N00b, Rebel T7 + old 50mm prime

Hey all, bear with me, I'm really green here.

Years ago I had a Canon Elan IIe, used it with a 50mm prime (EF 50mm f/1.8 II) and a USM 24-85 lens. It worked well for what I needed but I never really learned much. Everything worked properly 20 years ago when I put this stuff into a box and stored it. Its been protected ever since.

Fast forward 20+ years and now I'm wanting to get back into this. So I bought a Rebel T7, and figured I'd use my old lenses on it. Well, the 24-85 works, but the 50mm prime seems to not work. It *seems* to try to focus sometimes, but I can't get the shutter to open with it. I've tried it in auto mode as well as numerous other modes including all manual, and the flash flashes trying to illuminate things, and the auto mode wants to try ISO.

Is there an inherent incompatibility here? I think its about the most basic set up there is. And since my 24-85 and the other 18-55 lens I have works, I imagine the camera is ok. Must be the prime lens that's not jiving.

Again, I'm just beginning here so I apologize if this is a really stupid question. Any thoughts are appreciated.

It should work properly, specially since the substitute, the 50mm STM was released only in 2015. The 50mm II was the option before that.

I have a 24-90mm that is about 20 years old, from a film camera, that works in my T6 like a charm.

N6GQ wrote:

I've tried a few things...

If I slide the MF/AF switch to MF, it may shoot a shot. Moving it back to AF and it might shoot one more or not. Then it errors with ERR01. So I clean the contacts, still doesn't work.

I tried turning the lens ever so slightly off the locked position on the body, still same.

Going back to other lenses, they work fine.

If you clean the contacts well, it should not have the ERR01. I would try to sand the contacts of the lens just a little, to make sure that it's not any dirt or crust.

If it still doesn't work, probably it's the contacts on the lens themselves that doesn't work. You then have three options: get it fixed, buy a new canon STM or buy the Yongnuo version of it.

For the price and quality, I would try to fix myself the lens (since it's already gone, anyway), and, if it wasn't something simple, just toss it away. Then, if I had the cash I would buy the STM, if not, Youngnuo has two versions of it, and the cheapest (from reviews) compares to the one you have now, the second version should be a little better, but both are marginally worse than the STM.

Check your budget and make your choice...

PS: The first prime lens I bought was the 50mm, and makes awesome bokehs, but I found the 24mm STM a far more usable lens, from landscapes to portraits, it can make it all, with sharp definition and awesome colors. If I was to chose only one of them, I would keep the 24mm...