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  1. #71
    Mark Fisher's Avatar
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    Back to the original question.....Any of the quality name, modern 150 or 135 will be fine. In my experience there is more variation between lenses. Unless your enlarger is well aligned, I'm not sure how you could know a see any difference anyway. I am happy with my 135 componon s. If it has light fall off, I see that as a feature since I like to darken the edges subtly anyway.
    Your first 10,000 pictures are the worst - HCB

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  2. #72
    ic-racer's Avatar
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    Quote Originally Posted by polyglot View Post
    That said, enlarger lenses tend to be very much of the older robust designs that are easy to manufacture. While there is some sample variation, they still tend to be diffraction-limited and with little lateral CA; the APO versions have reduced CA. Enlarger lenses are not ultrazooms and they are not complex. While I'm sure you can find an occasional Really Bad one, it's not common and not nearly as bad as the sample variation seen on the really complex new designs.
    Real life example to demonstrate the point. I had inadvertently mis-seated one of the rear elements of a HM APO Componon during re-assembly. I'd say it was almost 0.5mm sideways. Six months later I decided to use the lens and was perplexed that the projected image was not side-to-side sharp after the laser alignment. I went and re-aligned the lensboard based on edge-to-edge sharpness with the Peak-1 magnifier. The results were surprisingly good and gave good prints during the printing session. To show how far off it was, laser beam needed to be about one centimeter off center to get the best print. Surprisingly all the prints (about 5x magnification) from the session were sharp, none needed to be re-printed.

    My conclusion is that a significantly mis-centered enlarging lens can be used if one aligns the lens so all 4 corners are sharp with the Peak-1, rather than making the lens barrel perpendicular to the baseboard.

  3. #73
    Greg Davis's Avatar
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    In the optics industry, we have a phenomenon called "prism" that relates to how much the physical center of the lens must be offset to cause a noticable shift in the optical center. The stronger the correction factor of the lens, the less it needs to move to be out of whack.
    www.gregorytdavis.com

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