| RWBlue wrote:|
FX lens on DX bodies are always a point of discussion.
First, there is vignetting. FX on FX or DX on DX can give you vignetting. Vignetting for those that don't know is darkening around the corners of the frame.
Not necessarily. You get vignetting if the lens is not optimized correctly for a given image size. You are right though that the probability of vignetting even with comparatively low end FX lenses on DX bodies is very small. However, for nice lenses that are discussed here, I would not worry about signetting too much.
Second, I think the image with better with FX glass. I don't know if it is the coating of quality of glass or how they put it together or....., but I can see some difference in some lenses.
If the lenses are of the same quality, you will not see any difference between FX and DX aside from sample variation. There are a few exceptions to that: cheap lenses where edge issues of FX lenses are not visible on DX bodies, wide angle lenses where many lenses have telecentricity issues that are less visible with larger FX lenses.
Third, I have thought I was going to get a FX body for several years. It is always just a little out of reach or, I see other needs or now the DX bodies are getting so good and several thousand less ......I have a hard time justifying the FX. Side note, I may have a lead on a body with almost no use on it. As it is just too heavy for the person who bought it....Trade them a D7100 for an D810 even up....
Fourth, They didn't have the 18-300 Nikkor when I bought my lens. If they did, it would have been more difficult to decide. But isn't the 18-300 a true 18-300 on a DX, where my 28-300 is really a 36-450mm (check my math) on a DX
Focal lengths are what they are regardless of the sensor format. You can convert the focal length into "35mm equivalent" to figure out the field of view you will get with a given lens, but that does not mean the lens is of actually different focal length. All that means is that a 300mm lens on a DX body will give you the same field of view as the 450mm lens on a FX body.