focusing


theonenadeem

Link Posted 26/06/2013 - 22:42
I have recently purchased a pentax k20d and an 18-55mm da smc lens from a seconed supplier.the issue is whenever I focus and shoot the lens reverts to its former position,so I then need to refocus. Is there a soloution to this?

secondly I shoot mainly landscape and would like to start portrait, is this the best lens or are there better ? regards

davidstorm

Link Posted 26/06/2013 - 22:50
Hi Nadeem, welcome to the site.

You have opened a can of worms with your question about better lenses! The simple answer is 'yes', but I would recommend that you keep the 18-55 and learn to use it and the camera fully before buying anything as a step up. When you do upgrade, depending on how serious you are, you could spend a fair amount of money! Possible alternatives are the 16-45, better than the kit lens and great value for money on the used market, 17-70, much better than the kit lens but a lot more money, then the 12-24 which is the best of the lot IMO, but even more expensive!

There are third party makes but I don't own any of these for landscape shooting, so I can't advise. I would however recommend an older prime which can be bought for very little cash, my favourite is the Pentax-M 28mm F3.5.

Regarding your issue with the 18-55, I'm a little puzzled by your explanation of the problem. I've never known a lens to revert to a previous focus position, unless it has 'lens creep', i.e. the focussing has very little resistance and when you hold the lens in a vertical position the focus moves. The 18-55 is not particularly prone to this, unless it is very worn.

Regards
David
Flickr

Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs

bforbes

Link Posted 26/06/2013 - 23:01
have a look in the menu Custom Setting, 13 AF Button Function, 1 Enable AF. also 14 AF by press halfway, 2 off.

These settings Allow you to Auto Focus using the AF button on the rear of the camera and the lens will remain set at that distance until you press the AF button again. i.e. half pressing the shutter does not operate the auto focus
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/
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