Adaptor lenses

I'm wondering if sticking a wide-angle or telephoto adapter lens designed for a digital camera would work on my 35mm cameras. I don't have it right here in front of me, but I have a canon powershot g5 that i bought the extension tube and a cheap 0.5x wide-angle adapter for. I think the thread size on the back of the adapter lens is like 52mm. If I used step down rings would I be able to use this wide angle adapter lens on my minolta x-700 with 28mm (49mm thread) lens? I know if it works the quality wouldn't be great, but it'd be like having a 14mm fish-eye lens and all I'd need is a step down ring. Is my reasoning flawed? Anyone ever try doing something like this? Thanks for any thoughts!

Hold it in front of the Minolta lens and see how it works. The sensor on the G5 is smaller than 35mm, so it is likely that you'll have some vignetting with that combination, but in general, it is possible that front-of-the-lens adapters can work with SLR lenses. You just have to test.

Some of these adapters are of high quality for video and cine lenses, and they can be quite expensive.

I've got a couple that I fart around with.
One fisheye & one slight tele. The male thread on both of them is Series 7 and I just use Series 7->49/52/55 threads as I wish.
They're OK if you're tolerant of some softness/flare. Some may be better/worse. I got both of mine at resale shops for ~$5 ea. I'm pretty sure the adapter rings cost more than the lenses.

I have a 1.4x telephoto adapter that Canon sold for their 814-XLS and 1014-XLS S8 cameras. I've used it, with appropriate step-down ring, on my 200/4 MicroNikkor AIS, 150/3.3 MacroYvar and 100/2 Canon TV-16. Not the greatest, but in a pinch it is helpful.

I also have the companion 0.65x (I think) w/a adapter, have never tried it on a lens for still cameras. On my 6-66/1.8 and 6-70/1.4 Schneider zooms it vignettes a bit because the adapters are too long.

Step rings are cheap enough, give your supplementary lenses a try.

I'm going to order the step ring, I held it up in front of the lens and it looked alright. I'm ok with vignetting, I really like messing around with really wide angles. I'm looking forward to getting the step ring so I can really have some fun with it. I'm also going to pick up a cheap 2x teleconverter lens for the canon g5, I found one for a video camera on keh for like $10 it just needs the appropriate step ring to fit on the adapter tube. Thanks for your thoughts!