Yasuhara Nanoha Macro Lens 5:1

I've never seen any examples of photos taken with one of these, but I have a few concerns:

- working distance is very small, only around 1/2"
- diameter is very large, so it is difficult to do any additional lighting
- it's unlikely the lighting is optimized for coins, and is not very flexible

On the other hand, the max aperture of f/11 is excellent for 5x magnification. Since f-effective = m / 2*NA = f-infinity * (m + 1), this means the NA is 0.23, and f-infinity is 1.8, which is amazing for a 5x objective. I worry though that the image quality is not all that great wide open, so most of that big aperture would be wasted. The very best 4x objective available, the Nikon 4x CF/CFI Plan Apo, has NA=0.2, so it's not likely this objective is very good at it's widest aperture.

If you're thinking about spending this sort of cash to do 5x magnification, I'd recommend getting a Nikon 5x MM objective instead. It will cost you less money ($200-$300 used), and has far more working distance (~3"), so lighting is very easy. Or if working distance is not a concern, get a Nikon M5 objective. It will cost you way less money (~$40 !!), has more working distance (~1"), and is very small in diameter so much easier to light. The 5x MM has NA=0.13, so is very good. The M5 has NA=0.1, which is average for the magnification, but has excellent image quality.

I assumed that the f/11 aperture was effective, not infinity. If it is infinity, it is unusable since that would be f/66 effective. The fact that the reviewer thought f/11 was a bit small says he has no idea how to review such a lens!

The MPE65 is a great lens but still suffers from short working distance. You can get the same IQ from the M5 for far less, though the MPE65 is more flexible across whole range from 1x...5x. The range of 2x...3X is tough and MPE65 does well there, better than most lenses...Ray

That's the one. It has an odd adapter on it. I'm not sure how usable the adapter is. The native threading of the objective is M26, so you will need an M26 to M42 adapter, then adapt M42 to your Sony or whatever.

This objective is telecentric, so focus stacking is a breeze.

The other objective I mentioned is the M5, which is usually available on ebay but I don't see any for sale. There is a seller who lists them for $27, which is a steal. The quality of the M5 is nearly as good as the 5xMM, but with less working distance (20mm vs 75mm). That 75mm WD is a joy to work with.