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12-05-2014, 09:58 PM   #16
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Lenses are really subjective. Even the reviews will not tell you a lot about a particular lens because so many photographers may use a lens differently to the next person and what may come across as a beautiful lens to one photographer may be panned as a dud by another. I didn't bother much with the Pentax lens database and bought up on lenses that I had experience with in 35mm and extrapolated to the 6x7 format. The one lens I did seek referral on and scrutinise was the 75mm f2.8AL. I did my homework with that one and also used one from a friend and was instantly smitten.

12-06-2014, 09:43 AM   #17
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Well, the 75/2.8 AL is way out of my budget for now. I'm really mostly interested in a good wide angle and a decent moderate telephoto to supplement the single lens I already own -- the 135mm f/4 "macro" -- which should really be called "close focus" from what I understand. Although I'll probably add a 105/2.4 to the system just to have at least one fast lens.
12-06-2014, 03:05 PM   #18
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The 55mm and 45mm f4 newer (SMC Pentax designation) lenses would be a flying start into the quality of the 67 lenses -- these are both exceptionally sharp (in fact, I put the 45mm f3 "just ahead"of the 75mm f2.8, but there really isn't a critical difference) and the angles of view suit myriad subject matter (45mm for landscape, especially). Add the 90mm 2.8 or the 104mm and you're set for 90% of photographic opportunity.
12-07-2014, 03:24 PM   #19
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Silent Street, I've already determined that the 45mm will be the WA lens for my 67. Being the 35mm equivalent of a 24mm, it just makes so much sense. When I bought my first 24mm for my 35mm SLR, I'll swear that my 28mm never came out of my bag again after that. To this day, I have 28mm lenses in my outfits -- never bought them deliberately, they were just part of outfits I've bought -- and I don't really know why I've kept them because the 24mm's get all the WA use, unless of course, I have something wider, like a 20mm or a 17mm. :-) There's nothing a 28mm can do that a 24mm won't do better, and I'm sure I can relate that to the 67: there's nothing the 55mm can do that the 45mm won't do better.

Yeah, I've been weighing the value of a 90mm LS, but of course it's slower than the 90/2.8. And honestly, I don't really need a 67 leaf shutter lens because I own a nice Bronica ETRSi with a few lenses, all of which are leaf shutter. It's "only" a 645, but that's plenty big enough for most instances I've come across. And the 104, being just a bit faster than the 90/2.8, but more importantly, a bit longer than the 90 is, for my way of thinking, a better choice.

I'm also still thinking very seriously about getting a 300mm f/4 -- despite the cautionary words from some of you. I think I have the experience with shooting slow, heavy outfits such that I should be able to get decent exposures, and I definitely have the gear -- three stout tripods and one monster tripod.

I also have a lathe and a milling machine and I'm thinking that a good project might be to see if I can fashion some sort of tripod mount for the 300mm. I won't know how possible it will be until I can hold one and see what sort of restrictions I'll be dealing with. But I think that if I can fabricate a mount, that will take care of much of the problems associated with the setup. Maybe even a dual mount that supports both the lens and the camera, given that the 67's quite a bit of weight to be hanging off the end of a lens. I wonder -- has anyone tried this sort of thing? They've bound to. I'd rather not have to reinvent the wheel if somebody else has done all the figurin' to get it working.

12-07-2014, 05:21 PM   #20
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The old 300 can be a good lens, it just depends what you are trying to do with it. Hand held portraits work well, but tripod work is another story, unless you are doing long exposure work. I owned this lens for 15 years and considered making a tripod mount for it. But there was just not enough room to attach the mount onto the lens. There is a good reason why Pentax put a tripod mount on their newer 300 (EDIF). The use of the 200mm Pentax with the 1.4X TC turned out to be sharper than the 300 Takumar. Part of the reason for this has to do with the 300 having 5 elements while the 200 + 1.4 has 10.
12-07-2014, 11:31 PM   #21
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More elements does not necessarily make for a sharper lens, however. Perhaps a better corrected one. I have two old telephotos built by Century Precision Optics of Hollywood, CA, called the Tele Athenar II 500mm f/5.6 and 650mm f/6.8 telephotos. Each lens is composed of a single well-corrected achromatic doublet. That's it -- just two elements that are glued together. Each lens has an optical flat in the front and the rear of the tube, but they don't add to the resolution or the power. These lenses produce exceptionally sharp photos, which are actually well corrected for CA as well. So, sometimes, less is more.

Just to put my, well, images where my mouth is, here's a shot of the moon, one day past full, taken with my Canon XS DSLR (10.1mp) and the CPO 500mm f/5.6. Exposure was f/11 at 1/125 at ISO 100. Shutter was up for the exposure, so there was no shutter bounce to deal with. Oh, and this is right at a 100% crop, what with the camera being only 10mp and a 500mm focal length still magnifying the moon maybe a quarter of the height of the frame, even with an APS-C format camera.



But your comment is noted. I've found from my own testing that a top quality teleconverter, in contrast to the myth that a TC degrades an image, actually can noticeably improve an image in terms of detail resolution. So, I don't disbelieve for a minute that the 200mm with the 1.4x can achieve outstanding results. I just wonder if its because of the additional elements, is all.

