Enlarger lens options.

Discussion in 'Darkroom Developing and Printing' started by otzi, May 7, 2008.

  1. otzi

    otzi Guest

    I am well aware that probably all modern enlarger lenses are pretty good.
    The question arises, is the Componon HM series any advantage for black &
    white printing
    over the Componon -S
    I am pretty thick about reading any graph curves but the Componon - S curves
    seem flatter than the HM ones.

    The Rodenstock charts seem to be a lot easier to understand, well they are
    marketed as such anyway.
    Would the lens folk of this community consider the APO-Rodagon - N enlarging
    lenses to be on a par with the
    HM series or the Componon - S series? And does it matter. What about bigger
    magnifications, say 12X.

    Would all the modern (new) enlarging lenses, apart from the amateur series,
    perform equally to the eye.
     
    otzi, May 7, 2008
    #1
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  2. Isn't the APO Rodagon-N intended for copy work as a taking lens?

    --
    Charles Hohenstein (to reply, remove Gene Robinson)

    "The sad huddle of affluent bedwetters, thumbsuckers,
    treehuggers, social climbers, homophiles, quavery ladies,
    and chronic petition signers that makes up the current
    Episcopal Church . . ." -‹Thomas Lipscomb
     
    Charles Hohenstein, May 7, 2008
    #2
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  3. otzi

    Peter Guest

    As I recall, the HM lenses permit a bit more magnification with a
    given set-up because they have a somewhat wider field. This permits
    using a shorter focal length lens and thus more enlargement.

    If you need that, it would seem to be of interest. You may be right,
    that there is something given up getting the wider field.

    Even so, extracting the last bit of performance from whatever lens is
    also an issue. You also need pretty good technique to see the
    advantage of a lens that is claimed to be better than the Componon-S
    (or a Rodagon). In particular, you need to eliminate vibration,
    eliminate any misalignment, focus accurately and avoid any curl or pop
    in the negative (for big negatives, this may mean a glass carrier).
     
    Peter, May 7, 2008
    #3
  4. otzi

    otzi Guest

    As I recall, the HM lenses permit a bit more magnification with a
    given set-up because they have a somewhat wider field. This permits
    using a shorter focal length lens and thus more enlargement.

    If you need that, it would seem to be of interest. You may be right,
    that there is something given up getting the wider field.

    Even so, extracting the last bit of performance from whatever lens is
    also an issue. You also need pretty good technique to see the
    advantage of a lens that is claimed to be better than the Componon-S
    (or a Rodagon). In particular, you need to eliminate vibration,
    eliminate any misalignment, focus accurately and avoid any curl or pop
    in the negative (for big negatives, this may mean a glass carrier).

    I just wondered if the HM was more for colour work, rather than B&W.
     
    otzi, May 7, 2008
    #4
  5. otzi

    Peter Guest

    Sometimes Bob Salomon posts on this board and he would have more
    details at his fingertips.

    My opinion is that unless you need the extra coverage the obvious
    choice is whichever is cheaper. It wll be hard to see a difference in
    image quality between the lenses using either B&W or color. The
    Componon-S, the Rodagon, the Nikon and the HM Componon are excellent
    lenses (usually - individual variation or especially damage in a used
    lens is possible).
     
    Peter, May 7, 2008
    #5
  6. Sometimes Bob Salomon posts on this board and he would have
    more
    details at his fingertips.

    My opinion is that unless you need the extra coverage the
    obvious
    choice is whichever is cheaper. It wll be hard to see a
    difference in
    image quality between the lenses using either B&W or color.
    The
    Componon-S, the Rodagon, the Nikon and the HM Componon are
    excellent
    lenses (usually - individual variation or especially damage
    in a used
    lens is possible).

    One problem with "wide angle" enlarging lenses is light
    fall off. Fall off is due to geometric properties and
    increases with the image angle. It can be reduced to some
    degree in some types of wide angle lenses but I don't think
    this principal is used for enlarging lenses. As an example I
    use a 135mm lens for enlarging 4x5 negatives and must burn
    the corners. Standard for this format is 150mm but 180mm
    would be better for corner to corner uniformity, however, it
    would require a very long throw (tall column). I concur
    that unless you need a wide angle lens because of lack of
    projection space its better to use a longer focal length.
    As far as the MTF charts from the various manufacturers
    go they really don't tell you much. Rodenstock's chromatic
    correction curve shows that their "apo" lenses are not
    apochromatic but acromatic and AFAIK so are Schneider's.
    This really makes no practical difference because both lines
    are very well corrected.
    For the most part the older Schneider Componon-S is
    excellent and there is not a lot to be gained by using newer
    and much more expensive lenses although their performance is
    marginally better.
    BTW, one of the reasons for the redesign of both
    enlarging and camera lenses in the last couple of decades is
    the lack of certain kinds of optical glass due to some
    components being considered environmental hazards. For
    instance arsenic was a common ingredient in glass to clarify
    it and must not be used now. Since some of the glass
    constants have changed the designs have had to be changed.
    Not a big deal with computer assisted design but it does
    require making some changes. The original Tessar could not
    be built now because the glass types it calls for are no
    longer available.
     
