Mine's Bigger Than Yours

[major_clanger]

Looking through my photos from the 2008 Farnborough Air Show, I remembered that I'd looked around during one of the flight displays and snapped this picture, but never put it online. 

I will leave it to my fellow photo-nerds to play Spot the Lens.

Comments

[ffutures.livejournal.com]

Yikes! Seems a bit big - but I suppose they've used the longer length to simplify the optical path and minimise distortion etc.

[major-clanger.livejournal.com]

There was a fashion for catadioptric camera lenses a couple of decades ago, being much more compact than normal designs, but they fell out of fashion when electronic exposure control came in, as the optics mean that you can't use a conventional aperture diaphragm to control light transmission; you have to use manually-inserted neutral density filters. Also, the bokeh (out-of-focus light pattern) is doughnut=shaped, which can look very odd in pictures.

[ffutures.livejournal.com]

I've got a 500 mirror lens, it's rarely useful - colours are muted and it's always a little fuzzy.

No, what I meant was that there there are various optical tricks which can reduce the real length, as opposed to the focal length, but it adds complexity to the optics. That one looks pretty close to a true 500mm.