big vs little lenses

[uniB]

I just picked up a cheap Schneider Angulon 90mm f6.3, what confuses me is how this lens can be so small compared to my Nikon SW 90mm f9. What is too be gained from such large lenses compared to the smaller lenses out there? Is quality compromised with small lenses? I guess this can't always be the case when lenses like the Fujinon 240mm A is so well respected.

[Ron Marshall]

I just picked up a cheap Schneider Angulon 90mm f6.3, what confuses me is how this lens can be so small compared to my Nikon SW 90mm f9. What is too be gained from such large lenses compared to the smaller lenses out there? Is quality compromised with small lenses? I guess this can't always be the case when lenses like the Fujinon 240mm A is so well respected.

The Angulon 90mm f6.8 has an image circle of 154mm, which does not permit movements on 4x5. The Nikon has an image circle of about 235mm, whice permits ample movements.

See Kerry Thalmann's article on lightweight lenses:

http://www.thalmann.com/largeformat/wide.htm

[uniB]

Oh yes, image circle, of course, I should have thought of that!

[IanG]

Also don't forget the more modern larger lenses apart from better coverage have far superior all round performance across all their aperture range.

Ian

[Kerry L. Thalmann]

While the older, smaller wide angles can be useful, especially for backpacking where weight is a concern, they are a compromise. Sorry, no free lunch.

As others have mentioned, the bigger lenses have greater coverage. They are also generally sharper in the corners and reach their peak performance at wider f-stops. The 90mm f8 Nikkor SW offers outstanding performance corner-to-corner (and beyond) on 4x5 at f11 (or smaller). To get any movements at all with a 90mm f6.8 Angulon you need to stop down to f32, and it won't be as sharp either in the center, or the corners as the Nikkor at f11, f16 or f22.

Also, the newer lenses have less illumination fall-off than the "classic" designs.

That said, if you shoot straight on and stop down to f22, a 90mm Angulon can provide excellent results on 4x5 - just make sure you have a good sample and you don't push the movements or the corners will start to go soft and the illumination fall-off will become noticeable.

For backpacking I use a hand picked 90mm f6.3 Congo WA as my standard wide angle lens on 4x5. It's a different design than the Angulon (think of it as a modern, multicoated version of the classic Wide Field Ektar), but coverage limitations and overall performance are in the same ballpark as the similarly sized 90mm Angulon. I've made some of my best images with that little lens. I also have a few where I pushed the movements too far and ended up with very noticeable vignetting in the corners. As I said, no free lunch.

Kerry

[Nick_3536]

Kerry I notice your piece on lightweight lenses doesn't have numbers for the Fuji-w F/5.6. Do you want me to find mine and a scale? IIRC your filter numbers are also bigger then mine.

[Ole Tjugen]

...
For backpacking I use a hand picked 90mm f6.3 Congo WA as my standard wide angle lens on 4x5. It's a different design than the Angulon (think of it as a modern, multicoated version of the classic Wide Field Ektar), but coverage limitations and overall performance are in the same ballpark as the similarly sized 90mm Angulon. I've made some of my best images with that little lens. I also have a few where I pushed the movements too far and ended up with very noticeable vignetting in the corners. As I said, no free lunch.

That's one of the practical differences between double-Gauss (Congo) and "reverse Dagor" (Angulon): The Gauss clips sharply at the edge of coverage, the Angulon goes to mush. Personally I often find mush more acceptacle than black corners.

[Dan Fromm]

Ole, might you be confusing inherent characteristics of the 4/4 double Gauss wide angles with manufacturers' decisions?

f/6.3 WF Ektars and Cooke Ser. VIIbs are both 4/4 double Gauss types, seem nearly identical, but Ser. VIIbs are claimed to cover 100 degrees while WF Ektars are claimed to cover only 80 degrees. A while ago I dismantled an 80/6.3 WF Ektar, found a field stop at the front of the rear cell. That's why WF Ektars have less coverage.

[Ken Lee]

Lens design has improved over time, with regards to image fidelity, coverage, etc. These are considerations of prime importance for landscapes, product shots, etc.

For portraits and other subject matter, where technically perfect rendering is not the goal, vintage lenses are sometimes used. Some of the old lenses are quite large, because they were designed as portrait lenses for use with large film, and open to rather wide apertures. Others can be small, because they consist of fewer elements than modern lenses.

They give a more shallow depth of field, and render out-of-focus areas in a flattering way. Some of them produce internal reflections and optical aberrations that contribute to the look.

