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  1. #11
    2F/2F's Avatar
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    I would say that for 90% of common photographic uses, and for someone with an average income and budget, the APO designation is not worth twice as much. Even lenses that are older than dirt are FINE. The best photos ever were taken on lenses that don't come close to the on-paper quality of today's lenses.

    Have you simply tried extension tubes? Not the same effect as a longer lens, but they will help quite a bit. Oh yeah. They're cheap in comparison as well.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

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  2. #12
    Lee L's Avatar
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    The "three wavelength correction" information that edz supplies is a correct description of traditional APO design. It doesn't guarantee, however, that the term APO is used consistently by manufacturers to mean exactly that, and the degree of difference between APO and achromatic designs varies as well.

    My only experience with a direct comparison of APO vs non-APO within a brand was with 180mm focal length lenses for Leica R, comparing their 180mm f:3.4 APO aerial reconnaissance lens (designed for military, but made available to the general public) to a regular 180mm lens. I don't recall if the regular lens tested was their f:4 or f:2.8, it was 30 years ago. The comparison shot was of the back of a car across a parking lot shot on Kodachrome 25 and the camera on a tripod in full sun, with specular chrome highlights off the bumper. There was a sticker on the bumper with fine print, a parking permit with multiple colors and black text. That sticker was much better defined in the APO shot, with no color fringing and text that was much easier to read. The non-APO shot wasn't bad, but at high magnification, the APO clearly outperformed it.

    That particular 180 APO was designed for performance at greater distances (being an aerial recon lens) and Leica provided their 180 f:4 with a helical that focused closer because it performed better at short distances.

    An APO should perform better than a non-APO from the same maker in both B&W and in color, but not all APOs are designs that truly fit the classic definition, being more ad hype than achieved design goals. APOs often contain extra corrective elements, special refractive index glass, or aspherical elements to achieve APO performance. That drives the prices higher. There are also other aberrations besides chromatic that contribute to a lens' performance, and those have to remain well corrected.

    The term APO has been stretched (if not abused) in many products, but many others do meet the classic definition, and are clearly better than their achromatic counterparts. The proof is in the negative/transparency. Sorry I can't help you with direct experience or second hand reports on the Mamiya gear.

    Lee

  3. #13

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    Thanks chaps, I'm assuming that the APO designation means that there is some element in the optical formula which reduces chromatic aberration in this longer focal length lens. I was just wondering if this improvement would actually be visible in a real photo rather than just on an optical test bench. I'm slightly suspicious as the Mamiya lenses are already very very good, and I wonder if I'm likely to notice the differece. For example, the floating element in the 65mm Sekor C is supposed to ensure edge to edge sharpness, so I ran some tests, taking shots of a piece of printed text at 1 m distance, and setting the floating element to 'infinity', then to '1m', exposures were flash, tripod mounted, mirror lock-up on FP4. I enlarged the neg to a 16"x20" print and I'm damned if I can see the difference where the floating ring was set. I can see the tiny smudges of ink on a piece of font size 16 printed text at a meter, but no real difference between the two. So I figure they are already very good lenses and any improvement would be beyond my powers of observation!

  4. #14

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    Quote Originally Posted by Lee L View Post
    The "three wavelength correction" information that edz supplies is a correct description of traditional APO design. It doesn't guarantee, however, that the term APO is used consistently by manufacturers to mean exactly that, and the degree of difference between APO and achromatic designs varies as well.

    My only experience with a direct comparison of APO vs non-APO within a brand was with 180mm focal length lenses for Leica R, comparing their 180mm f:3.4 APO aerial reconnaissance lens (designed for military, but made available to the general public) to a regular 180mm lens....
    ....That sticker was much better defined in the APO shot, with no color fringing and text that was much easier to read. The non-APO shot wasn't bad, but at high magnification, the APO clearly outperformed it.....

    An APO should perform better than a non-APO from the same maker in both B&W and in color....

