The first place to start is with things you can do. Remove the battery, leave for a few minutes and then re-insert the battery. See if that clears the problem.

If there's a firmware upgrade on the Pentax website, then to that and see if that helps.

Also use a soft dry cloth to clean the electronic contacts on the lens and camera body, in case a lack of contact is causing the problem.

Finally try another battery in case the one you were using has developed a fault.

Finally, return the camera to get a quote for repair if still necessary.

I would suspect that the 2x converter is what is killing the sharpness, plus a little bit the flat lighting that ring flashes produce. I think you need a small additional flash at 45 degrees to just add a bit of contrast and a highlight. This works well for images of teeth in the mouth where without it you get lifeless lighting.

Your new monthly competition has been updated accordingly. Unfortunately the date needs to be adjusted manually every month.

Perhaps you have set a digital filter that removes certain colours? If you have then it will remain set until you change the parameter to "no filter".

It's something that everyone will never agree on, but my logic is that having spent a large amount on a camera I'm not going to fail at the last hurdle with a battery of unknown quality. Therefore, I buy Pentax batteries. Two batteries should cover more than adequately. I actually rotate three, but only because an extra came my way at a very low price.

Please remember it's no politics on Pentax User...

If the photos are better with flash, that might indicate that too slow a shutter speed is the problem when the flash is not being used. Flash is very short duration, which gives an effectively very fast shutter speed. Also, the lens is likely to be stopped down a bit which will help depth of field.

Outside on a bright day is a better place to start trying out your new camera.

You don't need the document, the detail is in the K-1 brochure. It lists all 35mm-format compatible lenses, including the DA 300mm f/4.

Many of us will have seen this, but no harm in posting it for anyone who hasn't. It's interesting to see a few survivors from earlier times.

It's worth re-iterating the method to adjust the dioptre though as many users don't realise the viewfinder image should be out of focus whilst doing it so we can see when the etched lines on the focusing screen are sharpest.

Once the dioptre is correct then the focusing should be correct.

Are your AF lenses sharp when used with manual focusing?