Hi all you macro gurus out there,
I just bought a 2nd-hand Tamron 90mm Di f2.8 macro lens from a fellow CSer. I've found that I can only get the maximum f2.8 aperture when working at 3m distance or greater. Any closer and the maximum aperture progressively reduces. At its minimum focusing distance (about 30cm), the maximum aperture is only f3.8.
I was told by the seller that this is 'normal'. Just wanna check with other CSers: is this your experience with this lens/other macro lenses? Or did I just buy a defective lens?
Thanks for your input!
NB: I'm using the lens on a Nikon D80.