Blackmagic Forum

I'm working with a sound person who's using a Zoom F8n. I was going to jam the timecode from the recorder to the camera at the start of the day. How accurate is the timecode generator on the 6K Pro? Is that the optimal way of doing it or should I be using a tentacle?

AFAIK the timecode clock on the Pockets isn't that accurate over hours like the ones in the URSA Mini Pro series. It will also drift when you power down and up the camera.

Therefore I've always a Tentacle connected to my PCC4k and the audio recorder. Everything works perfectly in sync later in post.

The timecode clock on the 6K Pro is improved over the 4K and 6K, and is very similar in performance in the URSA Mini Pro.

Kristian Lam wrote:The timecode clock on the 6K Pro is improved over the 4K and 6K, and is very similar in performance in the URSA Mini Pro.

That's great news!

Nice to see the improvement, but the BMPCC4K for example will keep Timecode for a few hours so set at a morning and reset at lunchtime and so on )depending how mercilessly your are driven by the producer).

Still I follow the advice of Robert the Camera Whisperer and leave a Tentacle Sync E connected to the camera; that ensures Timecode accuracy for a day’s shoot, and you can always reset the Tentacles’ Timecode at lunchtime anyway if you’re obsessive like me.

The MixPre-6 II is also very reliable with keeping Timecode for a day’s shoot so you can safely set it with a Tentacle Sync E and forget it if you wish. No real need to leave a Tentacle Sync E connected to the MixPre. You can remove it and use that Tentacle to keep the BMPCC4K or BMPCC6K in sync. I’ve tested quite a bit to be sure.

I just got a BMPCC6K Pro and work with a MixPre-3 (version 1, w/o TC generator). I don't send TC from BMPCC to MixPre through HDMI because I need HDMI for an external monitor.
About TC sync, I need to be confident for at least half a day.
About budget, of course, less is better.
So I would relay on your experience for helping me choosing between 3 possible ways:
1/ Buying a single Tentacle, plug it in the BMPCC to set the TC, unplug it and then plug it in the MixPre to set the MixPre TC and keep it plugged in. Does it work ? Does the BMPCC continue to run TC after the unplug ?
2/ Buying 2 Tentacle, one for the MixPre, the other for the BMPCC to be absolutely confident.
3/ Selling my MixPre v1, buying a v2 to benefit from accurate TC generator (and 32bit). Sending TC from MixPre to BMPCC, then unplug it and "Hey presto", it's done. May be the same budget as buying 2 Tentacle.
Sorry for my bad English and thanks for your advice.

woofy75 wrote:I'm working with a sound person who's using a Zoom F8n. I was going to jam the timecode from the recorder to the camera at the start of the day. How accurate is the timecode generator on the 6K Pro? Is that the optimal way of doing it or should I be using a tentacle?

It should be accurate within a frame for 6+ hours.

A tentacle might means that if the camera looses power (like when you change a battery) then it's going to get re-jammed when you re-start the camera. If you have a way of powering the camera for many hours, it should hold pretty accurately with the internal clock.

JB

gillesvds wrote:So I would relay on your experience for helping me choosing between 3 possible ways:
1/ Buying a single Tentacle, plug it in the BMPCC to set the TC, unplug it and then plug it in the MixPre to set the MixPre TC and keep it plugged in. Does it work ? Does the BMPCC continue to run TC after the unplug ?
2/ Buying 2 Tentacle, one for the MixPre, the other for the BMPCC to be absolutely confident.
3/ Selling my MixPre v1, buying a v2 to benefit from accurate TC generator (and 32bit). Sending TC from MixPre to BMPCC, then unplug it and "Hey presto", it's done. May be the same budget as buying 2 Tentacle.

If you get two Tentacles, you'd be able to keep your timecodes synced without worrying about losing sync every time you swap batteries on the camera. Then if you upgrade to a MKII MixPre, you'd have an extra Tentacle for syncing a 2nd camera down the road, should the need arise.

