I would agree with Infrabasse. It's still worth trying the Chinon lens though because they can be extremely good. I don't have a Chinon 135mm, but my Chinon 50mm F1.9 is one of my favourite lenses. Excellent image quality and bokeh.

Regards
David

It might be worth getting a cheap AA battery adaptor from ebay and trying some AA Sanyo eneloops in it to see if the problem goes away?

Also, try cleaning all the contacts between lens and body thoroughly with isopropyl alcohol. It seems most likely to be a battery / contact issue of some sort.

Regards
David

Hi Charlotte, if you do the firmware update make sure your battery is well charged. Also, does your battery retain its charge or does it drain quickly?

Regards
David

The one you have bought is unfortunately not the correct sort. This one has a flange which stands proud of the camera body and will cause you problems with infinity focus. You need one that fits inside the K-mount on the camera so that your M42 lens is flush with the camera body. do not buy any other type.

The link I have posted is for the correct type; these are available from many sellers, but I have pointed you towards a particular seller as the ones available from here are reasonably priced and they fit very well. I have tried other ones which are very loose and no good at all.

Regards
David

Hi Melih

I have several M42 lenses and keep a PK adaptor permanently fixed on all of them. I have the flush type so no issues with infinity focus and they only cost just over £7 each from ebay. They are not original Pentax ones but they fit very snugly and I have had no issues with any them. Please see link below for the ebay seller.

link

If you want to leave these on the lens permanently I would recommend that you remove the little spring clip that attaches to the adaptor; it is held on by a small screw.

Regards
David

Hi Mike, I've also just acquired a K-5 although I've had a K-x (also excellent) for about a year now. A warm welcome to the site; don't forget to take a look at the Gallery and upload some of your pics!

Best wishes
David

Congratulations on your win Jim, fantastic landscape picture.

Best wishes
David

All good advice above, but you must make sure the dioptre is set for your eyes and that the grid in the viewfinder is sharp. If this is set wrong you have almost no chance of accurately focussing.

Another technique that is almost foolproof is to use the Live View feature on the LCD screen and zoom in on the area that requires critical focus (zoom is achieved by repeatedly pressing the 'Info' button). However, this is only possible if you're using a tripod and the subject is perfectly still. Great for indoor still life shots.

Regards
David

As stated above, it you are looking for issues, sooner or later your will find one or more. You have at least a year's warranty with your camera (not sure why you mention 7 days) and two years if bought from SRS. John Riley's advice is good and sound - use your camera as much as you can fgor taking the photos you want to take!!!!

If there's anything wrong you will come across it soon enough.

Regards
David

You can clean the sensor with a pec pad slightly dampened with isopropyl alcohol - it must be damp, not wet. Bear in mind when doing this that you will not be touching the sensor as it has a filter over the top of it. Make sure there's no dust on it first (use a blower) and wrap the pec pad around a wooden spatula with a flat end. Carefully drag this across the sensor with a very light pressure.

If you do this carefully, you will not damage the sensor. Many on here have done this.

Regards
David