Hi Leon,
Thanks very much for this, and sorry it has taken me this long to see it. I was in the Amazon rain forest for two weeks. I've also just found your 300mm 1:2 tests and your Sigma 1:2 tests. I look forward to the comparison of the two, which you mentioned in that thread.

The CO lens pair must have cost many thousands of dollars, while the Scanner Nikon ED costs as little as $200. And the image circle of the Nikon is 60 mm in diameter! I am very impressed by my Scanner Nikon. However my copy of the Printing Nikkor 105 A version is even better. (My copy, which I got f...

Do you think something like this could be done without filters by just killing the blue channel and reducing the green channel?

Thanks Rik.

Rik, what's the relaation between the sensor-side and subject-side EA? I have always assumed the sensor-side EA is what determines the amount of diffraction. Is that really the case?

So, calculated as NA = 1/(2*EA), but plugged in a sensor-side number and interpreted the result as subject-side?

Yep, that's what I did. I only thought about the sensor-side EA.

I had used the sensor-side EA to calculate the NA.

Thanks Rik, I knew you'd be able to figure out what was going on. I didn't realize the pupil magnificatiomn factor was so important in this calculation.

Wouldn't your eBay photos of the lens show the presence or absence of that cable?

Surely your original ebay listing contained good photos of the lens from many angles?

I imagine it would be very hard to maintain a level platform if it were set in sand. Not a problem for solid subjects but a problem for things in shallow dishes of alcohol.

Austrokiwi, thanks for the Sorbothane links. I'll try them. Also will try the tupperware containers...

Mike, yes, I think the principle is almost the same as the bags filled with viscous fluids. The fluids, however, have an additional damping effect through molecular "friction".

The unexpected thing about the NA is that the effective apertures calculated from them don't seem to increase with m as fast as one would predict from a simple lens on extension, or even a zoom lens, even with floating elements. Yet it sort of makes sense in terms of the entrance cone getting bigger...

In my case, shooting specimens in alcohol, even a perfectly rigid connection between the subject and camera doesn't help. Vibrations make waves in the liquid. I think coins are much friendlier subjects!