The Refconverter is the highest quality magnifier that Pentax make. I've not tried any of the Seagull 2.6x magnifiers, they would be handy if they are better. I've only ever used the Spotmatic 2x straight magnifier and it was very poor. I've not tried the latest version (£69 I think).

With a 2x Refconverter 'A' used for testing lenses say 50mm f/1.4 at 25x focal length I can usually get 1 out of 4 shots in focus. This is a semi-statistical distribution and will have included for any error in the position of the focus screen. I've never tried it with live view, but I'm happy with 1 in 4. I just look at the 4 shots in browser and pick the best.

At f/5.6 nearly every shot will be in focus because of DOF. Some lenses shift focus on stopping down, but this seems to be within the DOF.

This page Focus Fallibility: Lens Test Fallacies explains some of the problems encountered with focusing for lens testing purposes.

The water's upside down in Australia and it causes it to sag

The reason that more of your photos are now in focus Kris is that they are within the DOF which is fair enough. Anything requiring exact focus would need a 2x Refconverter and focus on the screen. Just do the focus test on a door to see what I mean.

A good tip for focusing on the screen is to focus on some lettering, if you can't read it.... it isn't in focus

Your as bad as my Microwave It seems to think
I've got ALL MINUTE!!

Lens now sold to winniebear. Bank payment cleared today and
I posted it within the hour. I'm sure that the new owner will
be very pleased with this lens, it was one of my favourites.

DELL now sell their own eSata enclosure for laptops ebay link

eSata is about 6x faster than USB2 and is the way to go if your laptop has eSata. You can of course get enclosures that will do both so that you can use USB2 for now and then if later you buy a computer that will handle eSata you only need change the lead and you can ZOOOM!!! away

This enclosure on ebay looks good, even comes with a good program to monitor temperature (on USB only sadly). It also has an on/off switch which a lot of ready built enclosures don't have these days. If you want to boot up the computer without the external drive you have to unplug the power supply if there isn't an off/switch (pain). Fitting a drive is simple.

The KPS actually looks downward and doesn't cut off much information.

Sadly looking for the sharpest image on the screen is the only way to get the image properly in focus. It's the way it's done on large format cameras. Split image finders are only approximate Try focusing on say the side of a door with the camera level on a tripod.... now move the camera up and down the door and see if the split image still shows that it is in focus.... if it does it's not very accurate

Not quite apart from having to change the external USB cable from USB1 to USB2 when I gave it a major upgrade a few years back, the cables completely original (almost)

It's better to buy an external enclosure and a separate HDD.
I've had mine for 10 years now....... replaced the HDD four times
and the enclosure three times and I reckon I should easily get
another 10 years out of it