There are lens bargains out there though with "problem" lenses though:
* Sticky apertures
* Haze inside the lens
* Light fungus
All are easily fixable for most typical designs.
If you don't have a non-ai camera, you need to get one to enjoy the non-ai era of Nikon. I know there are fewer good examples of those old cameras around but an F2 will last forever.
I send an old, unloved 50-300 non-ai to John to have modified. He did a beautiful job and the lens is fun to break out and occasionally use as it is so much bigger than anything out there......yes, I use it for shock value.....not the best glass they made, but certainly acceptable for what I use it for.
Find a good ai or ais lens to use with those "modern" cameras.
I recently posted these at full frame as part of a comparison exposure test, but thought they might be relevant here as a contrast/color/sharpness test...
All shot on Canon 30D @ ISO 1000 @ 2.8 jpegs out of camera @ max sharpness
They are the 50mm F1.4 AIS, 50mm F1.4 S, and 50mm F2 H ("K" version with rubber focusing barrel)
Results are very similar...a bit different in brightness/contrast at different parts of the spectrum (e.g. the "S" seems brighter on the near 18% gray in the background)
...and the "H" is stopped down only 1 F-stop whereas the 1.4 50s are down 2 stops...
All pretty impressive I think...and any variation would be more a result of user technique, whether focusing or exposure...
Nikkor 50ais1.4 100%Crop
Nikkor 50s1.4 100%Crop
I have or had AI/NonAI versions of the 50/1.4, 105, 135, 180 and 200 and they are all quality lenses...varying in their size and mechanics more than in their results...to my eyes at least.
30D? Get a rope.
well the resale value after a conversion is less. Unless you keep the original parts intact and don't lose them next time you move.
a series E lens from a charity shop is pretty cheap and they are all AI-S, you need to look if you disbelief this. The early all plastic ones look a bit ugly but take the same pics as the later ones with metal rings.
What you need is an early single coated non AI and a series E for their different signature, the early one is digital friendly but that is heracy -
With respect to resale value, if the AI conversion is either done with factory parts, or done properly, the value typically goes up, at least here in the states. Collectibility value not so much. But, if I remember correctly, APUG is more about using the gear than letting it sit on the shelf collecting dust.
It looks like the lens the OP has is the last 50/2 pre-AI lens, just before the AI lens came out. So, rubber focusing ring, black barrel, and multicoated glass. In which case, I still think it'd be a good idea to find a parts 50/2 AI with the five screw mount and swap both the aperture ring, plus the rear element baffle piece to his lens. Once that's done, the lens will be AI, except for two things. The color and softness of the focusing ring grip and the serial number.
Both lenses would be digital friendly. For that matter, the E lens will produce pretty much the same results as the AF version, maybe with a little more flare and less contrast, since it's single coated. Otherwise, same formula.
What I tried to say was that an earlier single coated Nikkor and a Series E give a different signature the single coated lens having less contrast less likely to get digital highlight burn note even in C41 mono the effect is useful.
The E and the AF were decades apart and even if the same double Gauss scheme unlikely to be same glass the glass catalogue changes.
I take SC and MC on a shoot even with retained Ag
Re: John_Nikon_F and Xmas...some PRE-AI "K" lenses were available with factory AI aperture rings...e.g. 135mm/2.8 Q.C and 85/1.8K, both of which I have...I think they are less available than their non-AI versions, so they'd be worth more I should think...
...and I would think that the market value of lenses converted with the "cut" notch at the rear of the aperture ring (I have one of those too) would likely be worth less than OEM...but its value to the owner/user is another matter of course....
In some cases it may be cost-effective to convert a lens...in other cases it may be cheaper to get the factory-AI version and sell the non-AI lens.
I also would leave a Non-AI alone. I run away from conderted or AI'd lenses as the conversion might be a partial one. There is an element of the AI specification that many conversions left behind: the max aperture signal post. And that is the reason why AI'd lenses will not work in Matrix mode on a F4, or so says the manual.