breakers.

Now that you know what outlets are available on each circuit, all that's left is to figure out how many of your lights you can plug in to each circuit, staying safe, and not popping a breaker!

I use this simple rule of thumb-- Each amp is "equal" to 100 watts of 120 volt power. Now this isn't correct-- but this rule of thumb leaves a nice safety factor, as it's not really a good idea to load a circuit all the way up to its maximum amperage limit.

So if you plug in a 600 watt light, that takes up 6 of the amps on a 20 amp circuit. And if you plug in two more 600 watt lights, the total is 1800 watts, or 18 amps; you're still under the limit, and won't pop a breaker. But if you start with a 1000 watt light, you only are safe for one more 600 watt light -- another 600 watt light would be 2200 watts, and that's over 20 amps, using our rule of thumb with a built in safety factor. But you could plug in another 400 watt light. If you need more than this, you should find a stinger (AC extension cable) and move on to the next circuit.

A word of caution-- Always keep an eye open for what else might be plugged into the circuit. They need to be taken into account too. So if there's a computer that needs to be left on, on the circuit you need for a light, you have to accommodate it's load also. If the computer draws 500 watts, and it's a 20 amp circuit, then you only have 1500 watts available on that circuit. I really really recommend against sharing lights and a computer on a circuit though.

Watch out for these appliances, that draw much more power than most people realize: Hair dryers and curlers, laser printers, coffee pots etc. Laser printers are particularly sneaky, as they don't draw much power till they print, then suddenly you will see a 600 watt surge, and your lights go out!

Most all of this applies also to offices and commercial bldgs-- These often have sub breaker panels on individual floors. Be vigilant about not overloading circuits that might be shared among rooms, or down a hall. You don't want to shut down someone's computer when they're trying to meet a deadline! A gotcha you'll find in offices is a coffee pot on the other side of a wall in a break room you don't know about, but is on the same circuit you've plugged a 1000 watt chimera into!

Save Money! Shoot 35mm Film!

2008-03-15T10:41:00.001-07:00

One of the great myths of low budget filmmaking is that the cheapest way to make a movie is by using a cheap camera and a smaller film guage, or to shoot on tape.

But it's not always true, if your aim is to create a film to watch in a theater-- This requires getting to a 35 mm print somehow.
Shooting in 35mm may well be the cheapest way to get to a 35mm finish. It has been in my experience with some type of projects.

Don't be fooled by the cost of tape stock vs the cost of film stock. The costs of making a digital intermediate and then a print out to 35mm can be far more than these costs. Just as the cost of making a blow up added greatly to the cost of 16mm origination.

Is this a documentary project or a scripted short? What do you anticipate your shooting ratio to be? If it's not a documentary, and you're going to have a reasonable ratio, say 7 to one or less, then you may be better off shooting 35mm

A lot depends on the local situation there for renting cameras and buying film. Here in the US, rental facilities always have older cameras, such as an Arri BL2 or BLIII sitting on a shelf, or if you don't need sync dialog sound, Arri IICs. In Italy I'll bet you can find great deals on Cameflexes. People starting out often turn up their noses at "Old" cameras, forgetting all the great films that were shot in the 70s and 80s with these "old" cameras.

Also, here we can get "Short Ends" and "Re-Cans" which are film cans left over from productions, and there are places that specialize in selling that here. It's not difficult to get 400' rolls that are much cheaper than new. The film is snip tested before they sell it to you.

The 35mm film/processing/workprint/neg cut process is very simple and well understood. You could even avoid expensive tape transfers for Non Linear editing, and cut on a flat bed. People are giving away flat bed editors. They take up a lot of space and there aren't many buyers, they'd rather see someone using it then send it to the recycling center.

Several years ago I was DP (and AC, and Loader for much of the shoot!) on a small low budget film, "FLOSS". I convinced the producer, that since he was in this to make a movie that could be shown in a theater, the best and easiest, and even cheapest route to go was 35mm origination.

Then we used the same techniques low budget film producers have used for decades-- getting bargains, getting people to work for little or no money, and as much for free as possible. Because it's the labor and all the other expenses that constitute most of the budget of the film, not the film stock.

Still when you are operating on this level, there are hard costs you usually can't avoid, namely film stock and processing, and camera rental (unless your DP is coming with his own lesson.)

