[Simen1]

I want to shoot an action scene from two angles at the exact same time with two different cameras (both K-5 or K-5 + K-3).

Can flash triggers be used for this? How exact is the timing? Even with 1/8000 sec i want the exposure to catch the subject at the exact same time so i can make a 3D photo. I know flashes can help in a dark environment, but i plan to photograph sports in full daylight.

[stevebrot]

The best you might be able to do is to use the wired remote ports to trigger exposure through a ganged switch. It may help to shoot mirror up in manual focus mode so the only element of latency would be for shutter release.

I would suggest using the IR sensors, but the latency is unpredictable.


Steve

[Bagga_Txips]

Use a single IR remote to trigger both? It's probably best to ensure that the remote is equidistant to both cameras.

[stevebrot]

Eh, I'm sure the speed of light is faster than the sampling rate of the IR sensor.

That is the trick. The sampling rate is fairly slow and there is also a handshake of sorts (IIRC). As a result, the response time to the IR signal is fairly long and not very predictable. This is readily apparent when comparing a wired vs. IR remote. One can expect a palpable gap between the release times for the two cameras if using the IR port.


Steve

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Last edited by stevebrot; 07-27-2015 at 05:16 PM.

[UncleVanya]

RF triggers, the shutter type not the flash ones.

Vello FreeWave Wireless Remote Shutter Release RW-C1 B&H Photo

Works on many brands with cable swap.

[Not a Number]

There was a thread a while back with one member making a dual release cord for stereo photography work. The trick was adding a couple of diodes to prevent back-pathing on the circuit. You should be able to find the thread easy enough with the search tool.

[stevebrot]

There was a thread a while back with one member making a dual release cord for stereo photography work. The trick was adding a couple of diodes to prevent back-pathing on the circuit. You should be able to find the thread easy enough with the search tool.

I was thinking about that one, but had no luck finding it.


Steve

[Not a Number]

Here we go, since I participated in the thread it was easy to search on member name and keyword:
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269939...ml#post2902529

[stevebrot]

RF triggers, the shutter type not the flash ones.

Vello FreeWave Wireless Remote Shutter Release RW-C1 B&H Photo

Works on many brands with cable swap.

Yes this might work, though you would need an additional receiver. Here is a link to the pdf user manual:

http://static.bhphotovideo.com/lit_files/93318.pdf


Steve

[stevebrot]

Here we go, since I participated in the thread it was easy to search on member name and keyword:
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269939...ml#post2902529

Woo! Hoo! Excellent thread!


Steve

[derekkite]

I'm triggering three bodies with a raspberry pi and piface board. if you write a byte to the register it triggers the outputs almost instantaneous. I trigger five flashes and get no ghosting.

Repeated shots with different bodies will have some odd delays from time to time.

[narual]

Given that you want to do 3d, this might be a better solution, at least, once they start selling to the public. (scroll down. it starts with the smartphone, then goes to the DSLR version)
Kula | 3D for any camera - Kula | 3D for any camera

---------- Post added 07-28-15 at 10:14 AM ----------

I was going to suggest a sound trigger, but the place I purchased mine from seems to no longer be in business.

[Simen1]

Here we go, since I participated in the thread it was easy to search on member name and keyword:
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269939...ml#post2902529

Thanks a lot! The double cable with diods will suit my needs. I will give you feedback on how it works with a pair of K-5.

I think the cable solution is a safer bet then wireless due to uncertain latency issues.

I don't want the portrait format from the Kula 3D solution, and think cropping to two side by side landscape formats will eat to much resolution. It will also prohibit experimenting with the axis distance and probably wont support wide angles. Also bokeh might be odd.