The next big problem with the Canon 550d or the t2i is that next to that it does not have sound control is that the SDHC card have a limit of max 4GB burst, so you can’t film anything that is more than 4GB mostly is about 12 minutes burst but sometimes can be more or less depending on the situation and environment.
For those who wonder if an exFAT SDHC have a 4GB limit like at FAT32, I have to say it does have a limit. I just test it out with an Toshiba 16GB Class 4 (SD-K16G read 20MB/s write 10MB/s) I have formatted it on my laptop to exFAT and it stopped at the time of 14.49, with the file size of 3.98GB – 4.182.028kB. It stopped at roughly around the 4GB limit. Making an exFAT of the SDHC does have it purpose it actually makes the card faster. Cause before it would normally already start off the recording saying it is busy and then record, but after changing it into exFAT it did not had that problem. However non SDXC or exFAT compatible cameras or equipment would not be able to use it, cause I tried placing the exFAT in my Kodak Playsport and it would not start up. I had to format the card inside my 550D to get it back to FAT32.
Other solution is SDXC which are also exFAT but build to be an exFAT, however there are not that much sold and the ones that are sold are too expensive for my taste. Also nobody have actually bought one and tested it out yet. Also I the exFAT SDHC I made after formatting it in the Camera it would change the SD card back into FAT32 so I am not sure what would happen if you format an SDXC if it would stay an exFAT or it becomes a FAT32.
With Magic Lantern there is an option to record longer but it lowers the quality of your shots by changing the bit rates so you would use less Mb/s. However there is still the time limit of the 29.95 set by Canon inside the camera also it still does get pretty warm to let it film for half an hour.
This test is to show you the differences in the Qscale how long it can film, but also what kind of file sizes, comes out of it.
Q-Scale test results with Canon EOS 550D t2i with Magic Lantern Januari 5 build filming 1920×1080 24P ISO 200 with Toshiba 16GB Class 6 (SD-F16G) read/write 20MB/s:
Q-Scale -1: time 29.59 – 4.30mbits/sec – 933,76MB
Q-Scale -2: time 29.59 – 4.67mbits/sec – 1012,96MB
Q-Scale -8: time 29.59 – 12.38mbits/sec – 2.59GB
Q-Scale -12: time 28.09 – 20.27mbits/sec – 3.98GB
Q-Scale -16: time 8.29 – 48.17mbits/sec – 2.85GB
As you might see there are few QSCALE numbers missing however I was more trying to dial in to the Qscale with the highest quality yet able to film the longest. Also you might see that the Q-Scale -16 is about 48mbits/sec and not like the high 82mbits/sec people claim, however that depends mostly on your ISO setting, which in my case was very low because I was also using a 50mm f1.4. If you use an higher ISO you probably would hit that or bigger number.
However pretty interesting able to shoot such high quality mostly could film scenes using -16 and lid well and use ISO100 or ISO200 and film those scenes with no problem.
Here is with High ISO values:
Q-Scale -1 ISO3200: 18.15mbits/sec
Q-Scale -16 ISO3200: 119.25mbits/sec
Q-Scale -16 ISO1600: 102.72mbits/sec
Those High ISO with -16 could only take an one second shot and are not that useful. I would recommend to get better lenses and light sources I would try never to use anything higher than 800.
Below is a list with ISO and Q-Scale to able to film full half hour footages at bit rate around 18 to 20mbits/sec.
Recommended Q-Scale with ISO to able to film 30min:
ISO 100 Q-Scale -11
ISO 200 Q-Scale -10
ISO 400 Q-Scale -8
ISO 800 Q-Scale -6
ISO 1600 Q-Scale -5
ISO 3200 Q-Scale -4
ISO 6400 Q-Scale -2
You basically can’t get pass the 4GB Limit on a SDHC, the only way to film longer is to either get an SDXC or use Magic Lantern and use Q-Scale feature. Or just stop and go at silent or non important moments.