    Richard Knoppow, May 7, 2008
    #6
  7. Perhaps, this might help solve your quandary or, at least, be
    enlightening.

    Years ago, a friend of mine, a Rochester Institute of Technology graduate
    in the photo processing and laboratory fields, owned a pro lab, a dream
    of his. He had all manner of enlarging lenses of all makes and models--
    Componons, Comparons, Rodagons, and some I'd never heard of. One day,
    the Rodagon rep came in and gave him a couple Apo-Rodagons to try out.
    They were a new design. To make a long story short: He ended up
    replacing EVERY enlarger lens in the lab with Apo-Rodagons for both color
    and b&w. He said that you could actually see the improved image quality
    with the naked eye even in an 8x10 print, and they did prints up to 8x10
    feet. But to truly benefit from the superiority and flatness of field of
    the lenses, you had to use glass carriers to hold the film perfectly
    flat, and all the stages of your enlarger had to be in perfect alignment
    and parallel to the vacuum printing easel.

    Stef
     
    Stefan Patric, May 8, 2008
    #7
  8. I've accumulated a large number of good lenses over some time and also
    recently got about 20 more in a purchase of a pro lab /business odd
    lot. I decided to test the most desirable ones for my own duty and
    took time with a Versalign rig to get all planes in proper alignment
    for a run through.

    The 40HM, 45HM and Rodagon APO 50 were judged about equal and all were
    only slightly ahead of the standard Rodagons and Componon-S but only
    discernible at higher magnifications. The single Nikkor 50 2.8 was
    slightly less sharp than the others mentioned but this could easily be
    a single sample variation as these enjoy a good reputation. An odd
    Fujinon 49.9 EFS did very well and was nipping at the APO heels and I
    believe anyone would be happy with it. A 63mm Nikkor was also in this
    same class as was a 40WA Rodagon.

    The Rodagon 80 APO and Componon HM 90 seemed equal to each other and
    in practice these show a very slight advantage for the Rodagon as
    there is something about how it renders mid tone/skin tones that is
    especially nice, at least with my materials and practices. Again, the
    standard Rodagons and Comp-S did well against these until more extreme
    enlargement sizes. A Nikkor 80 showed poorly but it had a bit of dust
    internally and may not have been a good sample. A single Componon S
    100 did nicely and did slightly better than a pair of 105 Nikkors.

    It was fun to have all of these nice chunks of glass all in one place
    for some comparisons. I learned that I could likely be happy with
    most any of them but use the APOs in general use for little more
    reason than the psychology of having the best glass on the machine. I
    would describe myself as "fussy" regarding optics and I'll admit that
    this entire exercise had me conclude that it is truly hair-splitting
    to discern any real world difference in any of these good quality
    choices. Perhaps if I worked in color, I would find characteristics
    that would favor one over another. In black and white, my best tools
    for quality in darkroom projection has turned out to be my alignment
    tool and grain focuser! Any of the differences I've highlighted were
    very, very slight and had me pondering long and hard to tell any
    difference.

    Craig Schroeder
    craig nospam craigschroeder com
     
    Craig Schroeder, May 8, 2008
    #8
  9. otzi

    otzi Guest

    Thanks for all the input folks. I was curious but unconvinced. Just
    wondered why so much was invested for so little gain. But these responses
    were very encouraging.
    Thanks.
     
    otzi, May 8, 2008
    #9
  10. The law of diminishing returns. When something is close to
    perfection the cost of even a miniscule gain becomes
    astronomical.

    There is a universal "80/20 rule": you can get 80% of the
    performance for 20% of the cost.

    The most cost-effective approach to improving photography
    is to buy a used Tessar-formula enlarging lens and spend the
    savings on something worthwhile that will make a noticeable
    and unequivocal improvement: a trip to someplace photogenic,
    a workshop, a really good timer ...
     
