Numerical aperture of Bausch & Lomb Stereozoom 7

[zzffnn]

Dear all, do you happen to know the numerical aperture number of B&L SZ7 at its highest magnification, with stock 1x objectives (without ancillary lens)? Thank you!

[Scarodactyl]

Yes, it is 0.1 (reported as 300 lp/mm, up to 600 with the 2x) though that's only in the center of the FoV.
Note that Leica's current top end greenough, the S Apo, tops out at exactly the same NA (though with allegedly apo optics and a wider FoV).

[zzffnn]

Yes, it is 0.1 (reported as 300 lp/mm, up to 600 with the 2x) though that's only in the center of the FoV.
Note that Leica's current top end greenough, the S Apo, tops out at exactly the same NA (though with allegedly apo optics and a wider FoV).

Thank you! I just Googled it and found it too, from eiman’s previous post (in reply to my inquiry, which I forgot!).

I have a SZ7 and was comparing it, in my head, to a Wild M450 with Epizoom objective (with non-removable 2x ancillary lens).

So a Wild M450 without 2x ancillary lens has about twice the numerical aperture. With the 2x lens, it has four times the resolution. That aperture iris is useful too, to trade for viewing depth and contrast.

I am finding my SZ7 (without fine focus) lacking resolution for casual documentation and identification of micro seashells (I do understand that the GMO stereo design doesn’t perform well in focus stacking). I tend to use my SZ7 at no more than 5x zoom.

M450 with fine focus seems exactly what I would need: a good compromise between viewing and photography: when I am lazy, I can close down that aperture iris for single shots; when I am diligent, I can open it up for focus stacking, along with a WeMacro MicroMate.

So I bought a M450 with epizoom objective just now.

I haven’t decided whether or not I would go for the afocal route for camera, or get “Tim’s” adapter for trinucular adaptation. My subjects (seashells, dead insects and minerals) are not alive, so I am not sure trinocular function is necessary. Any advice? I will open a new thread. I have micro four thirds (Olympus E-M10 mk III), 1.5x crop DSLR (Nikon D500) and full frame (Nikon D750) and prefer to use crop sensors for macro.

Anyone knows how much “Tim’s adapter” would cost? It has no optics, just a plain mechanical adapter. Tim Spauwen is “WildMicro” on YouTube
https://youtu.be/9iwkYaknVzI and “Tim” at GemologyOnline.com ‘s forum: https://www.gemologyonline.com/Forum/ph ... 91&start=0

[Scarodactyl]

It's not quite double overall--the makrozoom objective has something like a 0.12 max NA, 0.24 with the 2x (presumably the epizoom also maxes out at 0.24), though it does achieve max resolution at a lower magnification and across a larger field number. For photography the difference is definitely dramatic.

Tim is a cool guy, but this adaptation is really easy to DIY as well (and super easy if you have a 3d printer). The only kind of difficult bit is removing the extra polarizer behind the eyepieces which is glued to the splitting prism. It depends how adventurous you are mechanically.

[zzffnn]

https://www.microbehunter.com/microscop ... =5&t=17945

Sorry for the confusion. Let us continue there in the above thread? Thank you!

[apochronaut]

I had heard years ago, that Wild Heerbrugg ground to 1/4 lambda, wheras the industry in general ground to 1/2 lambda.