Originally posted by Des The trouble is that there is such a long distance between stations on the AF telephoto lens line, and the fare increases dramatically.
- Next stop after the xx-300 consumer zooms (in terms of weight and bulk) is a 300mm f4 or f4.5 prime (possibly with teleconverter). The lightest of them is the F*300 f4.5 at about 880g. This is an attractive option (stellar image quality, from what I have seen), but they are not easy to find, and cost upwards of $US750. FA*300 weighs 935g; Sigma 300mm f4 tele macro 1190g; Pentax DA* 1100g. Add some grams and $$ for a decent teleconverter.
- The Tokina 80-400 ATX is about 930g. Cheap, but reviews are mixed.
- Then there is the DA*60-250 + TC - 1120g + TC. Roughly the same price bracket as the DA*300.
- Then the Tokina/Sigma/Pentax 400mm f5.6 primes, all upwards of 1100g.
- Sigma 100-300 f4 (possibly with TC) - 1440g
- Then there are the Sigma xx-400 or xx-500 zooms, starting at about 1200g (Sigma 135-400) and going up to the Bigma at about 2kg
- And the Pentax 150-450, also about 2kg.
And there are some behemoths after that, including the DA 560.
For international travel, there is a world of difference between carrying and using a 440g lens like the 55-300, and a lens that weighs 2x, 3x or 4x as much. Not to mention the cost.
Yeah I would have been ready to pay X2 for something not much bigger but say sharp at f/5.8 300mm for more cropping capabilities. But this doesn't exist... It is already much more expensive...
I was thinking 70-200 of tamron + TC but that expensive for f/4... More than I'd wish to spend and I'am not even sure the Pentax TC would work well with it. I'am not 100% confident of the quality of the tamron at 200mm f/2.8 cropped to 300mm. Theoretically, cropped to 280mm it should give equivalent of f/4 apperture so nice for dawn/dusk. But is it significantly better than a 55-300 picture? Maybe it is too soft to really be work it except if you close it down to f/4 ?
There also the issue that this is much bigger... If I was to be sure the 70-200 cropped would be much better... maybe... the 70-200 from tamron the only one that not that expensive, and faster.
I was evaluating the 60-250 but this one is crazy expensive, has less good AF than even the 55-300 from Pentax Forum review and limit to 250mm f/4... The max apperture is really better only after 190mm and the 250mm limit that valid only at infinite mean a bit more cropping necessary still...
Primes I feel are the wrong idea for this kind of outing as I understand the wildlife can be really any distance. Maybe I got it wrong, but I expect I'll not bee always at 300mm? Otherwise yes I'd think of a DA*300...