    Nicholas O. Lindan, May 8, 2008
    #10
  11. Lots of snipping here.
    There are a number of reasons for the newer lenses. One
    is simply that lenses have a very long lifetime so buying
    one often takes the buyer out of the market for some time
    unless a "better" replacement can be offered. Another is
    that computer aided design makes it easier to make new
    designs and evaluate them. Before computers the lens design
    procedure could progress only so far through mathematical
    analysis at which point a sample lens had to built and
    evaluated on the optical bench. The computer allows very
    complex analysis to be made quickly so that new designs can
    be brought much closer to optimum before one is made. Often
    the difference between a computer optimized lens and one
    designed by the older methods is slight. I also mentioned in
    an earlier response to this thread that the optical glass
    types available had changed necessitating redesign of many
    existing lenses. Since many of these were designed before
    computer optimization became generally available the
    redisign for new glass types also resulted in either
    improvement in the original design or a completely new
    design.
    Nearly all modern enlarging lenses are based on a
    generic type known as a Plasmat as are many large format
    camera lenses. These have several inherent advantages such
    as low astigmatism which is important for flat field
    applications such as enlarging. They are also have
    relatively wide coverage angles.
    Modern multi-coating also helps performance by
    increasing the image contrast.
    Keep in mind that any lens with fixed position elements
    can be optimized for only one object to image distance. The
    performance at other distances can be good but will not be
    quite up to the optimum distance. Most camera lenses are
    optimized for approximately infinity but enlarger lenses are
    optimized for whatever distance corresponds to the
    magnification the manufacturer thinks it will be used for
    mostly. Some manufacturers, Rodenstock and Schneieder
    particularly, specify the magnification range for their
    lenses. While the lens can give satisfactory performance
    outside of this range special range lenses will do better.
    Both manuacturers offer lenses for relatively large
    magnification, i.e., photomurals, as well as for more usual
    size prints. Since the print size does not vary so much with
    differences in format (one makes 8x10 or 11x14 from all
    common negative sizes) the optimum magnification will vary
    with the lens focal length, that is, it will be greater for
    a lens for 35mm than for a 4x5 lens.
    A high power grain focuser will often show up
    differences in lenses that are much harder to see in a print
    but may also introduce its own problems, for instance, some
    grain focusers are not very well achromitized and will show
    color fringes due to its own optics which are not present in
    the image from the enlarging lens.
     
    Richard Knoppow, May 8, 2008
    #11
  12. True. Many fuzzy images are caused by tripod insufficiency syndrome.
    Of course, fuzzy concepts in the mind of the photographer can also be a problem.
     
    Jean-David Beyer, May 8, 2008
    #12
  13. otzi

    Pico Guest

    Sometimes astronauts become miniscule. It evens out.
    I got a good timer but I'm not having a good time.
     
    Pico, May 8, 2008
    #13
  14. otzi

    Martin J Guest

    I made a comparison between some better enlarging lenses for 24x36mm
    (Apo-Rodagon 2.8/50, Componon-S 2.8/50, Focotar 4.5/50, Focotar 2.8/40
    and Rodagon 4/60) and compared them at about 8x enlargement (20x30cm
    paper size). Each was perfectly adjusted using a Peak #1, a glass carrier
    and all enlarger planes were adjusted parallel using a laser tool. All
    lenses were closed 2 stops from wide open.

    The result: The only one you could distinguish from the others was the old
    Focotar 4.5/50. It had a little curvature of field visible at the extreme
    edges. That's all... no visible difference for the other lenses.

    You can see the differences between the lenses with the Peak #1. The curvature
    of field is readily visible for the two Focotars. The two Rodagon
    and the Componon-S were much better and nearly identical. The Apo-Rodagon was
    a little better wide open than the others, but all 2.8 lenses were unuseable
    with this opening (for my view of quality...). Stopped down, all
    were excellent.

    Martin
     
    Martin J, May 9, 2008
    #14
  15. That's quite interesting. I suspect the Rodagon and
    Componon designs are quite similar although I don't have the
    actual prescriptions. Since its likely all the relatively
    modern lenses were designed with the aid of computers I
    suspect the performance should be much alike. I think the
    Focotar is an older design. One of the characteristics of
    the generic Plasmat type, which is what the Rodagon and
    Componon are, is that they can be unusually well corrected
    for astigmatism. Forgoing an explanation of what exactly
    that is (different in a camera lens than in opthalmic
    lenses) it leads to being able to get a very flat field.
    While both manufacturers claim superiority I suspect its
    pretty much a draw. Some think the Rodagon is mechanically
    superior to the Componon. Do your lenses have metal or
    plastic iris blades?
     
