[Airehead]

Thanks glsammy.
Actually I have realised my 2 mistakes-
To shoot small objects I should be using a large format on the camera.
and
if I isolate a central object from a big pic I am not obliged to reduce to the size of the object - I can cut out a screen-size patch with the object in the middle. It will then be of the required size - though it does not make any difference to the size of the object.