How is the Zenitar 16mm 2.8 fisheye lens?

My canon new f1 came with a Zenitar 16mm 2.8 fisheye lens.
it is actually in m42 mount with a canon fd adapter, which is good and bad. Bad because I have to use stop down metering, good because I have 2 other m42 lenses and no m42 camera!

So.. how good is this lens? It looks like it can take tiny rear filters.. the one on mine says "c". Can I get more filters for it? Will m42 lenses focus to infiniti with the canon FD adapter?

Thanks for the info!

A friend of mine had that lens. The results seemed pretty good judging by her prints (5x7). She had quite a few of those rear filters in different colours, but was unsure about their optical quality.

It's not at all bad - that is, mine is not at all bad. From reviews it seems that quality can be rather variable.

They come with a set of rear filters, which are part of the lens design: The lens is BAD without a rear filter in place.

I also enjoy mine a lot. (I've got one in native K-mount and use it on my K-mount cameras, so there are no adapter issues.) I have no other 16mm lenses for comparison, but the photos I take with mine seem as sharp as the photos I take with any other lens, and sharper than some. I've enlarged up to 11x14, although that was actually a digital enlargement from a scan of a slide.

If yours didn't come with anything but the clear filter, you definitely lost something. AFAIK, the Zenitar 16's rear filters aren't used by anything else, so you'll have a hard time finding replacements for those filters, much less anything else -- say if you wanted an 80A filter for shooting indoors in tungsten light. I bought my lens new, and it came with red, green, yellow, and clear filters. The first three of those are intended for B&W photography. If you want more filters, you could check with RuGift, which sells Russian cameras and lenses. Kiev USA might also be worth checking. It's conceivable that one of these places could scrounge up a replacement set, or at least point you in the right direction. Beyond that, you might try a specialist filter supplier or try to get a glass shop or machine shop to make something custom for you.

While quality may be variable, mine was very good.

Compared to my Zeiss 16mm, it was very slightly sharper in the centre and very slightly softer in the corners. Not to a degree to be noticed without a direct comparison.
Coverage was slightly less: If the Zeiss was a true 16mm, then the Zenitar was around 16.5mm.
I didn't measure flare, but the Zenitar did very well.

I kept the Zeiss & sold the Zenitar mainly because I can use the Zeiss with full-aperture metering, so if your sample is as good as the one I had, I can highly recommend that lens.

Concerning flare, any lens this wide should be used carefully, simply because it can be hard to keep light sources out of the field of view or the area just outside of it. When I first got my Zenitar, I couldn't point the camera anywhere and not run into problems of one sort or another (unwanted light sources, flare, my own shadow, my own feet, etc.). I now know the tricks and don't even need to give these matters a lot of conscious thought, but it's an eye-opening experience to use such a wide lens!