Chris, thanks. I'm unfamiliar with the BE objective and searching for it isn't turning up anything ('BE' being too common a word, I suppose). Is it a Nikon objective?

My "poor man's Repro-Nikkor" is an answer to a challenge Rik made to me during our discussion of the advantages of coupled lenses and the capabilities of small sensors. I calculated that the sweet spot for the Oly hi-res mode would be at EA=4; this would minimize aberrations and should be just on th...

Sorry, back to the distraction of dancing butterfly scales, I just had an episode of dancing butterfly wings due to a static electrical field between my objective and the plastic gray card that the wing was sitting on. Very unnerving.

Curt, I had no idea that lens had such a wide field. How is the image quality? I hear lots of things about blue or purple fringing on non-Apo Nikon objectives.

I just tested my 4x Plan Apo. Wow!! Amazing image quality but small image circle. Even with a 90m tube lens the corners are mushy.

Thanks for this test Jorgen! Very helpful.

How do you think resolution-wise this 50mm back to back same lens type will compare to a dedicated macro at 1:1, say maybe the Nikon 105mm VR on a DX or APC sensor? I think this would beat it handily. Most consumer macro lenses are optimized for 1:10-1:2, not 1:1. Since this combo does so well on a...

Mike, I think this 50mm lens is very good; it is a macro lens, not just a regular 50mm. I chose it because it was reasonably sharp wide open, has a very flat field, might be approximately corrected for an MFT sensor filter stack, and has double the working distance in reverse versus any native MFT l...

Mike, this is the same camera, the Oly PEN F used in silent-shutter hi-res mode. It obtains the higher resolution by pixel-shifting.

Note that I cleaned up chromatic aberration in Photoshop; there was some magenta/green chromatic aberration, but not too much.

Zzffnn, yes, these are not very expensive nowadays on the used market, though you can still get them new for $500. Mike, the filter glass has to go between the rear element of the reversed lens and the subject. The lens was designed with the expectation that there would be a thick filter stack on to...

I've done the hi-res stack. Looks nice. At the reduced size of this forum it looks just like the non-hi-res version I posted above. To see the difference it has to be blown up to 100%, and compared with the previous image blown up to 200%. Here is the same section of the wing, blown up to 100% from ...

Metabones Speedboosters take the filter stack into account. The Canon-to-MFT Speedbooster for example takes the MFT thick filter stack into account. So perhaps Speedboosters are the best way to use non-native lenses on MFT cameras.

Rik, maybe telecentricity doesn't make a lens escape the problem of filter stacks. I just found this by Brian Caldwell: "And even a perfectly telecentric design wouldn't help with filter-induced spherical aberration at large apertures, which is the problem Roger and I initially encountered with the ...

Thanks Curt, I am processing and stacking the hi-res ones right now. I recently got a 4x 0.20 infinity-corrected Nikon PlanApo but I have yet to test its coverage, because I didn't have the right adapter for it. I figured that it would not be able to cover even the MFT sensor on a 50mm tube. But I w...

Fascinating! Thanks for posting this.

It is a great idea Pau and I will use it!!!! One challenge is that we don't know the refractive index of the filter stack. But it will be easy to do the experiment with varying depths of liquid. I suspect that at the apertures we normally use, we won't have to be very exact.