larryepage wrote:
Just as a general suggestion...it is pretty easy to set your Tamron at an estimated 28mm and zomming to 24mm while looking through the viewfinder at a frame that kind of looks like what you normally photograph. You can do the same thing, starting at 65 mm and zooming to 70. What you see happen will be much more helpful than trying to compare based just on the numbers.
That is one of the very first things I did to see how much difference the extra mm's made. My main concern was what the difference was, if any, the lens would make in the quality of pictures compared to the Tamron. I was considering this lens due to being lighter. As I get older the weight is beginning to become more important.I have all the focal lengths covered for my DSLR's such as the Nikon 14-24 f2.8 Tamron 24-70 F2.8. and the Nikon 70-200 F2.8 but these lenses are heavy and then I have to add the adapter to make them work. I must say that these lenses with the adapter work great but are heavy to carry around. I was just looking for something for my mirrorless that was a little lighter. I do have the 24-70 F4 Z mount. I just can't decide if spending the money for one more stop of light is worth it. Just thought I would get some input from fellow members.