Fujinon 105 SW f8

[HughC]

Would appreciate any thoughts on this lens. Looking at the image circle it has kind of peaked my interest.
Wondering if it would require a center filter.
Thanks

[xkaes]

Many will say, No, but it depends of several factors, including your taste.

I've used the NW 105mm, and currently have the CM-W 105mm. They have angles of coverage of 76° & 78°, respectively. On both, I use a weak CND filter.

Your SW, as well as the NSW version of the 105mm, have angles of coverage of 100°. So it also depends on your film format.

If you are using 4x5 with little shifting, there is about a +50% (+1 f-stop) light fall-off in the corners, but if you are shifting toward the edge of the IC of the SW, or using a larger format than 4x5, light fall-off close to 100° is very substantial -- 2.5 f-stops in the corners.

Compare the light fall off of 75° vs 100° on this graph.



http://www.subclub.org/fujinon/center4.htm

[HughC]

Ok, thanks for your info. Probably just skip this one, filter size is pretty big as well 77mm.

[Mark J]

xkaes, I looked at that graph and then at the article. It appears to be a cos^4 fall-off . This is incorrect for Super-Angulon lens constructions like the Fuji 105. They fall off at approx cos^3 . Hence the fall-off for the Fuji will be better. If you can find a datasheet for the Schneider or Rodenstock 105mm lenses, these will be very close.

For a specific example, the illumination level for an unshifted 5 x 7" negative corner will be 36%, which is -1.47 stops.

[xkaes]

Thanks for that info. Yes, the graph is based on COS^4 fall off.

One more reason to "test it with your own gear".

[Mark J]

To see what it means in practice, I agree yes, but actually predictions are quite reliable if you have some existing reference point. I was looking at a few fall-off graphs in more detail recently, and it's pretty accurate to assume that triplets, Tessars and Plasmats will all be around cos^4 fall-off ; Super-angulons ( & equivs ) and biogons are all around cos^3 , and inverse tele wides ( retrofocus ) for medium format are around cos^2 , although they are a little more variable.

[Dan Fromm]

xkaes, I looked at that graph and then at the article. It appears to be a cos^4 fall-off . This is incorrect for Super-Angulon lens constructions like the Fuji 105. They fall off at approx cos^3 . Hence the fall-off for the Fuji will be better. If you can find a datasheet for the Schneider or Rodenstock 105mm lenses, these will be very close.

For a specific example, the illumination level for an unshifted 5 x 7" negative corner will be 36%, which is -1.47 stops.

Mark, this is interesting if true. Where did you learn that SAs suffer cos^3 falloff?

[Mark J]

I'm a lens designer ( 34 years & counting ) but you can see it on the datasheets from Schneider & Rodenstock & work out the falloff, if you are comfortable with a bit of high-school maths.

[Mark J]

The -,+:+,- construction , often credited to Roosinov (Rusinov ?) , has a couple of key advantages vs. the older designs like the Dagor and Angulon. Firstly they have flat field over significantly larger field angles. Secondly, they have less illumination fall-off, because the ray bundles pass through the iris at a reduced angle, so it looks more circular. As usual in optics, there is never a free lunch. They are quite a bit larger and heavier.

Interestingly, i just found this thread from the forum -
https://www.largeformatphotography.i...a%EFl-Rusinov)

[Joseph Kashi]

Would appreciate any thoughts on this lens. Looking at the image circle it has kind of peaked my interest.
Wondering if it would require a center filter.
Thanks

I have 2 Fujinon 105 NSW lenses, one for each 5x7 field kit. The lenses are very sharp and with good contrast, plus they’re rationally priced. I don’t find them ungainly, and I’m a stickler for compact lightweight field kits, YMMV. Most SA pattern lenses will be very large relative to their focal length, with the exception of the Nikon 90/8, which is also a fabulous lens using 67 mm filters.

Marginal coverage and consequently limited movements would be a significant concern with most non-SA style lenses in the focal range. IIRC, the most readily available and feasible 4x5 alternatives might be the 100mm Wide-Field Ektar and the 108mm (4 3/4 inch) Wide Angle Dagor and WW Wollensak lenses. These are decent but older optics. There’s also the 120mm Angulon. These all have more corner illumination falloff compared to SA pattern lenses.