Nikkor (S) lenses?

[Matt Blaze]

The little instruction booklet that came with my new 90/4.5-SW has a table of all the current (as of when they stopped making them, at least) Nikon LF lenses. About a third of the lenses, mostly (but not exclusively) the SW lenses, have an S in a circle next to the name. For example, the 90/4.5-SW and 150/5.6-W are (S) lenses (and my 90/4.5 came with a big (S) sticker on the box), but the 150/8-SW and 200/8-M are not.

I can find no explanation anywhere for what the (S) is supposed to mean. Other lenses don't have other circled lettters -- it's either (S) or nothing -- and it doesn't seem to correlate with any obvious design feature documented elsewhere (number of elements, covering power, shutter type, etc).

So what's the (S)?

Apologies if this is an impossibly dumb question. But in my defense I'm new here, so please don't eat me alive if it is.

Thanks

-matt

[Oren Grad]

The Nikkor large format lens reference table in the 2003 Nippon Camera annual that I have explains the "S" as designating lenses in shutters that have a 7-bladed iris. If you check your listing, I expect you'll see that the S lenses are all in Copal 0. The "S" is to differentiate them from lenses mounted in earlier versions of the Copal 0 that had 5 blades.

[Matt Blaze]

Ah, thanks for the explanation. Indeed, all the (S) lenses have #0 shutters. However, not all the #0 shutters are (S) lenses (the 105/3.5-M being the exception), which is is why I had assumed it had nothing to do with the shutter type.

Thanks for the quick reply!

-matt

[Oren Grad]

(the 105/3.5-M being the exception)

Interesting... As best I can tell from my references, the 105 M was deleted from the Nikon line more than a decade ago. If that's right, it would make sense that it was offered only in the older shutter type - but leave open the question of why it's still included in an instruction sheet packed with a late-production 90SW.

Anyway, welcome to the LFF, and enjoy your new lens!

[Struan Gray]

Oren, can you say when the switch to 7-bladed irises occured? Do you know if all modern Copal 0 shutters have 7 blades - i.e. can I buy one blind and expect to get 7 blades?

I have a couple of lenses whose stopped-down bokeh is merely tolerable.

[LH1H17]

I have a Nikon W 105mm, as well as the W135, W150, AM120, SW65, SW75, SW90, SW90 f8, and SW120 (still missing the M200 :( ). All have the newer 7-bladed "s" copal #1 shutter. I've seen Nikon marketing that mentions this as a "Nikon exclusive", perhaps suggesting that other manufacturer's copal #0 shutters still have 5 blades only. Can anyone confirm / disprove this?

I'm not sure when the change happened but I have a Nikon catalogue from 1995 with all copal 0 shutters of the "s" type. :)

[Oren Grad]

The change occurred before 1995, for sure; I'd have to do some deep excavation in my files to see how far back I have literature before that. In rummaging through my lens collection I found, to my surprise, that a 150 Sironar-N in all-black Copal 0 that I have, actually has a 5-bladed iris. So perhaps this dates the change to sometime in the mid '80s.

No, it's not a Nikon exclusive, though perhaps they were the first ones to get the 7 blades. The Copal shutters used by Nikon have slightly different cosmetics than those used by the other lens makers, so perhaps they had some special deal with Copal. But so far as I know, all Copal 0 shutters have had the 7-bladed iris for many years now.

Struan, although comparing a 5- and 7-bladed Copal has now lodged itself somewhere on my "to do" list, I'd be surprised if you saw much difference in the OOF character of the same modern lens mounted in a 5-bladed Copal vs a 7-bladed Copal, apart from situations where you are getting specular highlights that show the diaphragm geometry directly.

[Gordon Moat]

My Nikkor-W 180mm f5.6 has the seven bladed Copal #1 shutter. However, I am not finding any "S" designation anywhere on it. This is the Copal shutter with the chrome shutter speed setting rim, and I am fairly certain the lens dates before 1995.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

[Oren Grad]

Gordon, I think the "S" designation was used only for the Copal 0's.

[Eric James]

Just to confirm what has already been said, looking at the most recent (last) LF Nikkor lens pamphlet: only Copal 0 shutters lenses carry the S designation - on the box and on the shutter. They include the SW 65mm f4, 75mm f4.5, 90mm f8 and f4.5, and the 120mm f8; the W 105mm f5.6, 135mm f5.6, and the 150mm f5.6; the M 200mm f8; and the AM ED 120 f5.6.

[Struan Gray]

Thanks Oren

Here at undergrowth central a five-bladed aperture manifests itself as a distracting crystallinity of the background. I haven't made direct tests between the same lens in different shutters, but comparing shots taken with my 150 Sironar-N (Copal 0, 5-blades) with my 150 Symmar (Copal electronic 1, 7-blades) I have come to the conclusion that a heptagon is close enough to a circle for my eyes, but a pentagon is not.

