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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 :)

Birger Lens Mount Reservations

Ken Willinger said:
The Birger mount worked with all the lenses we tested yesterday.
Click to expand...

More precisely,

1. Currently the long EF teles which have a large iris, such as 400mm/f2.8, 500mm/f4.0, 600mm/f4.0 do not work right now with the latest library. Erik is aware of the problem and will solve it.

2. Likely this is not an issue of Birger but rather that of Red: The lens data stops at 100mm. Say, with the 70-200mm/f2.8 lenses zooming from one end to another after 100mm the reading stops there.

3. The lens data does not come through with the 1.4x and 2.0x teleconverters.

4. Focus distance data is not shown in manual focus mode. However, in Jay's video it does work with the Impero.
 
Lauri Kettunen said:
More precisely,

1. Currently the long EF teles which have a large iris, such as 400mm/f2.8, 500mm/f4.0, 600mm/f4.0 do not work right now with the latest library. Erik is aware of the problem and will solve it.
Click to expand...

This would be a game changer for me! Hope it is a sooner than later fix - of course, I'm still waiting on the mount anyhow....

I would think some of Eric's military customers would be using these long lenses, maybe it's different with the Red mount to Birger mount interface??? I dunno, just guessing...and still hoping...and waiting...
 
Isaac Babcock said:
maybe it's different with the Red mount to Birger mount interface???
Click to expand...

Right now the cultivated guess is that it's a power issue of the Red One aux port. The camera can't give enough power to the big lenses. One solution is a d-tap cable directly from the battery to the mount.
 
Eric and Amy,

you send me this mail on Feb. 17th:

"Your Canon EF lens mount for your RED camera is available for shipment within the week. ..."

You charged my credit card - still not a mount or tracking numbers in sight.
I don't get it! This kind of planing (or better the lack of it) makes business really difficult.

-ralf
 
Lauri Kettunen said:
Right now the cultivated guess is that it's a power issue of the Red One aux port. The camera can't give enough power to the big lenses. One solution is a d-tap cable directly from the battery to the mount.
Click to expand...
But these are photo lenses right? So their only normal power source is the Canon camera they're attached to, meaning that the size of the lens should have nothing to do with how much power they draw since you'd imagine that the EF mount has standards that run off the lowliest Rebel up to the 1D Mk.X.

Can you give more info on where this guess has come from? I'm always ready to be corrected if I'm wrong on my theory.

Cheers,

Paul
 
Paul Leeming said:
meaning that the size of the lens should have nothing to do with how much power they draw since you'd imagine that the EF mount has standards that run off the lowiest Rebel up to the 1D Mk.X.
Click to expand...

Recall first that Erik said that the problem with the EF 85mm/f1.2 had to do with power. Second, can't quite see what you try to say precisely. For it's obvious that the bigger the mass the more power is needed to move or rotate the mass with some definite speed. And if you take one of these big lenses in your hand, you'll notice immediately that the fosucing ring is much bigger than in wide angle lenses.

But, if you say, why these lenses work even with the cheapest EOS bodies ran by ordinary batteries but not with the Birger mount powered by the Red One aux port that's indeed bit surprising. But, one should take into account the mount itself and the bluthooth requires already some power.

Erik told me, if the iris does not function, which is the case (the whole lens is dead) then it sounds like a power issue. But, we'll see.
 
Paul Leeming said:
But these are photo lenses right? So their only normal power source is the Canon camera they're attached to, meaning that the size of the lens should have nothing to do with how much power they draw since you'd imagine that the EF mount has standards that run off the lowiest Rebel up to the 1D Mk.X.
Click to expand...

4xAA batteries can provide a lot of current, and also have a thevenin resistance that acts as a power limit, and effectively limits surge currents very well, at the battery. RED camera has no Thevenin resistance, it can source almost infinite current (reative to its current limit), and it has a hair trigger at 2amps. It does not handle surge currents in nearly the same way... The problem is and always has been surge currents, not sustained currents.
 
