[mattmiles]

Hello,

I have just purchased a Pentax K20D and am new to photography. When I have tried taking pictures in the twilight I have tried focusing on the area I want but the lenses just moves backwards and forwards and then when I try to oush the button it won't take a picture. Am I right in saying that this is becasue the Camera can't actually focus on anything.

In that case if I select manual focus and the object is to dark or all of one colour to see if I have manually focused on it correctly how can I make sure the picture will come out in focus when I review it.

I hope this makes sense.

Thanks

Matt

[Ash]

Matt.
You must first understand how autofocus works.
In dim light, Pentax cameras struggle at the best of times to lock focus.
Given those conditions, the camera cannot find anything with enough contrast to focus on, so it constantly searches and finally gives up with a flashing hexagon in the viewfinder, indicating a failed focus attempt.

So what to do? Here's where manual focus comes in, you just set it to infinity distance, set a small enough aperture to capture what you need and fire away.

Metering under these conditions provides another challenge, but one thing at a time.

[mattmiles]

Thanks for that.

What is the best way of finding infinity focus on a normal kit lens?

[Ash]

The focus ring is aligned at the 12 o'clock position and should turn freely until just beyond the infinity mark. Track back just a little to slightly before infinity, between the infinity and the 2m mark I believe it is. Right on infinity can be OK too - just test and see your results.

[Marc Sabatella]

The distances are marked right on the lens - just turn the lens until it reads infinity. Which should basically be at or near the end of the focus range. Some trial and error may be needed.