Digital Infrared Black and White

Infrared light is by definition “invisible” light that resides above the threshold of human vision. It is not Kirilian, or aura photography, though it sometimes creates an ethereal, ghost-like representation that can be quit seductive. Like most things photographic that appear visionary, there is a bit of science behind the magic. This involves disabling the “normal” operation of the camera to allow infrared level light to record, something that is usually blocked by an IR cutout filter placed in the light path from lens to sensor. It turns out that without this internal filter the digital image would be “polluted” with IR, and would, for most people, create less than desirable image quality. In truth, digtal sensors often have considerably more infrared sensitivity than you might think.

In most cameras the filter is “hard wired” into the construction, which means that if you remove it you now have a fulltime IR capable camera that cannot be returned to normal use. This must be done by a service company that knows its stuff; it’s something you cannot do on your own. Some cameras come IR dedicated, mostly those used by law enforcement agencies for gathering forensic evidence. A very few can be converted in do-it-yourself fashion, such as the Sigma model DSLRs, where you can remove the lens and literally pick out the IR filter (which doubles as a dust filter), albeit very carefully, and reinsert it later. Those who are true IR fans would do well to investigate the cameras used by police departments; as of this writing Fuji makes a few such models.

Another step that needs to be taken to capture true IR images is placing a filter over the camera lens, something that is uncommon for most digital photography (as most filter effects can be added later in software.) If you shoot IR without any filters with an altered camera you will get a sort of reverse pollution of visible light, something that certainly diminishes the IR effect.

There are three types of basic filters that can be used, with one being quite expensive and, in my experience, unnecessary to gain the effect. The filters used include a red filter, something black and white film photographers might still have in their closet, (a Wratten 25A), plus two filters that block more and more visible light and do not allow for image recording below the infrared threshold. The two other filters, which go under various names and codes according to the filter maker’s markings, block light under 700 nanometers and 830 nanometers (and some higher) on the spectrum; in other words, progressively more IR light and much less visible light. The highest blocking filter (830nm and above) gets very expensive and is only for well-heeled purists and aficionados.

The effects achieved with the two blocking filters can be amazing but you cannot see what’s going on in the viewfinder, which means that you have to frame and focus prior to placing the filter over the lens and making the exposure. Some photographers view over the top of the camera for an approximate framing. The red filter, while not as “pure” lets you at least see what’s going on in the finder. If you are an IR fan then the blockers will be your choice—those who dabble in it, as I do, will find the red filter is fine.

Exposure is unusual as well. It has nothing to do with making readings and using metering patterns, since you are not dealing entirely or at all with visible light. It’s a strange concept, but that’s also part of the IR mystique—being out of normal bounds of having to read exposures and balance highlight and shadow. The best way to work IR exposures is to start at somewhere around f/11 at 1/125 second and then review the image after exposure and adjust accordingly. The view in the finder is quite different than you’d expect, so you will have to gain experience with what a processed IR image looks like according to a certain exposure level. This is the only way you will be able to make predictions about what the correct exposure might be, or at least what it should look like upon playback.

There is something in IR known as a “focus offset”, which means IR light bends a bit differently and may arrive at the sensor plane in different ways than visible focusing. This will become critical when doing close-ups, but does not have much effect, in my experience, for photos made beyond six feet. I often shoot at f/11 or narrower with a fairly wide angle lens just to take up that slack, changing the shutter speed accordingly.

The procedure some use for shooting is to purchase a filter that is a bit larger than the largest diameter lens they own (thus it can be used on all the lenses owned). They first frame and focus the tripod-mounted camera, then hold the filter over the lens when the exposure is made. This procedure takes care as it can result in some light leak from the corners, but that is usually eliminated with some practice in proper holding of the filter. Exposure is set manually. Some bold photographers shoot handheld in the same fashion, viewing over the top of the camera to yield an approximate framing and shooting a bit wider than they normally would for a “fudge” factor. They figure they can apply a more specific cropping later.

IR black and white has always been near and dear to landscape photographers, and now that high-speed IR black and white film has been discontinued by major film makers digital seems the only way to go.

