rdeloe
Well-known member
The Schneider-Kreuznach Componon-S 150mm f/5.6 is another great "bang for the buck" lens. I paid EUR 255 for the lens, so it makes it under the arbitrary USD/EUR 500 threshold for "bang for the buck". You'll see copies for a lot more than that from various vendors. Keep looking if you want one... they regularly sell for what I paid, or less.
This is my fourth try with a version of the CPN-S 150/5.6 if you can believe it. The first three were on my old Toyo VX23D with GFX 50R. I had a lot of trouble with veiling flare, and something about the first three didn't click. But I tried again recently even though I have an excellent 150mm lens in the Mamiya N 150mm f/4.5 L. The Mamiya is great, but it weighs 537 grams with caps and hood, and is fairly bulky. It's also not the absolute best choice for movements because of the way it's built.
But my main issue is the weight. My loaded pack weighs upwards of 22 lbs (nearly 10 kg) and is crammed tight, so I'm conscious of weight and space saving opportunities. On its adapter, as shown below, the CPN-S 150 clocks in at 293 grams, and is much tinier. Healthy young whippersnappers can carry a 10 kg pack all day without noticing, but I notice the weight these days after a full day working outside in the sun! I'll take those 244 grams, thank you very much.

The one I bought is the latest "blue aperture" variant. This is important because there were some stealth design changes that, in my opinion, make this the best option compared to the older designs.
The adapter I'm using is made by RAFCAMERA and takes me from M50x0.75mm (on the lens) to M42x1. It's a perfect fit, and leaves enough (but not too much) room for the rear of the lens. The adapter is treated with a semi-matte paint and has ribbing to break up stray light, but from an abundance of caution I flocked all the inside surfaces that could be hit with stray light.

These blue aperture housings had a little window that lets in light from the enlarger light source to illuminte the aperture scale in a darkroom. You have to cover it with something. I used a scrap of black electrical tape. While you're looking at this picture, take note of the mounting thread (M50x0.75mm). This is an odd size, which makes the RAF adapter a priceless find.

I have two ways to mount this to my F-Universalis: on my custom M645 to M42x1 adapter, or with a flat Copal 1 board an a locking ring on the rear. I use the custom M645 to M42x1 adapter because it also takes my APO-Symmar 100/5.6, and because the M645 board I built takes all my Mamiya N lenses.

The Componon-S was Schneider's penultimate enlarger lens line -- behind only the APO-Componon line, which had a much smaller selection of focal lengths. One of those is 150m so I did look at the APO-Componon 150mm f/5.6. However, they are rare; the MTF charts suggest better, but not vastly better performance; and for what they cost, I'm an APO-Digitar 150 would make more sense. I went with the CPN-S 150 because I think it's the best value for my purposes.
The Componon-S 150mm was designed for enlarging 4x5 negatives, which means it has a large image circle. That's helpful in that it gives me shift that is limited only by the mechanism of the F-Universalis, but it's unhelpful in that an unnecessarily large image circle is a source of stray light. Fortunately, stray light is not a problem with this copy on my setup (more on this below).
Componon-S 150/5.6 lenses are relatively cheap and abundant in older housings, including the B0 and a transitional "steam punk" variant that was used between the old Componon housing from the precursor to the CPN-S and the new B0. The basic CPN-S 150 lens cell design appears unchanged in those earlier variants. However, the version in the blue aperture housing has some important changes. First, there no longer is M42x0.75mm mounting thread on the rear of the cell, as in this example of a Componon-S 135/5.6 in the B0 housing (right). My CPN-S 150 in the blue aperture housing is on the left. The old CPN-S 150 rear cell looks just like the CPN-S 135, but the front lens cell is larger. The B0 housing for the 135mm and 150mm is the same size.

Second, while my blue aperture version was sold for enlargers, it was also sold for industrial applications, where it was used to inspect printed circuits, solar panels, etc. In the latter application, it is a taking lens, and thus Schneider had to deal with the fact that light could be coming through from the rear (enlarger) or the front (taking). I'm guessing here, but I think that explains the changed design of the rear of the front lens cell. Note the ribbed, matte black locking ring of my CPN-S 150mm (right) compared to the shiny locking ring of my old-style CPN-S 135 in the B0 housing (left). Without a doubt this late blue aperture version does not suffer veiling flare to the same extent as my earlier variants used on my Toyo VX23D.

The addition of a matte black locking ring on the front lens cell, possibly to manage stray light, is one important change. I'm really speculating now, but I think Schneider also made a slight change to the optical design; the values in the respective datasheets for the old and new lens versions are slightly different. Or maybe they just changed the way they create their MTF charts, or report the lens parameters. What I can say is that the reported MTF data for the new version (colour) are a bit better than the older version (black and white). Comparing these charts is a mug's game, but here we go...