Kristian Lam wrote:The timecode clock on the 6K Pro is improved over the 4K and 6K, and is very similar in performance in the URSA Mini Pro.

Will I need to re jam the timecode everytime I power down the camera?

I own three Tentacle boxes, one for each of my cameras and one for the audio recorder (sometimes it’s a Sound Devices, sometimes a Zoom F8 or F4). Doing that eliminates all questions of whether and how long any individual device will hold. I power up and sync the Tentacles first thing every morning of a shoot, plug them into each device, and then I just don’t have to think about it again for the rest of the day. One less distraction so I can focus on the image. In cases where more cameras/recorders are needed, I rent extra Tentacle boxes. They are affordable enough that it is more than worth the money.

I would not trust TC generators of cameras.
And though I probably could, not even the MixPre-10 II.

I am working with Tentacle Sync Es and some Tentacle Track Es.

The Tentacle Setup App makes it easy to wirelessly sync all devices even between shots / takes if needed.
It also starts and stops recording on all Track Es and shows audio levels.
Very convenient and reliable during production and in post.

It would be even better if timecode would be precise enough to be used as genlock.

vivoices wrote:It would be even better if timecode would be precise enough to be used as genlock.

Right now they are two very different things. LTC is basically barfed out numbers where Burst and TLS are explicitly timing signals. In the future (ST 2059.1) PTP will determine H/V sync. The SMPTE Epoch began Jan 01, 1970. Under this, the position of a single pixel (clock and phase) at any point in time is tied to a determined UTC value.

Good Luck

Howard Roll wrote:

vivoices wrote:It would be even better if timecode would be precise enough to be used as genlock.

Right now they are two very different things. LTC is basically barfed out numbers where Burst and TLS are explicitly timing signals. In the future (ST 2059.1) PTP will determine H/V sync. The SMPTE Epoch began Jan 01, 1970. Under this, the position of a single pixel (clock and phase) at any point in time is tied to a determined UTC value.

Yeah Timecode and "sync / Phase" are different things. Timecode isn't genlock.

Some clocks are able to provide both, but most of the pro-sumer cameras don't do sync INPUT so can't read the signal.

https://ambient.de/en/product/lockit/

But the Pocket 6K in this case doesn't do "sync" or genlock. (UMP, 12k can)

JB

I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

woofy75 wrote:I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

After all the information in this thread you still managed to make an avoidable user error?
And now you blame it on the camera?
Well, uhm...

Robert Niessner wrote:

woofy75 wrote:I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

After all the information in this thread you still managed to make an avoidable user error?
And now you blame it on the camera?
Well, uhm...

What was the user error, turning it off?

After turning it off and on you have to re-jam timecode. That’s the case with most cameras.

woofy75 wrote:I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

Maybe you missed the part where you have to re-jam on power cycles ?

Like most cameras ?

viewtopic.php?f=2&t=142050#p766532

JB

John Brawley wrote:

woofy75 wrote:I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

Maybe you missed the part where you have to re-jam on power cycles ?

Like most cameras ?

viewtopic.php?f=2&t=142050#p766532

JB

Yep, didn't know that. So weird, even the cheapest devices can keep time when powered off. As a still photographer getting to grips with timecode is one of the strangest part of cinematography!

woofy75 wrote:

John Brawley wrote:

woofy75 wrote:I shot a short yesterday with the BMPCC 6K pro, jammed time code with the sound person, seemed to synch well but then 3 times during the day it completely lost time, maybe when powering off or a battery died, need to look into it. But yes, turned it on this morning and it's about 6 hours out! Not too impressed!

Maybe you missed the part where you have to re-jam on power cycles ?

Like most cameras ?

viewtopic.php?f=2&t=142050#p766532

JB

Yep, didn't know that. So weird, even the cheapest devices can keep time when powered off. As a still photographer getting to grips with timecode is one of the strangest part of cinematography!

