Live feed and record internally?

[Jeroen Wolf]

I shoot with an EX3 but have never done a live feed. Now I've been asked to cover a live act which includes zooming in on an iPad.

My main question is: what is the best live feed out? I assume SDI. Can I record full HD and stream to a few monitors via SDI? Is that the way to go?

Anything special to consider when doing 'live work'?

Appreciate your input.

[Dave Sperling]

Yes, HD-SDI will be your highest quality output, and of course you can record internally simultaneously.

Of course when shooting for a live feed the big thing to remember is that you're always 'on' -- which means that you won't be doing snap zooms or zooming in to check focus (that's where the Expanded Focus button comes in handy - to be able th check and verify your focus without having to zoom in. If shooting on a tripod and using a remote zoom I'll normally set up another of the assign buttons so I can do the expanded focus check without having to reach around to the right side of the camera.)

Of course you need to fully check things in advance. If the color of the ipad image is critical, for instance, you might want to make sure the room lighting is adjusted to the same color temp as the ipad so it doesn't look too blue.

If feeding multiple monitors I'd suggest using a distribution amp for the signal.

Be careful of HDMI converters and too many inline video switchers since some may introduce a picture delay - which will look strange if everyone is watching a live speaker and the audio is 3 or more frames in advance of the picture on the monitors.

Obviously make sure you have plenty of power so you don't need to change batteries.

Also make sure your cards are sufficient that you won't have to change them. It is possible to switch cards on the fly, byt this often shakes the camera or otherwise effects the operation.

Surprisingly enough, I often use steadyshot even when on a tripod, since camera risers are often shaky, and the floor may not be solid enough to eliminate vibration from people walking by. This is a problem no matter how heavy the tripod is, since it's actually the floor and riser that will shake when in a telephoto shot. In these cases steadyshot can help a lot!

If it's a long shoot, also bring a small monitor to use as a viewfinder - and be in a comfortable position with a high chair or stool to sit on!

[Jeroen Wolf]

Great response, Dave, much obliged!

[Shaun Roemich]

Further to what Dave says, remember that if you are recording in a progressive format (1080p24/25/29.97) that the HD-SDI output IS 1.5G so the output will be interlaced (1080i25/29.97), which is what MOST video switchers (and most older monitors which feature 1.5G HD-SDI) require anyway but if recording the highest quality image is important, the internal recording MAY be superior to an external recording fetched from the HD-SDI.

Of course, the whole argument of PsF and pulldown comes up but be aware that if you want TRUE progressive recording, the internal recording is your easiest and safest bet.

[Jeroen Wolf]

Thanks, Shaun. I'll be recording 25P internally so should be fine.

[John DuMontelle]

A curiosity question on my part.

With my EX3 I do quite a few live shots for CBS Network News.

I shoot many stories for them in 30P. CBS Sunday Morning in particular, which are edited and broadcast on their shows...but live shots...always 60i due to the "switcher issues".

If I forget to switch my camera back to 60i the engineers in New York tell me they can't use the 4:2:2 signal coming out of my SDI port.

Yes, I do understand I am limited with my EX3 to only being able to record 4:2:0 on my installed SXS cards.

I have to switch back to 60i for the New York folks and all is happy and good.

So...I'm not sure it's possible to record in a 24P or 30P format while still putting out a signal for broadcast via SDI.

Of course my concern may be moot if the outgoing signal is simply going to in-house monitors and not for transmission and broadcast over the air.

I did not think I could choose a different SDI output format from what is being recorded onto my SXS cards.

Any guidance or insights by others is truly appreciated. ;)

[Dave Sperling]

Hello John,

I'm assuming that the 'switcher issue' is that when the camera is set to 30P the output through the HD-SDI is 1080-30 PsF, which to the switcher 'looks' like 1080i but will be out of frame cadence in terms of motion - with the switcher outputting 1080i for transmission..

If you shoot in 24P, you have a menu option to have the camera add a 3:2 pulldown to create a standard 1080i signal, so you could truck feed that properly (You select either 24PsF or 60i for 24p output -- I believe this is 'grayed out' unless the camera is set to record 24p.).

I don't shoot 25p, but would assume that the camera outputs 25 PsF if recording 1080 25p, which would have potentially the same issue as 30p if the system needs 50i.

However, your uplink situation may be different than the OP's... My assumption was that the 'few monitors' he's sending to was the 'live' portion of his feed - so it may not be an issue at all.

[John DuMontelle]

Thanks Dave,
Yes, you've explained very well what I was told was the problem by the folks in New York when I inadvertantly leave my camera set in 1080 30P instead of switching it back to1080 60i.

To be clear...as I understand it...it is NOT possible to record video to the SXS cards in a different format than the video format coming out of the SDI port on the camera.

If the camera is set to record 25P internally...it will be spitting out 25P video from the SDI port on the camera.

[Shaun Roemich]

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