Shutter speed for 720p on 550d

S

studio1972

Well-known member
Hi,

I use my 550d in PAL land in 720 50p mode, with eventual output to 720 25p for web and Blu-Ray and PAL SD on DVD.

I'm having a bit of a problem with shutter speeds. I would prefer to use 1/50 as this will be ideal once the footage is converted to 25p, but this is not available in movie mode. 1/60 is available but that seems to give problems with flicker under some lighting. 1/100 seems to fix this, but means I need more ISO and I fear that the footage might look jittery once converted to 25p.

Anybody know a fix to this problem?
 
studio1972 said:
Hi,

I use my 550d in PAL land in 720 50p mode, with eventual output to 720 25p for web and Blu-Ray and PAL SD on DVD.

I'm having a bit of a problem with shutter speeds. I would prefer to use 1/50 as this will be ideal once the footage is converted to 25p, but this is not available in movie mode. 1/60 is available but that seems to give problems with flicker under some lighting. 1/100 seems to fix this, but means I need more ISO and I fear that the footage might look jittery once converted to 25p.

Anybody know a fix to this problem?
Click to expand...

I'm in pal land as well and also found that at 50p it shoots at 1/60th. You'll probably have to live with 1/100 when light flicker is an issue, but it can work out if you are careful. Best to test out all the thing that can go wrong ahead of time , like what happens with different pan speeds, subjects moving through he frame causing strobe etc, then learn to avoid problem shots just like avoiding moire subjects. Even if you were shooting in film at 50fps, at a 180 shutter you would still be shooting at 1/100 sec. so this should look about the same as that. Test, compare then test again.
 
If you're using light fixtures you'll have flicker problems, for sure. You can rent pro lights that won't interfere with the video; kino flo, etc.

Otherwise, play with the available lights, turning them on and off, to see if you get the best results with flourescent, incandescent, etc. You might have to artfully position a lamp here, turn off a light there, gel a window here to get everything to work.

If that's not an option, then, yeah 1/100 with mo-blur added after or a more "video-esque" look.

If you don't have a lot of action and motion/panning and/or don't need slo-mo, just shoot at 25 fps.
 
ydgmdlu said:
Why are you shooting 720p? I don't see the point...
Click to expand...

I like having the option of conforming to 25p for slo-mo, and my main camera is a HMC151, which doesn't gain that much in resolution by filming in 1080p. Plus, many of my clients just want DVDs and even those with BR players only have 720p sets most of the time.

If these cameras had a 1080 50p mode, that would be ideal though.
 
if you shoot 50p 1/50 and convert that to 25p, that would have wrong cadence

50p shot on 1/100 would look exactly like what a 25p would look like shot on 1/50 once converted.
 
dcloud said:
if you shoot 50p 1/50 and convert that to 25p, that would have wrong cadence

50p shot on 1/100 would look exactly like what a 25p would look like shot on 1/50 once converted.
Click to expand...

You're right, if I knew I would be converting a shot to slo-mo I would want to film in 50p 1/100. However, I have often used 50p 1/50 from my HMC for slo-mo and it works pretty well, much better than 50i or 25p footage.

In reality I generally don't know before hand if a shot will end up as slo-mo, so my preference is to film in settings that are ideal for normal speed (50p 1/50) but can be converted to slo-mo if required.

Looks like the 550d won't do this so I'll have to experiment with 1/100 and see how that goes. I can always use 1/60 when I'm sure there is no fluorescent lighting.
 
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