Passed on already
Along with a few other things too
Matt

LOL! You're definitely missing out
Matt

It is Use PhotoME - it'll show you tonnes of information (including the camera temperature !)
Matt

You'll find it enlightening to read the Wikipedia entry:
http://en.wikipedia.org/wiki/Purple_fringing

Purple on one side with green on the other is lateral CA.

But this is going off topic...
Matt

I've never had a problem with CA or purple fringing on mine, let alone a "serious" one
Matt

Just a thought - there's always the approach of using an excellent not-so-wide angle prime and then stitching the images together.
Best results require a special tripod mount to locate the nodal point of the camera/lens combination.

I've seen some stunning stitches using that approach!
Matt

Sigma have just announced a 4.5mm circular fisheye and a 10mm diagonal fisheye for Pentax They both have 180degrees of view.

The Sigma 10-20 and the Pentax 12-24 are rectilinear. I have the Pentax - it's expensive, but incredible quality: flare resistant, contrasty, good colour, etc You do get what you pay for!
I often use it in the 12-20mm range. Super wide can be difficult to get an interesting composition!

Javam here has both the Sigma and the Pentax.

TBH, I don't think you'll get better value for money than the Sigma 10-20! The Pentax 14mm prime was expensive!

HTH!
Matt

Don,
As John says, the "Auto" is the little "finger" that stops down the aperture when you are using it in the "A" mode on the lens. However, this is distinct from the electronic contacts - the majority of teleconverters do NOT have these contacts

It'll be more helpful if you can provide a link or an item number
The tell-tale sign is looking at the end where the lens mounts. If you see just plain silver metal - then it's not got the contacts. There should be 8 little "bobble" contacts around one side of the extension tube.

Matt

PK mount will fit the K20D.
However, it is easier if you can get extension tubes that include electrical contacts - that will keep the aperture information between lens and body.

If you get tubes without electrical contacts then you'll have to have a lens that has an aperture ring and you'll have to use stop-down metering.

Mine are Triplus and include the contacts
Matt

Page 130, and custom function "One-Push Bracketing"

I'll send you the invoice later...
Matt