Your misconception seems to be that TIME = TIMECODE
Timecode has to be kept stable, sync and frame accurate over hours.
That is not what the clock in your cheap device does.

Your misconception seems to be that TIME = TIMECODE
Timecode has to be kept stable, sync and frame accurate over hours.
That is not what the clock in your cheap device does.[/quote]

Yes, this wasn't drifting slightly, it was like 8 hours out! Also, it wasn't happening every time I turned the camera off. If you have to re sink every time you power down then you really have to use a V lock battery on the camera as the internal batteries only last 30 mins so you'd have to re jam time code every 30 mins.

woofy75 wrote:... If you have to re sink every time you power down then you really have to use a V lock battery on the camera as the internal batteries only last 30 mins so you'd have to re jam time code every 30 mins.

That’s what I do when shooting on a tripod with large V-lock battery held in a bag hanging from the tripod. I only power down at lunchtime. Then power on camera before lunch break is over and reset Timecode.

woofy75 wrote:Yes, this wasn't drifting slightly, it was like 8 hours out!

It's not out by 8 hours.

It's likely your internal clock is set to the time that is 8 hours out from your timecode source. In the absence of the external timecode source, the timecode reverts to the internal CLOCK (not timecode)

Start your day at 8AM. Jam the camera with timecode set to 14:00:00. After working for three hours the timecode is at 17:00:00 and it's 11AM. You power down but do not re-jam the clock.

When you power up the camera the timecode will revert to the internal time of day clock that is 11:00 am, which means your timecode will be "out" by 6 hours.

woofy75 wrote: Also, it wasn't happening every time I turned the camera off. If you have to re sink every time you power down then you really have to use a V lock battery on the camera as the internal batteries only last 30 mins so you'd have to re jam time code every 30 mins.

Best practice is to LEAVE an EXTERNAL clock fitted FULL TIME. The internal clock can be fine, but requires a lot of discipline on your behalf. That's why most people get external clocks. It's takes all that away.

The "cheap" way is to jam from your audio device, but they often don't have great clocks either AND you have to do it every time.

JB

John Brawley wrote:

woofy75 wrote:Yes, this wasn't drifting slightly, it was like 8 hours out!

It's not out by 8 hours.

It's likely your internal clock is set to the time that is 8 hours out from your timecode source. In the absence of the external timecode source, the timecode reverts to the internal CLOCK (not timecode)

Start your day at 8AM. Jam the camera with timecode set to 14:00:00. After working for three hours the timecode is at 17:00:00 and it's 11AM. You power down but do not re-jam the clock.

When you power up the camera the timecode will revert to the internal time of day clock that is 11:00 am, which means your timecode will be "out" by 6 hours.

woofy75 wrote: Also, it wasn't happening every time I turned the camera off. If you have to re sink every time you power down then you really have to use a V lock battery on the camera as the internal batteries only last 30 mins so you'd have to re jam time code every 30 mins.

Best practice is to LEAVE an EXTERNAL clock fitted FULL TIME. The internal clock can be fine, but requires a lot of discipline on your behalf. That's why most people get external clocks. It's takes all that away.

The "cheap" way is to jam from your audio device, but they often don't have great clocks either AND you have to do it every time.

JB

Cool, thanks John, that all makes sense. Pardon my ignorance but what are the popular external clocks people use?

woofy75 wrote:

John Brawley wrote:

woofy75 wrote:Yes, this wasn't drifting slightly, it was like 8 hours out!

It's not out by 8 hours.

It's likely your internal clock is set to the time that is 8 hours out from your timecode source. In the absence of the external timecode source, the timecode reverts to the internal CLOCK (not timecode)

Start your day at 8AM. Jam the camera with timecode set to 14:00:00. After working for three hours the timecode is at 17:00:00 and it's 11AM. You power down but do not re-jam the clock.

