Long Telephoto Lenses

Our longest lens at the moment is the SMC Pentax-FAJ 75-300mm, which, compared to film cameras, is really quite long.

However, for photography of small wildlife we would be happier with something a bit longer.

In the absence of a suitable Pentax lens, what alternatives do you use and how good are they?

I use the Bigma. It is not fast but mostly that doesn't matter.

I am happy with it, apart from the weight. It's not going with me next week to the US for that reason, I may regret my decision once I'm there but I may regret lugging the thing around in 40C heat more.

The FA* F4.5 300mm seem to be going for more reasonable prices now that the DA* F4 300mm is out. You might find that with a Kenko 1.5x TC more manageable than the bigma, and with the sharpness of either the FA* or DA* you can zoom into the picture with minimal loss of quality (without the TC) compared to the 75-300mm (and the bigma, IMX).

The problem I had with the bigma was that at 500mm and F6.7 (as it reports on Pentax) you really needed a strong tripod and cable release to get the best quality out of it. Focusing at F6.7 in less than good strong light was also something of a challenge.

There's also the Sigma Sigma 135-400mm, which at F5.6 at the long end ought to be acceptable and is a cheaper solution than the others, it's also lighter than the bigma.

I tried to buy a Sigma 135-400 recently, and just couldn't find one anywhere!! I think it's discontinued now, but apparently it is going to be replaced with something similar, although Sigma UK couldn't tell me when.

I'm using a Sigma 70-300 APO f4/5.6 at the moment, with a Kenko 1.5x DG converter. It's not ideal in low light, and it's not the sharpest lens I've ever used, but it's ok until the 300mm primes come down in price.

Here are a couple of pics taken with it on a K10D;

A barn owl pic with the converter, so 450mm...




And some swans in flight without the converter, so 300mm...




Neither are cropped significantly, and I accept they aren't the best examples of this type of pic around!

I'd really like a lens with a wider maximum aperture so I can up the shutter speeds and freeze the birds, particularly the owls where the light is fading when they're active.

It's being replaced by the Sigma 120-400mm when it's released (SDM focusing only, i.e. no screw drive):
http://www.sigma-photo.co.jp/english/lens/telezoom/120_400_45_56.htm

Cameraking appear to have the 135-400mm in stock.

Thanks for the link chirpy, I'll drop them an email to see if it's in stock!

I like the look of the new Sigma too though, the SDM would be nice to have, and although in all reality doesn't make that much difference to the job it does compared to the 135-400, quieter would be better!

Just need a release date now.