We scheduled our shoot to start right after christmas, when most TV Series and movies are on breaks. This enabled us to get a great deal on a 35mm camera package from a hollywood camera rental facility. A 35mm Arri BLII with 5 lenses, batteries, 4 mags, Video tap, matte box, everything, for $4900 for 3 weeks!

Sure, the BLII is an old camera. But a heck of a lot of great films were shot in the late seventies early eighties with BLII's, right?

Next up, Film. We bought short ends from Dr Raw Stock in Los Angeles. Here was another example of how shooting in 35mm has advantages over 16mm. By choosing a stock that was popular with multi camera sitcoms, we were able to easily get all the 400' "short ends" we needed. The reason for this is that the multicamera film shows change loads when they get below 500' of film in their 1000 and 2000' loads. Whereas it is not nearly as easy to find a short end of 400' of 16mm, since 400' is the largest load almost everyone ever shoots with.

In all, our stock and processing costs were under $35k. We kept to a low shooting ratio as we knew our actors really werent' going to get that much better after 3 takes. We did more rehearsals, instead of the popular fad for rehearsing on film.

Lighting was a lot easier on Floss, because we weren't shooting on Digital Video. (Low cost HD cameras were still a few years away, the Sony CineAlta HDCAM would have blown Floss's shooting budget in 3 days. We basically lit from a couple of kits, with a 1k chimera as our key light, usually no fill light at all, and some accent lighting. To our eye, the scenes looked to contrasty to someone used to shooting on video, but the bounce from the walls provided nearly all the shadow fill we needed in most scenes.

This enabled us to move very fast and quick, yet looked great for a drama like Floss. In some scenes, such as a torture scene in a warehouse, we used a single hard key. But mostly it was just the chimera, and some rim light, and background lights. Locations were picked for their ability to look good with minimal lighting. We were able to paint the Dental Office so that it wouldn't have blinding white walls, as is typical. Then we used a large house for all the home scenes that gave us several different looks, and also had a lot of wood paneling, which looks good with minimal lighting effort.

Just putting an idea in your head. If you have to shoot a lot of footage, then this won't work. But people assume that digital is always cheaper, and yet make that conclusion without running the numbers on a spreadsheet, using real world quotes of what you can find great equipment for.

FAST FILTER FACTS

2008-03-08T11:36:00.000-08:00

The primary colors of light are different from the ones for Paint and Ink.

They are:
Blue, Green and Red.
Their complementary colors are
Yellow, Magenta and Cyan.

Primary Colors: _ Complementary Colors"

BLUE ________ yellow (GREEN+RED)

GREEN _______ magenta (BLUE+RED)

RED ________ cyan (BLUE+GREEN)

FILTER LAWS:
A filter transmits its own color.
A filter absorbs its complementary color.
A filter of a complementary color transmits its two adjacent primaraies, and absorbs its complementary primary color.

For Black and White photography:
To lighten a color, use a filter of the same color.
To darken a color, use a filter of the complementary color.

Behaviour of light through filters:

Transmittance- Light allowed to pass through the filter (A red filter passes red)
Absorption - Light absorbed by the filter (A UV filter absorbs UV)
Refraction - Bending of light passing through glass to air or glass to glass. Diopters, Prisms
Diffraction- Bending of light passing sharp opaque edge. (Star filters)
Diffusion - Breaking up of light rays from one direction into many directions,(Fog, Diffusion)
Dispersion - Breaking up of light rays passing through different mediums. (Oil, etc.)
Filter Types

Conversion Filters -

Used to convert Tungsten Color Film to Daylight (85 filter,Orange) or to convert Daylight Color Film to Tungsten Light (80A or 80B, Blue)

Light Balancing Filters -

The 81 (yellowish) and 82 (bluish) series are used to raise or lower the Kelving temperature of the light in smaller increments to match the balance of the film.

Color Compensation Filters -

Used singly or in Combination to get any color correction to any degree desired.

Polarizing Filters -

Used to remove reflections from non-specular surfaces. Also makes colors more vibrant by removing surface glare.

Nuetral Density Filters -

Used to reduce exposure. They absorb all colors equally.

Combination Filters -

Two different types in single filter, such as a warming filter and a soft, or cooling filter and a nuetral density. Cuts down on number of optical surfaces in front of lens.

