DA 50-200 WR

Did Pentax make a mark II version of the DA 50-200 to better match the cameras with larger pixel counts, as they did with the 18-55, If so was that carried forward into the WR version?

I don't believe they did. Certainly not seen one myself.

There was never a mark II version of the 50-200, and the WR version allegedly has the same optics as the non WR, despite a 49mm filter size instead of 52mm.

And I can confirm that my copy on K-7 is a competent performer.

Better than the 18-250 at longer lengths, not as good as the 55-300, but good enough for those occasions when you want a compact and lightweight lens that'll cope with the British weather. It's so much smaller than the 55-300, that I use it more, even though the latter provides superior image quality.

Thank you. You have covered the three lenses I'm looking at to replace a Tamron 28-300. Have you any further comment between the 18-250 and the 55-300.

here are examples of the 50-200: link

Hi Barrie.

The 55-300 is undoubtedly better than the 18-250 at the longer end - and performs very well for a consumer level telezoom. Even wide open at 300mm, the centre remains acceptably sharp and you can get some decent colour and contrast too. My main gripes with the lens are (1) size - although it is similar to the Tamron and Sigma equivalents so that's just what you have to put up with and (2) focus hunting at longer lengths - using quick shift MF can sometimes be a must with this lens. Unlike Tamron and Sigma 70-300 lenses, it does not offer a "macro" capability, if that's important (the 18-250 does).

The 18-250 is very good at what it does, and I think people could do much worse than have one of these and supplement with a few well-chosen primes or better zooms for when needs must. At the wider end, it is at least the equivalent and possibly better than the kit 18-55. Although at 18mm you do get a fair amount of barrel distortion and vignetting until it's stopped down a fair bit. It starts to fall behind the longer you go - and I think by the time you get close to the 250mm maximum, it would be easy to see the difference between the two lenses. The centre always remains acceptably sharp with my copy though, but bokeh can be ropey. The 55-300 gives slightly warmer colours and punchier results.

One other thing about the 18-250 - because it is an internal focus design, it's actually only 250mm when focused at infinity - and rather less than that the closer you are to the object you're photographing. Probably not a big issue for most people.

I've seen this claim made numerous times, but there's never been any thorough analysis to confirm it. (Normally) You can't just shrink the size of the front element by 3mm without making any other optical changes to the lens. Why bother to make a change to the front element if you've not made changes elsewhere? I guess we have to wait for someone like Klaus from Photozone to do a review.

I've personally found the 50-200mm WR to be a competent lens. My only complaint would be that the focusing speed is rather slow, particularly at 200mm.

The longer any lens is the slower it will focus, the parts have to move farther.

But on some lenses the diameter of the front element bears no relation to the filter size e.g. Pentax 12-24

You're forgetting the space between the edge of the front element and the filter thread and that it varies from lens to lens.

I've measured the WR and DA L versions: the front element diameter is the same. Probably the same for the original DA, too.