Fuji. W 150 5.6 vs Symar S 150 5.6 image circle

[John Chang]

Regarding the image circle of these lenses, I see conflicting info:

For the Fujinon, I have seen from 224 (http://www.thalmann.com/largeformat/mid-rang.htm) to 245 (http://members.aol.com/subgallery/byseries.htm)

For the Shneider, most of what I read is 210 (including
Schneider's own page:
http://www.schneideroptics.com/info/vintage_lens_data/)
But I have also seen it at 220:
http://www.largeformatphotography.info/lenses/LF4x5in.html
(This page lists the 150mm APO-Symmar, which I am told is the
same thing as the modern Symmar S).

Can anybody comment on whether the Fujinon really does give appreciably more *usable*
(ie. not suffering from light fall-off) image circle? I suspect this because the Symmar
tends to cost as much or more, and I've read Schneider is known to be modest in their
image circle numbers, whereas Fujinon can be "optimistic" as Mr. Thalman writes.

Any other comments on comparing the two?

Thanks.

[Nick_3536]

The Fujis come in different versions. The higher number is the older single coated version. Newer versions have the smaller coverage.

[Oren Grad]

This page lists the 150mm APO-Symmar, which I am told is the same thing as the modern Symmar S

They're both fine lenses, but they're not the same. The Apo-Symmar is a later design specified to cover 72 degrees rather than 70 degrees as with the Symmar-S, hence the larger image circle. Details of both are available on the Schneider Optics site - the Apo Symmar is still listed under the current photography products, even though it's out of production.

[Walter Foscari]

" ... whereas Fujinon can be optimistic..."
That is certainly true for the older single coated version (writings on the inside of the filter ring). Stay away from those if you are concerned with coverage. Data for the newer series on the other hand has always been close to the truth in my experience.

[Steve Hamley]

A wide(r)-angle plasmat will suffer additional light fall off beyond the image circle of a narrow-angle plasmat according to the laws of physics. All lenses, at least of a given design, will exhibit essentially the same amount of light fall off given the same amount of coverage, so more coverage also equates to more light fall off in the increased part of the image circle - no free ride from one manufacturer versus the other.

Steve

[Mike Kovacs]

Steve, does that not force the manufacturers to decide exactly how fuzzy the image is where "coverage" is deemed to end?

[Dan Fromm]

Mike, go visit Schneider's site. What they do is pretty clear and somewhat scary. Coverage ends where the MTF at quite low frequency is tiny. Without going there again to check, I recall that tiny is roughly 20%, and at that point the MTF curves are near vertical.

Rodenstock, IIRC and I could be wrong, does much the same. Except, that is, in the case of Apo Rodagon Ds. When I had a 1:1 75/4 I looked up its MTF chart, which turned out to look like the central part of a wide angle lens' MTF chart, i.e., very flat curves to the edge. No image at all past the edge, though, because of a field stop. No question about what that lens covers. Not enough for my purposes, alas.

Cheers,

Dan

[Bob Salomon]

"Apo Rodagon Ds. When I had a 1:1 75/4 I looked up its MTF"

There is also a 75mm 4.5 Apo Rodagon D as well as a 120mm Apo Rodagon D. Did you check the curves for these as well?

[Mike Kovacs]

I couldn't find any MTF charts on the schneideroptics.com website for the Symmar and Symmar-S. I don't think they exhibit as sharp a falloff as the more modern LF optics.

[Michael Gudzinowicz]

John,

What is the filter size of the Fujinon 150? See the following table for identification
of the different versions and their specs.

http://members.aol.com/subgallery/byfl.htm

The Symmar S is a good MC lens, but it isn't identical to the APO, and is
well removed from the plain Symmar.

Mike

[Dan Fromm]

Bob, 75/4.5 no, 120 yes. The 120 and 75/4 1:1 are phenomenal lenses. I really regret that the 75/4 wouldn't do for my application.

[John Chang]

Michael,
I don't know the filter size of the Fuji. I bought the Schneider yesterday afternoon.
Yes, I got straightened out as to the difference between a Symmar S and an APO Symmar.
It's a Symmar S. I figured they are all great and the Symmar S was in great condition at
a good price and I could buy it locally face-to-face. I'm just not into buying used suff over
the internet, even though I know many people have fared well there.

Thanks to you and the others for your great help! Now I'm off to have fun with my new
Excellent+ condition Symmar S 150!!

-John

[Steve Hamley]

Mike,

I'm not a lens designer, but based on what I've seen (lenses) and read, not really. Light fall off is roughly cos^4 theta for most lenses, cos^3 theta for those with tilting pupils like the Biogon or some Nikkor designs. The "standard" falloff is why most center filters are indeed usable between brands and models of lenses. Most of the center filters differ by only a half stop, with the "denser" filters being used on lenses with wider angles of coverage. The Schneider chart recommends a 2 stop filter for the 38mm SA, 47mm SA, and the 72mm SA XL, all over 110 degree coverage. All the Schneider lenses 110 degrees and less use a 1.5 stop filter. Naturally, these lenses of a given angle of coverage have wildly different image circles but the same fall off - for example the 58mm SA and the 110mm SS XL both use the same IIIb/1.5 stop filter, but the 58mm SA barely covers 4x5 and the 110mm SS XL will officially cover 5x7 with movement and is of course sharper where the 58mm SA's image circle would be black.

If a manufacturer wants more coverage (a larger image circle that's sharper further out), they can do that at least using bigger glass elements, for example the Rodenstock Apo Sironar-N versus the -S and -W, or the standard Dagor versus the Wide Angle Dagor. But even though the glass is bigger and the "sharp" image circle is bigger, the theoretical light fall off per degree from center is still the same.

Manufacturers certainly define what format or coverage for which they recommend a lens to be used, but that definition seems to depend as much or more on the intended use of the lens as resolution. So the manufaturer's "coverage" for a given lens depends a lot on what they think you're using it for and whether you're interested in distortion or resolution. Process lenses typically "cover" grossly more real estate than manufacturer's recommendations, but if you want to stitch maps together with a defined amount of edge distortion, their recommendations are very likely correct. If you're contact printing single stills on B&W, those manufacturer's coverage figures for process use (which may be based on distortion) will seem (and are) very conservative when all you're interested in is resolution.

If you want the real skinny on what a lens is doing, look at the MTF chart.

Steve