Rodenstock doesn't specify. My friend at Schneider told me two years ago that they were the only company making aspherical elements for LF lenses. Unless Rodenstock has come up with new technology since then, I'll stand by my statement.
He said the reason is simple: the R&D to create the manufacturing process for aspheric elements in those sizes was enormous. The company also faced very high failure rates for the first two years, which meant it took them a long time to recoup their investment. No one else in the optical industry was willing to take on such a high financial risk for such a relatively small market.
It was all about the $$$. He's the first to admit that none of the lens companies are able to keep conceptual secrets from each other. It's all about manufacturing technology, not design.
All the lens manufacturers are capable of making aspherics today. In 1993 the Rodenstock catalog shows aspherical diamond turned lens elements with the following specifications:
focal length ±5%, Back focal length ±5%, outside diameter maximum 400mm min. 1mm, center thickness ±0.02mm. For precision pressed max. dia. 60mm min. dia. 7mm.
Remember, these were their manufacturing capabilities in their June 1993 catalog, almost 18 years ago.
So your friend at Schneider may have been taking some license with other company's technologies.
Oh yes, in that same catalog Rodenstock also shows that these aspherics could be single sided with the other side of the element spherical or both sides aspherical. In addition it also lists Rodenstock's diamond turned aspherical mirrors.
But again, the shape of the elements isn't the question. The results on film or onto a digital sensor or array is the answer. And that you see in the MTF curves, fall off curves, distortion curves and the longtitudinal chromatic aberration curves. That is what will tell you how well the image will be catured at the image plane.
I don't know Bob. I don't see Rodenstock making the kinds of LF designs that are made possible by aspherics. Nothing like the XL lenses, which perform like the last generation wide angle lenses but weigh half as much and have wider maximum apertures.
Rodenstock may have the technology to make aspherics of a certain type, but they don't seem able (or willing?) to make these same advanced designs that Schneider is implementing with their aspherics.
You're right that the shape of the elements isn't the question. It's the characteristics of the end design (and it goes beyond optical quality ... Schneider's designs don't seem to substantially improve optical performance, but they improve everything else).
I dont have any of these lenses. I'm happy with the optical performance of my older design wide angle, and don't mind carrying around its cinder block form factor. I have a Super Angulon and am sure I'd be equally happy with a Grandagon. But if I were backpacking with the thing, or needed a brighter focusing image, I'd be turning to the XLs, as a lot of other people on the forum have.
Have you checked out the 23mm and 32mm? Although these are for digital but they are the latest technology.
If a lens (or any other technology) gives you the result you want, what does it matter how it does it? This is beginning to sound like digisnap mavens comparing megapixel count to the exclusion of everything else.
And Germany has been making aspheric elements since about 1943 (Zeiss binocular oculars), so it's been doable in some fashion for many decades.
They are ill discoverers that think there is no land, when they can see nothing but sea.
Good point, John.
Many of us were standing by to see who eventually wins this pissing contest.
"Just because you are able to argue the other guy down, doesn't necessarily mean that
you won the argument."
I apologize for the pissing contest. I was trying to provide some even-handed pros and cons that represented minor exceptions to general rule that both brands make equally great lenses.
It's degraded to tit-for-tat over minutiae because of what strikes me as deliberate obfuscation by one of the lens companies' sales reps.
Yes. And as I said in my original post, I think Rodenstock has leapfrogged Schneider in digital lenses. If I had the money to buy a digital technical camera system today, I'd almost certainly go with these.Have you checked out the 23mm and 32mm? Although these are for digital but they are the latest technology.
I think the weak factor will not be the lens anyway it will be:
1. the man behind the camera
2. the registration of the groundglass and film
3. are the standards of the camera 100% exatly as they should be
4. the wind!
Of course that's true. There are myriad factors which can enhance or degrade any particular image.
I've always subscribed to the philosophy that I use the best products available.
That way when something goes wrong, I need only look in the mirror to place blame.
'Tis a poor craftsman indeed who blames his tools.