Filter Factors:

These numbers, which are supplied with the filter, are used to adjust exposure multiply the number by the exposure or ASA of the film.

For example, a filter factor of 1.5 would reguire 50% more exposure. So you would open the stop by half, or slow the shutter speed by half a stop. Easiest way to work is to change the ASA on your meter to a number 50% lower. So 400 film would behave as if it were 300 film. A factor of two would require a full stop adjustment. You would rerate your film from 400 to 200.

Shaping the Light with flags, silks and cukes-- Film Grip 101

2008-03-06T11:54:00.000-08:00

Grip gear can be as important to crafting the lighting for a scene as the light fixtures. Often, more important--you can block, diffuse, shape, bounce and breakup the light using these tools. This is very crucial in creating a textured, realistic (or fantastic) look that is visually much more interesting than just blasting the light onto your subject.

Here's a look at the most essential grip items. These are all available to rent for very reasonable rates at film lighting rental companies. You can rent just a few items, or complete packages, even a grip truck to carry it all to the set. Or you may wish to buy. I’ve kept grip gear far longer than any camera gear. It never goes obsolete.

Century, or “C” stands are the most essential piece of grip gear:

Gobo Heads mount on top of the C-Stands:

These are used to hold extension arms:

Which in turn, hold everything else. The arms have fixed gobo heads with multiple holes for gripping flags, nets, silks, etc shown below :

Lighting Nets come as singles or doubles, like lighting instrument scrims, except the netting is thread, instead of wire. A red bordered net is a double, and cuts the light one stop. A green bordered net is a single, and cuts light by half a stop. Flags, nets, and silks come in these sizes: 18”x24”; 24”x36” ; 36×48 and 4’x4’.

Flags, (or cutters) are used to block or cut the light. You might use one to keep a light from shining into the camera lens, or to shadow a wall or another part of the scene.A silk is similar to a flag, but the black fabric is replaced with silk to diffuse rather than block light. Most of the time it is used to create a larger light source that throws softer edged shadows. But it can work as a flag, but one that makes a brighter shadow. It will cut more light than a net, and will also bounce more light into the scene.

Smaller versions of all three are called dots or fingers. These are used more for table top or product shots, but are also useful for many other purposes.

Long narrow flags are called cutters. These are usually 18″ to 24″ wide, and 4′ to 8′ long. When used as a “topper”, they block light from above, casting a horizontal shadow along the top of a set wall.

A cukoloris is a wood panel with random shapes cut into it. It’s used to break up light. Most of the time the light is focused through it so as to create soft, vaguely defined shadows, and not a hard edged pattern. Often these are made up quickly on the set by cutting random shapes into Foamcore boards.

Baby plates are special light stands that can be nailed to an apple box or a wall:

Reflectors are large 42” square boards mounted in a yoke, with a diffused silver side, and a shiny silver side.

They’re used outdoors to manipulate sunlight.

Butterfly overhead frames can hold large silks or nets for diffusing or reducing sunlight, or solid white or silver “Griffolyn” tarps for bouncing light, or large black "griffs" for blocking light.

They're strapped into 6’x6’, 8'x8' 12'×12’, and 20'×20’ frames and are held up by large “high roller” stands:

To keep all these stands from tipping over or blowing away, sandbags are placed on the legs.

Sandbags are usually available in 5, 15, 25 and 35 lb weights. When used with large reflectors or butterfly frames outdoors, several of the heaviest ones may be needed on each stand to keep everyone safe when it is windy.

Apple boxes have numerous uses from lifting props, to making actors taller, to seats for the crew. They come in full, half, quarter and pancake sizes.

Collapsible reflectors made of fabric are usually called Flexfill's or Photoflexes (brand names). Sizes range from small 24" diameter discs, unfolded, to 48" diameter, or even 48" x 96" rounded-off rectangles. The most common type are white on one side and silver on the other. But gold sided and other color variations are also available. They're light enough to hand hold, or can be clamped to a stand.

Grip Blankets (also called Sound-blankets) are multi-purpose, from deadening sound reflections to protecting location floors and furniture. Also called furniture pads, they’re usually considerably heavier than the ones found in moving stores.

This is just a very basic overview of the world of film grip equipment, to get you started. There's much more, and I'll be expanding on most of these in future posts.

