Pancake lenses. Not many people use it nowadays, preferring the do-all zoom lenses. Going back to the old days when photographers would carry one prime lens per camera, and still be able to take amazing photographers, there is nothing a prime cannot do in the hands of someone with the right photographic vision. In short, nothing wrong with a pancake lens. In fact I love pancakes because it keeps the camera side profile smaller, making it possible to squeeze a pro-body with built in grip into a small bag. And most of the time you can zoom with your feet anyway.
A pancake lens is the name given to low profile lenses, normally around the 50mm focal length range. Up for this test are the two that I own. First up is a Nikkor 50mm f1.8 AIS. Now there are many versions of this lens, and the 0.60m minimum focal length version is the one I have, which is noticeably shorter than the other models. The other lens I have been using quite a bit is a Voigtlander 40mm f2 SL ULTRON. Yes a mouthful, I’ll just call it AIS and ULTRON for the short version hereforth. They’re both manual lenses. And they only meter on Nikon’s semi pro bodies like the D300/D700 and up.
This is not meant to be a full on test, so I will not bother to perform an exhaustive test on it. On the question of bokeh, I have noticed that the ULTRON has this harsh donut shaped bokeh, perhaps because of the Aspherical element in the lens. But I’m not a bokeh freak so it is not an issue for me.