Playing with the Cat. The Nikkon 500mm.

Nikkon's 500mm f8 Catadioptric, that is...

This old cat lens is built like a tank but unfortunately also performs like one. It's an odd lens, this. No aperture control, no auto-focus, no gizmo's at all, but wonderfully light and compact. Yet the image quality is poor. 

Its over thirty years old now, and when I used this with film I more or less gave up on it, packed it away and forgot about it. Too many problems. Severe fall off, so slow you need LOTS of light for a decent exposure, and very, very hard to focus with critically shallow DoF. Yet the mirror design of this lens produces unique bokeh, giving OoF areas especially in the highlights, a ring-donut shape. I rather like the look, but it's a look that some hate.   

So, yesterday, as the band were performing at a local school fete I decided to release it from its solitary confinement in the loft and stuck it on the D90 just for fun. Reasoning that the  smaller sensor of the D90 would limit the fall-off problem and that the lens might perform better using just the centre field with the inherent image softness being tweaked later in PS. 

The smaller sensor meant that the focal length increased to something like 650mm, and when stuck on the mono-pod it was immediately clear the lightness of the lens worked against getting any semblance of steadiness. The image bounced around so much that to focus and shoot required bracing myself against the camera and holding my breath until I almost keeled over. And because the sun was constantly diving behind dark clouds, shooting as low as 1/250th wasn't giving me confidence in getting anything sharp. Adding to all the difficulty was the subject matter... people, especially kids - they keep moving! So please, bear all this in mind when viewing the following pictures ... Personally, I don't think they turned out too bad. And from this rare view of the genus Sillyhatisphotgraphis at play, you can see how small the lens really is. 

Tug-o-War. Unsharpened.

Notice the circular highlights above left. Unsharpened.

 An underexposed image that's been sharpened.

 Above shot, unsharpened, as is.

 The above shot has received some sharpening, while the two below are 'as shot'.

The 'donuts' here are very obvious. Sharpened.

This lens can be bought for a couple of hundred pounds on ebay, but it's a hard lens to use. It's a fun lens for when you require a unique image, and I won't be getting rid of it for that reason, but whisper it, I'm looking for a  300mm f/4.5 ED-IF second hand... mmm, I have my two-time converter ready!