The Tamron and Pentax are more or less the same lens and both are better than the Sigma. The later Tamron models might perform slightly better than the Pentax (closer focus etc) but I doubt there will be much in it. The Tamron lenses are usually a fair bit cheaper than the Pentax as well, but the Pentax should retain its value better and be easier to sell.

I've got one of the Pentax lenses and it's not at all bad if you're expectations are reasonable. I've not seen any signs that it's any better than the equivalent Tamron for flare etc though.

Tried the FA 28-200 & 2x TC on my Z1p and MZ5 tonight - approximately the same results with both of them. With a high-contrast subject both AF'd fine with the TC when in the 28-50mm range but above that it was hit and miss, with more miss than hit. Beyond 100mm AF never worked.

It sounds to me like a 28-200 might be the best option for you. There are plenty of cheap 2x tele-converters available in Pentax AF fit however most of them are 4-element ones and not all that great performers. If you find a 7-element one then usually they are significantly better.

I can't recall how well the AF works with a 2x TC on a 28-200 - I'll try and remember to give it a go tonight and let you know.

The 28-300 isn't going to be the sharpest of lenses, particularily at the long end however, depending on what 100-300 you currently have, it might not be at all that much of a disadvantage.

I have a Pentax 28-200 that I used to use as a single "walkabout" lens with 35mm cameras. I didn't expect all that much from it quality wise but I was a little surprised to find that it outperformed both my powerzoom SMC-FA 28-80 and 100-300 lenses.

How much do you use the 300mm end of your zoom? If it's not all that frequent then going for a 28-200 instead of the 28-300 should save a fair bit of cash as the Pentax & Tamron 28-200 lenses are reasonable performers and cheap 2nd hand.

If you want to go longer than 300mm then the Sigma 170-500 and 50-500 lenses get pretty decent reviews although they are both still quite expensive. Tokina also have the ATX 80-400 which is also supposed to be a good lens.

I much prefer the handling of internal zooms however I can't say I've had much in the way of problems with wobbly front elements on many of the lenses I've owned.

The only lenses I've had that suffered from that were the FA powerzoom 28-80 and 100-300 (they weren't all the great performers however I don't think that was just the wobble) and one of my SMC-M 50mm F1.7's. The wobbly 50mm doesn't seem to perform noticeably worse than the other SMC-M 50mm F1.7 I've got, and that one doesn't wobble.

Very nice shots. I visited the area and the graveyards back when I used to live in Brussels and the sheer volume of graves (plus the huge number of names of missing men who's bodies weren't found) was a very sombre experience.

Thanks for that. I've asked there and it would appear that the closest place that'll do the developing is in France now.

I've still got a few rolls of Agfa Scala kicking around unused. Any idea of anyone in the UK who can still develop it? Joe's Basement used to do it but they're out of business now I think.

Ah well - at least mine makes a nice paperweight...

It's the difference between 24mm and 28mm and therefore quite significant.