[texbaz]

Since I received my K5, 5/2011 I have been pretty happy. I also have a K7 that is also pretty good. I have a Pentax DA 17-70 that was on the K7 now on the K5 all the time, it's forum reviews indicate it's not exactly a "go to" lens but it does have some fairly good qualities at least better than the Kit 18-55. what I really wanted know, anyone else have a DA 17-70 and also purchased the Pentax DA 18-135 how does it compare, according to forum reviews it has a slightly better user rating

With about +6 AF units used for the K5 I can get pretty good results as far as sharp good contrast, with the 17-70. Can I get good sharp images with the 18-135 or is it just a total disappointment. Don't have the resources for the 50-135 but the 18-135 is something I can look at right now.
Any suggestions greatlly appriciated.

[twitch]

Other than a bit of extra reach and WR, I don't think the 18-135 will offer you anything you don't have now by way of improve IQ, in fact it might be worse. The 50-135 is exceptional though, that would be a significant step up in IQ. I think if improved IQ is what you are after then I'd save your money a little longer for the DA* zoom, otherwise you could look at a prime like a DA70 or DFA100 macro.

[liukaitc]

by logic, longer zoom should have worse optical.

I think there are 2 reasons to buying super zoom.

1. want to shoot wide range of topic, so need wide zoom range, but do not want to switch lens
2. for movie maker. for video, usually we need superzoom.

[cpk]

I have just purchased an 18-135 as a carry-around combination with a K20D. My other option was the 17-70 which I also have. I had the use of a second-hand 18-135 but returned it and bought a new one because I wanted the two-year warranty, especially in the light of the WR qualities of the lens.

A comparison:
18-135: lighter, longer zoom, weather resistant
17-70: better image quality, faster

The optical shortcomings of the 18-135 can be corrected to a large degree by using a raw converter such as DxO which I use as my first step before doing the finishing in Lightroom and Photoshop. DxO will correct image issues for certain lens-camera combinations they have tested. If it were not for this I probably would not want the lens as a carry-around.

[cpk]

I should add that as a carry-around, the k20D 18-135 combination will be used outdoors with the lens set at f8 most of the time. The extra zoom range is handy but I really wanted the weather resistance so that I didn't have to be a "sunny-day" photographer. The lighter weight and smaller size helps as well.

[texbaz]

Interesting comments. Not to far, from what I was thinking. I do want longer reach but, not at the price of lower lens resolution, I like the performance I get from the DA 17-70 not great, capable. The 50-135 definitely not in my price range at this time. Whats really odd is it seems Pentax had an opportunity to come out with a decent walk around lens along with the K5 and they just plain missed the mark. I had Ultra high hopes for a not so, Super Zoom like the 18-135 Anyway, Their is the DA 50-135 at least. ashame it has it's issues, also.

[Clarkey]

I haven't used both - I had a 16-45mm, and now have a 18-135mm.
I find I do miss the F4 of the 16-45 (which would be similar to the 17-70, especially inside - 5.6 slows down really quick), I really like the smaller size (filter diameter) of the 18-135mm. The weather sealing is a bonus and a definite consideration if you are using your kit outside in weather.
I imagine the focus speed of the 18-135mm to be a lot quicker than the SDM of the 17-70mm, but I don't know for sure.

In terms of image quality, I am happy with the colour, and mostly happy with the contrast. Sharpness is OK, and very good when stopped down. It is a "centre-centric" lens. It's no prime, but it is a very useful companion, and if you are out in the rain it is sealed and has a useful range.

Edit - If you are a wide shooter, stick with your 17mm - I miss the difference that a 16mm wide end gives. I find the 18mm quite constrictive at times.

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Last edited by Clarkey; 07-27-2011 at 06:26 PM. Reason: inside/outside switch