Birger Knob - the great whip debate, etc...

[Erik Widding]

There have been various comments made about the knob... except for tension issue, which we are already have a fix for, these comments have been mostly positive.

It goes without saying (or at least it should) that there will be a rail mount, and a single witness mark on that rail mount. The rail mount, and the knob will be removable from the spindle/housing for integration into underwater housings.

I met Finner for the first time at the REDuser event - and once again - the topic of whips and speed cranks. I want to make sure we aren't making any short-sighted decisions. We will be contracting for the molds (approximately a $5K expense) in the next few days.

I will start this off by saying, for a $300 accessory there is a limit to how far we will go to match the exact details of a chrosizel...

As far as the whip goes, I am satisfied that a cable and second off camera knob is a reasonable, though not perfect, compromise.

Finner raised the topic of the speed crank. What purpose does this serve if we can map the entire range (or any subrange) of focus throw to a single turn of the knob?

Evin (or was it Brook?) mentioned that he is used to FF knobs being a little taller. Is this desirable? If so, how tall? We are already the same diameter as an Arri, and accept Arri marking disks.

Finner also raised the topic of additional witness marks that are both movable and tactile. How many people see this as important, and would see it as important enough to buy a more expensive knob? (don't worry there is still going to be a $300 knob.)

When a lens is calibrated, the mount will go out and look for knobs. The default will be to map the first knob in the chain to focus, and the second to iris. Later software will allow this to be user configurable. Any objections to this mode as the default?

We have three push buttons on the mount, (T)op, (M)iddle and (B)ottom. At the demo, the following button combinations were assigned:

T+B: iris open to widest stop
M: calibrate focus/knob, one turn equals full range
T: iris open 1/2 stop
B: iris close 1/2 stop
ReplaceLens: calibrate focus/knob, one turn equals full range


Changing the "gearing" of the knob was a common topic of discussion. Maybe we change the interface to the following:

T+B: iris open to widest stop
M(2 seconds): recalibrate all knobs to respective axiis, one turn equals full range
T: iris open 1/2 stop
B: iris close 1/2 stop
M+T+KnobRotate: set far focus stop, remap knob range
M+B+KnobRotate: set near focus stop, remap knob range
ReplaceLens: calibrate all knobs to respective axiis, one turn equals full range


Please discuss/propose what the default should be. Want to have something that will work out of the box before remote controls, pda software, etc, are ready.

[Shawn Bannon]

-I'd like an adjustable witness mark. (you never know where your Camera assistant has to be to view the mark)
-I'd like to see the FF knobs to be the same size as Arri
-being able to change the gearing of the knob would be awesome so each user can adjust the sensitivity of the knob for their own desires.

also having a place to put the whip or speedcrank is one less complaint from the Camera Assistant. They never know when they are going to want to use it. they might never want to use the follow focus from a wire. they might want that follow focus knob on the rods as often as possible. throwing up a whip takes 3 seconds, installing a longer cable and removing the knob from the rods can take 30 seconds maybe longer, beyond precious time for an AC. so if you can put it in there, please do.

[Brent J. Craig]

Finner raised the topic of the speed crank. What purpose does this serve if we can map the entire range (or any subrange) of focus throw to a single turn of the knob?


Muscle memory - many of us focus pull by remembering where the crank should be for various marks. It has already been discussed with some good points made here http://www.reduser.net/forum/showthread.php?p=158932#post158932

[Nathan Garofalos]

I saw your mount and nob, played with it for a few minutes, its good.
-I want a longer nob, the diameter is fine, except for the follow focus nob is sort of short. Arri's sticks out more towards yourself allowing more space for your fingers.
- Additional marks would be nice.

[NateWeaver]

Muscle memory - many of us focus pull by remembering where the crank should be for various marks. It has already been discussed with some good points made here http://www.reduser.net/forum/showthread.php?p=158932#post158932

Good point.

Erik, remember you're making something akin to a guitar neck. Some people using the gear have been doing so for many years, and rely on certain conventions when the going gets rough (300mm, wide open, talent coming straight at lens, and the DP or director is very cranky). ACs call those "zen moments" :-)

[Mike Prevette]

Eric can I call you?

I have a lot to express on this as I was an AC for a long time.

The speed crank thing is completely a requirement! Just because you can remap the range, doesn't mean you should. AC's are used to it, it's standard working practice, it must be there. Taking it off is like asking a surgeon to work with a butter knife. Most AC's aren't going to fuck around with the remapping or taking it off the rods at all.

PLEASE have a tactile mark or bump or knotch for the witness mark on the frame of the knob. The zen of focus pulling requires this. There are 3 main reasons that I'm just to busy to type out now.

(see my comments in the thread posted above by crewpix)

[Mike Prevette]

Don't get me wrong remapping is a great feature. BUT when you remap to a shorter throw you also loose resolution. A speed crank is great because you can zip it around 90% and then still have the fine control over feathering the last 10% plus more accurate adjustability once you land.

Remember your rarely racking from one static thing to another. Your racking from one moving thing to another moving thing. And the shot doesn't necessarily end once you land on your mark, you still have to deal with target A moving in and out, and target B leaning around. So if your stuck in your remapped short throw mode your fucked for those fine adjustments.


A lot of times I don't even use the speed crank as a speed crank. I use the lever principle to give me extremely hair thin control over low DOF shots. (close ups of eyes 135 t1.8 shots) With your system obviously I'm limited the the lens motors resolution and your encoder, but the crank still gives you finer control. Essentially a larger focus knob.