The difference is especially clear when comparing MF photos taken with my 150 and 250 mm lenses wide open (when the aperture is round) and stopped down even one stop (pentagon). The visual effect is more distracting than just the background becoming more distinct as you stop down: texture appears parallel to the sides of the pentagonal aperture. I interpret this as a half-way house between defocus-and-aberrations and the pure pentagon of a background specular highlight - a convolution with an aberrated pentagonal window.

In LF I usually use longer lenses in larger, 7-bladed shutters for the sorts of photos where it matters, but I have been idly speculating about trying to find a rounder aperture for my 150 Sironar-N. I like the look of the lens otherwise - especially the clarity of the colour rendition - but at close-ish distances and wide-ish apertures with a background made up of densely-hatched lines it doesn't please me in the way my old Symmar does. I'd like a combination of the transparency of the Sironar and the less fractured background of the Symmar.

I haven't seen any mention of a 7-blade option in the specs I have seen for loose shutters bought new, but perhaps it is only a question of asking. I'll probably just wait until a Apo-Sironar-W drops into my lap at a bargain price, but if it's possible to buy a 7-bladed Copal 0 I suppose that's more likely to happen before hell freezes over. A Nikon 150W isn't a pricey item, even by my stringent standards.

[Oren Grad]

Struan -

The ultimate test, of course, is to look at the same glass with different iris diaphragms.

I ran a simple comparison test on 5x7 a while back, with a 150 Sinaron-WS (Apo-Sironar-W) in a very late Compur 1 with a 10-bladed, near-circular iris, and a 150 Apo Sironar (W) in Copal 1 with 7 blades. At least eyeballing the negatives, it was difficult to tell much difference in medium-distant (across the backyard) bokeh.

Close up, and with 5 vs 7 blades rather than 7 vs 10, things could be different. The one corner of subject space where in my experience the Apo-Sironar-N/S design shows a bit of soft frizz is in close range OOF stuff near open aperture. I suppose a convolution of the aperture shape with a close-ish background of densely hatched lines could produce some fireworks.

As luck would have it, I do have a 150 Caltar II-N (Apo-Sironar-N) in 7-bladed Copal 0 on hand as well as the 150 Sironar-N in 5-bladed Copal. I guess I ought to just run that comparison and see.

EDIT: Can you hazard a guess at a particular subject configuration (focus distance / background distance) that you think is likely to show this behavior at its worst?

[Struan Gray]

I think Chris Perez has done something similar, swapping glass between shutters with different numbers of blades. I don't know if the photos are still up on his site though.

My most egregious examples are of autumn and winder undergrowth with more undergrowth in the background. I can't remember where you live, but if you have a briar patch nearby they are perfect at this time of year.

The absolute worst case I have is a photo of a Turk's Head Lily stalk four feet or so away from the camera, with a background of hawthorn, lime and ash seedlings about five feet behind that. That was with a 150 mm lens on 6x6, but now I know what to look for, I get edgy even in LF at repro-ratios of 1:2 or 3 especially when there is a busy, line-dense background about twice as far away as the subject. I find it very hard to judge the final effect on the ground glass, so it's the only time I bracket - in aperture/DOF.

[Oren Grad]

The absolute worst case I have is a photo of a Turk's Head Lily stalk four feet or so away from the camera, with a background of hawthorn, lime and ash seedlings about five feet behind that. That was with a 150 mm lens on 6x6, but now I know what to look for, I get edgy even in LF at repro-ratios of 1:2 or 3 especially when there is a busy, line-dense background about twice as far away as the subject.

OK, that's useful. No briar patches in these parts - but plenty of bare branches in the snow.

I agree, I can't judge bokeh on the ground glass either - in that respect, I think a GG is not WYSIWYG at all.

I've seen Chris's tests - a very ambitious piece of work. Alas, the space of possibilities - optical designs, diaphragms, subject configurations - is so large that it seems there are always surprises, and always more to learn...

[Oren Grad]

Here is Chris's test, for anyone who wonders what we're talking about:

http://www.hevanet.com/cperez/test/BigMash210.html

[Struan Gray]

Here are a pair of scans that illustrate some of the ugly things that can happen with pentagonal apertures. They are 6x6 MF negs, but they are of the sort of subject I like to use LF on if I can manage the logistics.

To my eyes, the occasional highlight pentagon is distracting, but not actually too bad to look at. Keith Laban used to have some wonderful defocussed images on his website which were entirely made up of such hard-edged pentagons (but they obviously didn't sell, so they've gone :-). The real horror is the odd angulated texture where overlapping pentagons of various hues combine to produce a traffic accident in the rear of the image: you don't want to look, it's nasty when you do, but you just can't help being drawn to look at it.

The photos are taken wide open at f2.8 and stopped down at f11 with a 150 mm lens on 6x6. The lens was almost at it's closest focus (4' or so), and the background saplings the same again behind the lily stalk.

PS: I know the stopped down image is ugly as hell anyway - this was an attempt to isolate and examine what I thought I was seeing turn up in other less blatently bad images.