7D Video question
Discussion
I have hardly used the video on my 7d but part of my plan for 2012 involves a short film on freestyle motocross. The times that I have switched it to video, what I get is a very juddery playback like the fps are very low. What is it that I am doing wrong? is that just what the 7d churns out or is there something i can change in the settings to be able to be able to get some footage that is usable. I had asked a guy that i saw on track that seemed like he knew what he was doing and what he explained is that the camera struggles with a lot of movement like tracking a motorbike passed a complex background such as woodland.
Anyone know if this is the case?
ETA: after a quick look at the settings, I have changed from 1920x1080 at 25fps to 1280x720 at 50 fps but the query is left open and asking if there is a way of improving the quality at 1080?
Anyone know if this is the case?
ETA: after a quick look at the settings, I have changed from 1920x1080 at 25fps to 1280x720 at 50 fps but the query is left open and asking if there is a way of improving the quality at 1080?
Edited by curtisl on Thursday 15th December 20:54
Theres a few issues here.
First a cmos sensor reads each line as it goes for each frame. This is called a rolling shutter. So if your shutter speed is 1/25th (slowest you can go for 1080/25) the top line will be read 1/25th sooner than the bottom line on the sensor. This means that a straight vertical moving quickly will appear as a jagged sloping line!
You can combat this in a few ways.
Move to 720/60 (or 1080/30, you can enable 60/30 fps by changing a setting, think pal to ntsc or something).
Increase your shutter speed. Shoot in manual (all the time for video!) and use a faster lens/wide open and higher ISO. A shutter speed of 1/500th will be much more effective for action than 1/25th.
Playback can be stuttery on anything that isnt a first class PC as the compression is very intensive and theres a lot of data. Get round this by re-encoding to a less compressed video stream, this will help a lot with editing too, but will take an extra step.
First a cmos sensor reads each line as it goes for each frame. This is called a rolling shutter. So if your shutter speed is 1/25th (slowest you can go for 1080/25) the top line will be read 1/25th sooner than the bottom line on the sensor. This means that a straight vertical moving quickly will appear as a jagged sloping line!
You can combat this in a few ways.
Move to 720/60 (or 1080/30, you can enable 60/30 fps by changing a setting, think pal to ntsc or something).
Increase your shutter speed. Shoot in manual (all the time for video!) and use a faster lens/wide open and higher ISO. A shutter speed of 1/500th will be much more effective for action than 1/25th.
Playback can be stuttery on anything that isnt a first class PC as the compression is very intensive and theres a lot of data. Get round this by re-encoding to a less compressed video stream, this will help a lot with editing too, but will take an extra step.
RobDickinson said:
Theres a few issues here.
First a cmos sensor reads each line as it goes for each frame. This is called a rolling shutter. So if your shutter speed is 1/25th (slowest you can go for 1080/25) the top line will be read 1/25th sooner than the bottom line on the sensor. This means that a straight vertical moving quickly will appear as a jagged sloping line!
You can combat this in a few ways.
Move to 720/60 (or 1080/30, you can enable 60/30 fps by changing a setting, think pal to ntsc or something).
Increase your shutter speed. Shoot in manual (all the time for video!) and use a faster lens/wide open and higher ISO. A shutter speed of 1/500th will be much more effective for action than 1/25th.
Playback can be stuttery on anything that isnt a first class PC as the compression is very intensive and theres a lot of data. Get round this by re-encoding to a less compressed video stream, this will help a lot with editing too, but will take an extra step.
Perfect. Thanks Rob. Top knowledge!!First a cmos sensor reads each line as it goes for each frame. This is called a rolling shutter. So if your shutter speed is 1/25th (slowest you can go for 1080/25) the top line will be read 1/25th sooner than the bottom line on the sensor. This means that a straight vertical moving quickly will appear as a jagged sloping line!
You can combat this in a few ways.
Move to 720/60 (or 1080/30, you can enable 60/30 fps by changing a setting, think pal to ntsc or something).
Increase your shutter speed. Shoot in manual (all the time for video!) and use a faster lens/wide open and higher ISO. A shutter speed of 1/500th will be much more effective for action than 1/25th.
Playback can be stuttery on anything that isnt a first class PC as the compression is very intensive and theres a lot of data. Get round this by re-encoding to a less compressed video stream, this will help a lot with editing too, but will take an extra step.
Does swapping from pal to ntsc effect playback at all? as far as I know i thought that ntsc was some american format but never understood if that meant anything concerning viewing.
Well it will affect playback depending on what your playing back.
In Europe 25/50 fps is probably preferred as thats what TV's usually expect on the whole and it also helps with artificial lighting etc too (50hz power).
To be more movie like 24fps is good.
30/60 is not wrong and you can always convert but this does have some issues (i.e ntsc pulldown effect etc). Its better if you want to slow the motion down tho.
In Europe 25/50 fps is probably preferred as thats what TV's usually expect on the whole and it also helps with artificial lighting etc too (50hz power).
To be more movie like 24fps is good.
30/60 is not wrong and you can always convert but this does have some issues (i.e ntsc pulldown effect etc). Its better if you want to slow the motion down tho.
As mentioned, you may have playback issues due to your computer or software. Certain software like Premiere can handle native Canon movie files, others may need transcoding to a different codec, like Apple ProRes, for smooth playback at editing stage (not as an output codec).
Rolling shutter is a possibility, but that depends to affect certain types of movement in the scene or a camera move. If it's jerky allover, I suspect it's more to do with shutter angle...
Rolling shutter is a possibility, but that depends to affect certain types of movement in the scene or a camera move. If it's jerky allover, I suspect it's more to do with shutter angle...
RobDickinson said:
Increase your shutter speed. Shoot in manual (all the time for video!) and use a faster lens/wide open and higher ISO. A shutter speed of 1/500th will be much more effective for action than 1/25th.
…. in which case shooting at higher shutter speeds makes things worse. An optimum shutter speed is 1/50th (48th really), at 24fps to give a nice amount of motion blur between frames. You need some blur in the image to keep it fluid, every frame sharp will give you jerky playback (think running up the beach in Saving Private Ryan where it was done for effect). The problem with this is if you want to shoot stuff wide open on a sunny day, you need to buy some ND filters, or a variable one, plus step up rings for different lenses.Edited by Bacardi on Friday 16th December 02:16
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