Since last September I have used two high quality old lenses. One is my Nikkor 28mm F3.5 AI and the other is my Asahi SMC Takumar 300mm F4.0. The 300mm is the older design and according to "PentaxForums.com", the optical design goes back to 1965, but this "SMC" version came out in 1971, incorporating full-aperture metering and Asahi's "Super Multi-Coating". According to Ken Rockwell's wesite, my 28mm F3.5 Nikkor AI was produced from 1977 - 1981, which implies that it was probably being designed around 1976. It's 6 elements in 6 groups optical design and multicoated were contemporary for its day, but not really class leading. Nikon had brought out a 28mm F2.8 around 1974 with 7 elements in 7 groups, which was overall larger, better and higher priced. Moreover, Nikon had 24mm F2.8 lenses as far back as their earliest 28mm F3.5 lenses. So all 28mm F3.5's could be looked on as targeting a more "popular priced" market. But this is a "relative" idea, and no doubt, if you checked the bags of a lot of Pro photographers, some would have carried a 28mm F3.5 in their kit. In common, they both have fairly high chromatic aberration. Later versions of the 300mm reduced this problem. The Nikkor had higher quality models which might have had less chromatic aberration, even when it was introduced. I don't know. I haven't checked around for any recorded tests. But it is fair to say that chromatic aberration was likely to be less of a priority in "pre-1970's" lenses. The reason is that colour photography, though available, was not as popular as "black and white" until around the mid-1960's. The cost and availability of colour prints were prohibitive for casual photography until around this 1960's to 1970's period. Even for Pros, black and white was the staple for news, including sports, corporate photography including portraits, and architecture. So, chromatic aberration was not going to be as serious an issue even until "later", and "later" varied from company to company. Again, I will point out that the Nikkor 28mm F3.5 AI was not Nikon's top lens in its focal length, so the more expensive lenses might already have been better. Optimizing Monochrome With Filters Since monochrome was widely used by Pros, there were well known method of getting the most out of it. These were no secrets. If you asked any camera store salesman you'd be taught this stuff in about an hour. A good salesman could give you a good education, and had a good motivation, because s/he could legitimately advise you to spend a little money and buy some filters. A new professional or hobbyist could be shown examples of using Red, Green, Blue and Yellow filters. Most stores had example pictures. You would be taught that for sharper pictures, you would do well to remove the blue spectrum which scatters more from haze and fog. "Anything but blue" was good for this. You would also see that each of the RGB filters resulted in distorted representations of the scene. Red was generally the most dramatic, darkening the sky and plants. Green was often called the most "natural", though green leaves tended to be brightened. Yellow was called the "fog or mist" filter. Blue was, well, actually "kind of useless", but if you bought one, the salesman would take the money. . . . But it might also be mentioned that this was also a good way sharpen a picture because of chromatic aberration. The salesman might not mentioning this because you'd already expect the picture to be sharper, so it was to an extent "redundant information". But a more experienced expert or Pro would probably use carry red, green and yellow. The red was "sharpest", the green was "almost as sharp". If there was a "Pro - trick", then it was the yellow filter. Yellow only got rid of the blue content so it did not sharpen quite as much as red or green, but it also did not affect the exposure quite as much, so shutter speeds were higher or apertures were small, either of which can also contribute to sharper pictures. And it also resulted in pictures that looked comparatively natural. Translated to Digital If I take a picture with normal settings, I can convert it to monochrome. That much will probably not affect the sharpness of the picture, but some people might prefer it simply because it got rid of the chromatic aberration. However, some (probably most) processing programs will be able to make color separation files. They might support RGB, or CYMK, or both. So it is possible to simulate using these black and white filters. The red and green files will be fairly straight forward. The Yellow, is not so clear -- at least to me. The cyan, magenta and yellow files are meant to be used for colour printing, but they are meant to be used along with the others, including the Black ('K') file. There might be a useful way to combine some of these to create a good monochrome image, but I have never tried to do so. Not yet anyway. . . . Simulated v Real Filters One last issue is whether using the color separation files is really the same as using real filters? At this point, all I can say is "maybe". I can go further and say that if there is a difference, then I do not expect it to be very big, and it is probably different for different bodies. Most colour sensors have small filters which define their sensitivity as red, green or blue. But the purity of the filter is not absolute, and in fact, the degree of overlap might differ from one model to the next within a camera line. If this is true, then the colour separation files might also not be "pure". So yes, there might be a chance that a "better" file could be made if you start by adding a purer filter on the lens. The only way to know for sure is to do the tests, and for now, I am not interested in doing so. If you are, then go ahead. Uploaded Files: This is a file created on the YiM1 with my Nikkor 28mm, F3.5 AI on my Shift Adapter, so the chromatic aberration is representative as far off-axis as would be expected when the lens is used on a 35mm film camera. It isn't a "horrible" amount of chromatic aberration, and it could be handled by most chromatic aberration functions, but the alternative of converting to monochrome was also available, as was the creation of colour separation files. P9110009.DNG [A version of this file was previously uploaded.] Partial EXIF: Sept 11, 2018, 16:51:55 Image width 5200 Image height 3902 Components per pixel 1 Pixel height 3888 Pixel width 5184 Component configuration YCbCr Color space Uncalibrated [AdobeRGB] Exposure mode Manual exposure [actually P] Exposure bias 1.00ev Exposure time 1/80 sec. F number f/0.0 [probably F11] Max aperture f/1.0 [actually f/3.5] Focal length 0.0mm [actually 28mm] ISO speed 200 Metering mode Center weighted average Gain control Low gain up The uploaded files were made from the DNG (raw) file with only white balance adjustment. No other changes (sharpening, noise reduction, etc.) were used. The first is the normal colour render. They "Grey" is the default grey conversion for Corel Paintshop Pro X9. The Red, Green and Blue files were the separation files that Corel makes normally. Conversion White Balance: Temperature 5830 Tint 27 "P9110009 -1b-Colour-C1.jpg" "P9110009 -1c-Grey-C1.jpg" "P9110009 -1d-Red-C1.jpg" "P9110009 -1e-Green-C1.jpg" "P9110009 -1f-Blue-C1.jpg" Both the Red and Green files are visibly sharper than the straight grey conversion, but as expected, the Green file looks more "natural".