When you power up the camera the timecode will revert to the internal time of day clock that is 11:00 am, which means your timecode will be "out" by 6 hours.

woofy75 wrote: Also, it wasn't happening every time I turned the camera off. If you have to re sink every time you power down then you really have to use a V lock battery on the camera as the internal batteries only last 30 mins so you'd have to re jam time code every 30 mins.

Best practice is to LEAVE an EXTERNAL clock fitted FULL TIME. The internal clock can be fine, but requires a lot of discipline on your behalf. That's why most people get external clocks. It's takes all that away.

The "cheap" way is to jam from your audio device, but they often don't have great clocks either AND you have to do it every time.

JB

Cool, thanks John, that all makes sense. Pardon my ignorance but what are the popular external clocks people use?

Timecode clocks


Ambient Nano. Expensive. But uses a wireless tech for rejamming the clock itself. Also what the “real” location sound mixers would use. Lemo connectors (popular for TC) I own a pair of these. They sell as a pair kit which is a bit cheaper.

https://www.bhphotovideo.com/c/product/1333498-REG

Tentacle Sync. Popular. What a lot of people use especially on consumer-ish equipment. It doesn’t use Lemo but uses headphone style jacks for example.

https://tentaclesync.com/sync-e

Moze TIG

Very very small. Runs a long time on AAA replaceable batteries (the two above are internal batteries that you can’t replace)

Also the most accurate over time I’ve found. (If you’re not network jamming the clock) I have four of these. They seem cheap but are quite indestructible. I’ve tried. They use temperature regulated clocks. This means the clocks accuracy is designed to compensate as ambient temperature changes. One of the things that makes clocks not accurate

https://www.trewaudio.com/product/mozegear-q28/

Haven’t previously heard of the Moze TIG and seems a good option as long as you have a good idea how many hours you can use them before replacing the batteries.

I use Tentacle Sync E which can run for more than a day so no issues charging them overnight etc. and no worries they’ll die during a shoot.

rick.lang wrote:Haven’t previously heard of the Moze TIG and seems a good option as long as you have a good idea how many hours you can use them before replacing the batteries.

I use Tentacle Sync E which can run for more than a day so no issues charging them overnight etc. and no worries they’ll die during a shoot.

The rental house in me dislikes a product where over time the battery will get worse and worse and eventually fail but not be user replaceable (in the field)

Like with your phone, what happens in 3 years to the battery ?

I’ve had the Moze for 5 years

JB

No argument there. How many hours appropriately would you estimate a fresh battery in the Moze lasts?

rick.lang wrote:No argument there. How many hours appropriately would you estimate a fresh battery in the Moze lasts?

Typically a couple of days of work on set. Normally replaced at the beginning of each third day on set. Some people use rechargeable AAA’s but they often don’t last as long.

Some sound recordist would use rechargeable and just replace them as a matter of course each day.

JB

Knowing the regular batteries provide good sync for a couple of days is great. For AA and AAA, I no longer use rechargeables; I only trust my Tentacles for a day. Thanks!

Cool, thanks for the help! Who knew timecode was so tricky!

Once you start using it with multiple cameras and/or external audio, it’s one of those “how did I ever work without it?” moments.

rick.lang wrote:Once you start using it with multiple cameras and/or external audio, it’s one of those “how did I ever work without it?” moments.

Yes the project I just did was with an external recorder, 3/4 of the clips the timecode worked fine for synch and for the rest the waveform matching tool in Davinci did the trick just matching to the scratch track.

Good show. Best reason for having a scratch track recorded even when you think you don’t need it; I always keep it just in case.