Operation Information Overload

The pace of change in photography these days is breathtaking, photographers wondering when it will relent. Guess what—it won’t. As competition on all levels and product lines continues to grow, the pressure on manufacturers to innovate will be even greater. Long ago these software and hardware makers realized that as products and ideas become commodities the only way to realize profit was via change, with innovation leading the way. That’s why you can set your clock on when software will move to the next version or when the megapixel and sensor size ping pong match will start all over again. Even with some consolidations and buyouts in the works there still will be new players who see enough gold in the digital hills to keep the momentum going.

There are many ways to stay informed. There are web sites that dedicate 10,000 words to point and shoot cameras, and enough digicam orgs and bloggers out who fill every free hour of the day churning out reports for anyone so inclined to read them. But most people have a life, and reading the arcane and the obvious about every aspect of a camera, software or printer is not what they tend to do.

For most folks photography is a pleasant pastime, a part of holidays or special events that records memories. For travelers it’s a way of bringing back trophy shots of their trips. And for the enthusiast it’s a way to show a creative side, one that helps them escape the everyday and perhaps even put some bread on the table. For most of us, photography is an integral part of the social fabric, one that has been passed onto us by generations before as a valid way to keep close the memories of their families and individual lives.

For the many of the years I have been involved with reporting on all this, photography had been regarded as a “mature” industry, one that could be counted on to continue to grow, not fluctuate much from year to year. This point of view all seems rather naïve now, what with the pace of change the consumer electronics component brought to the mix.

We have been asked to learn many new things, to grasp the meaning of megapixels and how various levels of resolution should be put to use. We have been required to become computer savvy beyond the simple tasks of sending emails and downloading recipes from the web. Terms like optical stabilization and shutter lag, technology so obscure that only pure techies even considered them only a few years ago, are now part of the parlance. In short, we have been engaged in Operation Information Overload, and thrown a few curves in the bargain.

While the benefits of digital are many there are also a few dark sides to all this growth. One example would be upgrades. In the past that might have meant getting a camera with a better lens, or switching over to an SLR. Now it might mean that the memory card that works today might not work in a future camera with the same size memory card slot, a switch in capability without a change in format. Or it could mean buying a new computer and discovering that all the software you already own won’t operate well, or at all, in the new operating system. (Indeed, Adobe just announced they will only be developing future software for Intel-based Macs—the rest can go swim.) Or that the Raw files shot today might not be capable of being read a few years down the road. In some cases the changes are proper responses to new and better ways of doing things. In others, viewed through an admittedly cynical eye, it’s a case of flipping solely for the sake of getting us to dig into our pocket once again.

It’s selling soccer moms cameras with very impressive integral long range zooms so they can catch the action as their daughter streaks in for a goal, only to find that the camera’s intolerable shutter lag makes any hope of actually getting the shot they want slim indeed. It’s telling folks that an 8 megapixel camera can get them great 11x14 prints, only to trump that with 10 and 12 MP cameras a year or two later. It’s offering inkjet printers and even some kiosk setups that produce prints that are known to fade so quickly that future generations will never see the images from the family’s past. Indeed, one of the greatest fears folks seem to have about digital photography is that it is as temporal as their hard drive and as a corruptible as a cheap CD.

Yet, we have all taken to digital in droves, a case of technology replacement that has shocked even futurists who are paid to know better. The advantages of digital are legion and most folks quickly understood the benefits of this new form of photography. Walk through any tourist site these days and all you see are digicams; go to any family occasion and that night you’ll be able to look at, download and even order prints right off the web. There are literally billions of images loaded on servers the world over, with new personal sites and public sharing spaces coming on line every day. Digital has changed photography forever, and there’s no return to the old days, despite some grumbling from some pros and old guard film fans.

So, how do we sort out all the confusing jargon and make it less of a grind? When will we finally arrive at some standards that all can agree to so that we can make some judgments about what’s best for us and the type of images we want to make?

In many cases we will vote with our wallets and certain systems and companies will prevail. And with all the blogs and forums out there, savvy consumers will have their voices heard as well. But for now, Operation Information Overload goes on, and on.

Copyright George Schaub 2009. All Rights Reserved.