Remote follow focus for £150/$300

niceknob.jpg
 
Avenger007 said:
so the marking wheel stays put and the knob with the arrow rotates around?
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Yeah, doing it the other way, with a single piece knob and marking ring would mean designing and having my own knob made, which would cost a fortunate. I think this is a good compromise though, still looks like a follow focus, you can use your own mens on it etc etc, but it is much cheaper than getting a custom knob machined up for us...
 
Well I did think about that, but I think it would be hard to make it tough and hard wearing. The only way I can think of doing it without getting my own knobs machined is to just superglue the disk to the underside of the knob, and it seems likely that a little knock would separate the two, and I dont want any element of this device to be breakable in any way....
 
The electronics for the RFF have changed somewhat from an analogue dual 555 timer system to a PIC programmed chip.

The unit will now have two buttons on the case which will control the limits of the servo. This is so you dont move too far and strip the gear or damage the lens. It works like this:

set the knob to middle position and the lens to middle position and engage the two together. Move the knob until the lens is at infinity then press and hold the infinity store button. It will then remember this position. Do the same for the other end of the lens, and the servo will now remember that it cannot go across these marks.

One other feature that I am thinking I might add at this stage is a pause button. If you set your focal distance and you do not want to loose it (other than drawing a line on the marking disk) you can press the pause button. This will lock the servo at the current position and turning the knob wont do anything. When you press the button again it will revert back to normal mode and it will jump to wherever the knob is at that moment.

Are these updated and changes a good thing? Im still looking at about a month for a fully working unit...

Thanks for any input....
 
Peter,

Sounds good. Will the unit have preset focus positions like the foveas? This is great for storing focal points and getting back to them with a touch of a button.
 
well it could, but since this one has a marking disk, i thought using that would be just as simple... It probably would be possible but not for the first version...
 
Nah the components cost the same, the guy thats coding it is an old friend and hes doing it for me, The only additional cost will be the buttons, the actual circuit costs no more than the old analogue one.
 
hoarp001 said:
One other feature that I am thinking I might add at this stage is a pause button. If you set your focal distance and you do not want to loose it (other than drawing a line on the marking disk) you can press the pause button. This will lock the servo at the current position and turning the knob wont do anything. When you press the button again it will revert back to normal mode and it will jump to wherever the knob is at that moment.

Are these updated and changes a good thing? Im still looking at about a month for a fully working unit...

Thanks for any input....
Click to expand...

Sounds good. You know what, you could call the Pause button "Hold" like music players call it when they lock out the controls.
 
I really like the implementation of the infinity and close focus buttons. Sounds like an elegant and inexpensive solution to what could have been an interesting problem.

I don't see myself using the hold button very much.
 
the hold button could be good but its not a deal breaker. If you feel it helps and its not a pain then more features are always better, assuming they work properly and don't detract from the performance. This thing sounds great :)
 
We have also decided to put a crystal clock in the RFF unit to keep it acurate. Like in a watch, a lump of crystal vibrates at 20hz, and the PIC chip counts the vibrations to keep the timeframe accurate.

Sounds sex-aaay :Drogar-BigGrin(DBG)

Hopefully have the new electronics sorted in the next week
 
hoarp001 said:
... The only additional cost will be the buttons, the actual circuit costs no more than the old analogue one.
Click to expand...

I like buttons :) but I also like the concept of a low cost RFF, so easy on the einstein developments :Drogar-Thinking(DBG (semi-joke) but those improvements DO sound awesome! nice work :)
 
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