[dshombert]

After a couple weeks in Alaska earlier this year, a trip that included nature hikes nearly every day and MANY situations where a lens change was necessary (and inconvenient), I swore I'd get a superzoom for the next such trip. Yeah, I know, it's slower and not prime lens IQ. I'm okay with that.

Recently, I got a Pentax 18 - 270 from KEH at a very reasonable price and thought I was all set. Well, no, it turns out it could hardly ever find focus if it was extended much beyond 100mm. So back it went. But I thought the image quality, when it happened, was pretty good. Is this difficulty in focusing at long distances typical of this lens? Anyone else had this experience? I liked it well enough that I'd be willing to pay full retail, but not if it's gonna wait until I'm in the wilderness and then decide to quit working.

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Last edited by dshombert; 03-02-2015 at 07:49 PM.

[Adam]

Is this difficulty in focusing at long distances typical of this lens?

What camera were you using? The effective aperture at those longer focal lengths is small (F5-6.3 range), but it should still be enough for the camera to be able to focus in decent light. I didn't experience any significant issues when pairing the lens with a K-5 IIs, but the K-5 had trouble indoors. The best low-light results will of course only be attainable with the K-5 II/IIs, K-S2, or K-3, but other bodies shouldn't be too problematic in daylight.

It's possible that your particular copy of the lens suffered from an AF calibration issue. It'd try a brand new copy to see if you get better results (both B&H and Adorama have 30-day return policies, and the lens is currently on sale for $599).

[dshombert]

Yep, I should have added that this happened with my K-3. Most of the shots where it couldn't focus were outdoors on a sunny day. Plenty of light and I was shooting at ISO 400.

[blackcloudbrew]

Well, I've used mine on my K20, K5, & K5 recently and not had any issues with the image quality (or focus either for that matter). I still own my Tamron 18-250 lens bought new in 2009 (it will be up for sale soon), and I've found the DA 18-270 is better than the Tammy, which itself was a good lens (not stellar but always good although a little on the dark side). Anyway, thinking you had a bad copy.

[dshombert]

Well, I've used mine on my K20, K5, & K5 recently and not had any issues with the image quality (or focus either for that matter).

Thanks. How long have you owned it?

[blackcloudbrew]

Thanks. How long have you owned it?

I bought my DA 18-270 last fall, about 4-5 months.

[dshombert]

UPDATE: Thanks to Adam and Blackcloudbrew for their input. KEH, of course, refunded my payment for the lens (plus return postage) with no questions asked. Well, they did ask what the problem was, but there was no argument, they took my word for it. They are a class outfit, for sure.

I purchased a new copy from B&H and I'm glad to report that it has no trouble focusing at any focal length. I was out with it for much of the day today (the sun is actually shining for a change) and haven't really tried it in low light, but it appears this will meet my needs very well. If it was weather resistant, it'd be perfect. No, it's not razor sharp, but I wasn't expecting that from a superzoom. But that aside, this lens - combined with the DA 21 - seems to be the perfect travel setup with my K-3.

[blackcloudbrew]

How about that! Glad I checked back in on this thread. Happy to hear you had a happy ending. It's a good lens, just not a great lens, but for the purpose it was intended, I'm glad to have mine.