I posted this a little while ago, as a bit of information for those people who are wondering about the different magnifications available using 1 lens in different ways.
I did this little test ages ago for a mate of mine to show him the differences.
They were taken on a Nikon D70, using a Nikon 105mm f2.8 micro lens.
It also shows how the depth of field changes too.
Here is the first image, which is just to show the size of the subject (A cactus of some sort),as you can see the width of the pointy bit is 5mm.
Reference_105 by
scubacrazy, on Flickr
This is a shot using just the 105mm at closest focus, the working distance is around 10" (250mm):
105mm_closest by
scubacrazy, on Flickr
Next a shot using the 105mm but with a Canon 500D "close up lens" (2X Dioptre) attached.
This is effectively a filter which screws in to the filter thread on the front of the lens, it gives a similar magnification to using a 25mm extension tube, but of course doesn't effect light transmission.
Working distance now is 3" (75mm):
105mm_with-500D by
scubacrazy, on Flickr
Finally, a shot using the 105mm with a reversed (old) nikon 50mm f1.8 attached to the front. This is done by using a reversing ring screwed into the filter thread of the 105 lens, and the 50mm screwed into that using it's filter thread. I leave the 50mm wide open, and focussed to infinity.
Working distance now is a mere 1.5" (35mm):
105mm_with-rev_50 by
scubacrazy, on Flickr
Not very exciting piccies I know, but thought it might be of interested .
Hope this helps !
Cheers,
Gary.