APO Ronars Do they make good Macro lenses?

Discussion in 'Large Format' started by john_cremati, Apr 17, 2005.

  1. I have several Rodenstock APO Ronar CL process lenses in various
    focal lengths ..... Do these make good macro lenses?......
     
  2. Yes, and no. If you are making 1:1 and larger images of flat or very nearly flat objects
    they will be fine since they were designed to photograph flat objects (e.g. paper) at close
    distances. If you are photographing three dimensional objects they may or may not work
    any better than a standard plasmat or tessar design lens. If you are working at near macro
    distances bu tnot 1:1 then your regular lenses will do fine.

    At macro distances or larger you will get the best images with a macro lens but onluy you
    can tell if you need such a specialized lens.
     
  3. The prime design goal of a process lens is linearity; ie almost zero distortion. Sharpness is important; but is not the most important thing. An enlarging lens is usually sharper; but has more distortion. In pictoral and normal photography; 0.5 to 1.5 percent distortion is no big deal. With repro and mapping; this is a TOTAL disaster; the map panels WILL NOT fit together at all. Thus a process lens is used for low distortion; so exact scales can be made; panels fit together exactly. There were ultra low distortion process lenses too; these had 0.005% of focal length or less distortion. Note this is 200 times better that a typical 1 percent great enlarging lenses distortion.<BR><BR>Process lenses are used from about 1:1 to usually 1:5 ratios; and are designed for ultra low distortion; decent sharpness; and are usually used at F22. They are not sharper than enlarging lenses or still camera lenses. Non process camera lenses when used on a process camera are total garbage; they have distortion; panels don fit wlll; scale varies over a precsion map. <BR><BR>In still camera usage a process lens will work well with a 3D closeup situation. An enlarging lens will be as sharp; or sharper; and allow a faster fstop to be used. There is no 2d versus 3d issue; this is BS. In a table top settup; a process camera lens might be at F22; and a an enlarging lens might be at f11 to f16. <BR><BR>Process lenses are also not flat field lenses either; they require stopping down to get the corners in focus. This BS myth get repeated by folks who have never seen; never used; never owned; never done any process camera work for the public.<BR><BR>A mess of process lenses are on the surplus market; folks are using them in many LF applications; that have moderate to low enlargements when shooting at infinity. At closer distances; they work better. Many times they are good enough. <BR><BR>Here we have about 5 process camera lenses; from 150 to 890mm. most are APO Ronars. The factory data on ours shows a curved field; our test data shows a curved field, the process camera maker explains about the curved field of these lenses. <BR><BR>The main problems with using a process lens is that they are slow when used on a still camera. Adding a decent sixed lens hood helps too. Here we have owned process cameras since the 1960's; and current still operate one.
     
  4. These lenses were designed as Process Lenses for the printing and graphics art trades. They were used at reproduction ratios near 1:1 and so in essence are macro lenses. Most of the Apo-Ronar-CLs that I have seen are of rather long focal lengths -- few LF cameras will have sufficient extension to use them at 1:1. To get a lifesize image (i.e., 1:1 reproduction ratio), the bellows extension needs to be twice the focal length.

    The Apo-Ronars are of the symmetrical dialyte design, which is also used in the well known Artars. By a basic optical argument, a lens which is symmetrical is optimum for 1:1. The symmetry argument doesn't tell us how much worse the lens is at reproduction ratios far from 1:1, such as 1:infinity. The design of the Apo-Ronar has a good reputation for maintaining its corrections even at 1:infinity, and Rodenstock sold the Apo-Ronars in shutters for that use.

    A weakness of this design for some uses is that the coverage is smaller than some other designs. In a brochure for the shutter-mounted versions, Rodenstock listed the Apo-Ronars as covering 48 degrees, or smaller for the longer focal lengths, perhaps because of the shutter.

    Bob Solomon, the US representative for Rodenstock, has stated that the Apo-Ronars are best suited for flat subjects and optically unsuited for 3D subjects. The only interpretation that I can come up with is that the limited coverage of the Apo-Ronars won't allow large amounts of movements such as front tilts. So for a studio photographer who wanted to use agressive front tilt movements for tabletop photography, an Apo-Ronar might be a poor choice. The macro lenses that are currently made, Nikkor-AM-ED, Apo-Macro-Sironar, and Makro-Symmar, have larger coverage.

    Within their coverage, the Apo-Ronars will work well as macro lenses.
     
  5. Kelly,

    thank you for your comments about the "only for flat-field" myth, these symmetrical process lenses are for 5:1 thru 1:5 range,and macro may fall about into this range.

    Best

    Joerg
     
  6. Here is the 150mm F9 Apo ronar on a speed graphic; using a Phase one 4x5 scan back; at NOT the highest scan setting. The full image here is only 26 megabytes; ie 3600x2500; 9 megapixel. A full bore scan would be a 105 megabyte scan; ie 35 megapixels.. This was shot with the tungsten filter in place; and about F11 to F16. The dog is 1/2 way to the ronar.

    [​IMG]

    [​IMG]

    [​IMG]

    NOTE! The 150mm Ronar is no DOG :) in the out of focus arena.

    It would make a decent focus pull lens on a movie camera; if the there was scene use could use a long 150mm lens. But the lens is probably not up to snuff for a mvie camera in sharpness; and slow as dirt too. [​IMG]
     
  7. This is just an older apo ronar; not a CL or what ever that means. Mine is just a single coated lens in a barrel mount. Maybe Michael can mention whae the "CL" variant means. None of my Ronars are a CL version; ie are "CL" marked. The "4x5"scan back has an active scan area of about 7x10cm; this is about the coverage of this ronar. It is spec'd at a 2 1/4 x 3 1/4" coverage at infinity.; here this shot is probably technically in error; but so is the digital back on a speed graphic too. I guess I am a bad student :)
     
  8. Remember when old Bob Solomon would aways pop in when process lens questions came up? All these surplus lenses on the market must have driven the marketing guys nuts. Sometimes they do work OK for non process applications. I think the protests long ago were just to sell more lenses; since it is a conflict to admit that a low cost surplus lens might be just as good for many applications; as a more modern "proper" lens. <BR><BR>These pupplies are harder to focus. With the digital back one can do a pre scan; and adjust the focus say to the "radio shack" logo on the clock. The obsolete scan back "tends" to make even a plain lens appear good. There is no film and scanner "transfer functions" to degrade the performance.
     

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