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Camera Speed Test


Guest

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Hi,

 

Any one know of a cheap and easy way to measure a cameras fps rate?

 

How can I determine the fps the camera is running at even when the "dial" is set for 24fps?

 

The camera is undercranking a little, but I can't tell exactly by how much.

 

I thought there might be a way to measure this is telecine but there is not of course, because frames are frames, the telecine computer has no idea what the fps was.

 

Is there some thing I can shoot, and then watch on playback to determine the fps?

 

Thanks

Richard

Edited by Guest
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some ruff and cheap test

 

mark one frame thrue the lens hole, roll the camera for 5 sec and count the perfs

cam speeds ups and slowes down.

 

then you need a stoboscopic gun set at 24 or 25 fps that freez the movment.

you can use those guns at rental houses

 

another test i did on a set i had a doubt is :

set your cam in front of a tv at 25 fps as the tv is in 50 hertz the bar should freez then set your cam at 24 fps the bar should go down slowly

same at 30 fps for tv set at 60 htz

oldies can slow down when batteries are dead

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Ok so for the totally math brain dead people like myself :D

 

This would be done by shooting the running stop watch and then seeing if I capture 24 frames with each passing second?

 

Richard

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Guest JoshuaNitschke

I'd think this would be done by running the camera for five seconds (start the watch when you start the camera) and then stopping it and the watch. Find out how many frames were filmed, and divide it by the number of seconds (5).

 

That should yield the Fps unless I'm an idiot.

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You could shoot the stopwatch in xcu, then run the stopwatch when you playback your video dailies footage and see who wins :D

 

Of course to be really precise you'd need a 'pulldown' capable stopwatch <_<

 

The question is do you need to be "close enough" or exact in which case a visit to a rental house/vendor and have them strobe it is best.

 

-Sam

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  • Premium Member

You are putting a very accurate time-reference in the picture taken by the camera. At 24 fps each frame should show an increment of 0.041666666666666666666666666666667 seconds. Or rather, more sensibly, check that 24 frames is showing an exact 1 second increment. 20 seconds should be enough to check your frame rate within a few zillionths of a percent.

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i just went through this with my camera, and was given a good idea for a decent low budget fps check.

 

get something else that is crystal controlled (other camera, progector), with the camera to be tested frame up something on the other camera (i shot into the lens port of an 16bl). run the camera to be tested, looking through the viewfinder, if it appears that whatever your framed on is not moving, then your running at the same speed.

 

when i did this, i found my camera running a little off, so i adjusted the variable speed motor on the bl until it matched, reading the tachometer on the bl told me what the camera in question was running at.

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Thank-you all for the info.

 

I found a device that does just what I need from Tobin systems. You point the camera at it and watch the LEDs via the viewfinder, easy to use. Only $79.00 if any one else is interested.

 

Thanks

Richard

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  • 7 years later...

Old news but;

You can edit in 24fps and have a sound or a snare/whatever occur at every frame.

 

Since film cameras are mechanical they have a repeating noise pattern that reflects the speed. If it's off, the sound will start to reverberate. You should be able to tell which one sounds faster, the camera or the repeating snare.

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