Can anyone explain to me why I should AI'd my 50mm 2.0 H-C.
I mount it without problems on my D40x with or without tubes.
I do not understand the modification CGrindahl is talking about, since I have no probs operating it on D40x
See
http://www.fredmiranda.com/forum/topic/1001614/16

just do Not put it on most of the other bodies unless you want to cause damage to the body. Someone will link to which bodies but it is a lot of them. But on yours it's OK

as John states, it works on the D40X. If you were to put the on most higher end cams (D200; D300; D700) it would ruin the camera. Getting them converted costs around $25.00 to $35.00, and then allows you to use them on any camera. I have several MF lenses & love them, as do most who use them. My first ever lens is a 50mm f2.0 I bought in 1975. I had John White convert it for me & now I use it on all of my cams. So - that would be the reason(s)

thanks all
I have NOT tried it on my D90 😃
I live in Denmark, so any modification has to be done locally.
BTW : The lense was a kit lense on my SLR from 1973/1974, and it was not in high estime even then.
I love it though.

I forget whi it is about the D40X that allows one to get away with it but not other camera bodies. Anyone remember?

OK : Maybee we are talking about more than one version of the 50mm 2.0 H-C, because the modification seems to me to indicate welding or raising material of part of the circumference.
Now I do not want to stir the pot, but this may be of interest to owners of that lense.

There is only one version of the 50 f/2 H-C and it is called a pre-AI lens. It looks like this...



There were 188,800 of them made. There are other 50 f/2 lenses made though all had the same optical design.

The modification required is to the aperture ring. Here is a link to photos that show the differences between pre-AI and later versions of manual focus lenses which are designated AI and the AI-s. Pre-AI is an alphabet soup of labels.

http://www.momentcorp.com/review/nikon_mf_lens_versions.html

Nikon made AI conversion kits for pre-AI lenses but these are no longer in production. There are a few of the kits still floating around, so it is possible to make the conversion using a kit, if you're able to find one. Without the kit, it is still possible to make a conversion, but as you note, for the camera you're using it is not necessary to do so. Nikon cameras without a lens focusing motor will accept these lenses without a problem. Cameras with a focusing motor are best not used. Here is a link to a description from Thom Hogan of which lenses work with which cameras.

http://www.bythom.com/lensacronyms.htm

This is not an expensive nor much sought after lens because of its smaller aperture. That is one reason they can be bought so cheaply, even later versions that include the AI design. As I noted on the Shooting with Tubes thread in the Macro forum, I bought a pristine copy of the 50 f/2 H-C with the Nikon AI conversion kit for $56. AI versions of the lens cost under a hundred dollars. This is not a lens that calls for a great investment simply to mount it on a later camera. I'm very happy with older lenses that have scalloped focusing rings, but I'm only interested in such lenses that have the Nikon AI conversion kit. I have no interest in butchering aperture rings on these old lenses. That feels like crashing a 1957 Chevy BelAire simply to have an authentic crash in a period movie. These beauties of yesteryear will not be replaced. They are best appreciated in their original form. But that's me...

Andre Labonte wrote:
I forget whi it is about the D40X that allows one to get away with it but not other camera bodies. Anyone remember?



The higher end bodies have the aperture ring index tab on the exterior part of the lens mount. This tab will be crushed by pre AI lenses. The lower end bodies that don't meter with old lenses don't have this tab to damage.(D40, D40x, D60, D3000, etc.)

mfletch wrote:
Andre Labonte wrote:
I forget whi it is about the D40X that allows one to get away with it but not other camera bodies. Anyone remember?



The higher end bodies have the aperture ring index tab on the exterior part of the lens mount. This tab will be crushed by pre AI lenses. The lower end bodies that don't meter with old lenses don't have this tab to damage.(D40, D40x, D60, D3000, etc.)


Ah, that makes sense. Thanks!

Thank you all for explanations.
I learn every day 😊