Anyone near Boston, MA, USA with a 65mm Nikkor-SW?

[Steve Goldstein]

Here's my problem...

I recently purchased a near-mint 65mm Nikkor-SW. Unfortunately, some time in its previous life someone mixed up shutters and it now lives in a very nice Copal 0 marked "Nikkor SW 75mm 1:4.5". Functionally it's not an issue, but the aperture markings are not correct for 65mm. I'd like to recalibrate it by comparing it to a proper one.

If there's someone in the Boston area (I live in North Reading) with a 65mm in the proper shutter, I'd be very grateful if you could donate a couple of minutes of your time to help me set things straight.

Curse you, Nikon, for your specialized shutters with non-interchangeable aperture bands!

BTW, does anyone know if the proper outer shutter band is available from Nikon? It's not a hard thing to remove...

[Michael Mutmansky]

Every lens from every manufacturer is this way. It is a function of the aperture and not the lens design that each focal length has it's own scale.

I can't help on the scale issue, but the proper aperture is about 1/3 to 1/2 of a stop smaller than posted on the scale (the scale says f11 and it really means f8-2/3).

---Michael

[eric black]

seems to me that all you really need are the diameters of a few of the aperture openings- I have one of these lenses coming to me from Australia and will check back when I get it and see if you are interested in these numbers- it may take a couple of weeks to get the lens though- not too sure how quickly things get shipped from down under- its supposed to leave there on Monday- just be careful if you are putting a calipers near the aperture blades- I know that I will! IN the mean time, someone can correct me if my logic is wrong.

[Steve Goldstein]

Michael, thank you. I figured it was around 1/2 stop difference, based on the square of the ratio of the focal lengths. But if possible, I'd still like to compare to the real thing.

Eric, yes, I'd be interested in these measurements when you receive your lens. Since the scale marked on the shutter barrel is equi-spaced (same distance between each full stop), the actual iris opening at any one convenient f-stop setting is all I need.

[Nathan Potter]

Steve, I always worry about lenses that are sold without the original factory installed shutter. When the alternate shutter was installed were the proper shims also installed and checked for accurate spacing? Some lenses are particularly sensitive to this for yielding maximum optical resolution.

I suppose you could make a temporary scale using the brightness comparison from a known other lens and a meter reading off the GG.

Nate Potter, Austin TX.

[Steve Goldstein]

Nathan, you bring up an interesting point. "Everybody knows" that the shims are critical, but has anyone ever actually done controlled experiments to look into this? Certainly I haven't. I'm not trying to pick on you, I ask this out of intellectual curiosity.

As an extreme example, consider the Computar/Graphic-Kowa lenses. Web wisdom has it that for copy work you use it with the 1mm spacer, for landscape without (or is it the other way around?). 1mm - that's one mighty fat shim. The claimed benefit is improved corner sharpness. Certainly this is not trivial, but it probably has to be taken in context. Would I notice a difference with a 210mm Computar on 4x5 or 5x7? Or is it only important up at 7x17? If I had an ULF camera I could try it, but I doubt that my 5x7 has enough movements to allow me to answer the question.

I'll grant it probable that some optical designs are more sensitive to cell spacing than others, but I really wonder how often there's a meaningful detectable difference. By this I mean something that can be seen in the final photograph, and not just on an optical bench. The 65mm Nikkor-SW would be a good test case because it's pretty much limited to 4x5, so if I can focus it on my MQC I could explore this pretty easily. And I seem to recall that my 90mm f/8 Nikkor has a shim - this might be even more interesting than unscrewing the front cell of the 65mm in fractional turns, because now I've got what Nikon thinks is right, and I can change it in a very controlled fashion.

Now for some free time....


Flame suit on ;)