David: > What I suspect is the manufacturers were having the marketing guys write > up > whatever they liked to convince buyers that they needed new lenses - aside > from the obvious problems of using lenses designed for 35mm on what is > often essentially a competitor to 110 - and this is no different from the > issues one would experience using a Pentax MF lens on a 35mm camera. :I'm allergic to "conspiracy theory", and this has all the hallmarks of that to my ear. I am not a believer of conspiracy theories, believing more that incompetence, ignorance or greed is behind many of such things.. :However, I'm not an expert myself and so I can't exactly explain everything that's really going on, either. I just don't believe that there aren't experts who would blow the scam writing blogs on the internet. Eventually this would become news at a level I would see it. Not all companies do such things knowingly (they're not all 'experts' even when they work in the fields)- I know from personal experience that divisions within Canon have utterly no idea what other divisions are doing - when companies get that big it's inevitable that things go screwy. Especially when the marketing guys are seen by the company as the people who have the most direct affect on the incoming dollars :( In the college I was at, the marketting people seemed to never consult with the staff on the floor (or even directors). Subsequently we had a year long promotional pamphlet that had to be redone as the front illustration showed people breaking 3 occupational and health rules of the college. Our most highly qualified and awarded staff member of some 10 years in photography didn't rate a mention while staff who had left 3 years prior were still named as student contacts (on incorrect phone numbers). This is one of the largest colleges in the state I'm talking of. .. I was the senior technician for 1200+ students and 50+ lecturers.. not a small operation. Something bigger - Kodak didn't understand why their selenium toner wasn't working at preserving images (I wrote about this here before with refs and a statement by the scientist behind this revelation and kodaks' admission) - but they still kept selling it - coz it sold Kodak also didn't seem to understand the chemistry behind their own antihalation dye in the tmax range of films either. The dye was probably developed in an obscure division within Kodak for its own reasons and communication between this branch and the film guys may have been poor (wild speculation on my part) - whatever.. the solution they advocated was unneccesarily longer wash times when all that was needed for a short wash time was a lower pH. As to whether it woulkd become newsworthy, well, it all starts somewhere and then there has to be people who care. Atop that, the explanation relating to the term "telecentric" is relatively new to me - prior to that it was vague claims of light hitting at certain angles. Maybe a marketing guy hit on this term recently and it's taken off from there. I'd certainly like to know more. > Shiny is another one that gets me. Some film surfaces have been *very* > shiny, and atop that, some very pale - reflecting a *lot* of light around > inside cameras. : None of the film I've used has had shiny surfaces that I can recall; particularly not on the emulsion side. And I was making the point that that meant it could reflect actual images, rather than just blurs. My point was that people are more likely to notice actual ghost images than mild flare blurs, and hence were more likely to complain about them, making it perhaps worth worrying about improving some aspects of the lens, that being the part the lens-makers can control. Assuming 100% refelctance, an image would not be formed elsewhere in the camera to create a ghost image as it would be out of focus at the point the light struck the other surface - and should that surface reflect back again to the film or sensor it would just be adding fog. :I did have a fascinating experience involving TTL flash and a film with an unusual reflectivity. It was the Polachrome slide film. Interesting film that - some fascinating properties :) :I was using it on-stage at the World Science Fiction Convention in 1989 (in Boston). I'd been in charge of photography for a retrospective slide show on the convention, to be shown at closing ceremonies. This was pre-digital, so presenting slides at the end of the convention was a slight financial challenge -- we had to pay a lab for extra hours and special courier service. To carry through the theme of "immediacy" we planned to have me take a photo on-stage at the beginning of the ceremony, which would appear at the end of the slide show. Hence, Polachrome. I'd done a test run with a previous roll, so I was slightly familiar with the processing mechanics. It hadn't occurred to us that exposing the film would turn out to be a problem, and the test roll didn't show a problem (it was done by available light). Here's your case for making your test conditions as close as possible to real conditions, and losing sleep over any differences at all :-). oh absolutely! =) :Speaking