Some thoughts on MP-E 65mm
I have conducted a comparison between the lenses shown above:
Canon MP-E 65mm f/2.8 1-5x (I'm just calling this MPE65 from now on)
SumRay 50/1.9 (Summar 12cm & Raynox +12 (see explanation below))
Leitz Focotar-2 50/4.5
EL-nikkor 50/2.8 (old version)
Leitz Milar 40/4.5
Below you'll find full resolution samples from each lens at three different aperture settings.
Camera body used: Canon 7D
All but the MPE65 were mounted on the Nikon PB-6 bellows.
Each test image is stacked from 9 exposures in Zerene Stacker. This is to get around the fact that aligning focus exactly the same between different lenses is practically impossible. Also: some lens flaws seem to be amplified by stacking and at this magnification stacking is often crucial to get the best results. Therefore even if it was possible to align focus identically – I find stacks are more telling than single exposures at high magnification.
I have included three EL-nikkors for two reasons:
1) I wanted to know if there is a difference between the old and the new "N" version
2) It's nice to know how much sample variations plays a part in this kind of test and as it turns out it is far from insignificant.
There are a lot of lenses I could have included in this test (such as the Zeiss Luminar 63/4.5 or Leitz Milar 65/4.5) but I wanted to use lenses with roughly the same focal length. The MPE65 is called 65mm but I'm fairly certain it achieves its 5:1 magnification by means of focal length shortening (the relatively short maximum extension and working distance indicates this). My guess was that the MPE65 is between 40 and 50mm at 5:1 but it could be even shorter – I'll see if I can find this out.