Pre-Ai Lens Compatibility

[Xia_Ke]

So I was looking over a lens compatibility chart and saw that Pre-Ai lenses are a big no-no for my D50 as it will damage the body. Stupid me just realized that my 300mm K-Type falls into this category. However, I use this lens all the time and have had absolutely no problems at all. Now have I just been lucky so far and should I stop stop using it before chit happens? Or should I not worry about it at this point and keep using it? I can't afford to replace my D50 due to stupid mistakes

[deckcadet]

Take a pic of the lens mount- many Pre-AI lenses were "AI'd" meaning they were converted to AI/s spec with either full aperture ring replacement or modification of the existing ring.

[Xia_Ke]

Thanks Harrison Here's my 2 Pre-Ai lenses that I have used. One is a 135mm Nikkor-Q and the other is a K-Type 300mm. The 135mm I have only used a handful of times but, the 300mm I use all the time. I have had no problems from using either. The serial numbers are 833869 for the 135 and 486103 for the 300 if that helps.

Thanks Again,
Aaron

[deckcadet]

Both of these lenses have been modified to AI-spec by full aperture ring replacement. Notice the cutouts for the EE aperture control tab (small tab, look at the lens from the back, aperture ring at f/5.6, at about 3:30/4:00 position), and the AI Indexing Tab (90:00-11:30).

[Xia_Ke]

Thanks deckadet So I guess I'm good to go with these then? I don't suppose you have a pic or a link to a pic of a non-ai lens mount just for comparison?

[deckcadet]

Don't have one on hand, but basically, the non-AI lenses' aperture ring:

a) lacks the second set of aperture readouts (the smaller aperture direct readout scale below the main one on the aperture ring)

b) extends backwards without any notches at all, about as far back as the tabs on the AI lenses

c) the 'rabbit ears' couplings lack the cutouts in each 'ear'.

Ironically, the D40 and D40x, while depriving many lenses of autofocus, are the only Nikon DSLRs that can use non-AI nikkors (albeit with manual metering) without modification and danger of damage, excluding those lenses which require mirror lock up.

[Xia_Ke]

Thanks Harrison, now I understand the difference Thank you for taking the time to clarify. Much appreciated.