Help my Kid with photography - DPChallenge Forums

Canon EF 24-105mm f/4.0L IS

10/27/2005 09:38:43 PM · #1

Hello,

My 12 yr old asked me a photography question. Not wanting to let her down, I said we would give her question a try...but failed ...sort of...

She wanted to know if I opened the shutter for a few seconds...with a fast strobe light going...and a black background... what it would look like if we threw a playing card into the frame.

I said it would take a shot of the card at each "flash" of the light and all would appear on the finished photo...

Strobe was set at 5 flash/sec...shutter at 1.5secs. I figured we'd get 5 shots of the card on 1 frame, however, each time we did it only 1 shot of the card "stuck" and this was usually the last place the card was before the shutter hit the ground....

What happened?

ShutterPug

Canon EOS-6D

10/27/2005 09:40:16 PM · #2

thanks - you just fried my brain

Sigma 105mm f/2.8 EX DG Macro for Canon

10/27/2005 09:41:45 PM · #3

My eyes and brain fried after that strobe!

sgauria

Panasonic DMC-FZ30

10/27/2005 09:50:30 PM · #4

Not sure what happened, but there are many things you can try :
- maybe not all the flashes of the strobe were equally bright, so maybe you can try reducing the number of flashes.
- Try increasing the ISO to see if you can see anything in the other positions
- maybe the card was side on in some of the shots, which might not be very noticeable or well lit by the flash
- also could be that your flash was illuminating the wrong side of the card.

Maybe you can post some pics.
Sounds like an interesting puzzle... :)

10/27/2005 09:51:32 PM · #5

Hmmm...

Why don't you try instead of throwing the card have your daughter walk fast in front of the camera?

10/27/2005 09:54:01 PM · #6

Also, what is the distance between the card and the camera?

Canon EF 28-80mm f/3.5-5.6 II

10/27/2005 09:56:02 PM · #7

Thanks...I'll try more tomorrow and post results...any other suggestions?

Originally posted by sgauria:

debitipton

Canon EOS-5D Mark II

10/27/2005 09:56:03 PM · #8

This sounds like a problem for.... Graphicfunk!

debitipton

Canon EOS-5D Mark II

Canon EF 28-80mm f/3.5-5.6 II

10/27/2005 09:56:06 PM · #9

This sounds like a problem for.... Graphicfunk!

Dang -- I'm repeating myself

Message edited by author 2005-10-27 21:56:45.

10/27/2005 09:59:11 PM · #10

Try to increase the distance from the camera to your subject, that will increase the time your camera will capture the free fall of the card.

Message edited by author 2005-10-27 21:59:46.

10/27/2005 10:03:56 PM · #11

Is it possible that with each flash of the strobe the "previous" shot of the card is "overwritten" by the black background? I didn't think black would "overwrite" a lighter object.

Originally posted by CODE:

Try to increase the distance from the camera to your subject, that will increase the time your camera will capture the free fall of the card.

10/27/2005 10:24:30 PM · #12

It shouldn't since in theory black will not reflect any light back to the camera (given the surface is not polished). Also if that was the case you should see ghostly images before the last image from the last strobe.

What I'm thinking (If I'm understanding the way your are doing it) is that the card could be falling fast and only the last strobe will catch it. That's why if you test with somebody walking at a speed that will cover from the left side to the right side of the frame in about 1.5 secs then you should see multiple images (about 7) on the picture. If that test is successfull then I believe you can get the effect by increasing the distance between the camera and where you trhow the card (by increasing the distance your frame will capture more height from top to botton, gravity is the same and the card will take "longer" to fall in relation to the area your frame is covering.

I hope I explained myself.

Originally posted by kenskid:

Is it possible that with each flash of the strobe the "previous" shot of the card is "overwritten" by the black background? I didn't think black would "overwrite" a lighter object.

Originally posted by CODE:
Try to increase the distance from the camera to your subject, that will increase the time your camera will capture the free fall of the card.

Message edited by author 2005-10-27 22:34:29.

10/27/2005 10:32:21 PM · #13

Yes...I see now...I'll reset tomorrow and back off a little. I'll have my daughter walk by and see what happens!

Thanks,

KS

Originally posted by CODE: