Landscapephoto
The 100mm is a very good lens, but was not designed for what you want to do. It is a fast double-Gauss design and shows the advantages (for portraits) and disadvantages (for what you intend to do) of that classical design. If you need a lens around that focal length, you will probably be more satisfied with the HD-120 II macro (not the first version), which is very well corrected even at large distances. Unfortunately, the HD-120 II is quite large and heavy.
I'm not disagreeing with you but from the images I've made with the 100mm it seem to preform to a degree that was astonishing in the final image. Again we might have a different opinion when tested with the larger sensor without the x factor. I must admit though shooting 40-50 images with a Seitz Roundshot VR head with both the 100mm and the newest 120mm the 120 was a bit more touchy weight wise but the seitz handled it well. More of the issue one can have is with the brackets you use giving unwanted vibrations setting a delay in acquiring the image sequence seem to solve the vibrations but...that brings into play with nature movements of leaves, branches, water and clouds. Can't win for losing? In my experience the purple fringing comes in to play based on the direction of the light. I love to shoot into the sun but several of my lenses don't this is when I noticed the most image issues then the camera, lenses and/or sensors can handle. However maybe the images with sunspots, flare and fringing have there appeal to some people and we shouldn't be so critical.
Changing the channel I even used the 120mm with the HTS 1.5 and it works but as I was told by Hassy its to heavy and not recommended. Also for what I was photographing the tilt for small products didn't make enough of a difference to completely solve the entire problem of depth of field but did knock down my image stacking by about 30%. That use of the HTS 1.5 also creates a new monster with the 1.5x even when backing up you still can't fill enough of the sensor to get the most out of 50MB. (without shooting 80-100 stacked images bring in to play many other issues) Its more like you only get 50% of the sensor covering the image.
On another note if anyone has had some experience with the 100c I sure hope (wish) they would share it on this forum. I know several units have been shipped but it seems the owners are tight lipped at this time.
Regards
Barry