Fixed lens and SLR lens

[Beth Ellen]

Hello, I am new to photography but wondered why an SLR lens will not work on a fixed lens camera?

Beth Ellen
Panasonic FZ5
www.eclecticcafejournal.com/WordPress

[JimC]

For one thing, they're not designed to let you mount a lens for an SLR.

Also, each SLR manufacturer uses a different lens mount. It's not a standard the way filter threads are (although some lens mount systems like the M42 Screw Mount were adopted by more than one manufacturer at one time).

In more modern SLR models, you've got proprietary lens mount systems with electronic contacts that allow the camera to "talk" to a lens (they even have a CPU built in). The camera is also doing things like controlling the lens aperture and more, sometimes via mechanical and sometimes via electronic communications with the lens.

So, you'd lose that ability. You've also got Autofocus to consider. Some manufacturers use a motor in the lens, some use a motor in the camera to drive the lens focus. You'd lose that trying to attach the lens to a fixed lens camera's lens.

Even if you used an older lens design and were willing to give up things like Autofocus and Control of the Aperture from the Camera, you'd still need a way to mount it. You could probably rig something up, depending on the lens mount design and how friendly you are with someone that knows their way around a machine shop. But, it may not work (ability to actually manually focus the lens at the distances you want to shoot at, etc., because of the distance the lens is from the sensor).

You've also got vastly different focal lengths being used on fixed lens digital cameras. Most have very tiny sensors compared to 35mm film. So, for any given actual (versus 35mm equivalent) focal length, you're going to have a lot more apparent magnification.

From time to time, you see someone that uses a lens designed for a 35mm camera reversed on a non-DSLR model for macro purposes (using a reversing ring setup to mate the front of one lens to the filter threads on another). IOW, it's mounted backwards. But, for most other purposes, it's just not practical to use one.

[Beth Ellen]

Thank you much. I see I didn't quite understand how the SLR lens attaches and now reverse macro make more sense to me. I also didn't quite understand the motor aspect of the lens'.

Beth Ellen
FZ5