Differences between K and AI versions of 24mm f2.8?

Discussion in 'Nikon' started by philip_dygeus|2, Nov 27, 2017.

  1. I'm wondering what the differences are between the K and the AI versions of the 24mm f2.8 Nikkor.

    Over at Photosynthesis I see that the K doesn't have the ADR ring (though I've seen the K version with such a ring actually) and that it has 9 elements in 7 groups as opposed to the AI which has 9 elements in 9 groups.

    Are there differences in optical performance?

    Thanks in advance
  2. Non-Ai (or pre-Ai) lenses don't have the second set of aperture values for ADR; the one you saw must have been Ai'd.

    Wide-Angle Lenses For Nikon 'F' Mount
    philip_dygeus|2 likes this.
  3. The Ai and Ai-S versions incorporate Nikon's Close Range Correction (CRC), which is a floating element system that holds high optical correction throughout the focussing range.

    Some early pre-Ai lenses had only single AR coatings. Whereas all Ai or Ai-S lenses have multicoating (NIC or SIC).

    Personally, I'd rate this lens about a '3' on modern hi-res DSLRs, compared to the much better 14-24mm f/2.8 Zoom Nikkor. Of course they're not in the same cost or size class at all.
    Last edited: Nov 27, 2017
    philip_dygeus|2 likes this.
  4. Thank you very much for your replies. I appreciate this a lot.

    I see now that there was an "AI kit 22" which could be used with the K version, so that would explain the ADR on the one I saw.

    I'm a bit confused though. Photosynthesis says the K version also has CRC but perhaps that's an error.

    I am looking for a wider lens for my FM3A and am leaning towards 24mm but perhaps 28 would give higher optical quality? I've read good things about the 28 Nikkors.


  5. Corroborated by what Bjorn wrote in the link I provided: Nikon released its major achievement, CRC (Close Range Correction) with this lens in 1968 and it got a well-deserved popularity in the years afterwards.
    philip_dygeus|2 likes this.
  6. Depends which one, they're not all created equal.
    On film, there is nothing wrong with the AI and AiS 24mm lenses. A little wider, I much prefer the AiS 20mm f/3.5: smaller, lighter, flares little and a very pleasant rendering, just not too great near and at infinity. My AI 24mm f/2.8 doesn't drop the ball on film (and also not on my DSLR, but its resolution is modest and I don't care much for pixel-perfection anyway). It's a safe choice, maybe not Nikon's finest but a long way from its worst too.
  7. As Wouter implies, on film you won't see much difference in performance between any of Nikon's wideangles. Even the 35mm f/2 Nikkor O gives good results on film, although it's pretty poor on a D800 or similar.

    Sorry about the misleading info on CRC. I was under the impression that the older 7 group design didn't have CRC, but I was mistaken.
  8. Just to confirm some of what was written earlier:
    1. All Nikon 24/2.8 lenses have CRC (or floating elements) to give better performance at distance and close range.
    2. The original Nikkor-N version is not multicoated, the Nikkor-N.C, K, AI, AIS and AF versions are all multicoated.
    3. All the pre-AI versions use the 9/7 optical design, all AI, AIS and AF versions use the newer 9/9 element design.
    4. Many of the pre-AI versions were upgraded to AI by Nikon, by swapping out the original aperture ring.

    I have the K 24/2.8 which has been AI converted, which I shoot on my D600. Compared to the AI version it is a little bigger but it is still a compact lens. It is capable of delivering excellent results. Sharpness is good for landscapes and at close range. With my style of shooting I tend to use it stopped well down for greater DOF, I have not assessed performance at wider apertures. Some barrel distortion is present but it is well controlled and reasonably uniform so is easy to correct with software. Although this is hardly a "bokeh" lens, backgrounds are usually rendered with a pleasant rounded look. Contrast and colours are good. When shooting into the sun there is some loss of contrast and you get a lot of green flares across the image.

    I have not used the AI version, from what I have gathered, performance is similar, it flares more easily but is more resistant to ghost images. Background rendition may be on the harsh side.
  9. I have pre-AI and AIS 24/2.8 .. both intensely (sp.?) used on slidefilm.. never noticed any difference..

    On D200-300-800 they lost their lustre.. first because of them 'becoming a 35mm' on DX.. then on showing too much CA and bad corners on all and on (D200 and) FX in particular..

    Like Wouter wrote: 20/3.5 proved to be a survivor, bridging film --> digital.

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