Am I late to the party? Cell phone to check shutter speeds.

[campy51]

I recently discovered that I can use my cell phone to video in slow motion the curtain gap on focal plane shutters to confirm changing with speed changes. Has this been common knowledge all along? Here are some screen shots at different shutter speeds. These happen to be from a Canon IVSB but I did this to confirm the shutter at 1/1250 after working on a Contax IIIA with shutter problems. Not sure what this tells me other than the speeds do change the 1st and 2nd curtain gap, but I have no idea if these are correct. The yellow is a post it note slipped in the film plane.

 

[Don_ih]

I wouldn't say you're "late," but it's been known for a while.

That gap at 1000 looks too big to me.

The main thing I use it for is seeing if the gap is even across its travel. You can usually tell if the the shutter is tapering or capping by watching the video frame by frame.

 

[BrianShaw]

You’re not late; I am. I had no idea that a cell fone will SLO-mo.

 

[Chan Tran]

What frame rate did you do the video?

 

[campy51]

Whatever the default is.

 

[4season]

Yes, I've been using my iPhone 11 + free high speed video app ("SloPro") in that manner for awhile now. But said iPhone tops out at ~200 frames/sec which may be adequate for a slower moving shutter, but too slow for examining the higher shutter speeds of a Nikon F3, where important details may occur between frames! My understanding is that some Android phones offer higher frame rates.

Got a Nikon 1 camera cluttering your closet? It may have real value here, because these cameras are supposedly capable of up 900 fps. Sony RX100 VI and VII offer similar. Perhaps there are others as well.

 

[MattKing]

Thread title updated - now people can find it!

 

[kl122002]

I still don't know where to locate my cell phone's slow motion function. Any good articles I can study ?

 

[Niglyn]

Curtain gaps seem to be all over the place.

You can build a very simple optical shutter tester for a few £

Or build a fully featured one for a bit more, or build both )

Here is a link to my simple optical and comprehensive testers..

There are Photrio threads for them also

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