Lauri, you are right in that the bigger lenses have bigger manual focus rings with more heft to operate, but actually when engaging autofocus it's normally the UltraSonic Motor (USM, ring type in most of the EF range except for the cheapest and/or oldest) doing the work and those are designed for extremely low friction so that the camera can power them sufficiently.

You'll find that with only a couple of exceptions most Canon EF lenses either have full time independent manual focus which can be used even with AF mode set, or they must be switched to MF mode in order to disengage the AF motor from the system and manually turn the focus ring.

One such exception apparently is the 85L/1.2 which is probably the cause of at least one of the issues (I don't own this lens sorry so I have no direct experience with it).

I'm not an expert on all Canon lenses so whilst I know a fair bit, I'm hoping someone who has more experience or first hand knowledge will confirm or deny what I'm saying.

Cheers,

Paul

EDIT: Erik posted just as I posted, so.... what he said! :)
 
birgerEngineer said:
4xAA batteries can provide a lot of current, and also have a thevenin resistance that acts as a power limit, and effectively limits surge currents very well, at the battery. RED camera has no Thevenin resistance, it can source almost infinite current (reative to its current limit), and it has a hair trigger at 2amps. It does not handle surge currents in nearly the same way... The problem is and always has been surge currents, not sustained currents.
Click to expand...

Hmmm...so what now? Does this mean powering through the D-tap for larger lenses? Dare I ask what this does to the shipping schedule? I'm not trying to gripe, sorry - just trying to find out what I can to refrain from calling...

It'd be nice if there was a way to solve this and still have the ability for the knob to start/stop the camera - My vote would be for a short y-cable: connects to the birger mount at one end, to the D tap for power, and to the RS-232 port for camera start/stop function. (yah, back to the 232 port because it allows for slick cable management, short cable and right angled lemo connector) I'd wire a slimline mini-rocker switch into the D-tap cable so I can turn the power to the lens on and off easily when the camera is powered up/down. I'd draw up a diagram, but I wouldn't know how to get it onto this page... I don't know if this is possible or jibberesh....and I hate to make further delays, but if this is what it takes...just saying...
 
Isaac Babcock said:
Hmmm...so what now? Does this mean powering through the D-tap for larger lenses? Dare I ask what this does to the shipping schedule? I'm not trying to gripe, sorry - just trying to find out what I can to refrain from calling...
Click to expand...

Isaac, no effect on shipping schedule. It will probbly be a software fix. But it may require the d-tap cable.

BTW. Your mount is currently being tested. You will have it shortly... and for anyone else that wants an anser to the same question I just answered my last phone call for the day as I need to be getting shipments ready for fedex.
 
Just got off the phone with Erik. I promised him I'd call, and I didn't want him to feel like he'd been forgotten. ;-)

My serial number is on the current test tray with 11 other lucky mounts.

We talked about the power issue, and it sounds like Erik is already wrapping his head around multiple solutions to the problem. And no mention of any shipping delays or redesigns as a result. :woot:

Kyle
 
birgerEngineer said:
The problem is and always has been surge currents, not sustained currents.
Click to expand...

Sounds like the Birger mount has a voltage regulator but the current may vary a lot depend ing on what is going on inside the camera. At the first glance makes sense and explained why the Canon XL-series EF-adaptor had a battery of its own.

As Isaac suggests one could always split the cable such that one part goes to the aux port (enabling the rec/stop of Impero) and another branch to some external battery.
 
birgerEngineer said:
...
It does not handle surge currents in nearly the same way... The problem is and always has been surge currents, not sustained currents.
Click to expand...

Erik, could a good capacitor connected parallel to the power line solve the problem? Maybe that would work providing extra current supply when necessary automatically, without a need for any additional batteries.
 
Paul Leeming said:
You'll find that with only a couple of exceptions most Canon EF lenses either have full time independent manual focus which can be used even with AF mode set, or they must be switched to MF mode in order to disengage the AF motor from the system and manually turn the focus ring.

One such exception apparently is the 85L/1.2 which is probably the cause of at least one of the issues
Click to expand...

Erik, all these long lenses have the "focus speed" switch. Any chance this is the source of problem and explained why they do not work?
 
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