I don’t know what type of internal battery is in the Tentacles, but I’ve had three of them for over 4 years and they still hold more than 50% charge after being on for 12 hours. I haven’t tested to see how many hours they’ll run before running out of battery, but I’d assume it’s a solid 24 hours or more.
The Tentacles don’t have a Lemo port on the device, but Tentacles sells a 3.5mm to Lemo cable
https://shop.tentaclesync.com/product/tentacle-to-lemo/

Jamie LeJeune wrote:I don’t know what type of internal battery is in the Tentacles, but I’ve had three of them for over 4 years and they still hold more than 50% charge after being on for 12 hours. I haven’t tested to see how many hours they’ll run before running out of battery, but I’d assume it’s a solid 24 hours or more.
The Tentacles don’t have a Lemo port on the device, but Tentacles sells a 3.5mm to Lemo cable
https://shop.tentaclesync.com/product/tentacle-to-lemo/

Nice! With the tentacles, do you need 2, one for the camera and one for the external recorder?

woofy75 wrote:

Jamie LeJeune wrote:I don’t know what type of internal battery is in the Tentacles, but I’ve had three of them for over 4 years and they still hold more than 50% charge after being on for 12 hours. I haven’t tested to see how many hours they’ll run before running out of battery, but I’d assume it’s a solid 24 hours or more.
The Tentacles don’t have a Lemo port on the device, but Tentacles sells a 3.5mm to Lemo cable
https://shop.tentaclesync.com/product/tentacle-to-lemo/

Nice! With the tentacles, do you need 2, one for the camera and one for the external recorder?

You could go with one. First jam-sync the external audio recorder and then keep it plugged in to the camera.

Personally I prefer to have one Tentacle for each of my devices so I can be sure there's no drift.

Robert Niessner wrote:

woofy75 wrote:…
Nice! With the tentacles, do you need 2, one for the camera and one for the external recorder?

You could go with one. First jam-sync the external audio recorder and then keep it plugged in to the camera.

Personally I prefer to have one Tentacle for each of my devices so I can be sure there's no drift.

I agree, but I have tested the MixPre-6 II with a recent firmware update for a full day and it has maintained sync after jamming to a Tentacle; so if needed I could leave a Tentacle on a second camera.

If you’re on a different audio recorder, test first. My MixPre-6 II did not keep sync with its original firmware but that issue was addressed by a later update.

Robert Niessner wrote:
Personally I prefer to have one Tentacle for each of my devices so I can be sure there's no drift.

This is the way to do it.

Each device used has the same (brand) external clock.

JB

woofy75 wrote:Personally I prefer to have one Tentacle for each of my devices so I can be sure there's no drift.

I agree,
especially with the current generation of Tentacles that can be synced remotely with the Setup App.

Some shoots I work with 4 x Sync E and 2 x Track E and syncing all of them takes only a few seconds.

Sometimes audio in post is half a frame off, so I re-sync every two hours or so.

Back in the days of the film and AatonCode TC, the internal camera clock was accurate for about 6 hours. It did not have to re-jammed when the camera was power cycled. This also happens to be true of the Alexa Classic / Plus series of cameras. They were built with accurate TC clocks the ran int the background whether the camera was on or off. Apparently this is no longer true of the Alexa Mini etc. not to mention most "modern" cameras. Seems crazy that camera manufacturers are not including accurate TC that will run in the BG. Is having to stick another box and wire on the cam progress? All pro sound recorders include a TCXO (Temperature compensated oscillator) clock. Strange that this has been dropped from cameras.

They haven’t been dropped.

All the current BMD camera have very accurate TXO clocks. Some of the very early models did not.

They are good for sub-frame drift for 6-8 hours. Yes you do need to power them.

I came up on Aatons, Origin C’s and GMTs. While they were good you always re-jammed after 4 hours and definitely wouldn’t go past 6 hours with them. And you had to change a battery within 60 seconds as well. You couldn’t leave them unpowered either.

Ambient make the clocks in Arri cameras. Also they are TXO. They made changes in the first mini for the sake of space.

Good practice has always been to use external clocks. This accounts for speed changes in camera, unexpected power interruptions. The clocks are so small now it’s an easy redundant way to work.

JB