Eddie Houston's selling this cleaner on ebay looks
interesting.

I've never seen a cleaner that removes everything off older
lenses.

Leica used to recommend cleaning radially from the centre outwards.

3M make a decent microfibre lens cloth for about £1 hard to
find though

EDIT: Well I'm blowed.... someone just posted a link to
them in Leads to Deals..... 12 for £5.10 + £2.50 packing
only 63p each..... BUY NOW!

Front and Back Focus issues only apply to AF and the green MF indicator.
The dioptre adjuster doesn't effect them. It can be way off and they still work.

I'm sure Stefan did a drawing of this

What's in the manual and what John has said is broadly OK with standard Pentax screens apart from the clear ones, but people are also using 3rd party screens (Katzeye etc) which are often cut down Nikon and Canon screens, because the Pentax range isn't very large and they don't make an equivalent.

The design of a screen is a very complex business and without knowing exactly what's happening it's always safer to make sure that what your photographing is sharp on the screen even if the engraved lines are OOF.

One area that doesn't show up correctly on bright screens is the OOF areas mainly because extra fresnel lines have been engraved into the screen to throw up extra light and these are at varying focal lengths.

Canon make quite an assortment of screens and just picking on one (type Ec-S)that shows the OOF areas more accurately when using fast lenses.
They actually warn you that you won't see the markings on the screen properly.

============Paste===========================
The Ec-S screen is optimized for lenses with maximum apertures between f/1.8 and f/2.8. Outside of that range Canon states the following will happen:

* With lenses faster than f/1.8, the auto focus reticle and spot
metering circle may become difficult to see.
=======================================
LINK

There's more than one way to do most things John and this is certainly one of them, so not really a problem In the past I've usually had cameras with plain screens and I usually manual focus even with AF. With earlier M cameras it was only possible to buy fixed +2 Dioptre etc. correction lenses. My Bronica had a plain screen and the magnifier was adjustable.

You couldn't use the etched lines on say the Pentax ME-60 Plain Matte Focusing Screen on a K-7 (K-5) because there aren't any and this screen is advertised as "greatly enhancing manual focusing". You would have to use my method
in that case? link

Really pathetic considering that they gave the D7000 90%. Does that have 77 weather seals? or is it a case of waterproof doesn't matter or count

If your happy about focusing on etched lines that's probably OK. Personally I only trust small lettering that I can only just read. I wouldn't be happy focusing on anything else such as a flower. Also taking the photo with MF I'll always try to focus on some lettering.

Our eyes can be easily fooled into thinking that somethings sharp when it isn't... they automatically sharpen it. They can't do that with lettering either it's readable or it isn't.

Video players such as Media Player Classic let you make a contact sheet of a video. If your jpeg viewer doesn't automatically zoom to 1:1 pixel view, its impossible to say looking at the pictures when the view is 1:1. The lettering is the giveaway in the top left hand corner it only looks right and readable at 1:1

To set the dioptre I AF on to say a box that has lettering on it and then adjust the dioptre so that I can easily read the lettering on the box. This way even if the screen has excessive shims WYSIWYG

So it's a separate flashgun mounted in the hot-shoe?

The trouble with any flash even low powered at the camera position is that it will reflect back off any reflective surface in front of the camera. What I used to do was use a foil cooking tray to send the flash to one side so it didn't reflect back..... bit messy so I bought an RF-602 trigger.

You can actually buy a slave unit with a variable delay that picks up the pre-flash waits for x milliseconds and then fires the off camera flash in time with the shutter opening..... still leaves the problem of a flash on the camera..... so a trigger is better.

Are you sure about that Gareth?..... I thought the pre-flash was
also used for anti-red eye?