Nikon lenses have a stellar reputation for quality, dependability and durability. However, the price tag for a Nikon lens can be steep and some photographers might consider using a less expensive lens made by another company to use on the front of their SLR camera. Lenses like these are available and they can be purchased and installed directly on a Nikon body without the use of an adapter ring.
Backward compatible Nikon lenses
Nikon lenses are often interchangeable, yet a particular lens is not necessarily interchangeable with all Nikon camera bodies. Over the years Nikon lenses and camera bodies have changed so that older model lenses will not always fit newer bodies and vica versa. The Nikonians website has a chart that lists in detail the various combinations of compatible Nikon lenses and camera bodies.
Also keep in mind that older Nikon lenses were manufactured under the name Nikkor.
Vivitar is a lens optical company that for years has been making specially designed lenses that fit directly onto a Nikon camera body. These lenses have a reputation for good optics, but may not hold up under heavy use as well as a brand name Nikon lens. The good thing about the Nikon camera system is that the newer digital SLR cameras seem to function just fine with some older pre-digital lens. If the lens fits, then it will probably work, though there may be some image cropping and magnification taking place. The same should be true for Vivitar lenses that were originally made to fit directly on a Nikon body. In any case if the older lens fits onto a new digital model, then take some pictures and closely analyze the results before putting the lens to use.
Sigma is another third party lens manufacturer that makes lenses that will fit directly onto a Nikon body. As is the case with most lenses of this type, optics is rarely the issue, but durability and ease of operation may vary. Still, for someone looking to use a cheaper lens on a Nikon body, Sigma is a popular option that satisfies many photographers. However, a good understanding of how the Nikon systems have changed over the years will help the lens buyer pick out an appropriate substitute lens. Tests using the third party lens can help you decide, but choosing a compatible lens by researching the different Nikon metering and focusing systems will give the prospective lens buyer better choices.
To research a lens look up its lens system designation and see when this type of lens was manufactured. Then look for a Soligor, Vivitar or other third party lens that was also made during that time.