I have both a 90mm Sekor C and a 127mm Secor C for my RB 67. Both work great and produce great shots. Is there any reason to keep both "normal" lenses?
I have had the 127, and although I have only praise for the optics, I found myself always having to take a step (or several) back so that I could get more in the frame.
Taking one or two steps back may, or may not, help your perspective. Or maybe the longer length makes you crop the shot a bit tighter. It depends on what you shoot, and what you like.
Call Mamiya USA or e-mail & ask them to send you the RB67 Pro SD brochure. They have sample shots taken with most lenses. It's worth asking for.
It's a matter of personal taste, at least in my opinion. I have the 65, 90, and 140 and find that these work very well for what I do most of the time. I had longer lenses but sold them off for lack of use and the desire to keep the weight down. At one point my RB67 pack weighed enough that the lens caps used to orbit it if let go too near the pack.
The response tells me that it is just personal preference rather than some technical reason to select one over the other.
Nick My wife and I were in your wonderful country 2 years ago and NZ may be the most beautiful place on earth. I didnt want to come home!
for portraits i always shot my 127, i suppose it depends on what you are shooting, some say that the 90 is there top lens, i really couldt tell the difference between the two. I realy like the bokeh on the 127