Approaches to Afocal Photography
By Bjørn Rørslett
Many people have contacted me wondering how the afocal images shown on my web pages were obtained. When I told them the "secret", most simply laughed and thought I was pulling their collective leg. So much for being sincere. Seems I have to publish the "method" in detail after all.
As I wrote in the Introduction to Far Side, refractory processes take place in Nature all the time. This is essential to afocal photography, thus,
"Afocal photography, another lensless approach, doesn't use an aperture at all and the imaging rays are recorded directly onto the medium. If all rays striking the medium are randomly orientated there will be no perceptible density variation in the image and no meaningful photograph can result. On the other hand, if the rays are not random at least within a sector of space, variations of image density occur to give rise to a photographic image".
People still didn't get it. Obviously, I have to be more explicit. Thus, the images below show the "equipment" I used for taking my afocal images. This is the truth, the whole truth and (almost) nothing but the truth, folks. I said "almost" because a b/w recording media cannot exhibit colours without a certain amount of digital tweaking. This is obtained simply by scanning the b/w record as a colour image and subsequently "massaging" the tonality curves in Photoshop.
|
| Essentials of Afocal Photography I: Sheets of b/w photo paper, an 8x10" film holder and a flash. Load the film holder with photo paper and expose the sheets at will. No lens, no aperture, just pure afocal photography! For daredevils, I recommend substituting 120 format print film for the b/w paper and a roll-film holder for the sheet-film cassette (in fact, I have tried this too). Be warned though that only the sheet-film holder can be used under water! |
Why the flash? Well, you have to stack the odds in your favour. A water surface refracts light rays to an amazing degree, but the "image" focused by the water surface jumps back and forth in spatial location all the time. Without the flash, you'll be hard pressed to get a clear image at all because the refractory processes "smear" the potential image. Basically you need a short exposure and that's what the flash brings about. However, I have obtained quite good images at night without the flash so it's not essential for acquiring afocal images. Also, some afocal images I did during day-time were captured without using a flash at all because the sun was up.
|
| Essentials of Afocal Photography II: Nikonos body, without lens. This is my setup for afocal UV photography under water. |
Lest you should exclaim "Gotcha - He's using a Lens", I beg you to examine the picture displayed above. Yes, it is a Nikonos-II camera (essential if film is to be brought under water), and yes, there is the casing of an 15mm Nikonos lens mounted on it, but where is the lens itself? It simply isn't there because I removed the optics of a drowned UW-Nikkor 15 mm and kept the casing for experimental use. In lieu of a lens, there is a Hoya U-360 visually opaque filter placed inside the lens casing. This filter, appearing virtually black, is transparent to UV rays. I load the Nikonos either with with Fuji RTP (my standard film for UV colour photography), or with Fuji SG100 print film, and happily set out shooting afocal images under water. Count on a very small ratio of keepers ...
|
Sunray Refractions at Water Surface Afocal underwater, using stacked ND400 and ND 4 filters, Fuji Superia 800 film. Water surface-mediated "light flashes" are amongst the easiest motifs to capture with afocal methods. Perhaps you get a 1:100 keeper ratio, which for this kind of work is excellent ... © Bjørn Rørslett/NN 2002 |
