Lens advice

Have been looking at this forum for a while but have now signed up as a newbie and a loyal Pentax user!
Are there any other aviation photographers on this forum? The reason I ask is that I will shortly be in a position to purchase either the DA* 300mm or the Sigma 100-300 EX, I know that there are threads on both lenses which I have read but still can't make my mind up. I have just got rid of my Sigma 135-400, I was not very happy with it at all.
I realise that with a prime lens photos of aerobatic teams and take off/landing shots will be limited compared with a zoom but the quality of images looks far superior.
Any suggestions/comments welcome.

Welcome, Rob.

Is the Vulcan in your avatar a recent one? If so, where did you see it?

I can't comment on the DA* 300, although one or two here have it, and they seem pleased with it.

I had a reasonable time recently with the DA 55-300, if you're interested.

Why didn't you get on with the Sigma?

Hey, I'm just old school and think that primes always out perform zooms.

Well that was the case in the old days, nowadays I think when looking at the results some of the guys here get with their zooms, that performance difference is getting smaller.

If you can, try em both out and see which suits you best.

I have the Sigma 135-400mm as well and seem to get very mixed results from it. Sometimes its very good and other times quite disappointing (Of course that could just be me ). I am waiting to see how the new Tamron and Sigma 70-200mm f2.8 lenses perform with a teleconverter.

I also have the Sigma 135-400 and have used it for aircraft in flight. The biggest problem I have is the time it takes to focus, particularly if the camera decides to hunt end-to-end in the focus range.

While I hanker after something faster I, like ChrisA, have found the Pentax 55-300 very reasonable. An advantage with this lens is that the quick-shift focus allows manual adjustment to get it close without disengaging the auto focus and helps to avoid the camera doing an end-end focus hunt.

I have some very similar Vucan pictures and you can see a selection of my Farnborough 2008 pictures here:

http://s172.photobucket.com/albums/w20/GlynM/Farnborough%202008/?albumview=slideshow

Glyn

Does the Sigma 100-300mm EX have the quick shift feature?

Lee

I don't think so. None of my Sigma EX lenses have it. I believe that quick-shift is a Pentax feature that seems to have been introduced with their DA range of lenses.

Glyn

Thanks for all your comments so far. I was lucky enough to be present at Waddington this year for 558's first public display, took some good photos of it some of which had a clear blue sky as the background which was unusual this year.
My main gripe with the Sigma is with photos in flight. When I first bought it I went to Duxford and took some photos of static aircraft outside which didn't cause any problems, but then during the flying display at Farnborough I gave up on it and used my brother's Sigma 70-300 DG, the photos were a lot better, I've used it since and I don't want to rely on it the results were awful.
If I could stretch to it I would like a prime and a zoom and those are the two that I probably would get. I ordered my K20 recently from SRS, do you know if they have a shop that also sells equipment or is it just mail order?

Im pretty sure SRS have a couple of shops.

I wonder actually how dificult it would be to build quickshift into the camera body, or even a button on the back within easy reach that would disengage/engage the auto focus rather than that terrible lever.
Since most of the lenses I have bought since getting my K10D have been old good quality manual focus I actually tend to use autofocus lenses the same way.

FWIW, possibly not too relevant, I had an oldish Sigma AF 400mm F5.6 on another K10D at Farnborough, which I used a little.

I was glad I only used it a little. The purple fringing against the bright sky was pretty bad, and the colours weren't as good either; nor was the sharpness of the results.

I've seen some of your photos Chris and didn't have a problem re the fringing just the sharpness which I was disappointed with.

Saying that, have you tried using the Sigma at 300mm?, when I did the results werre more than acceptable.
As that is the lengtrh you are looking at with a replacement perhaps it would be better to just limit the length you use the Sigma at.

Edit: my spelling is atrosious, atrocus, artrociouse, terrible.

Actually I've just looked at my images taken so far this year and most of them were taken at the 300mm range so that is something else to consider thanks.

Two shops - see below :-

www.srsmicrosystems.co.uk/editorial/4/Contact-Us.html