Convert SLR to DSLR

I don't think anyone makes a product like that. There are a lot of nuances that would make a product like this difficult to implement well.

You could make it a do-it-yourself project like this guy, but I don't think it's worth the effort.

Your best bet is to buy a new digital body from Canon so that you have some lens compatibility and don't have to invest in new glass or accessories.

Buying a new Canon DSLR is the way to go however, lenses that worked for his old AE-1 use a mount system call FD. These lenses will NOT work on a DSLR. The mounts are completely different. You can get an adapter but it can cost as much as a new 50mm lens. It also will not allow you to focus to infinity using most FD lenses.

Bite the bullet and go for a new camera with a "kit" lens. They can be had for around $600

I have a an old Canon F-1n and a great set of lenses for it and I was asking myself the same question. I am considering getting a Sony NEX-7 camera. Because it is mirrorless I can attach my old manual focus lenses using an inexpensive adapter. There are adapters for almost ever kind of lens. Here is an example of what kind of lenses people are using on the NEX http://forums.dpreview.com/forums/read.asp?forum=1042&message=40466896 I think the NEX body is about as close as you can come to a universal digital back.

Beware of the Adapters. . . Most reviews point out the cheap construction of these units. Also attention must be paid to the fact that very few actually support FD/FL lenses. Also understand that you won't be getting the same focal length as the original lens. The farther away the lens is from the focal plain/sensor, the greater the crop factor. IE, a 50mm will not give the same viewing angle when used with these adapters, you are more likely to get the equivalent of about 70 to 90mm in 35mm terms.

I have several really nice pieces of glass that I've collected over the years, a m42 mount Leica 35mm, f1.8 135mm for example and I have bought the expensive adapters (not the ones out of brass;they are too soft and wear quickly.) adapters for my Canon bodies. Unless I'm shooting with a tripod and have the time to properly set up a shot and execute it is a waste of time.

You will also have to try and focus a lens that does not have a a system built for manual focusing. You will not have the split prism that you have in your old Canon body. Thus you will be trying to get an accurate focus using the small screen on the back of the Sony. So in bright light focusing will be very hard to accomplish, second, the aperture must be set to wide open in order to have enough light to see the subject well enough to focus then you need to adjust the aperture to achieve the right combination of shutter speed and aperture for your photo to be properly exposed, possibly knocking your shot out of focus. Moreover, in low light conditions your focusing will be difficult because your depth of field will be hard to gauge since you will have to stop down the lens which will darken your screen appropriately.

Lastly unless you own really good glass, ie f2 or less telephoto lenses or older Ziess/Leica etc.lenses its not worth it. You are better off getting a good Sony mount lens and using it since it will auto focus, auto exposure and maybe even have stability control built in.

Parting wisdom . . . just because it is possible, doesn't make it right

Many many years ago there was a vaporware product called Silicon Film which would have done exactly that; it was basically a 35MM sensor that you placed in your camera, with the control circuitry in an ersatz film canister. It never made it to market, however, and what market potential it did have disappeared overnight when better-specified DSLR bodies came out.

There isn't really any value to trying to save your film camera body for digital use; the lenses are where all the goodness comes from. Get a DSLR that accepts your current lenses. Or, if your lenses aren't that wonderful after all, why bother? Start fresh with one of the new mirrorless systems like the Sony NEX.

Before you go to all the expense of trying to find a way to use your old lenses, consider getting a point-n-shoot digital camera.

My father thought he wanted an SLR like his old Canon AE1, so he bought a Rebel with the kit lens. But he rarely used it. Finally he bought a pocket camera (Lumix) and he carries it with him everywhere and LOVES it, uses it all the time.

You can do FAR more with today's digital pocket cameras than you could with the old film pocket cameras. You have control over the exposure, control over the focus, many different metering modes, many exposure modes, exposure compensation, etc. Some models (like my dad's Lumix) come with really great glass (his lens is made by Leica).

For most people's purposes, a pocket camera is MORE useful than a DSLR because you will have it with you more often. Once you buy a pocket camera and use it for a while, you may find that there are certain things you want to take photos of that you can't do well with the pocket camera (sports is one of those things) and then, if so, you will be prepared to figure out what you need in a DSLR. HINT: A ~$600 DSLR with a kit lens is not likely to fit the need that a pocket camera failed to meet. If you really find you need a DSLR or similar camera, you will likely still find yourself happy to have a pocket camera to talk along with you "everywhere" when you don't want to tote the bigger camera. If you really don't use the pocket camera at all, you can sell it on Craigslist - there's a very active marketplace for people to buy used well-cared-for newer pocket cameras. (In fact, you could BUY your pocket camera this way, saving even more money.)

Also, you can rent higher level DSLR cameras and lenses, which makes it easier to try before you buy.

Finally, you may find that you would like to use your old film camera again. There are some specific techniques that work best on film rather than on digital (some night photography techniques, etc.) Some photographers are using digital as "poloroid" type cameras for test shots, and then once they know the exposure and lighting techniques are right they take the final photo with film. So don't be in too much of a hurry to sell or give away the old film camera stuff.