disaster

Just came back from a trip to Patagonia and looking over my shots on photoshop. To my shocking surprise all my shots taken with my new 55-300 pentax lens are out of focus. To the naked eye on the lcd screen they seemed fine but back home on the computer they are terrible. I have no idea why! All shots were taken with a low f stop and shutter speeds above 1/200 sec, focus automatic and generally centre point. I am going to test the lens at home at various settings and see if I can get to the bottom of this terrible disaster, but prior to doing so, anyone had any similar problems with this lens? I find that shots taken at 300mm are way more out of focus obvious than say at 200mm, where at 55-150mm some images are almost acceptable if you weren't too fussy.

Sorry to hear that, did you test the lens and apply any required AF focus adjustment before using it?

I have 2 copies of the 55-300mm, one I have left in Spain and the other is here in the UK. I can honestly say they are like night and day, the one abroad is excellent, it's nice and sharp throughout the range whereas the one here is a right dog ... I just can't get a decent picture with it (especially at 300mm)

The lens here is going somewhere for a service soon (your post reminded me, I had totally forgotten about it)

how do I apply this focus adjustment?

Which camera body do you have?

On my first camera (K-x) I had the same problem. No issues with the same lens on all subsequent cameras, it is sharp as a knife. This proves the camera was the issue, not the lens.

Since then I've had two K-x's, a K-m, a K-5 and a K-5IIs. The K-5 required quite a bit of AF adjustment with all my lenses, including the 55-300.

One question - did you use a filter on this lens? I have found that for some reason I can't quite fathom, the 55-300 really does not work well with filters of any kind and especially so with circular polarisers.

Regards
David

Checking your other posts I see you have a K5. Have a look at this thread.

This might salvage something from your shots

http://www.focusmagic.com/

Ouch. I do feel for you. I would be gutted.

It just serves to show that it's imperative people check the AF Fine adjustment on all their lenses.

I learned the hard way. A few years ago I bought a K10D and Sigma 17-70 on Ebay as a second body to my K20D. Went out on a shoot, took a thousand pics with it and got home to find them softer than a soft thing. All out of focus.

Once I'd calibrated the lens with the cam ) which required debug mode on the K10D ) it was sharper than a sharp thing.

In fact I'm convinced the reason the lady who sold it on ebay did so because the cam/lens combo was giving OOF results.

You have to be careful with the 55-300 as it is slow to focus so you need to keep it steady, but once it's focused it should be plenty sharp. It sounds like you have a front focus or back focus problem.

You might also try this (which is free)

http://yuzhikov.com/projects.html

So, how would I go about checking calibration on my K10d?

This explains how to get into debug mode.

From there you need the AF Test menu.

Unlike the K20D and newer DSLR's which can hold individual adjustments for up to 20 lenses, the K10D applies whatever adjustments you make to all lenses so you need to test all of your lenses for AF accuracy and determine whether or not you actually want to make this adjustment.

You could end up with one lens focusing perfectly with the others producing OOF images.

I have a pentax k5

the only filter i used was the uv o filter