I am about to make a change into the dslr world from a HMC150 and am just trying to nut some things out. I do alot of filming of skateboarding and snowboarding and one technique that is common in both is zooming whilst panning and this is something i really cant get my head around with the 7d.
I am correct in assuming the only way to achieve this would be to put your hand onto the lens and twist whilst recording (a technique i would imagine that is sure to result in jumpy footage escpecially zoomed in).
Or is there some kind of follow focus type system that allows you to do it a little easier. Or can you just change the ring and put it on the zoom wheel.
If there is such a system that doesnt break the bank i would love to know about it.and any help on other techniques would be much appreciated.

Sorry Stu, but this is something the DSLR's are just not capable of doing.

Yes, you could probably rig a follow focus onto the zoom ring but you are going to be cranking that while also panning while tracking a fast moving subject. It's alot more difficult than rubbing your tummy and patting your head.

Plus any change in zoom will also require a focus adjustment because most still photo lenses are varifocal, meaning they do not maintain focus through the zoom range like a [I][parfocal/I] lens on a videocamera does.

It is generally accepted that you can't zoom mid-shot with a DSLR, unless you plan on cutting that section of footage out. Maybe there are people who are pulling it off successfully in controlled, rehearsed situations with a focus puller and assistant cameraman, but action sports is a different story.

On the other hand, these cameras are great for close-up wide angle action sports work. They are small and light so make great tracking cameras espescially when comibined with a steadycam of some sort. There is also a plethora of wide lenses available which will minimise camera movements and let you really get amongst the action. Not to mention the 60p which is great for slo-mo.

Thank you for the in depth reply John. I thought that was unfortunately the case. Still going to get one, the image quality is just too good to pass up...and yeah, love the look of action sports up close with the wide angle and steadycam combo.
Thanks again

Hi Stu,

While the lenses are not designated as such many will hold focus well while being zoomed. You can read a bit more about it here - Doug Chinnery Photography: Canon Parfocal Lenses (http://dougchinnery.blogspot.com/2010/01/canon-parfocal-lenses.html)

My Canon EF 70-200mm f/4L USM is a good example of this and stays perfectly sharp while zoomed. One thing to remember is as you zoom in the DOF drops (sometimes dramatically) which will exaggerate any focus errors.

For sports I'll do some snap zooms while recording for effect. Don't overuse it though. The camera will need to be on a good tripod to minimize shake from handling the lens. The photosites on this camera are so small that shake is magnified. It doesn't take much shake to ruin a shot with these cameras.