Fujinon 90mm/f8 shutter on a Schenider 90mm/f8?

[m00dawg]

Sorry for asking as I did read up on this quite a bit but haven't been able to find a confirmation on what I'm trying to do. I have a Fujinon 90mm/f8. Wonderful lens! Until it had a love affair with the pavement back in January. I was pretty gutted. Optics are compromised (the bokeh looks...weird) but the shutter seems like it's ok.

I bought a Schneider 90mm/f8 to replace it. The lens itself is pretty lovely. The shutter though is rather laggy. I'm thinking of having it CLA'd but it may not be ready by the time I'll be taking a trip and will want to use it. Both lenses go down to f45, both use Copal 0's. They are of very similar design but of course different brands.

I removed the shutter from the Fujinon and didn't see any spacers. I haven't tried that on the Schneider yet. In reading up the main thing I need to worry about is that the aperture scale may be shifted, correct? Would this be true for lenses which are so similar to each other as well?

If so, is there a good way to somehow verify that? I was thinking of somehow taking a light reading through the groundglasss of my camera, swapping the shutters, and taking the same readings to see if they matched. But that doesn't seem super scientific.

[Dan Fromm]

Take the Fuji cells out of their good shutter. Take the Schneider's front cell out of its bad shutter. Screw it into the front of the good shutter. Open the diaphragm as wide as it will go. Hold the lens in front of you, front towards you, and sloooowly stop down. If the aperture pointer is at f/8 when the diaphragm's blades just become visible through the front of the front cell, you'll be fine.

[m00dawg]

Ah right on! I gave that a shot and it's close. It looks like it's just slightly off (where the blades close a tiny bit sooner than the Fujinon). It's close and, in fact, I think the Fujinons blades can be seen a bit before f/8. Not sure how much play there is but it looks close enough, less than 1/3rd of a stop for sure in looking at the scale.

I went ahead and tested the shutter using the Ethan's Arduino shutter tester (the Cameradactyl guy). It's definitely better than the Schnieder's shutter but actually they both aren't amazing haha so might not be worth the risk. The Schnieder is about 1/3rd stop slower at 1/125, 3/4th slower at 1/250 and 1/500. Whereas the Fujinon is 1/4th slower at 1/125, 1/3rd at 1/250 and 1/2 or so at 1/500.

Speaking of Cameradactyl, thinking about getting an OG for when I can't bust out my 45F2 and would use this lens which is why the faster shutters are more of a factor.

[Bob Salomon]

Ah right on! I gave that a shot and it's close. It looks like it's just slightly off (where the blades close a tiny bit sooner than the Fujinon). It's close and, in fact, I think the Fujinons blades can be seen a bit before f/8. Not sure how much play there is but it looks close enough, less than 1/3rd of a stop for sure in looking at the scale.

I went ahead and tested the shutter using the Ethan's Arduino shutter tester (the Cameradactyl guy). It's definitely better than the Schnieder's shutter but actually they both aren't amazing haha so might not be worth the risk. The Schnieder is about 1/3rd stop slower at 1/125, 3/4th slower at 1/250 and 1/500. Whereas the Fujinon is 1/4th slower at 1/125, 1/3rd at 1/250 and 1/2 or so at 1/500.

Speaking of Cameradactyl, thinking about getting an OG for when I can't bust out my 45F2 and would use this lens which is why the faster shutters are more of a factor.

A shutter’s speeds are within spec if they are +/- 30% of the marked speed.

Put the SA front group back in the original shutter and compare when the blades become noticeable.

Your biggest problem if you need a shim with the new shutter.