My Lens Opus
I should put this in context first: Any lens on this list is wonderful and has, in my opinion, very good to excellent quality. They are in that top tier Otus / Sigma Art / best Canikonsony place on the shelf. Some are a bit better than others, but all can be used with any digital back available, including the IQ4 150. All this is IMO, so take it for what it is worth; not much...
Most of us say, “Pick the widest lens you want then gap up from there.” That’s a reasonable approach. Or if you have a favorite focal length, pick that and gap up/down from there. Don’t forget that you can do two-image stitches by shifting the back. For example, with the sk60xl and the back in the portrait orientation, shifting left/right ~15.5mm gives you a 54x72, 4:3 stitched image. In “FF” equivalents, the 60mm becomes a 29-39mm mini-zoom; the 90hr-sw becomes a 44-58mm zoom (in FF equivalents). Most of these lenses handle that amount of shift except for a few of the wider Schneiders (sk28 and sk35).
For a three-lens kit:
The cost/weight be damned options:
- 32hr, 90hr-sw, 138hr-sw float.
- 32hr, 50hr, 90hr-sw
The sensible really good alternatives; just depends on what FL spread you want:
- 40hr, sk90 apo-digitar, sk120N or sk150N
- Sk35xl, sk72/70hr, sk120N
Mix and match to your heart’s content.
Wide:
- Sk28: Very good, but you really should have the IQ4 150 to go with it. Too much color cast for any shift on other backs. Needs the CF.
- 32hr: Excellent lens, big, heavy, expensive and you need to transport it with some care; don’t walk with it on the camera attached to the tripod over your shoulder. If you want the absolute best wide lens and don’t care about weight or filter size, this is it. 86mm filter threads
- Sk35: Very good out to about a 10mm shift. Really a 36mm. Need a CF or the IQ4 150. Smaller and lighter than the 40hr. No distortion vs the 40hr.
- 40hr: Very good, slightly better than the sk35 with much less color cast. Can shift ~ 15mm. Really a 42mm.
- Sk43xl: Very good if you can find one. On par with the 40hr, but more color cast. If you have the IQ4 150 this is an excellent option. Any other back the 40hr is probably the better choice.
I’ve owned the sk43xl, 40hr and the sk35. I sold the sk43 to get the 40hr because with Alpa you cannot tilt the 43, but you can tilt the 40hr. After several years of not using either lens much, I realized both of those options are not really wide enough for me. 42/43mm is ~ 28mm equivalent, which I’ve never connected with. I prefer ~24mm and 35mm FF equivalents. I now have the sk35, which I really like. Although again with Alpa I cannot tilt that lens.
I would pick the one that fits your needs and not worry about the slight difference in quality from one to the other. The most popular and “safest” option is the 40hr.
50-75mm:
- 50hr: A bit larger than the others, but excellent lens with a very usable image circle. Probably the best of the bunch, with the sk60xl on par or close.
- Sk60xl: Another excellent lens with very big image circle. A bit smaller than the 50hr, but you need the CF with anything but the IQ4 150.
- 70hr: Splitting hairs between this and the sk72. 58mm filter threads.
- Sk72: See above. However, the 72 is really a 75mm.
All these are excellent lenses. Again, choose based on the focal length you want, and where it fits with other lenses. You may skip over this range initially. See how you get along with the technical camera “gestalt” and then decide. That being said, personally this is my most-used focal length. I had 70hr but wanted something a bit wider. I moved to the sk60xl and love that lens. It is my one-lens kit.
90-120mm:
- 90hr-w: The older Rodenstock digital design, “90mm f/5.6 HR Digaron-W.” Very good lens on par with other options except the hr-sw below.
- 90hr-sw: Best lens of the 90-100mm options. Very sharp in the whole image circle out to >100mm. Expensive and heavier with a 72mm filter thread.
- Sk90 apo-digitar: If you are ok with the slightly degraded performance off-center vs the 90hr-sw, this is a great, light lens w/ 40.5mm filter threads.
- Sk100 apo-digitar: Similar to sk90; just a focal length choice. Harder to find.
- 100hr-s: Smaller stated image circle, but it is actually larger than stated. 58mm filter threads.
- Sk120N apo-digitar: Similar in quality to the other schneiders in this range, just longer. Still, 40.5mm filter threads.
- Sk120 asph: Schneider released this lens not long before they got out of the business, so there are not many out there. I’ve never seen an MTF graph but by all accounts, it is one of the best lenses available. 110mm image circle.
This is perhaps the toughest choice. If money and weight are no object, then the 90hr-sw is the winner. The sk120 asph is probably as good, but hard to find. The other 90-100 options should all have about the same quality. My opinion in this range: if you can afford the 90hr-sw and don’t mind the size, go for it. If one of those two things is a limitation for you, the sk90 is almost as good, and the smallest/lightest of the bunch.
If you prefer the longer 120mm focal length, then spend some time trying to find the asph, but don’t lose too much sleep if you can’t find one. Many people love the sk120N.
I’ve owned the 100hr-s, 90hr-sw and now the sk90. My original two lens kit was the sk43xl and the 100hr-s. The 100 got decentered at some point. Instead of repair I traded it in for the 90hr-sw. After using the 90hr-sw for several years, I recently moved to the sk90 to lighten my kit and help fund the IQ4 150 upgrade.
>120mm:
- 138hrsw-float: Dealers now have this in their hands. There are probably a few out in use but I have not heard any user reports. It should be the best lens out there. Huge image circle sharp out to the edge. $12-15k, long and heavy. Two kilos of pure love. Note f/6.5, but probably plenty sharp wide open.
- Sk150N: 40.5mm filter threads. 40.5mm! Punches way above its weight, but not in the rarefied air of the 138 above. Similar quality to the 90-120 field (not counting the 90hr-sw / sk120 asph)
- 180hr-s: this is a really good lens, especially if you have a bellows-based technical camera vs. helical mount. The helical mount version is pretty long; that takes up a lot of space in the bag. Like the 100hr-s, the useable image circle is larger than stated.
Technical cameras are not known for longer lenses. At this point many adapt to other, older lenses. The Zeiss/Hasselblad 250/350 superachromats are popular.
My current lenses: sk35, sk60xl, sk90 apo-digitar, sk150N, Zeiss 250 superachromat. I care a bit more about size and weight and am willing to sacrifice a bit of sharpness at the edges of image circles to get there.
Whew. If you got through this you must really be interested in a technical camera.
Dave