Is the difference suggested by these two MTF charts real? I've never had an old one and a blue aperture version at the same time, so I can't offer a comparison. But I can say that my blue aperture version is as good as my Mamiya N 150mm f/4.5 L at infinity and f/8, and the Mamiya is a superb lens.
Of course, what you really want to know is, "How does the CPN-S 150 compare to the APO-Digitar 150, which costs a lot more??" You will not be surprised to learn that the APO-Digitar is the better lens... but not by a whole lot where it matters to me. In this chart, the 20 lp/mm sag and tan lines for the APO-Digitar are the first set. At f/8, the APO-Digitar 150 is not a whole lot better than the CPNS-S 150. Where the APO-Digitar 150 leaves the CPN-S 150 for dead is at f/5.6. Clearly that's where Schneider invested its lens designers' energies. However, if you're like me and you generally shoot at f/8 to f/11, this might not be an improvement you'll use a lot.

Now that I've given the lens a good thorough initial evaluation, on its own and against my Mamiya N 150mm f/4.5 L, there's a lot more I could say. But this is a long post already so I'll cut to the chase regarding this bang for the buck lens:
This is my fourth try with a version of the CPN-S 150/5.6 if you can believe it. The first three were on my old Toyo VX23D with GFX 50R. I had a lot of trouble with veiling flare, and something about the first three didn't click. But I tried again recently even though I have an excellent 150mm lens in the Mamiya N 150mm f/4.5 L. The Mamiya is great, but it weighs 537 grams with caps and hood, and is fairly bulky. It's also not the absolute best choice for movements because of the way it's built.
But my main issue is the weight. My loaded pack weighs upwards of 22 lbs (nearly 10 kg) and is crammed tight, so I'm conscious of weight and space saving opportunities. On its adapter, as shown below, the CPN-S 150 clocks in at 293 grams, and is much tinier. Healthy young whippersnappers can carry a 10 kg pack all day without noticing, but I notice the weight these days after a full day working outside in the sun! I'll take those 244 grams, thank you very much.

The one I bought is the latest "blue aperture" variant. This is important because there were some stealth design changes that, in my opinion, make this the best option compared to the older designs.
The adapter I'm using is made by RAFCAMERA and takes me from M50x0.75mm (on the lens) to M42x1. It's a perfect fit, and leaves enough (but not too much) room for the rear of the lens. The adapter is treated with a semi-matte paint and has ribbing to break up stray light, but from an abundance of caution I flocked all the inside surfaces that could be hit with stray light.

These blue aperture housings had a little window that lets in light from the enlarger light source to illuminte the aperture scale in a darkroom. You have to cover it with something. I used a scrap of black electrical tape. While you're looking at this picture, take note of the mounting thread (M50x0.75mm). This is an odd size, which makes the RAF adapter a priceless find.

I have two ways to mount this to my F-Universalis: on my custom M645 to M42x1 adapter, or with a flat Copal 1 board an a locking ring on the rear. I use the custom M645 to M42x1 adapter because it also takes my APO-Symmar 100/5.6, and because the M645 board I built takes all my Mamiya N lenses.

The Componon-S was Schneider's penultimate enlarger lens line -- behind only the APO-Componon line, which had a much smaller selection of focal lengths. One of those is 150m so I did look at the APO-Componon 150mm f/5.6. However, they are rare; the MTF charts suggest better, but not vastly better performance; and for what they cost, I'm an APO-Digitar 150 would make more sense. I went with the CPN-S 150 because I think it's the best value for my purposes.
The Componon-S 150mm was designed for enlarging 4x5 negatives, which means it has a large image circle. That's helpful in that it gives me shift that is limited only by the mechanism of the F-Universalis, but it's unhelpful in that an unnecessarily large image circle is a source of stray light. Fortunately, stray light is not a problem with this copy on my setup (more on this below).
Componon-S 150/5.6 lenses are relatively cheap and abundant in older housings, including the B0 and a transitional "steam punk" variant that was used between the old Componon housing from the precursor to the CPN-S and the new B0. The basic CPN-S 150 lens cell design appears unchanged in those earlier variants. However, the version in the blue aperture housing has some important changes. First, there no longer is M42x0.75mm mounting thread on the rear of the cell, as in this example of a Componon-S 135/5.6 in the B0 housing (right). My CPN-S 150 in the blue aperture housing is on the left. The old CPN-S 150 rear cell looks just like the CPN-S 135, but the front lens cell is larger. The B0 housing for the 135mm and 150mm is the same size.

Second, while my blue aperture version was sold for enlargers, it was also sold for industrial applications, where it was used to inspect printed circuits, solar panels, etc. In the latter application, it is a taking lens, and thus Schneider had to deal with the fact that light could be coming through from the rear (enlarger) or the front (taking). I'm guessing here, but I think that explains the changed design of the rear of the front lens cell. Note the ribbed, matte black locking ring of my CPN-S 150mm (right) compared to the shiny locking ring of my old-style CPN-S 135 in the B0 housing (left). Without a doubt this late blue aperture version does not suffer veiling flare to the same extent as my earlier variants used on my Toyo VX23D.