Wish I could afford both lenses and the 1.4x to see what sort of test results I'd come up with. I just blew a bunch of money on a 45mm f/4 tonight, so I'm feeling a bit poor at the moment. I found that KEH is not the only photo store out there with good prices and a good inventory of 67 gear. Roberts Camera of Indianapolis also has a ton of 67 gear and their prices are just as good as KEH's -- as are their warranties: 6 months. I went with Roberts for this 45mm for a couple reasons -- a $10 off offer and free shipping. Every little bit helps. $266 shipped to my door for a late 45mm with both caps in EXC condition.
12-08-2014, 10:24 AM   #22
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QuoteOriginally posted by cooltouch Quote
More elements does not necessarily make for a sharper lens, however
Agree, it can be done and I do remember the Century 650, as a friend had one in the mid 70's. They were fine performers but they were somewhat slow and that fact gives a clue as to why they were able to get away with using only 2 elements. Oblique aberrations are not a major consideration with slower lenses and therefore the axial aberrations were the major consideration using each element surface to correct an aberration. Century probably used exotic glass that could have actually corrected 3 colors (an APO doublet). The Leica Telyt 400 and 560mm lenses for their Leicaflex cameras were slow and used a doublet as well. For faster telephotos with more oblique aberrations, two elements would be impossible to use successfully. Designers need degrees of freedom (element surfaces, glass types, surface curvatures etc.) to be able to correct all major aberrations, not to mention higher order aberrations. More elements, in general provide this freedom. But more elements are not a guarantee of performance but there is a correlation.

I believe that the 200 Pentax + 1.4X is so sharp is because each piece of the optical system is so well corrected. The 200 is based on the German Ernostar design, also seen in the 180mm Leica Elmarit-R. A proven design combined with a TC that is obviously corrected for all seven aberrations and one ends up with a sharp system.

"...in contrast to the myth that a TC degrades an image, actually can noticeably improve an image..."

I agree, as the TC intercepts the rays before they reaches the focal plane. This means in a long lens with secondary spectrum colors separating, a highly color corrected TC will prevent further separation and reduce CA at the focal plane. This is seen with the 600 Takumar and 1.4X.

I know of Robert's having lots of 67 equipment but National Camera Exchange used to as well.

Last edited by desertscape; 12-08-2014 at 12:05 PM.
12-09-2014, 09:17 AM   #23
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Years ago, I had the pleasure to meet the then past president of Century Precision Optics, and I told him about the 500mm f/5.6 I had purchased just shortly before then. He told me, and I quote, the 500/5.6 consisted of a "well-corrected achromatic doublet." So it isn't an APO, but I'll tell you what, it's close to it, and f/5.6 for a 500mm lens isn't exactly slow, although f/6.8 for the 650 is somewhat. Both lenses, in fact, have identical diameters, just different powers.

I find myself agreeing with everything else you've written, except I wasn't aware of the design pedigree of the 200mm. How about the 300mm f/4 -- do you know what design it is modeled after? I've tried googling it, but haven't had any luck so far.

12-09-2014, 10:46 AM   #24
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The 300 mm five element design is very similar to the 250mm Telyt-R f/4 designed for the Leicaflex SL-2 and later R series cameras. The only real difference was that Leica had a cemented achromat near the rear, while the Pentax had a single element there. Both had an air spaced APO triplet up front and a single negative element at the rear (probably used to flatten the field). Both used conventional glass, so there was some difference in color focus by lens zone (spherochromatism). Both lenses are most probably APO but only in the narrow Zonal area of the optic. The 300 shot wide open in high contrast scenes will color fringe in violet, meaning that some of the poorly corrected Marginal colors are not focusing at the focal plane. These lenses are both telephoto designs but to call the 300mm a Telyt-R based design is a stretch. Sub-designs within the telephoto category are not well differentiated.
12-09-2014, 11:11 AM   #25
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Thanks for that. Where do you get this data, might I ask? I''ve got a couple of old Joseph Cooper 2-volume loose leaf sets for Nikon and Minolta, which show the optical construction for every lens of each manufacturer that were being made at the time, and I have a couple of Canon F-1 tomes that show the same with Canon lenses.I even have a couple of smaller books on some Leica lenses. With the exception of the Leica books, I don't believe they discuss the design types and names. And I've yet to run across anything similar to these for Pentax lenses. I like having this sort of reference material handy.
12-09-2014, 11:45 AM   #26
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I have loads of cross sections from various brands (mostly Pentax Medium Format, Leica and Zeiss). Many cross sections are from Pentax and Leica sales brochures and owners manuals. I also have a background in Optics and lens design. I recognize the cross section heritage of many Pentax designs and am happy to share that with those interested. I believe that most Japanese optical firms don't like to advertise the connection between German designs and their own.

A really good book that addresses design types is by Rudolf Kingslake, called, "A History of the Photographic Lens".

Last edited by desertscape; 12-09-2014 at 12:22 PM.
12-12-2014, 03:38 AM   #27
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Appreciate that. I'll see if I can turn up a copy somewhere. Well, I can't say I have a background in optics, but I did try to pay attention to the basics when optics were being discussed in my college physics class. That was probably quite elementary compared to a more thorough background. And I've often wondered where a person picks up a background like that. I've seen engineering specialties that included mechanical, chemical, civil, heck, even petroleum. But never optical. I've always thought that would be a cool specialty to have, though.

Oh, and by the way, I took you guys' advice, and ordered a late 200mm f/4 for my 67, and also a gray 2x for it. The lens is coming from Indianapolis, but the 2x is having to come from Japan, so it'll take a bit longer to get here. I might still pick up a 300/4 later on down the road and see for myself if I can tame what is, to me, only a moderate telephoto.
12-12-2014, 11:20 AM   #28
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Optics is rarely a part of an Engineering department of a university. It is usually a sub-part of the Physics dept. With the University of Arizona, the Optics dept is a separate entity. My background in Optics is not formal but self taught over 20 years.
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