Are these lenses capable of producing sharp images at the maximum zoom range?
What aperture setting are you using. I have no doubt at all that images taken at the long end of the zoom range with a wide open aperture, will be soft, possibly very soft.

Who are the makers of these lenses?

Come on Jeanette, you must know that old joke. Knowing your favourite subject, if I said I was game, you'd probably shoot me.

Your images are very good on the whole, you have to stop doing yourself down all the time, and don't give up on those flower shots.

My best advice is to develop your post-processing skills. To do that you might need to invest some money in a decent editor. My recommendation is Lightoom for RAW processing and probably Photoshop Elements. If you get really good, move up to a full copy of Photoshop if you need to.

Oh, and change your image saving to .PEF RAW.

Well this is totally off topic now, isn't it. Sorry to the OP.

Well I'll be in High Wycombe late September but I'd be surprised if you can't get some help before then.

I'll assume that, given those focal lengths, these are manual focus lenses.

Have you adjusted your viewfinder dioptre correctly?
Do you wear glasses when using your camera?
Do you get the hexagonal indicator in the viewfinder which confirms correct focus?
Is shake reduction (SR) turned on?
Do you wait for SR to stabilise before fully depressing the shutter?
Do you have a sample image you can post?

OK then. This is my attempt at improving your image. What do you think of it?

EDIT: I haven't tried to match the other photo, the colours are all wrong in it. It has a definite green cast in my opinion. The colours in your image are much better. This was all done in Adobe Lightroom 2.4.

Good idea cloning out the incomplete cubs head Don. Good job done too.

#2 is a better image than #1 in my opinion. Using a polariser would have reduced the reflections in the glass somewhat.

Once you have correctly set the focal length for a manual focus lens (50mm in the case of a 50mm lens), and if it is the only MF lens you have, you need do nothing more than press the shutter button to turn off the 'Select focal length' menu because the camera will 'remember' your last setting and use it ever time until you change it.

You won't be posting then?

Jeanette, I think your image would be vastly improved with a bit of PP.