of losing sleep, I was also running on two hours of sleep the previous night, due to having been up all night processing film (the last night we didn't have time to send it to the lab, so we processed 65 rolls ourselves) and marking and sorting the rolls (I did the initial technical quality control before handing it over to the people who did the final slide show; I was also responsible for the photo team and handing out assignments). I was very lucky. When I started shooting pictures on stage before the ceremony begin (I had 36 to play with, after all), the flash reported inadequate light under conditions where this was not believable. If the problem had been slightly different, I would have had no symptoms until the roll came out of the processor horribly overexposed. Luckily, I had a symptom, and I got as far (at the time) as figuring out that there was something wrong with the TTL exposure system. I switched to A mode, and the symptom went away, and I got a usable slide for the show. nice - and this clearly demonstrates your being a 'photographer' rather than a camera operator. (nice job too - it's always interesting to hear peoples experiences in tough conditions, congratulations!) :Later, after some sleep, I realized that the Polachrome film was visibly very much darker than "ordinary" color and B&W films. Doh! I should have noticed that earlier, of course. Just like I should have done a test using exactly matching conditions, meaning TTL flash, before the night of the actual use. lesson learned.. :Some of Ctein's work on brightness ranges I remember as coming to the conclusion that flare was the limiting factor in anything short of very extreme controlled conditions. and a good reason to use a lens hood! :) I use a hasselblad bellows type one on my 35mm gear masked down to the frame size - it makes quite a difference on not just contrast but overall sharpness and image quality :Note that Leica has published diagrams and photos (and I think there are third-party photos) showing an offset micro-lens placement (varying across the frame, centered in the center, offset at the edges) in their M9 and I believe M8 cameras, which they say are specifically to make them work better with old rangefinder wide-angle lenses (and new ones, designed for film). I don't feel I have any reason to doubt that oblique rays are an issue for digital sensors. It's been repeatedly said by experts from a wide range of companies, and the outside experts aren't calling them on obvious mistakes. This is of course very different from being an expert qualified to really argue the question, from either side, myself! Herein lies a problem I have. Experts. being science trained, I am not given to trusting experts. Oh sure, someone with a pile of peer reviewed articles and a body of recognised research in the given field can be judged to be more reliable, but I should be able to confirm their research or at least examine in depth their findings, revelations, work or whatever. Diagrams just don't cut it when there is the capacity to show actual images of said sensors, and my searches to date haven't produced much - so naturally I doubt until I see something. here's one image: http://www.chipworks.com/uploadedImages/Blog/Test_Blog/Nokia6(2).jpg and more http://www.chipworks.com/blogs.aspx Actually, these guys look like experts ! "Canon seems to follow the "if it's not broken, don't fix it" philosophy. For example, Figures 3a and 3b show the pixel BEOL from the EOS 5D and EOS 5D Mark II, respectively [6, 7]. Essentially the same fabrication process was used on these two sensors, fabbed three years apart and used in markedly different classes of DSLR. Despite a modest evolution in pixel architecture, to date Canon's pixel fabrication seems to be locked down, and we suspect Canon is getting significant performance gains from its Digic line of image processors." (ie, the processors are doing the work, not the sensors ..) i'm going to spend some time digging around here.. i'd like to see more images. again, a light pipe and a hemispherical lens are going to gather the light quite well at the normal angles an image producing lens yields and I can't comprehend the need for parallel light (if the sensors were flat with no lens then yes, I could..) ;) > Again, I'd love to hear from anyone who owns a 'digital' lens made by a > manufacturer who claims any such thing who can look through the lens and > see if the aperture look *really* far away (like infinity?) :I've got a Sigma 12-24mm F4.5-5.6 EX DG ASPHERICAL HSM lens. That "DG" is their "for digital" mark ("DC" is their mark for lenses for small-frame digital, that won't cover the full 35mm frame; this lens covers the full frame and hence is DG rather than DC). So I'll look when I get home. I've also got the AF-S NIKKOR 24-70mm f/2.8G ED. They say "Fast-aperture, high performance wide-angle zoom optimized for FX and DX-format sensors and features Nikon's ED Glass and Nano Crystal Coat." Does that count as sufficiently "digital" for you? I can check it, too Unfortunately I no longer have the 17-55/2.8 DX, I sold it off when I got my D700. Thanks David.