    Lee
    At high magnification the difference should be apparent. The comparison of two 180mm lenses in 35mm format would be similar to a comparison of the 360KL and the the APO 350 Mamyia lenses. I would expect to see, at high magnification, a better performance by the APO 350 over the non-APO 360 but not such a difference between the those in the shorter focal lengths, such as 210 - 250, APO vs non-APO.

    The need for APO designs - to correct for chromatic abberation - increases as focal lengths increase from 200mm in MF. This is the reason why there are no APO lenses offered in focal lengths less than 200mm (Mamyia RB). The correction isn't needed.

    Paul
    "Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing." Stephen J. Gould

  5. #15
    Chazzy's Avatar
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    Quote Originally Posted by panastasia View Post
    The need for APO designs - to correct for chromatic abberation - increases as focal lengths increase from 200mm in MF. This is the reason why there are no APO lenses offered in focal lengths less than 200mm (Mamyia RB). The correction isn't needed.
    So it's focal length that matters, not magnification? Would you mind saying more about this? I'm fascinated.
    Charles Hohenstein

  6. #16

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    Quote Originally Posted by Chazzy View Post
    So it's focal length that matters, not magnification? Would you mind saying more about this? I'm fascinated.
    Chromatic abberation (color fringes) are more difficult to correct for when designing telephoto lenses. It's a light refraction characteristic of these types of lenses - inherent in the design - and you might say that magnification does matter since it's synonymous with the longer focal lengths; telephoto lenses, telescopes, microscope objective lenses, etc.
    "Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing." Stephen J. Gould

  7. #17

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    Um, Panastasia, how about long focus lenses of normal construction, as for example most process lenses? I ask because I shoot a variety of process lenses, focal lengths 135 mm (too short to be included, here for completeness) to 480 mm with no color fringing or softness issues. Some have "Apo" in their name, others don't, all are very well corrected. And of course my tiny little 700/8 Questar of nothing at all doesn't have color fringing problems. Motion control is hard with it, though.

  8. #18

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    Quote Originally Posted by Dan Fromm View Post
    Um, Panastasia, how about long focus lenses of normal construction, as for example most process lenses? I ask because I shoot a variety of process lenses, focal lengths 135 mm (too short to be included, here for completeness) to 480 mm with no color fringing or softness issues. Some have "Apo" in their name, others don't, all are very well corrected. And of course my tiny little 700/8 Questar of nothing at all doesn't have color fringing problems. Motion control is hard with it, though.

    Dan,
    I cannot answer your questions, I'm not an expert in optics, I was generalizing. Apo designs generally apply to the longer focal lengths in a lens series, designated 'telephoto'. I don't own any apo lenses and don't have any color fringing or softness issues with the lenses I own. I can say that they're all very well corrected, but to what degree? Good enough for me.

    I consider Apo lens design to be at the cutting edge of the technology but the improved performance of these doesn't attract me. Double the price for slightly improved image quality doesn't fit my needs (or budget). I guess this is my answer to the original question the OP asked. "Is it worth it?"
    "Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing." Stephen J. Gould

  9. #19
    Lee L's Avatar
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    Quote Originally Posted by Dan Fromm View Post
    And of course my tiny little 700/8 Questar of nothing at all doesn't have color fringing problems.
    Reflector/mirror optics with a corrector plate, right? There's no inherent chromatic aberration with reflector/mirror optics because there's no differential refraction of varying wavelengths when the light doesn't pass through varying materials with different refractive indices, air/glass/air. You can make a rainbow with a prism, but not with a front surface mirror.

    Lee
    Last edited by Lee L; 05-16-2008 at 01:13 PM. Click to view previous post history.

  10. #20

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    The Mamiya APO lenses are called APO because they use low-dispersion elements, same thing as Nikon ED glass, every lens manufacterer has a name for it. The APO designation does not neccesarily mean that the lens has no chromatic abberation, so it is still not a true apochromat. But I've found that the low-dispersion elements does help make a difference.

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