Thread: The SDI issues

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  1. #1 The SDI issues 
    Senior Member Christoffer Glans's Avatar
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    I've seen a lot of people having problems with their SDI ports. Personally, I've yet to use the one on mine but plan on getting a monitor to use in a setup like everyone else. But all of these issues make me wonder what is going on?

    I'm not talking about people using unshielded 3G cables going through a startup sequence that increase the risk of shorting the SDI port, but those who bought 12G cables and still had their SDI ports stop functioning. Why? Shouldn't a shielded 12G connection be somewhat safe? And if the monitor uses onboard batteries, does that not mean there's no current flowing from the camera power source? And what happens when you need to change batteries on the monitor, do we have to turn off everything and go through all the decoupling sequences in order to start things up again? So if the monitor dies during a shoot and you change batteries, what happens then?

    The number of people having problems with the SDI port worries me and I don't understand why Red doesn't sell tested SDI cables or recommend brands when they've at the same time pointed out how important the cables are when working with this camera. I actually don't know where to get cables because there are no direct "approved cables" and when people get problems with 12G cables that should work it could be that the cable itself is of bad quality.

    In any case, I've never seen so many issues with SDI outputs on a camera. It's like it's made of glass. Even though the startup cable sequence is standard for any camera, I've never seen such a large number of cases. It should be extremely rare that this happens?

    Can red please answer this, or put together a list of companies and cables that are considered tested and approved to use. As well as more details on which methods of powering monitors are considered low risk? I really don't want to do a hit-and-miss getting cables or powering cables that screw up the SDI because it's as sensitive as putting a fork in the power outlet.
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  2. #2  
    Senior Member Blair S. Paulsen's Avatar
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    Had good luck with these:

    https://www.pacrad.com/noshorts-custom-cables

    Cheers - #19
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  3. #3  
    Senior Member Jacek Zakowicz's Avatar
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    isn't it the age old SDI problem with the ground loop?
    Jacek Zakowicz, Optitek-dot-org, jacek2@optitek.org
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  4. #4  
    Senior Member Christoffer Glans's Avatar
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    Quote Originally Posted by Jacek Zakowicz View Post
    isn't it the age old SDI problem with the ground loop?
    Yes, but there seems to be an increasing rate of failures compared to previous cameras and others like Arri, Sony etc. So the SDI connection on Komodo seems to be very sensitive to failure and when people follow the instructions and use 12G cables and such it should not happen this much.
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  5. #5  
    Senior Member Robert Hofmeyr's Avatar
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    Does the sequence matter when using a battery powered monitor? I thought it was just for monitors powered from the same battery as the camera.
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  6. #6  
    Senior Member Jacek Zakowicz's Avatar
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    Quote Originally Posted by Christoffer Glans View Post
    Yes, but there seems to be an increasing rate of failures compared to previous cameras and others like Arri, Sony etc. So the SDI connection on Komodo seems to be very sensitive to failure and when people follow the instructions and use 12G cables and such it should not happen this much.
    I don't think cables would prevent it unless they are a very high resistance and burn up upon power spike. Typical video cables are 75ohms- that will not prevent a power spike going through SDI..
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  7. #7  
    As I understand the 12G connectors are more sensitive, that together with unshielded power is a problem. Or you could say the sensitive SDI connectors are a problem. Simply cameras should not brick just because people connect cables or turning things on in the wrong order. But thats how it is as of now. The problem is not a RED or komodo problem Arri is dealing with the same thing and had a long writeup on their web page about the order of connecting and turning things on... Yes not at all practical in a real world scenario, filming is like war, what ever can break will usually when you need it the most sadly.
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  8. #8  
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    All BNC 75 ohm co-ax cables are shielded. Doesn't matter what G they are. Only 2 conductors: the center conductor and the shield/s. The difference between 3G and 12G is signal loss per unit/s of length. Double shielding is better because it keeps radio frequencies inside the cable better after flexing which can reduce possible interferance through voids due to wear to outside components and systems.
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  9. #9  
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    Quote Originally Posted by Björn Benckert View Post
    The problem is not a RED or komodo problem Arri is dealing with the same thing and had a long writeup on their web page about the order of connecting and turning things on...
    1-minute video on the Arri site explaining the issue Björn references and the proper connection order:
    https://www.arri.com/en/camera-syste...outputs-195968

    Hope I'm not jinxing myself, but I haven't yet had any problems with the SDI out from the Komodo.
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  10. #10  
    Senior Member Christoffer Glans's Avatar
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    Quote Originally Posted by Robert Hofmeyr View Post
    Does the sequence matter when using a battery powered monitor? I thought it was just for monitors powered from the same battery as the camera.

    I wonder about this as well. If it's a problem that can be totally avoided by just using monitor batteries instead of a P-Tap or 2-pin from the camera battery, then there's nothing to worry about? Right?
    "Using any digital cinema camera today is like sending your 35mm rolls to a standard lab. -Using a Red is like owning a dark room."
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