I'm going to have to disagree with Philmerrin, my 2 best lenses are Tamron SP series in Adaptall-2 mount. The 90mm macro and 300mm F2.8 are both stunning in every respect.

The Tamron BBAR coatings aren't up to Pentax SMC standard, but in general use I've never seen either lens flare without good reason.

the SP 300 5.6 is generally said to be ok (I haven't used one, I only have the rather inferior non-SP version and the monsterous F2. so I'm surprised that it's not performing better than the Tokina.

perhaps if you put up an example or two we might be able to see what the problem is?

I think you're right, a combination of funny bokeh from a very complex lens with perhaps a little bit of subject movement (by subject I mean those branches, which arn't really the subject at all but I can't think of a better word).

thanks Chris, I'll drop that guy an e-mail and see what he thinks.

I have a Kiron 105mm Macro lens which I bought on ebay silly cheap 18 months or so ago. When I got it, it turned out to have a damaged focus mechanism and ended up in a box not being used. Recently my Dad and I have been playing around with it and it turns out that it totally deserves it's legendary reputation. The thing makes shots taken with my Tamron 90mm SP look like they were taken through a beer bottle.

So now I'm thinking about trying to have it repaired. The focus sticks at about 1:1.2 and the focus ring has become offset from where it should be so that the markings don't line up with the correct distances. I think it probably just needs a professional to dismantle it, clean it up, lubricate it and put it back together.

Any recommendations where I should send it?

also, that Sigma has been "soon to be released" for quite a few months now.

I haven't taken any test shots to intentionally compare it, but I didn't notice any significant difference in the OOF rendition between the two lenses.

I'll get around to posting some of my test shots eventually.

couldn't agree more, I must admit I haven't bothered to check how the DA 55-300 does at anything other than 300, because if I buy one then that's where it will be used 95+% of the time.

If there was a budget model DA 300 F5.6 prime, I'd buy that. Alas there is no such thing as a consumer grade long prime anymore.

The DA 55-300 at 300 is usablely sharp from wide open and really rather good at F8.

I don't have a Tamron 70-300 to compare to, but my Dad's new 55-300 blows my Pentax FA 80-320 out of the water. There is absolutely no comparison between them at any aperture. The DA is both sharper and has less CA.

The 55-300 is slightly, and I mean slightly, less sharp than my Tamron 300mm F2.8 prime, but it's also 1/4 of the weight, ~1/3 the size and 2/3 the price, plus it's auto focus.

Some CA is present at highlight boundarys, I would say it's CA rather than purple fringing although TBH I find it hard to tell the difference sometimes. Whatever it is, you have to have a pretty high contrast boundary to see it and I don't think it's enough to notice in a real print.

My conclusion from my short time playing with it is simply that I want one.

alas the lens you describe doesn't exist at any price, and if it did then it would be easily into the £1000+ range.

The options you have are:

1. Get a second camera body and mount your two existing lenses one on each camera so you can use either as becomes necessary. (~£400 if you can find a K10D)

2. Be content to boost the ISO and get a slower lens like the Tamron 18-250 or Sigma 18-200, ~£200-300 depending on the lens and the badge on it

3. decide you need the speed and can live without the wide-angle, get a Pentax 50-135 F2.8

4. decide you need the speed and the 18-50 is NEARLY long enough, get a Tamron 28-75 F2.8 or Sigma 24-70 F2.8.