Monday, May 27, 2013

The Nikon 55mm f/1.2 lens is anything but "normal"

A nuance that's forgotten about film-based photography was the endless challenge of film speed. We wanted to make prints with great resolution at large sizes, but to do that we needed to use film that was "slow" in reacting to light. You see, to make a proper exposure with film, enough photons  have to strike enough molecules of light-sensitive silver bromide/halide (or color film dye layers). The finer the apparent "grain", or resolution, of the film, the more densely packed the granules of silver salts were and thus the greater amount of light required to expose each shot sufficiently.

Today's digital cameras largely ignore "speed ratings" as their electronic sensors can see quite well in even very low light. Light levels that are now "normal" for image-taking. But back in the day, a roll of 1936 Kodachrome transparency film had an ASA/ISO value of 10. To put it in perspective, shooting original Kodachrome meant exposures on a very bright, sunny day of 1/60th of a second shutter speed at f/5.6 lens apertures. Even a dull day meant putting the camera on a tripod. Sports? Not easy.

That's why your elder film camera users/collectors get so excited about "fast" prime lenses instead of great zoom lenses. For us, the extra one-half to one full stop of light gathering ability at minimum aperture was the difference between using a tripod or not. Old habits will die with us. Even though a 135mm, f/3.5 lens shot brilliant, clear images, we held out for a f/2.8 version to buy. These days f/3.5 or f/4 maximum openings on a lens is considered fast (enough).

So, OK, now let's get to Nikon here. Partly to help with the needs of professional photographers shooting in varying lighting conditions and party to show-off their manufacturing prowess, most film camera manufacturers - especially Nikon - offered a few very high speed (and coincidentally very expensive) versions of lenses in the most popular or useful focal lengths. 

For "prime" lenses (what we called "normal") of around 50mm (1x magnification on a 35mm camera), you generally had two lens speeds from which to choose; something around an f/2.0 Nikkor, and a "faster" lens of f/1.4 Nikkor. Either lens took great images at shooting apertures of f/8 or so. Ah, but that extra light-gathering of the f/1.4 might get you a better exposed negative in lower light. Average consumers swallowed hard and bought the f/2.0, well-heeled consumers and pros opted for the f/1.4.

Then in 1965, Nikon introduced a 55mm f/1.2 lens. A beast of glass and brass. It allowed you to shoot in very low light when you needed it and in any light otherwise. It was big, heavy and well outside of the price range for anyone other than a pro with paying customers.

The other thing a lens with such a large minimum aperture offered was a razor thin depth of focus ability. When you focus a lens you're moving an area of sharpness forward and back from the camera's position. With a lens set to f/4, that area is decently large (maybe a few feet at distance). With an f/1.2 lens that area of focus is only a few inches wide when you shoot images closer-up; fabulous for shallow depth of field images in portraiture. Shallow as in you could have one eye in focus on someone's face, their other one blurred kind of effect. Today, you'd simply whip open Photoshop and add Gaussian blur to an area. Not back in 1965, it was all done live on film (or in the darkroom if you had one).

The Nikon 55mm f/1.2 of 1965 was a bit longer focal length "normal" lens. This was done to aid construction to accommodate the large mirror box of an SLR camera in those days. The lens didn't need to protrude into the mirror box as much. Optical formulas were worked out by hand, not computer then.

By 1977 Nikon had developed a 58mm version designed with special aspherical elements (more showing off). Marked the Noct-Nikkor (Noct meaning night) the lens improved the cancelling ability for the prominent flairing and coma effects typically produced by lenses of the f/1.2 variety when shot at full aperature. Of course, nowadays, we would WANT those in-camera defects.

 The final 50mm AI variant came along in 1978 just as film speeds with tighter grain arrived. The days of the Nikon f/1.2 normal lens ended in that year. Too bad. They were marvels of optical construction, the likes of which we may never see again.

Friday, May 17, 2013

"Photo paper", not photo paper.

Short story.

Visited a nice second-hand store. After cruising the aisles for a few minutes, I knew I wouldn't find any vintage cameras about. Oh, well. On my way to the exit, I see something out of the corner of my eye; a familiar yellow box with red lettering: It just screams Eastman Kodak. I recognize it as being a box of some kind of photo paper. From the looks of it, not too old (in a relative sense compared to my own age). The box was in a glass presentation case, the reason why it needed secure storage I could not guess.

I move to it to get a good look. Cool. It's a box of Polycontrast Rapid RC II photo paper. 250 sheets. Five bucks for the box, I'm in. I ask a clerk for help in finding someone who could open the case to show me the box.

A very young woman with several facial piercings soon arrives with the keys to the cabinet. She reaches in and does her best to assist the potential sale on her part with some chatter. Things like, "It looks almost new. There's plenty of paper inside for printing." I nod knowingly and wait for her to present the box to me for a quick examination on the way to the checkout counter. Instead, she cradles the box with one hand, and before I can stop her, she lifts off the top of the box. I see white paper.


I'm gurgling some kind of incoherent response while my face contorts in a questioning look. "Why did you just do that? Are you stupid?" She sees my confused expression and quickly states, "It's paper for printing photos on an inkjet. You know, Kodak photo paper. Like at Office Depot." She draws out the words "photo paper" slowly in the hope that I would understand her better.

"See, it says it right here, photo paper." She gestures with her index finder adorned with a white skull on shiny black fingernail polish. "Photo paper." Thinking I need some further visual stimulus to get her meaning, she lifts up about fifty sheets from the box and fans them back. I imagine billions of atomic exchanges going on as each sheet gets full exposure.

I finally blurt out, "Yes! It's PHOTO PAPER!" Now it's her turn to look at me with a furled brow. "Right, photo paper," she finally nods in agreement.

I take a cleansing breath and say, very calmly I might add, "No, you don't understand. Light-sensitive photo paper. By opening the box in the store in this light, you ruin the paper's ability to be used to print photos. You might as well toss that in the garbage now."

Oh, yeah. Whoosh. Right over her head. She looks down and sees (to her) ordinary white paper. She looks back up at me.

"Look," I say, "this kind of paper was used in photographic DARKROOMS. It's a special kind of paper with a thin coating - an invisible coating - that must be kept in the dark until its ready to be used. When you project a negative on it - in the dark - where the light strikes an area of the paper, it will eventually turn that part black during chemical developing and fixing and . . . ".

Whoosh again. Well THAT little lecture didn't help. Her expression remains fixed and befuddled.

"Photo paper?," She says. "Photo paper," I reply. She turns her head slightly to one side. She takes on a thousand-mile stare. I begin to back slowly away from the counter. I smile and give a little wave. "Thanks, but I'll pass on the . . . photo paper."

As I turned to go, she looks down and fans a stack of sheets again, perhaps looking for some confirmation of what I was talking about.