Nikkor 50mm f/1.8 Ai!!!

[richardHaw]

https://richardhaw.com/2020/05/23/repair-nikkor-50mm-f-1-8-ai/

Not much info about this lens, seems like a forgotten Nikkor

[Roland Vink]

This is the first time we see a 50/1.8 Nikkor, it’s a totally-new design which is of the Gauss-type comprising of 6-elements-in-5-groups. The optical formula is one of Nikon’s most successful designs in terms of longevity and we’ll see this used in every succeeding Nikkor in the 50/1.8 family up until the recent AF-Nikkor 50mm f/1.8D.

Hi Ric, the series-E 50/1.8 has a different optical design from the AI 50/1.8 featured here and the similar "long nose" AI-S 50/1.8. It was the series-E design which was used in the later AI-S and AF versions.

The original series-E lens was extremely compact with an all-plastic barrel. It was later upgraded with a slightly larger barrel with the chrome grab-ring. There was also a Japanese-only version featured here: https://imaging.nikon.com/history/story/0060/index.htm. The Japanese version looks similar to the chrome series-E version, but it has better coatings and can focus to 0.45m instead of 0.6m. The same optics were then used in the compact AI-S version (which is really a Series-E lens in all but name) and then the AF and AF-D versions. The AF-S version is a completely new design.

I use the AI 50/1.8 a lot, it is a good lens - nice and sharp, compact but not too small. The bokeh is nicer than most other 50mm Nikkors, fairly smooth in the center of the image but gets a little rougher towards the periphery.

[richardHaw]

Hi Ric, the series-E 50/1.8 has a different optical design from the AI 50/1.8 featured here and the similar "long nose" AI-S 50/1.8. It was the series-E design which was used in the later AI-S and AF versions.

The original series-E lens was extremely compact with an all-plastic barrel. It was later upgraded with a slightly larger barrel with the chrome grab-ring. There was also a Japanese-only version featured here: https://imaging.nikon.com/history/story/0060/index.htm. The Japanese version looks similar to the chrome series-E version, but it has better coatings and can focus to 0.45m instead of 0.6m. The same optics were then used in the compact AI-S version (which is really a Series-E lens in all but name) and then the AF and AF-D versions. The AF-S version is a completely new design.

I use the AI 50/1.8 a lot, it is a good lens - nice and sharp, compact but not too small. The bokeh is nicer than most other 50mm Nikkors, fairly smooth in the center of the image but gets a little rougher towards the periphery.

Thanks, Roland. That's what I was thinking but the diagram looked the same. could it be that the tweaks were minimal?

[Roland Vink]

The AI 50/1.8 and Series-E 50/1.8 are both double-gauss designs with 6 elements in 5 groups. You would certainly see similarities between the two optical designs, as you would with 50/1.8 lenses from most other manufacturers at the time. Maybe the design of the AI 50/1.8 was even adapted for the series-E lens, but I think it is going to far to say it is the same lens with some "tweaks".

The AI 50/1.8 (left) has a larger front element and different curvature of lens surfaces. The Series-E design (right, in AF version) was designed to be compact, as the 1001 nights article shows, with smaller gap between front and rear groups, so I think it is safe to say they are different designs.

[Akira]

Roland, as you would probably know, the "Japanese-only" version of 50/1.8 is actually an Ais Nikkor without the prong and not the Series E.  I believe that the optics is identical to that of the "long-nose" Ais 50/1.8 which was the "export-only" version.

[Roland Vink]

Roland, as you would probably know, the "Japanese-only" version of 50/1.8 is actually an Ais Nikkor without the prong and not the Series E.  I believe that the optics is identical to that of the "long-nose" Ais 50/1.8 which was the "export-only" version.

There is a strong resemblance between the chrome-ring Series-E and the Japan AI-S 50/1.8, I have no doubt they share the same optical design, although the AI-S version has better coatings and focuses closer. The "long nose" AI and AI-S 50/1.8 have a distinctly larger front element. I'm not sure why Nikon decided to make a Japanese-only AI-S 50/1.8 based on the Series-E version , and a different "long-nose" AI-S version for export.

[Akira]

There is a strong resemblance between the chrome-ring Series-E and the Japan AI-S 50/1.8, I have no doubt they share the same optical design, although the AI-S version has better coatings and focuses closer. The "long nose" AI and AI-S 50/1.8 have a distinctly larger front element. I'm not sure why Nikon decided to make a Japanese-only AI-S 50/1.8 based on the Series-E version , and a different "long-nose" AI-S version for export.

Thank you for sharing your observation.  I didn't realize the difference of the size of the front elements.  I believe that the reason for the Japan-only Ais version is to satisfy the Japanese strong brand-oriented mind for "Nikkor", not Nikon Series E.  The Japan-only version was sold with EM and FG bodies as a kid lens.

I believe that the "long nose" version of Ais 50/1.8 was not sold with those entry models as a kit lens, right?

[richardHaw]

I just updated the article.

yes, the optical design is indeed different

the curvature of the rear elements are different, too.

[John Geerts]

Thank you for sharing your observation.  I didn't realize the difference of the size of the front elements.  I believe that the reason for the Japan-only Ais version is to satisfy the Japanese strong brand-oriented mind for "Nikkor", not Nikon Series E.  The Japan-only version was sold with EM and FG bodies as a kid lens.

That was my impression too. It are both, so called pancake lenses, but the Japanese one (series starting with serialnumber 2.) is of much higher quality than the Nikon Series E and the pancake starting with serial number 4.) At f/1.8  the 2. series is  pretty good.