Possible long length filming gig. Questions.

So I might have a gig filming 2x 2 hour stretches... on my T4i.

This is to be recorded, but also fed via HDMI to a live viewing monitor.

Will I have trouble doing such long record times? Can I get an AC adaptor for the camera?

I'll need to figure out how much memory I'll need for 4 hours. I'm sure I can figure this out myself.

Is it 2 hours non-stop of recording?

For example, according to the specs...
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Approx. Continuous Shooting Time Based on 8GB Memory Card (1920 x 1080)
30 fps: 22 min. / 25 fps: 22 min. / 24 fps: 22 min.
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At that resolution with an 8GB memory card you'll only be able to record up to 22minutes. I'm not entirely sure if let's say you get a 16GB you can do 44 minutes and so on. I have read that it does work that way though I haven't tried as I use a dedicated video camera when I do any sort of video work.

You will definitely need an AC adapter. I think the part number is Canon ACK-E8 for OEM.

You wont be able to record a 2 hour block. Not to mention that'd be incredibly numbing to watch.

You may want to look into recording externally.

It's actually a live surgical event that's to be fed to a viewing room as well as recorded. So no second takes.

If I can get a memory card big enough to handle it, it should go fine... I guess?

Pretty sure your camera has a file size/length limit (most/all Canons do). This is typically 4GB or 29 minutes, 59 seconds, whichever comes first. So, it doesn't matter how big your card is, the camera will stop the recording when it reaches that limit.

Apparently I do have a 29min limit, but the camera will automatically (seamlessly?) start a new file as it's recording.

Hire a video camera.

Dan Kearley wrote in post #14948962
Apparently I do have a 29min limit, but the camera will automatically (seamlessly?) start a new file as it's recording.

Ahhh...I did not know that...that's good news!

Have you thought about battery life? Do you have a grip? 2hrs of recording may push the limits of a single battery.

Your battery will have problems going that long. Your sensor may overheat and shut down and then you're stuck. SD cards would be the least of my worries.
Canon has to give the new DSLRs (5d3, T4i, 1dx) 29min cutoffs otherwise they would have to classify them as video cameras (learned that from Phillip Bloom) so my guess is it shuts off and the operator has to start it again.
I would think 4 hrs of recording would overheat the sensor first. Unless the DigicV helps in some way. That's a long time to run and the plastic bodies don't dissipate heat as quickly as the mag alloys do (a comparison between the T2i and 7d I saw showed the T2i got hotter faster, stayed hotter longer, and shutdown sooner than the 7d)
A real camcorder with an AC adapter would solve all your ills

The manual for most Canon DSLR's mentions that video recording can shut down if the sensor overheats. From my understanding that only happens after 15-20 minutes but could be sooner if you are repeatedly recording videos, even in segments.

As others have pointed out, a class 10 card should be OK, but keep in mind that there are a tremendous number of counterfeit cards in the on-line marketplace. They may be labeled 10 but could be something altogether different. Get your memory from a reputable source, read that not eBay!

Also, be aware there are some limitations on how much you can record, even with the best of memory cards. More than 12 minutes can be recorded but there are some limitations. When the file size reaches 4 GB on most Canon DSLR's, recording will automatically stop. That means that at 1920x1080 dpi and 1280x720 dpi the maximum recording time of a single movie clip is about 12 minutes. At 640x480 dpi it is about 24 minutes. Check your specific T4i manual.

The capacity of the card differs in recorded time; at 1920x1080 dpi or 1280x720 dpi you can stuff 44 minutes total of video onto a 16 gig card. At 640x480 dpi or crop 640x480 dpi this goes up to 1 hour 32 minutes. However, from the 60D manual, "the maximum recording time of one movie clip is 29 min. 59 sec. Depending on the subject and the increase in the camera's internal temperature, the movie shooting might stop sooner than 29 min. 59 sec." This, except for the temperature point, is for legal reasons as someone pointed out.

This is not just the Canon line, Pentax for instance states "Like competing DSLRs, the Pentax K-5 also monitors sensor temperature during recording, and will halt capture if the temperature rises beyond a certain threshold." A reputable source also states "This limitation is due to the different (European) import duty rates for still and video cameras." There is no reference made to differing duty rates of product entering the United States however. So there may really be two limitations, one the 29 min 59 seconds limitation imposed legally, and a sensor temperature issue that might also be reached in some rare circumstance.

By the way, the shutdown due to temperature can be a real drawback, hence my recommendation to heed the advice of those that stated rent a true video device. At a recent horse show I was recording almost continuously and my 60D stopped based on sensor temperature. I had to wait several minutes before I could restart. Obviously if you are filming surgery, then that might come at a critical moment you desire to capture.

Could you send the video feed to a laptop and record on that?

There are some videos out, I think at B & H, about using a DSLR for video. Overheating was one of the issues. A I remember the narrator was a film industry pro, he said he only uses 8 gig cards and switches 5d's as he shoots to avoid overheating. 2 hours continious might be a problem for you.

Jack

xarqi wrote in post #14948990
Hire a video camera.

What he said .

It's a paid gig? Rent an XA10 or XF100 for a week, you may even be able to include the rental cost ($250 or less depending) into your rate; but more importantly having the equipment that does the job the way it's requested and producing the desired results is going to go a long ways to furthering your referrals from the client that hopefully provides you with more paid gigs. If 1/3 of the surgery is missed because you're waiting for your DSLR to cool of, it's not going to be a fun day. Also the models mentioned above if memory serves, do offer dual SD card slots so you can record to one let it fill, the camera starts on the second, replace the first when the second is full the camera switches back etc so there is no need to stop recording. Also if the rentals are in a fixed location you may be able to get clips here and there with the t4i to splice in if you need specific close ups and such (as the primary camera would be streaming to prevent motion sickness I'm assuming it'll at least be on a tripod if not fixed zoom hit record make sure the feed is working and leave it) so that in your final product you can show more detail.

I wouldn't risk damaging the sensor. Even with a HDMI output, the sensor is still working hard and will overheat. Memory space is the least of your worries. No matter how you figure out the battery and memory space, the big thing is going to be your camera body and sensor. If a battery of memory card gets damaged, those are cheap to replace. If a sensor gets damaged, it would be multiple issues and expensive.