90mm and the Novoflex macro LEM/VIS II

[Jakobben]

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Hi

 

I have read that I can expect 1:0.84 magnification if I combine the new Novoflex macro LEM/VIS II adapter with a 50mm lens. But what if I put a 90mm on it? I assume I'd get an even larger magnification, correct? Or is it for some reason not possible to use a 90mm on it?

 

Thanks!

 

 

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[drew.saunders]

You'll get less magnification with a 90mm lens, but quite a bit more with a 35mm lens.

 

With a 50mm lens, focused at infinity, the rear nodal point is 50mm from the image plane.

At 0.5x, it's half again the focal length, or 75mm, at 1x, it's double the focal length, or 100mm. That works for any lens.

At 0.84x, it's about 92mm, or 42mm more extension than infinity focus.

 

A 50mm lens focused at 700mm (the normal minimum distance for a Leica M lens), the lens is "racked out" to 53.85mm. Rounding up to 54mm, that means you need 38mm extension to get to 92mm. The Novoflex setup is 3x10mm tubes plus the adaptors, so I'm guessing the adaptors add up to the extra 8mm. I wish they listed that information somewhere, and in theory, I could measure my Visoflex, but 38mm seems about right.

 

The 90/2 APO focuses only down to 1m, which means it extends from 90mm at infinity focus to 99mm at 1m focus. Look up the "thin lens equation" to see where this comes from, it's 1/90 - 1/1000 = 1/98.9mm. To be at 0.5x, it needs to be at 1.5x the infinity focus, or 135mm extension, and at 1x, 180mm. Adding 38mm to the 9mm that the lens provides will get you to 137mm, or just past 0.5x. Actually, using the stacking feature of this set, you can add 8, 18, 28 or 38mm, which is quite versatile with a 90mm lens.

 

A 35mm lens needs 35mm more extension to get you to 1:1, so adding 38mm extension will get you beyond 1:1. You'll also be very close to the subject.

 

If you get this set for an M240, look for a Bellows II and the adaptor ring (UOOND) that lets you mount regular M lenses on the bellows, as that will let you experiment with all your lenses and get some extreme close up options. I have a regular Visoflex, a Fuji X to Visoflex adaptor, the bellows, and the UOOND, and with my 35/2, I get over 2x magnification. The lens is so close to the subject that I can't leave the hood on!

[swamiji]

It is my understanding that you can use any lens on it. However Novoflex only provided the calculations for 50mm.

[swamiji]

Oh, I forgot to mention, that the Novoflex LEM/VIS II is for the M240 only (requires LV), it provides no focusing information for the M8/9/M/E.

[luigi bertolotti]

I have the LEM/VIS : it's a well made device but, used alone, is so-so for macro given that you can count only on the focusing extension of the native lenses : apart bellows (which is a not so portable device) it's useful to couple it with a OTZFO and lenses / accessories made for it (Elmar 65, heads of 135 etc...) ; I think it should be useful if Novoflex or someone else (Chinese...) would make a similar device with an helicoid (if only Leica had a bigger market they surely would make one... ); otherwise, one can count on "stacked OUFROs" which are available by the usual Chinese, at reasonable cost (but are curiosly HEAVY... a pair of them weight more than a LEM/VIS). Of course,as Swamiji points, is a M240-only solution.