I just received my Nikkor 105 f2.8 Macro lens and I have a question about the operation. When I close focus, I cannot get the aperture to open all the way to f2.8. The aperture will usually settle in between f3 and f4. When I focus farther out, the aperture will open up all the way to f2.8. I had the camera in aperture priority. It has the same operation on my D2x and my F100
This is my first macro lens. None of my other Nikon lenses act this way. Is this normal operation or did I get a defective copy
I have found with my copy of the 60mm 2.8 macro, that it rarely actually will shoot at f/2.8. This is due to all the elements of the lens shifting for the close focus. Completely normal afaik.
normal, a macro lens "grows" as it gets toward 1:1 , essientially it is a regular lens with a set of tubes built in.
since the lens f stop is a function of focal length and aperture is a function of the diameter , the diameter is fixed but the length is not , hence less light is getting thru at higher mag thus the fall in the maximum aperture
jmcfadden wrote:
normal, a macro lens "grows" as it gets toward 1:1 , essientially it is a regular lens with a set of tubes built in.
since the lens f stop is a function of focal length and aperture is a function of the diameter , the diameter is fixed but the length is not , hence less light is getting thru at higher mag thus the fall in the maximum aperture
J
It's not exactly that there is less light passing through the lens. In fact, it should be about the same. However, because the front element gets further and further away from the sensor, the light is being spread out more and more. So, only less light is reaching the sensor.
