Question Regarding Printing Nikkor 105 MM

AK...I actually rarely use the 105PN at 1:1, except in "shootout" comparison tests. I mostly use it for imaging Cents on APS-C, around 0.7:1. In this range it has no equal for sharpness and color correction. Field flatness falls off at 0.6:1 but for coins it is no issue, having dropped maybe 10% by the edge of coin, still diffraction-limited at f3.3 or above. On FF I'd shoot a little above 1:1 (maybe 1.2:1) for Cents, still in a good range for the lens, and then around 0.6:1 for Dollars. So on FF the 105PN can span virtually the whole range of US coin sizes within its optimum range. Some day when I find a FF camera I like enough to buy, that's exactly what I'll be doing with it...Ray

PS...which other true APO lenses do you have? The only other one I know of is the 105/5.6 APO-EL-Nikkor. Other "APO" lenses are generally not truly apochromatic. Even the 75ARD1, while it is called "APO", is just a well-correct achromat. Far as I know, none of the lenses sold as "APO" from any of the lens mfrs are true apochromats, but like the 75ARD1 just good achromats.

Are any of the "Plan APO" microscope objectives truly APO-corrected, or are they really just good Plan achromats?

I suppose the 1:1-optimized lenses (like the 75mm APO Rodagon D and the Olympus 80mm Macro) would have to be considered real macro lenses, since their best magnification is supposedly from somewhat less than 1X to somewhat more than 1X. In the past, there were many bellows lenses optimized for more than 1X, like the Olympus 38mm and 20mm, the Canon 35mm and 20mm, and many others.

I've never liked the definition of macro starting at 1:1, instead preferring 0.5:1. Many macro lenses were made back when it was tough to make a 1:1 macro, and folks considered these "macro" lenses back then, so why not today? But even if you call 1:1 the start of macro, there are lots of lenses that will go to 1:1, most current "macro" types in fact.

I also don't like to call anything other than purpose-made lenses with standard lens mounts and focusing mechanisms "macro lenses". A lot of bellows, duplication, and enlarging lenses, even microscope objectives can be used for macro imaging but I don't call them "macro lenses".

OK enough soap box.

The Plan APO series from various mfrs are indeed apochromatically-corrected, and don't require any further optics for correction.

AK...have you seen color curves on the 90mm Apo Rodagon that show apochromaticity? I have not seen any curves but would be interested to see them. Maybe I will look them up...

Is this the 90mm Apo Rodagon lens you have:

http://www.qioptiq-shop.com/out/Gra...120708_0.pdf

Of course! Doesn't stop manufacturers from using creative marketing




No thats the N, I have the older version, the 90mm N has been discontinued in favour of the 80. I would guess my version of the 90mm will have a CA graph worse than that one.





I should have been clearer 1-1 (from my point of view) is the cut off for close up photography and above 1-1 is macro. But yes there are differences in approach Enrico Savazzi describes close up as 0.05X to .5X so I guess you disagree with him. I have taken Lefkowitz's point of view which is "macro" means larger than life sized. Lefkowitz strongly implies starts at 35:1 which does seem a high cut off to me.

I have yet to see an "Apo" lens from Rodenstock that is actually apochromatic. I love the 75ARD1, but it does show color shifts above and below the critical focus plane. This actually makes the resulting images have more "character" than they do when I shoot same coin with the 105PN. The 74SP does a similar thing, but in Zeiss fashion. The 105PN looks "sterile" in comparison, because it presents the coin exactly as it is with no added flourishes.

You can easily discern if a lens is apochromatic (or nearly so) by using an un-toned silver coin, brightly-lit and correctly white balanced, and taking 3 images of it at a large aperture at 3 focal planes. Compare the images after, and you'll see the color shifts.

You may be confusing the two types of CA. Most of the CA folks are worried about is lateral CA, and this is affected by sensor array layout. It is also very correctable in software and during the demosaicing process some amount of correction is always applied before the image makes it out of the camera. It is this type of CA that creates color fringes, halos, and such around high contrast objects. Lateral CA is 2-dimensional in nature so all the information needed for correction is contained in the image.

What is corrected at 2 wavelengths in an achromat, and at 3 wavelengths in an apochromat, is longitudinal CA. LongCA is a 3D phenomenon, so is tougher to correct since the required information is not generally contained in the image.

I'm intrigued by the info on the new sensor, though, since lateral CA is always a problem and if the new type of array is better at correcting it that may be a big improvement. I remember similar claims about the Foveon sensor, which IIRC is also back-lit. Getting rid of the metal interconnects that are in the light path just seems like a smart thing to do, so hopefully this is the future of sensors. I suspect that some of the lateral CA problems that have been associated with sensors (such as purple fringes) are due to optical reflections off metal traces, and if these are gone then image quality should improve.

But none of this should have any effect on LongCA effects, which are purely optical in nature. In fact the better sensor may actually show the effects more prominently since they won't be masked by other problems.