    Richard Knoppow, May 10, 2008
    #15
  16. When I first got into 4x5" work, in the mid 1970s, I got a Schneider
    Componon-S f/5.6 to f/45 180mm enlarging lens, # 11 973 xxx. It works fine.
    Its diaphragm has lots of blades (about 19 of them), enough to make the
    aperture look round, and they appear to be metal. At least 10 years later, I
    got a Componon-S f/5.6 to f/45 150mm lens, # 14 588 yyy. It has only 5
    blades, so the aperture looks approximately like a pentagon (except the
    edges are not quite straght. I cannot tell if they are metal or plastic; the
    180 blades are shinier than the 150 and darker, reminding me of blackened
    brass (but I do not know what they are for sure), and the 150 blades are
    duller, but slightly lighter in color and rougher, reminding me of anodized
    aluminum (but I very much doubt they would actually be aluminum). Perhaps
    that is what plastic blades look like.

    For normal photograph use, is there any benefit to having a round aperture?
    I know in half-tone work with a sealed half-tone screen, there is a benefit
    to having a square aperture, but round holes work OK -- you just get a
    little bit of a different transfer function from the original to the half-tone.

    Unless you use the lens in the hot sun or something, there might even be a
    slight benefit to having plastic iris blades: less likely to rust or corrode.
     
    Jean-David Beyer, May 10, 2008
    #16
  17. otzi

    Pico Guest

     
    Pico, May 10, 2008
    #17
  18. It appears that the shape of the iris affects out of
    focus areas of the image. This is perhaps part of the effect
    called bokeh by the Japanese. In any case bright points
    which are not sharply focused are rendered in the shape of
    the iris. This may not be as noticable for enlarging where a
    flat surface is imaged onto another flat surface.
    In making half-tone plates the iris is imaged by the
    half tone screen as an array of spots or dots. By using a
    square aperture the intestices of the dots are at the
    corners so the variation is smoother. For color work each of
    the images is photographed using an iris with a
    lozenge-shaped aperture at a different angle. I can't
    remember now if this is to prevent moir but I think it is.
    In any case there is an optimum set of angles for the
    apertures. These apertures are usually in the form of
    Waterhouse stops and is the reason process lenses usually
    have a slot in the side. My barrel mounted Apo-Artars have
    the slot but the shutter mounted one does not. The barrel
    mounted Artars also have 20 blade irises and a very nearly
    perfectly round hole.
     
    Richard Knoppow, May 10, 2008
    #18
  19. Right, although I find that a round hole is not too bad. But I do halftone
    starting with a continuous tone negative (a positive print or other positive
    flat art is usually used) and make the half-tone on OrthoLith. These dots
    have soft edges (undesirable) so I contact print them onto another piece of
    OrthoLith to get a suitable half-tone negative.
    That might be so, but I never heard that.
    When my great grandfather (F. E. Ives) devised the process, he angled the
    half-tone screen to prevent moire, but AFAIK did not use lozenge shaped
    diaphragms.
    This is true for the angles of the half-tone screens as well.

    In fact an amusing thing happened to F.E.Ives. When he first made color
    half-tones, he naturally angled the screens between the different colors. He
    did not bother to patent that because it was obvious. Years later someone
    else patented the idea of angling the screens and sued Ives. Ives had to go
    to court at considerable expense to prove that the patent was invalid both
    because it was obvious (kiss of death for patents) and because of over a
    decade of prior use.
    In any case a slot is needed to set the aperture (square or not) to the
    correct angle. This is all about sealed glass half-tone screens, not the
    plastic contact screens more recently used. Of course, with a round
    aperture, none of this makes any difference.
    The 150 mm Componon-S 5-blade iris does not make a geometric pentagon. What
    would be straight edges are actually semi-circular convex to the edge of the
    lens. I.e., at the "corners" of the iris the diameter is larger than in the
    middle of what would be a straight line. In other words, the corners are
    farther from the center than would be expected if a true pentagon were used.
    This clearly because the iris blades are made that way. It would be
    perfectly easy to make them straight if Schneider had wanted to. I assume
    this was done for optical reasons and not to make the mechanics cheaper.
     
    Jean-David Beyer, May 10, 2008
    #19
  20. I think you may be right that its the screens which are
    made at an angle rather than the aperture, its been too long
    since I learned about this stuff and the books are not
    handy.
    Soft dot edges have always been a problem. Monckhoven's
    intensifier was intended to remedy this. It has the peculiar
    property of being both an intensifier and reducer because
    the cyanide will dissolve the low density silver before the
    intensifier works so the net result is to increase the
    contrast of the edges of the dots.
     
    Richard Knoppow, May 11, 2008
    #20
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