Well I agree to some extent except that I often see this happen even in major motion pictures. Depending on the scenario it can actually make a rack focus even more dramatic. However I can see how it would be a problem also.

What do you mean when you say you likes its softer more film like image? I find it to be uber sharp and many others have reported the same, some even claiming that it is sharper than the 20x. I love the lens but I don't feel it is less sharp than the 20x. However slap a .7x WA adapter on this badboy and you'll find it's optical properties start to get closer to a 35mm lens, as far as DOF goes.

Oh absoulutlely. I've had the opportunity to recently play with some better lenses and they breathed as well, but not as much, however they were also much more expensive. Plus if you really are just worried about doing a rack focus, the macro trick really does work, I just have to see if I can do it without the camera moving.

Maybe softer is the wrong term. The images are certainly sharp and clear, and just as crisp as the 20X, however they have a softer feel to them - to me. More film like if you will. Film is sharp but not like video, the latitude/colors are somehow different. It's like there is a softness within the sharpness, does that make any sense? It's not a huge difference, and I do like the 20X lens, but the 16X just seems different to me. Maybe it's the lack of Flourite?

Do tell about the .7 WA adapter and DOF. What are you experiencing. Could you use that adapter with a mattebox?

after reading this thread for a few weeks, I finally rememberd it while i was working the other day. i work at a cbc affiliate news station and checked out their lenses for the amount of breathing during rack focus. I found that even those lenses, beeing close to $30,000 a peice showed some breathing. i have not used the 16x canon lens yet, but it was definatly noticable even on the $30,000 lenses. It must be something that just happens to be common on full manual lenses. Just work with it and if you can disguise it anyway then you know you are doing a good job.