Nice try. It's not called a diaphragm or "diaphram" as you spelled it though. Why don't you use wikipedia to look it up.
the iris
Lenses for Nikon camera can be purchased from any local camera stores. However, one can find a better deal on some online stores like eBay and Amazon.
A camera's diaphragm and your eye's iris perform the same function in the same way. They both control how much light is allowed through the lens by expanding and contracting.
I'm just going out on a limb here but I'm GUESSING that it is used to hold a camera or camera accessories like an attachable flash or different camera lenses.
You can get cheap camera accessories at cellularfactory.com. It has all your camera needs like usb cables, camera bags, lenses,etc. It even takes care of the shipping.
well,they focus like your eyes,when things are far,the lenses moves back and forth to adjust the clearness and blurness.<3vnh
As in a camera, this part is usually called an iris diaphragm. It can make the aperture bigger to let in more light, or smaller to make the image sharper. The shutter in a camera is not the same thing.
Lenses like this are usually available in places like Well's Camera Shop. Some stores like Walmart may carry them and online, Amazon lists this product.
Like virtually all camera makers, Nikon's camera mount is propriatory to Nikon, but there are third party manufacturers - Sigma and Tamron are probably the most well known - who make compatible lenses.
It depends on the brand of camera and the type of lens. Most Nikon film SLR lenses will work (in manual mode) on their digital SLR cameras. Many Canon lenses will work on new Canon SLR cameras, but you have to check compatability between the camera model and the type of lens. Sony purhcased the Minolta digital camera division, so all Sony Alpha DSLRs will use Minolta lenses.
Sigma lenses can be found in specialty camera stores that are local or national chains. They can also be found in large retailers of technology products like Best Buy.
Unfortunately no. With an adapter one can use a Nikon lens on a Canon body, but the distances between lens and register (the critical point in the camera body where the image is recorded) make it impossible to even create an adapter to use Canon lenses on Nikon bodies.