It's also the basis for the high end flatbed scanners like the Scitex EverSmarts.Originally Posted by richardman
It's also the basis for the high end flatbed scanners like the Scitex EverSmarts.
Not to quarrel with you, but the trick was mastered before 1910. See http://trichromie.free.fr/trichromie.../27/PERIGRAPHE
Engineering wide-angle lenses for digital capture without color fringing is trickier than doing it for conventional film. Maybe what you are thinking of is the Sinar Epolux system, which originally cost a small fortune, but now somebody would probably have to be paid to haul it to the dump. It worked with an automated rotating turret with the necessary RGB filters. That kind of thing might be nice for someone to cannibalize on a 3-shot sequential color film camera. It only worked with still life or otherwise stationary subjects.
I have owned a Kodak Zeiss Protar V (in the Volute shutter, because of some of those engineering constraints), and I still own a beautiful Darlot lever-stop wide angle, that both predate that advertisement. They're very good lenses, but the engineering problems were far from solved: they have significant light fall-off around the edges, they have tiny apertures, they often require bag bellows or dedicated cameras just to focus, and they permit almost no movements. Yes, they can make beautiful images, in the right hands (unfortunately, not mine).
I've been looking to buy a Perigraphe for a couple of years, I just haven't found the right bargain yet. I do own a later clone, a Cooke (?) 'Luxor' f6.8 for 5x7, that is an amazingly good lens. I should use it more often.
Jody, what you're really saying is that you find bright modern w/a lenses with flange-focal distances > focal length easier to use than old crocks whose flange-focal distances nearly equal to focal length. You didn't mention what I see as one of modern w/a lenses great advantages over the old blunderbusses. Modern w/a lenses are usually in shutter, the ancients are often in barrel.
Interesting that you think the f/6.8 TTH Luxor is a Perigraphe clone. I've wondered what they were, suspected triplet because of low original price. Perigraphes (f/6.8 and f/14) are Dagor types.
The place to look for f/14 Perigraphes is ebay.fr. Try leboncoin.fr too. Going rate depends on focal length. 90/14s typically go for around 100 Euros.
I once again wrote a post without bothering to go upstairs and check the lens in question. The Luxor is an f16 lens, though only because the iris is mechanically blocked from opening any further. It appears to be a WAR design. I do periodically look on ebay.fr (and uk) for lenses, but 100 Euros is still over my budget for an ancient lens. Plus I'm looking for something in the 240-300mm range and they usually go for a lot more.
Bob - BH website is showing the 150 Sironar S as being discontinued and unavailable. Same with View Camera Store.
They are both wrong. But then this is the internet.
The 135, 150 and 210mm APO Sironar S lenses are in current production.
Also, in the USA, while no longer manufactured, there are still one each of the 65mm 4.5, 90mm 6.8 and 90mm 4.5 Grandagon-N lenses still available new.
@Richardman
A bit OT but FYI here's a link to the book I mentioned.
http://www.amazon.com/Planning-Compu...ystem+buchholz
I still have mine here somewhere and I'll rustle it up one of these days.
"I am prepared to accept that the 'digital' wides have a few tweaks in their design to optimize them for digital sensors instead of film (an obvious one is using retro-focus designs on small-sensor cameras [compared to my 8x10] due to size constraints, but it's not like a retro-focus wide-angle is a new invention). Beyond that, I do remain firmly in the camp that says the marketing material is just that, marketing material. I don't mean they're trying to sell inferior product by using a load of hype (a polite way of referring to animal husbandry by-product). Just that they are trying to create a need. But then much of the digital photography world has more to do with hype and marketing than it does with photography. So perhaps they are correctly reading their customer base, which, with a few exceptions, is not us."
Both yes and no. At first look, the older lenses are quite fine with a digital back. I got a stitching back and put it on a 4x5 camera with a couple nice analog lenses, and the images were just fine. Ahah, (I thought) they were messing with us, these older lenses (58, 90) are just fine. And on center, they were.
The problem was at the edges - and especially with stitching and moving the smaller digital back around. With modest shifts, say 5mm, they were fine, but at about 15mm shift, or say (if you do the math) at the edge of a 60-80mm lens circle, they began to not look so nice. A bit of distortion, a bit of smearing, and when looked at critically, they just weren't there. Some of the later "analog" lenses, like the 47XL, still work well with digital, but one generation older and there are real limits to working with them. Its not just marketing.
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