I have owned Rolleiflex cameras with 3.5F Planar, a 2.8F Planar and a 3.5 Tessar. They were all fine but there are differences. All cameras were in like new condition. My favorite is the 3.5F Planar as I love the resolution and contrast from about 4.5 through 16. It's the 6 element version and is about the sharpest lens I've used. The 2.8 Planar lens was about as sharp but at the wider apertures has a softness that can be very beautiful and becomes tack sharp at smaller apertures. You can see the look of the 2.8 in images by Richard Avedon. The 3.5 Tessar was also very sharp but had a slight falloff in the corners at wide apertures. The Planars seem to have finer tonal transitions as well and a flatter field with the 3.5. Anyway, I went with the F with the 3.5 Planar but they are all fine and none would be disappointing. Good luck.
Originally Posted by Dave Wooten