Pentax k10d extension tubes

I have just bought a set of Hoya extension tubes to use with my 50mm 1.7 lens as a macro system, but I can't get the lens to focus. Am I doing something stupid?

Hi Martin

Probably need a bit more info.

Do you mean auto-focus? Is your 50mm 1.7 a manual or autofocus lens? Do the tubes have electrical contacts or are they manual only?

The lens is manual . As are the extension tubes I believe.

I have just tried the same set-up and it works fine. With say a 20mm tube you will need to be about 4 inches from your subject and about 2 inches with a 36mm tube....the lens focussing adjustment will be very fine and, hand-held, effectively unnecessary. At those distances, using a tripod, you ideally need what Manfrotto call a 'Micropositioning Sliding Plate'.

Roger

Hi Martin

You shouldn't really have any problems getting focus with a M 50mm and extension tubes.

As Roger says you need to be pretty close, but that's to be expected as it's macro. Only a small amount of whatever you are photographing is likely to be in focus at any time so it's sometimes hard to judge the moment. Best bet is to get the focus as close as you can by turning the ring and then move the whole camera backwards or forwards as necessary to get the exact focus.

Using a smaller aperture will increase the depth of field which might also help, but that will, of course, affect the light which is another problem when doing macro.

Not sure if the K10D has 'catch in focus' or not, but if it has that's worth a go. I use it a lot, but others don't use it at all.

At least with digital you can experiment to your heart's content.

Thanks for the advice "cbrog" and "milamber". As you say I need to be close to the subject and experiment to my heart's content.

Thanks again

Martin