The addition of a matte black locking ring on the front lens cell, possibly to manage stray light, is one important change. I'm really speculating now, but I think Schneider also made a slight change to the optical design; the values in the respective datasheets for the old and new lens versions are slightly different. Or maybe they just changed the way they create their MTF charts, or report the lens parameters. What I can say is that the reported MTF data for the new version (colour) are a bit better than the older version (black and white). Comparing these charts is a mug's game, but here we go...
- The vertical dashed red line marks the edge of the image circle needed to cover GFX; I added that because Schneider's X-axis is percentage of image circle, unlike Rodenstock which uses mm.
- On the "blue aperture" version (mine -- first chart), the blue lines are 20 lp/mm for sag and tan. Notice how the sag line is running above 80% contrast at f/8 within the GFX sensor area. The green line is 40 lp/mm and the red line is 80 lp/mm. Clearly Schneider considered this a high performance lens, which makes sense given the purposes for which it was sold and used.
- In the B0 version (bottom chart), the middle sag and tan lines are 20 lp/mm. Notice how sag is at ~77% contrast for f/8 within the image circle covered by the GFX sensor. It's not a huge difference, but if it's real and not just a measurement or reporting variation, then it matters.


Is the difference suggested by these two MTF charts real? I've never had an old one and a blue aperture version at the same time, so I can't offer a comparison. But I can say that my blue aperture version is as good as my Mamiya N 150mm f/4.5 L at infinity and f/8, and the Mamiya is a superb lens.
Of course, what you really want to know is, "How does the CPN-S 150 compare to the APO-Digitar 150, which costs a lot more??" You will not be surprised to learn that the APO-Digitar is the better lens... but not by a whole lot where it matters to me. In this chart, the 20 lp/mm sag and tan lines for the APO-Digitar are the first set. At f/8, the APO-Digitar 150 is not a whole lot better than the CPNS-S 150. Where the APO-Digitar 150 leaves the CPN-S 150 for dead is at f/5.6. Clearly that's where Schneider invested its lens designers' energies. However, if you're like me and you generally shoot at f/8 to f/11, this might not be an improvement you'll use a lot.

Now that I've given the lens a good thorough initial evaluation, on its own and against my Mamiya N 150mm f/4.5 L, there's a lot more I could say. But this is a long post already so I'll cut to the chase regarding this bang for the buck lens:
- At f/8, the CPN-S 150 is terrific right across the GFX frame, and keeps on being terrific as you shift. It remains excellent at f/11, and is a strong performer (subject of course to diffraction's toll) at f/16. These are the apertures I use, so for me it's a winner.
- At f/5.6, it's fairly awful at longer distances. There's plenty of detail in the images, but there's also very low contrast and glowiness, and a bit of purple fringing can show up in some high contrast areas. These problems are greatly reduced at f/6.7, and gone at f/8. I'd use the lens at f/6.7 without hesitation if I needed that aperture.
- Shift capacity is excellent. As the MTF chart suggests, image quality is excellent within the part of the image circle that can be used on my GFX plus F-Universalis outfit. A 30mm rise in portrait at a distance of ~ 1 metre at f/11 produces excellent image quality. I also had great results with 25mm of shift in landscape (the most my F-Universalis can manage) at infinity and f/11. Maximum shift performance at f/8 is only slightly less strong than f/11.
- There's plenty of swing and tilt room with the CPN-S 150. I can get greater than 15 degrees of tilt, but swing is limited to around 14mm before vignetting starts. This is about the same as the Mamiya N 150.
- Flare and ghosting are amazingly well-controlled. Schneider never says it's multi-coated, but Robert O'Toole said that it was; he knew people inside Schneider USA so I'll take his word for it. I tested it without a hood or any protection with the sun within the lens' angle of view, and experienced only a slight contrast reduction. My previous earlier (non-blue aperture) copies were quite hopeless in that situation -- overwhelmed by veiling flare until I installed a special rear baffle.
- Purple fringing on the edges of out of focus things against sky and other bright areas in the corners is minimal to non-existent unshifted at f/8. At full shift, I saw a bit at f/5.6, but I saw as much with much more expensive lenses, and it cleans up nicely.
- If this lens has any distortion or field curvature, I have been unable to detect it.
- Colour is nice, by which I mean it's the same as my Mamiya N and G lenses, and my other Schneider lenses, and I like those.
- If this lens has a weakness, it's out of focus areas at distance and wide open. I'm not a bokeh enthusiast, but if I was I'd call it "nervous and jittery" wide open. Closed down a bit, it's fine, and it seems to be the most jittery and nervous at longer distances.
- Best of all, I can focus down to about 1.5 metres on my F-Universalis with the standard rail and the wide angle bellows. If I throw on an extension tube, I can get even closer. The image I posted here today is ~ 50 cm.
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