Has anyone done this before?

[NothingRare]

Has anyone ever taken the lenses off a point and shoot and stuck a DSLR bayonet mount to the sensor?

There would be a huge crop factor... 2/3" sensor that'd be a 4x crop factor, I think??
A 50mm f/1.4 will become a 200mm f/1.4 equivalent? That is awesome.

People have done this before with a webcam to take pictures of planets...
And I have a spare webcam..!

[Bob Nichol]

There would be some interesting challenges indeed!

The bayonet would have to be positioned to accommodate where the mirror box would be in a DSLR and a light tight enclosure built to support it.

The cameras have a mechanism to hold the aperture open while focusing and composing then closing it for shooting so you have to factor that in. In addition some brands, such as Nikon, don't have an aperture ring on the lens as that is set by the camera body. You could always remember to set the aperture before taking a shot. You may have to use an external light meter however.

Some lenses have a built in motor for focusing but others require an external motor in the body. Manual focus is always an option.

[richardh]

I would think that the biggest problem would be the camera is expecting response from the lens and if its not getting any kind of signal (from the motor that zooms the lens etc) I would think you would get an error and it wouldn't work. If you could find a way around that it might be interesting to see what you could do. You might wind up with something that resembles a 4/3 camera. There would also be the issue of how to focus (is the lcd going to be good enough to manual focus and or would the cameras focus detection be bale to function with a foreign lens?

I had kind of thought about building a point and shoot camera (or some of its components) into the back of a film slr body?

[TCav]

"Focal Length" is a physical property of a lens, and doesn't change with the size of the image sensor it projects an image onto. If, for instance, you took the 4.5-108mm zoom lens off a Panasonic FZ100, and replaced it with a 100mm dSLR lens, the resulting angle of view would be the same as it was at the 100mm setting of the original lens.

A major impediment would be that SLR lenses are designed to project large image circles, and what you'd be doing amounts to taking a very high resolution 100% crop of that image. Any optical flaws in the lens you used would be very obvious. I think I'd go with an old manual focus, fixed focus lens, with an aperture ring, from the used market. These can be had for a song.

[TCav]

I think you'd do better with a P&S that has a small sensor, a manual exposure mode, and probably manual focus. Also, just to keep things simple, you shouldn't disconnect the original lens, just take it out of the light path.