Originally posted by Damian.T I currently have a 18-50mm, 10-20mm and 50-300mm lenses and whilst I'm out and about taking pics of Land Rovers in action for my magazine, there's situations when I really don't have time to change lenses and therefore I miss potentially great shots. So, I was thinking of a more flexible lens.
My question is, why would I want to go for the 18-200mm as opposed to the 18-270mm which would give me a better range?
Ta...
Damian
Your post is a little confusing Damian. Pentax doesn't make an 18-50 or a 50-500. I assume you mean the 18-55 and 55-300mm? Unfortunately there is no 18-270 available in Pentax mount. Tamron used to provide an 18-250, and Pentax sold the same lens with different cosmetics, but they are now discontinued, therefore only available used. There is a current Sigma 18-250mm.
It is pretty universally accepted that the 18-200 lenses by Sigma and Tamron are a little weaker optically than the newer 18-250mm designs. Whether they meet any given person's standards is a personal decision. I stopped using the 18-250 because it was a bit disappointing in difficult conditions. I much prefer the 55-300 as a telephoto, it has longer range, better colour and contrast, slightly sharper and far less purple fringing. Note that the superzooms are internal focus lenses. There are advantages to IF, but the disadvantage is that the lens only reaches its stated focal length at infinity. I compared my Pentax 18-250 to my 55-300 and found for example that at 30 feet subject distance, the 18-250 at 250mm had a field of view of about 200mm. That makes quite a difference for birding.
Have you considered adding a second body instead of a superzoom? You could mount the 18-55 on one body and the 55-300 on the other. Since you're mostly in a vehicle, it should be easy to pack both?