[Rainer]

I'm just experimenting a bit with my Fuji x100 and some

screw-on teleconverters. Most will lead to heavy vignetting,

but some interestingly do not vignette at all. Nevertheless,

even most of those that do not vignette have poor borders

an very pronounced pincusion distortion along with heavy CA.

 

I do not have a PTlens-profile for any of my test-objects, but

eventually I can get along for now if I use the profile of a

completely different lens that also produces strong pincushion

distortion.

 

So far, my best find is the Canon EF 70-300 (non L , non DO)

at 300mm on fullframe. (2.58%) ... I need to apply this profile

two times (which already overcompensates a little).

 

Anyone of you knows a lens that has more pincushion distortion

(regardless of camera system and sensorformat or lens and

focallength)? I just want to try some other PTlens profiles

in order to check if a converter along with stopping down and

correction of the distortion and CA might serve as a 50 - 80mm

substitute for the x100.

 

Rainer