ARD, I'm going to respond to your PM here because this information may be of general interest, OK? You mailed the following...
Many thanks for the replies to my thread. I seem to be getting a bit better at this, but it isn't as easy as I thought. Because the lens is so good, I seem to only have to move a small amount to loose focus, or if I am shooting a Moth for example, I can get so close in that the head is focused but the rest isn't.
I am right in thinking that for Macro shots a study tripod is requied. I like the sliding head you mentioned, do you have any info on this, make, model etc.
Finally, and sorry to be a pain, could you give me advice on sensor cleaning. I have read numerous different ways of doing this, but I have read a lot of your posts and trust your judgement. Also there seem to be a lot of products available to clean sensors with, again, any advice would be much appreciated
I use a Really Right Stuff B31A Slider for extremely close-in macro focusing. To use this, both your camera and tripod head need to be equipped with standard Arca-Swiss style quick release fitments (a plate on the camera and a clamp on the tripod). They also make a gear rack model that is more precise and expensive, but I don't really find the need for that. Another manufacturer that makes this stuff is Novoflex.
Look it up at: http://www.reallyrightstuff.com/
Yes you need a very sturdy tripod, head, and clamp system. And - it must stand on firm ground. If only part of the insect you describe is in focus, then shake may not be your problem. Investigate:
1) Not enough depth of field - stop down to a smaller aperture
2) The bug moved out of the focus plane - use dead bugs
3) The wind blew - take several shot and wait for a calm
Sensor cleaning? I've tried many things but never got to like anything that well. For the rare occasion when I need a wet cleaning, I use a Copper Hill Paddle with a Pec Pad and Eclipse fluid (Google for this stuff). Normally, I just hold the camera upside down in a clean area, give it a few shots with a rubber bulb blower, and then use that very expensive Visual Dust brush according to directions (again, Google). This isn't always perfect but is far handier and much less nerve-racking than wet cleaning. A tiny amount of dust is a non-issue for me. I seldom get to shoot any grand landscape skies where this stuiff shows that much and if it does, that little bandaid tool in Photoshop works magic.