[Mike Prevette]

EDIT: Disregard stupid idea. It would create way to much play in the system, and you'd risk the knob popping off


If your worried about manufacturing costs, why don't you put the knob itself on a 1/2" drive, and Just have a receiver on the encoder shaft. Sure you would have to pop the knob off to use a whip or crank, but it's not totally unreasonable (5 sec max switch). You could build a whip or crank that had a mini knob mounted to the end of it, so you'd have best of both worlds.

[Joel Kaye]

Finner raised the topic of the speed crank. What purpose does this serve if we can map the entire range (or any subrange) of focus throw to a single turn of the knob?

It's easier to feel where a focus point is without looking. So you can set the ending focus point to a position such as "speed crank pointing towards the floor". Now you can hit that second spot much easier whether you're an AC or an operator pulling their own focus.

So I'd say making a hole in the knob for standard whip accessories is close to critical. As others are saying - it's what people are used to. It's a complaint that's worth avoiding.

When adjusting sensitivity there should be a way to map small changes in focus to large moves of the wheel. You'll find yourself in situations where you want to rack focus from 11 feet to 13 feet, but very slowly. Like maybe you want that move to be 180 degrees. That would mean instead of 360 degrees being 0 to infinity it's more like 1440 degrees (4 rotations) to do 0 to infinity. That needs to be in there eventually.

(edit: looks like Mike and Finner will steer you the right direction... listen to those guys)

[chuck colburn]

One could also change the throw by changing out the final drive gear.

[Hans-Georg Daun]

FWIW, FreshDV did a nice tutorial on focus pulling some time ago. It includes a rather convincing demonstration of why you would want to use a speed crank and how. See here

http://www.freshdv.com/2007/09/freshdv-film-school-the-art-of-pulling-focus-part-1.html

[LEON]

Changing the "gearing" of the knob was a common topic of discussion. Maybe we change the interface to the following:

T+B: iris open to widest stop
M(2 seconds): recalibrate all knobs to respective axiis, one turn equals full range
T: iris open 1/2 stop
B: iris close 1/2 stop
M+T+KnobRotate: set far focus stop, remap knob range
M+B+KnobRotate: set near focus stop, remap knob range
ReplaceLens: calibrate all knobs to respective axiis, one turn equals full range


Please discuss/propose what the default should be. Want to have something that will work out of the box before remote controls, pda software, etc, are ready.

I would like:

T: iris open 1/4 stop

B: iris close 1/4 stop

IF POSSIBLE !

[Justin McAleece]

I have a feeling that when i get your system the first thing I'm always gonna hear is 'where do I put the whip?' and then I'm gonna say 'no, it's really cool, all you have to do is map this digital gearing to...' and that part will fall on deaf or uncooperative or nostalgic ears and it just won't work. It's the type of thing that will immediately be bitched about even though I know that having it be remote anyway is very similar, it's just not 'the same' changing the world in big steps is often easier than changing peoples habits.

[jbeale]

I think the Canon cameras offer either 1/2 or 1/3 stops, so the lenses may well do likewise. I don't think any Canon still body offers control in 1/4 stop increments... hmm, although they do have the EOS adaptor for the XL1. I've never seen this in action; how does it control iris?

[Adam Levins]

It would be good to have the option for a whip/speed crank. Focus Pullers each have there own little ways of doing things, and these habits have developed with the current tools of the trade.

I guess Eric is saying that it is going to cost too much to have all the standard options in a $300 Wheel/Knob. But the option to use a whip would be top of my list. A single adjustable witness mark is good too.

I am used to working in 1/3 stops but 1/2 should be fine and something we have to accept.

[Harry Clark]

Just FYI...
One of my only complaints about the otherwise excellent Arri FF systems (FF-3, 4, 5) is that the short whip does not provide for a speed crank when using the lightweight disc. They DO make that strange plastic disc/knob combo thingie that I think is really meant for the silly long whip, but it's to kludgy in my opinion.
Too bad; that was always my preferred setup on a Panaflex. FF, short whip, crank. It gave you precise control, plus the ability to zip the barrel around quickly. And the whip helped to add a "soft touch" so as to not bump the camera on those long lens shots, or anytime the camera was moving. And YES to the "muscle memory" comment. Very much a part of focus pulling.
I've often thought about trying to add the receiver for the crank to the end of the short whip light weight disc, but the cost and PITA factor makes it not seem worth it.
I'd pay careful attention to the ACs here. They are the ones who will be using the device...
Cheers,
Harry

[Erik Widding]

Okay. Whip socket will be there. We have it down to adding single additional plate and four pop-rivets. I can live with this. The knob will also be longer, for the tactile reasons and to provide space for the socket.

Does anybody want to post a side view of an arri knob with a ruler in it so I can get some last details of length and taper?

I already have the solid model modified. I will print it over the weekend. This puts first production knobs going out 30 April, and final Beta knobs going out early next week.

[Justin McAleece]

great decision, thanks Erik

[Harmonica]

Okay. Whip socket will be there. We have it down to adding single additional plate and four pop-rivets. I can live with this. The knob will also be longer, for the tactile reasons and to provide space for the socket.

Does anybody want to post a side view of an arri knob with a ruler in it so I can get some last details of length and taper?

I already have the solid model modified. I will print it over the weekend. This puts first production knobs going out 30 April, and final Beta knobs going out early next week.

Did anyone get this photo to Erik?