Who's afraid of the big bad rental house?

2008-03-01T23:56:00.000-08:00

HD / Video Camera
Rental Checklist

When I talk to people just getting into advanced video production, I’m always struck by how obsessed they are with having to buy their own gear. And of course they’re usually stunned at the cost of all of it. Though I think a five thousand dollar camera is cheap, relative to the cost of the gear used to produce feature films and commercials, it’s still expensive for an individual.

So I ask them — “How many movie cameras do you think Steven Spielberg or Peter Jackson own?”

The answer is, probably none–or at least none that they use to shoot their movies. They rent. While there are a very few directors who own their own gear, (Robert Rodriquez and George Lucas come to mind), these are by far both the historical and present exception. Producers generally rent all of it, whether they are shooting a commercial, a corporate video, or a feature film.

For that matter, if you want to shoot with Panavision equipment, you have no choice, as their cameras and lenses are only rented, never sold.

The reasons are many. Prime among them is that they just don’t use such an expensive item often enough to make it worthwhile. It’s like buying a motor home that you’ll only take out once a year. Also, no one camera or lens is perfect for every task. And equipment is updated and obsoleted all the time. By renting, a producer can always have the most up to date equipment– and know that it’s in perfect operating order, completely checked out by the rental company before it’s picked up. Plus there’s all the ancillary lenses, specialty cameras, camera mounts, filters etc etc that need to be rented anyways. That gear can easily end up costing as much as the camera alone. So it makes sense to rent it all as one big package. When the production wraps, it can all be returned to the rental house– no concern about paying for a place to store it, or pay for maintenance on the inevitable wear and tear that occurs!

However–when renting a video camera, it’s vital to check it out before leaving the rental facility.
–The personnel there will be glad to see that you are concerned about their equipment.
–They’ll likely have a space set aside just for customers to check out gear.

Perform the following checks:

Batteries charged?
Camera powers on, from both batteries and AC adaptor?
Image in viewfinder? Image from monitor out of camera to a monitor?
If renting a monitor, is the monitor working? Set up monitor to color bars from camera to test.
Insert tape, make test recording. Play back test on color monitor.
Lens Check. Check for dirt and scratches, front AND back of lens.
–If using filters ensure that filters fit on lens, no stripped threads.
–Check all rented filters for scratches.
Back focus check. Use a backfocus chart to check backfocus of zoom from full telephoto to full wide.
Check condition of additional lenses you are renting. Make sure they fit on the cameras and are correct type, and cable connections fit.
Check that audio gear works in connection to camera. Do an audio playback test.
Tripod mounting plate in case, and correct one for camera, with mounting screws?

If unsure of any camera function, or operation, ASK QUESTIONS!

Do it now before you are on location.
Get a contact phone number for after hours problems.

Why I'm Here, and So Can You!

2008-03-01T21:21:00.000-08:00

Hi, I’m Steven Bradford, and I’ve been a professional cameraman for over 25 years. I created this blog to share some of my experience with lighting and camera work, whether for film or digital video. I’ll be posting articles explaining both underlying theory for lighting, and useful tips and techniques for getting great pictures.

Anyone who has met me knows I love to share my experiences and knowledge, especially anything to do with my career choice as a cameraman. I’ve had some static web pages up for a long time, and I’ve taught workshops and college courses in film production. I also was the director of a film degree program at a four year college. Now I’m back to work as a full time free lance Director of Photography.

Over the years, I’ve come up with what I think are some clear and practical explanations of lighting and camera concepts. My goal is to use this blog to put those out there to a wide audience and with luck get some feedback and learn some new things too.

Here's my most current demo reel, with film and video examples from productions I've shot, in film and video.

All original material on this site created by me is copyrighted to me, Steven Bradford, and I reserve reproduction rights. Other websites and blogs are free to directly link to this site or to the pages on it. Images and text may only be posted or quoted on another web site if they link back to the original page where they appeared on my site, and show a credit to me, or to www.lenses-and-lights.com at the linking page.

If you are a teacher, and would like to use one of my pages in your classroom, you may display it directly from www.lenses-and-lights.com on a screen in your classroom with out seeking prior permission for me. This applies to K-12 and college uses, whether your school is a private, public, or proprietary institution.

Contact me directly at bradford@seanet.com for any other uses, including printing out for distribution to a class.