How to Change a Lens on SLR Cameras
SLR cameras are used by professionals. One of the key differences between a professional and consumer camera is the ability to change lenses because lens have a great influence on your depth of field. Changing a lens is quick and simple, however, one should remember that lenses are expensive and very fragile. If you drop one then that mistake will cost hundreds of dollars--always be careful.
Holding the camera firmly in one hand, press the lens release button with your free hand.
Use your free hand to grab the lens and twist it, usually counter clockwise, but all manufacturers are different.
Once the lens is free, place the lens caps on it to avoid damaging the glass by scratching it.
Take the new lens and twist it into the lens socket in the opposite direction you used to remove the previous lens. You will hear a click when the lens is locked into place.
The lens should be firmly in place. If it feels loose, then remove it and re-insert it. A loose lens means it is not properly in place and it could fall out.
Go out and shoot until you need another lens.