I think it’s probably important to know what kind of old SLR she had- some of them have similar digital controls to the old film ones. For example, I had a 35mm Rebel 2000 back in 1999 or so, and when my wife and I got our Canon T2i about 6 months back, I was pleasantly surprised to find that the basic controls and settings for manual, aperture and shutter priority and program modes were identical to the ones from 12 years prior.
If you can find one that does that, it may be a LOT easier for her.
I made one for my wife. I made a centering jig out of a disk of aluminum and used that to put a 1/8" hole dead center in the cap. Then I used a 1/4" counter-bore on the backside of that hole. Turns out that 1/4" is just about exactly the diameter of a paper hole punch and that a paper hole punch works perfectly well to punch little aluminum disks out of a soda can. The tricky part is getting a clean hole in the little aluminum disk. I used a standard pin to carefully press on one side of the disk and then the other, sanding every once in a while until a small hole was formed. I ended up with a .24mm pinhole. Inspection with a microscope revealed it to be pretty close to circular. Finally I dropped the disk in the hole in the back of the cap and held it in with black gaffer tape. Works fairly well. At one time I calculated the apparent f/stop of the pinhole but can’t find those numbers at the moment.
That’s not hard to calculate, if you know the diameter of the hole and the distance of the hole from the sensor. If the hole is 1/8 inch – say 3 mm – and it’s 60 mm from the hole to the sensor, the f/stop is 3/60, or f/20. That’s quite fast for a pinhole camera – and, as a result, you’ll get a very fuzzy image.
Here’s a related question - full frame cameras are much better than cropped, so I understand. Are there any quality used/older full-frame cameras that one could consider when looking for a DSLR?
Well, “better” is subject to all sorts of interpretations, but let’s just go with the premise. (I do prefer full frame for most things, but I’d hesitate to call them inherently “better” than crop sensors.) The Canon 5D would probably be the one you would want to look it. It’s not the first full frame dSLR (that would be the Contax N Digital, as far as I know) and the Canon had a pro body in 2002, the 1Ds, but in terms of quality low light performance, relative light weight (although it’s a good bit heavier than the intro-level dSLRs), and ease-of-use, that would be the camera I’d recommend. Hell, I still use that camera almost every time I work, and plan to continue using it until the shutter bites the dust (I’ve already had the mirror fall out of the camera, which I superglued back in.) My main qualm with the 5D is it’s a little slow (3 fps) for my tastes, but it’s still a great camera that produces great images, and the body that almost had me switch to Canon (before Nikon introduced the full–fram D3, which literally is everything I’ve ever wanted from a digital SLR).
It’s a good time to be a photographer.
Still, a used 5D body is probably going to run you in the $1000-$1500 range, and it’s over five years old.
That was somewhat prescient. Two weeks after that post, my 5D’s shutter finally did bite the dust. I didn’t get a shutter count from Canon (the replacement and repair was only $250, and they put in a new mirrorbox assembly, as well as a new control dial), but it was well over 150,000. Probably 200K+. So I’m still using that 5D.
Just an aside: I’ve gone back to shooting manual with my DSLR and am much happier with it. I’ve also enrolled in a Photo Shop Elements class and am totally impressed with the software so far.