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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Gauging interest in BRIGHT TANGERINE FOLLOW FOCUS

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Michael Lindsay said:
I had the same concern .. (Also a LFF 1 user)...

I will count some teeth this weekend..

Thanks
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Remember... number of teeth in the desired range, NOT total number of teeth on the lens gear

So if the lens rolls over (e.g. a macro), the number of teeth in the full range would be more than the count on the gear.
 
Jim Elias said:
Hi CB

you mean 300° not 300mm right?


The actual determining factor is the number of teeth you want to drive, not the rotational angle. From the data you give, your situation would appear to be that the gear barrel has a diameter of ~= Ø114mm:


total teeth on gear are then ~= 140
140*300/360 ~= 117 teeth lock to lock
117/1.8 ~= need 65 teeth on driver with basic "cine" ratio driving


If the gear barrel were larger (smaller), it would have more (less) teeth and the 300° sector would thus then require more (less) speed.


In any case, the best way to start would be if you were to count up the exact number of teeth you want to drive in one handwheel rotation and shoot that info over to BT.


Cheers
Jim
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Yes, pardon me, I meant degrees rather than mm's.
Correct 114mm lenses, I indeed have the Arri 64 tooth gear on the LFF-1 and achieve slightly less than one rotation. However, on an FF-4 I go beyond a single rotation. So even though both are supposed to be cine (?), they are in fact different...I will check with BT
 
How would we use the Revolvr with a still lens? Will Bright Tangerine offer any gears for the lenses? To compensate the short throw are there any good gears for still lenses that compensate for it?
 
C. Burkhart said:
Yes, pardon me, I meant degrees rather than mm's.
Correct 114mm lenses, I indeed have the Arri 64 tooth gear on the LFF-1 and achieve slightly less than one rotation. However, on an FF-4 I go beyond a single rotation. So even though both are supposed to be cine (?), they are in fact different...I will check with BT
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Can't comment on this much in detail as it might breach confidentiality and/or help product copiers.

Counting teeth will keep things apples-and-apples (unless of course you're Immortan Joe)
 
Jim Elias said:
There is a lower ratio driver arm for shorter-throw lenses.
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So if I'm using both cine lenses and still lenses what is it that I'm switching? The gear head only or the entire arm that holds the gear?
 
Christoffer Glans said:
So if I'm using both cine lenses and still lenses what is it that I'm switching? The gear head only or the entire arm that holds the gear?
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As best fits what you need.

With the lower-ratio arm, the driver gear rotates one time per handwheel rotation.

With the cine arm, the driver gear rotates ~1.84x per handwheel rotation.

So with the 35 tooth gear, you output either 35 (slow arm) or ~64.5 (cine arm) teeth/handwheel rotation

And with the 43 tooth gear, you output either 43 (slow arm) or ~79 (cine arm) teeth/handwheel rotation

Calculate that against the number of lens teeth you're driving, and then you'll know what you're dealing with in terms of handwheel rotation.

And if the numbers don't add up optimally for what you're doing, write BT with your parameters and maybe something can be developed.
 
Alright, now I understand the difference between the lower ratio arm and the cine arm. I maybe need to combine the cine handwheel with the lower ratio arm. I want the bigger handwheel but using it with still lenses.
It's hard to know how many gears my 24-70 lens ends up with because some "strap-on" gears protrude to give even more turn capacity. Are there any recommended "strap-on" gears that really works well? That you could also leave on the lenses so you don't have to change it when changing lenses.
 
Christoffer Glans said:
Alright, now I understand the difference between the lower ratio arm and the cine arm. I maybe need to combine the cine handwheel with the lower ratio arm. I want the bigger handwheel but using it with still lenses.
It's hard to know how many gears my 24-70 lens ends up with because some "strap-on" gears protrude to give even more turn capacity. Are there any recommended "strap-on" gears that really works well? That you could also leave on the lenses so you don't have to change it when changing lenses.
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sorry, I don't know much about the differences between various makes of zip gears.


this bit of gear-geekery might help:


The involute curvature of gear teeth decreases proportionally with the number of teeth, until you have a rack with an infinite number of teeth and no flank curvature. (just google pictures of "rack and pinion" or such in order to see this, the flanks of the gear teeth will be curved and the flanks of the rack teeth are straight.)

For our purposes here, there is only one "correct" curvature corresponding to the number of teeth of a given gear, and the larger the deviation away from this ideal curvature, the less smooth the gear will run. So a zip gear will theoretically never run 100% right, because the teeth cannot change their curvature to adapt to the working diameter. The noticeable effect of this is however very much reduced when dealing with low-speed gear trains such as with FF/lens.

If the zip gear tooth form corresponds to a rack (i.e. the teeth are straight-sided), it follows that you will get smoothest running when the zip gear is given the largest diameter possible. If the zip gear tooth flanks have been given curvature (perhaps to try and find a lucky average), they will run smoothest at the gear diameter corresponding to that curvature.
 
I didn't even know gear teeth had flanks. I thought that was only reserved for cows.
 
Jim Elias said:
Here's the skinny to date:

A supplier of a tricky part is still working on getting it right and consistent. If he gets there quickly, yes, 6-8 weeks. If he doesn't... need another try. It's a pain, but there will be no technical compromise accepted.

As for missed box rental, if you absolutely NEED to own a follow-focus right now, then best to just go for one of those other fine products available. The worst that can happen is that you end up with regrets once you see the Revolvrs, right?
Click to expand...

So that is mid-july best case it seems.
 
Jeff Garton said:
So that is mid-july best case it seems.
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That is best case. We have not heard anything definite on shipping, except that very possible effort is being made to adhere to BT's high standards, whilst doing repetitive MTBF testing of several components, with custom designed machinery. This is much akin to the testing of automotive carriage doors' MTBF, for opening and closing, etc., etc..

I wonder if any other manufacturer of matte boxes does/has do/done that...
Thank you very much

Fury
 
What's admiral here us that Andy (and team) are putting the effort into really making this Revolvr and Revolvr|Atom quality follow focus units. At the moment BT has already propelled themselves in an incredibly short time to producing some of the highest quality gear. There is a lot on the line to nail this FF. R&D, unexpected surprises, manufacturering, etc.... None of this is easy or cheap.
 
Phil Holland said:
What's admiral here us that Andy (and team) are putting the effort into really making this Revolvr and Revolvr|Atom quality follow focus units. At the moment BT has already propelled themselves in an incredibly short time to producing some of the highest quality gear. There is a lot on the line to nail this FF. R&D, unexpected surprises, manufacturering, etc.... None of this is easy or cheap.
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Isn't this a kind of normal thing for every new company that gets huge attention in a short time span? I mean, Red was like this when they first started out. A lot of people have never been involved or know how it is to drive a company with such a big demand for the product, it's not easy. I'm in "luck" that I don't really have any huge jobs with my Dragon right now, so if something comes up I'm renting at that time, it's not a huge loss to rent an FF on a paid job. I just hope that BT keeps the low price they announced.
 
Wow, really a buyer beware for these group buys. I've been involved in a couple with mixed success. I wll definately be more careful in the future, hang in there you guys and hopefully there will be a happy ending.
Aloha
A
 
Nobody has spent any money yet Poi Boy. It's just an interest list. And I am still interested!
 
Med D said:
Nobody has spent any money yet ...
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Correct. Getting these things made is admittedly taking longer than initially hoped for, but the company can finance their own developments, they're not gonna take your dough for something that isn't finished.
 
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