Santa Baby ...

... hurry down the chimney to me.

Well, the time has come to actually place an order for (drum roll please ....) my new K-5 and zoom lens.

Serious question now - having read reviews about the 18-135 zoom I'm a wee bit concerned about image quality, and one reviewer actually recommended the 17-70 zoom instead. Both lenses are identically priced so it really is a toss-up between the two. I can read reviews until I'm blue in the face, but I'd rather hear from those who've actually used these lenses in anger.

Main factors to consider are the weather resistance of the 18-135 and the apparent superior image quality of the 17-70.

Help me with my quandry, please.

B.

PS - What's the deal with SRS - free postage for PU members?

It's actually your call

18-135 users seem happy with its IQ.

Plastic bags or rain sleeves will also help to WR a non-WR combo.

Have not got either lens, so cannot help there, but, the free postage from SRS was in place when I got my K-5 back in May, simply put your user name and number (if you have it) on the on-line order form - I assume if ordering by post or by phone the same would apply

I initially bought my K-5 with an 18-135.

It's nicely built, very compact, super quick and quiet to focus, and pretty good at the short end. It has lovely Pentax rich colours.

However, away from the centre I didn't think much of it at all. I was umming and err-ing for a while, and then this picture clinched it:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Problems/IMGP0232.jpg[/IMG]

(PM me if you'd like the DNG to have a closer look at it)

In the middle it's great, but even reduced to web proportions, the softness on the left is apparent, and even though it would probably be better stopped down more, I ended up concluding that I'd just forever be fighting it, and traded it in against a Sigma 50-500.

Whether you'd be happy with it depends on what you'd shoot with it, and how fussy you are

I have a 17-70 now, as it happens, just back from having its AF sorted out, so I've yet to make friends with it. I'm hoping it will live up to its reputation

I have them both. The IQ of the 17-70 is undoubtedly superior.
The focussing on the 18-135 is faster and more accurate however. The 17-70 can hunt at times, which can be bloody annoying.

That said, whilst I may sell the 18-135, I will not be selling the 17-70 any time soon. It has btw survived downpours in the Pacific Northwest and snow storms in Norway with no ill affects.

Now if they made a 17-135 with the IQ of the 17-70 and the focussing speed of the 18-135 I would seriously consider selling the 17-70.

Talking of the 17-70, is the front meant to wiggle a bit?

The 17-70 hardly ever leaves the front of my K20D despite owning the DA*16-50, could I ask if you've had the AF sorted because it sometimes won't lock focus between 50-70mm? I'm using the "rest your finger on the focus ring" trick with mine, but if there's a relatively inexpensive fix I'd be interested. It's a fine lens if a little frustrating when it won't lock focus. BTW mine wiggles a little when extended, just a little bit though.

John

No, I haven't seen this hunting at the long end that people talk about.

The problem with mine (not purchased new) was that it back-focused horribly - a lot more than the K-5 would let me adjust.

Stopped down it was Ok, and otherwise in mint condition, but I had some strange results which led me to look at the focus accuracy and it was out by a country mile on both the K-5 and the K10D.

I've checked that aspect of it since it's been back, and it's fine now at +7. I just need to get out and use it now.

Since reading about the hunting issue, I've been trying to provoke it into misbehaving, but without success. Or without failure, depending on how you look at it

Back to the finger trick then Thanks for the reply, I'm sure you'll enjoy the lens now it's sorted.

John

I had this same dilemma and plumped for the 18-135 because (i) I got a great deal second hand (mixed opinions = lower s/h prices ) and (ii) I really wanted WR on my general purpose lens. I do a lot of 'bad weather' photography and need to be confident that I can take the lens out in pouring rain and not worry. With the 18-135 I can ). But again Gwyn is pretty clear about the 17-70 being robust to the odd dampening, given suitable precautions and after-care. I've been happy with the IQ of my copy of the 18-135.

I suspect that if WR wasn't such a priority for me I'd have gone for the 17-70...