Optical differences between Nikon CF-BD-M plan objectives?

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mortenoen
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Optical differences between Nikon CF-BD-M plan objectives?

Post by mortenoen »

Hi,
I'm shopping for older finite lenses for photographing at 4-8x. I have a macro setup for 0.5x-4x, in lenses, that is. I have found an old Nikon M-plan 5x, and I have bought a cheap no-name 4x Plan objective. I want images (opaque) of insects, done with bellows. I know different brands have different name schemes, and what M stands for, what BD stands for and CF or CFI and APO and PL and all that. But for reflective light, are there differenses in the optics? Should I buy an M-plan lens or a BD-plan lens or a CF? The CF Plan Apo 4x would be the obvious choice, but a bit out of my league as I'm not going to use this kind of mag. very often.
The limits of my language means the limits of my world -Ludwig Wittgenstein

Pau
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Post by Pau »

M - Metallurgical, i.e. meant to be used without cover slip like in your application (although for a modest NA 5X this doesn't matter)

Plan or PL - Flat field corrected. Always a good specification despite when focus stacking you really don't need flat field usually they are better corrected at the periphery than no Plan objectives[/b]

BD - (Bright/Dark) They are metallurgical objectives with an external dark field epi condenser bundled with. Often they have the same optics than M, if not mounted in the adequate microscope you need to block the external ring to avoid light entering through it, they have wider mounting thread

CF - Nikon objectives that not need complementary optical corrections at the eyepiece. Some CF nikons do not have it engraved, so to be sure post an image or search at documents like
http://www.krebsmicro.com/Nikon_CF.pdf
Older series are not adequate for bellows use because the need of compensating eyepieces.[/b][/b]
Pau

mortenoen
Posts: 56
Joined: Tue Feb 14, 2017 7:29 pm
Location: Nissedal, Norway
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Post by mortenoen »

Thank you for clearing that up. That was my main concerns, if the BD and M were more or less identical designs. I got my two objectives for $30 a pice, so I can afford some experiments with them, befor buying somthin I'll actually use on a regular basis, if I like the concept.
The limits of my language means the limits of my world -Ludwig Wittgenstein

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