(UPDATE) I purchased this unit with a rig system for $750. The price fluctuates a lot on all of Gini's products, as he is constantly updating his designs. You can think of this as buying a product that is in constant Beta testing. Often you will find identically labeled products that have different color bolts, different connectors, and slightly different machining. This isn't do to sloppy quality control, just the constant refinement of his designs.
One the the most useful, yet under used pieces of kit in the digital shooter's bag is the follow focus. A few years ago this was something that was pretty much only used in high end commercial and cinema applications, most of the units available were in the $1000+ price range, with some of them costing much more. Those shooting prosumer cameras relied on auto focus systems and the depth of field afforded by the small sensor size to keep things in focus.
With the start of the "dSLR Revolution" there came a bunch of new companies building "affordable" rigs, mounts, matte boxes, and the like to try and overcome the ergonomic shortfalls of these adapted stills cameras. Part of the appeal of these large chip cameras is their shallow depth of field and the ability to use a variety of fast, sharp lenses. The "shortfall" of these new cameras is that most of them don't autofocus while recording, and those that do, don't focus smoothly nor accurately enough to use for most applications. It is possible to focus manually using the focus ring on your lens, but in order to achieve smooth, controlled results, using a follow focus is the way to go.
There are a few standards by which follow focus units are rated. Probably the most important is the amount of lash in the gearbox. Lash is basically how much play exists in the mechanical system, and as a result how much you will have to turn the knob on the FF before it begins to turn the focus ring on the lens. A FF with too much lash makes it difficult to repeat focus movements, especially when you are moving back and forth between two or more marks. After lash, build quality, durability and ergonomics all factor in to the effectiveness of the unit. In this respect, you will probably get what you pay for. A higher end unit will almost certainly last longer and maintain it's performance better then a cheaper one. Certainly you budget will dictate how expensive a unit you can buy, but this is one of those situations where you should probably buy the best you can afford. A good quality unit will last a career if you take care of it properly.
The Gini iFocus is a very well constructed focus unit. It is made completely out of machined aluminum. The "machining" part is not an important, except that it has a different look then cast units, it does indicate that this is a limited run product though. The iFocus uses a single clamp design, initially I was worried about there being too much flex in a single 15mm rod to hold the FF rigidly to the lens. In practice, however, this has not been an issue. Overall the finish of the unit is very good, Gini went with a gloss anodizing that is a little on the thin side. I would have preferred a matte finish with a longer ano time, but both of these options would have added cost and time, so I guess I can't complain too much.
The single clamping arm holds a custom gear box that has only the slightest hint of lash. It's there if you want to find it, but is not noticeable at all while using the unit to pull focus. The gearbox is mounted to the arm with a pair of circular clamps, allowing you to level the unit on the fly, or set the knob at an angle if you want. This feature combined with the single arm design makes changing lenses with different diameters really fast and intuitive. Loosening a single clamp allows the unit to swing out of the way while you swap lenses and return to working position in just a few seconds.
One of the few criticisms that I have of the design is the non-movable marking indicator. There is an additional mounting point for the indicator on the underside of the gearbox so you can run the unit on the dumb side of the camera or with a reversed focus throw if you want, but there is no option to run the marker in a horizontal position so you can set marks with your eye to the viewfinder. I don't do this very often, but it sure would be nice to have that option.
I know that is isn't a complete review, nor a "how to" guide on this follow focus, but I was really just hoping to answer some of the questions that I had before I bought it, so others can make a more informed purchase. I also realized that I ramble a bit with this sort of thing, so if it is annoying to you, leave a comment. If you have further questions that I failed to answer, leave a comment and I will update the post with the answer if I can.
Much more to come, check back soon.