[Void]

Is there a difference between Schneider Angulon 90mm/6.8 and Wollensak Raptar Wide Angle 90mm/6.8? If no, as I suspect, then why thw Wollensak ones are cheaper?

What's the difference between Wollensak 90mm Wide Angle and Extreme Wide Angle
http://www.cameraeccentric.com/html/info/wollensakl/p4.html except that one is much darker?

[Ole Tjugen]

http://www.cameraeccentric.com/html/info/wollensakcatd/design.html

Totally different. You just read the wrong page. :)

[Gene McCluney]

Is there a difference between Schneider Angulon 90mm/6.8 and Wollensak Raptar Wide Angle 90mm/6.8? If no, as I suspect, then why thw Wollensak ones are cheaper?


I don't know the optical differences, but I do know, from a performance standpoint, the Raptar has a sharper cut-off of image at the edges and has less covering power (for movements) than the Angulon does. I have (stopped down) achieved decent results with the 90mm Angulon on 5x7...sure can't do that with the Raptar.

[Void]

Ole, You are right. Wollensak is 4 elements in 4 groups and Schneider is 6 elements in 2 groups (here) (http://www.schneiderkreuznach.com/archiv/pdf/an_su_1963.pdf).
What difference in reality I can expect?

[Ole Tjugen]

The difference - apart from what Gene McCluny just mentioned about the cutoff, under similar conditions (and assuming similar coating) the Angulon should have slightly better contrast.

I use an uncoated 210mm f:6.8 Angulon on larger formats (8x10" to 12x16") where it gives very good results. An uncoated 4 in 4 would be very much more difficult to use, and impossible to "stretch" to 12x16".

[Arne Croell]

Ole, might you be confusing inherent characteristics of the 4/4 double Gauss wide angles with manufacturers' decisions?

f/6.3 WF Ektars and Cooke Ser. VIIbs are both 4/4 double Gauss types, seem nearly identical, but Ser. VIIbs are claimed to cover 100 degrees while WF Ektars are claimed to cover only 80 degrees. A while ago I dismantled an 80/6.3 WF Ektar, found a field stop at the front of the rear cell. That's why WF Ektars have less coverage.

Dan, that kind of stop is pretty common in 4/4 double Gauss lenses. In addition to the W.F. Ektars, it is also used by the Leitmeyr Weitwinkel Anastigmat (a cheap version of a stop,by painting part of the inner meniscus of the back cell black), the Voigtländer Ultragon, which has a double Gauss front (by limiting the maximum aperture setting mechanically), and the Rodenstock Geronar WA 90mm, which has them on the inside of each cell. The Cooke VIIb is more the exception than the rule.
I would not qualify them as field stops - a field stop limits your field of view, keeping out light that will not be used in the image area. The film gate or a compendium are field stops. A stop that is 100% a field stop should be rendered in focus in the image plane. The extra stops in those lenses are physically quite close to the aperture stop (or are the aperture stop, as in the case of the Ultragon), so they are also closer to an aperture stop in their optical use. My understanding is that these stops are used to keep the spherical aberration of these lenses in check.

[Dan Fromm]

Arne, so they limit maximum aperture rather than vignette?

[Arne Croell]

Arne, so they limit maximum aperture rather than vignette?
Yes, pretty much. I tried a larger opening with the Ultragon once, since the blockage of the aperture to 5.5 is just done by a little screw on the outside of the shutter. After removing it and opening the aperture more, things got brighter but also became mush immediately with a haze over everything. They need the larger glass elements for the angle, I assume, but not the maximum aperture that would result from the rims of the lenses acting as the max. aperture.
To spin this a little further, the double Gauss-derived Planar types usually don't have those stops, but they are a) better corrected for spherical aberration and b)the inner negative menisci are much thicker and by tapering towards the inside provide that stop by their rim, whereas the 4/4 Gausses use thin menisci which don't allow that taper.

Just speculating here, but I recognize that the Cooke VIIb has much larger radii ("flatter surfaces") of their lenses than most other 4/4 Gauss lenses I am familiar with. Maybe thats the reason they did not need it?

[neil poulsen]

My idea of downsizing lenses would be to drop from an f5.6 to an f8 super-wide 90mm lens. This maximizes image quality. Also, why photograph with large format, if one can't use movements?

[Peter K]

My idea of downsizing lenses would be to drop from an f5.6 to an f8 super-wide 90mm lens. This maximizes image quality. Also, why photograph with large format, if one can't use movements?
This was used with the 120mm Hologon, but this lens was only buildt in a prototype and never in series.

Peter K