Quote: ....For your M50, this would have a 49mm male thread on one side and a PK bayonet on the other. Reversing the lens gives you edge-to-edge sharpness but no magnification....
You will have some magnification or demagnification depending on the details of lens construction (how deep the lens is recessed from the filter ring). It is easy to find out. Just hold the lens backwards in front of the camera mount while looking through the viewfinder. Look at a laptop screen and move the camera in & out until you see a focused image.
Extension tubes are more versatile than simply reversing the M 50 as they'll give a range of magnifications, while the reversed lens will have essentially a single magnification. Further the extension tubes will be useful for future lenses. Bellows might be even better, but they cost more than simple tubes.
Last edited by newarts; 03-06-2011 at 12:03 PM.