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Strobe speed vs. SS

Strobes SS

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#1 gdiver25

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Posted 14 September 2018 - 03:35 PM

I'm pretty new to underwater photography but I'm look for which strobe or strobe manufacture allows for the fastest shutter speed possible?

 

Any and all help would be greatly appreciated.



#2 Tom_Kline

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Posted 14 September 2018 - 04:37 PM

The synchronization speed is determined by the camera's shutter not the strobe. This speed is the highest shutter speed where the all of the shutter is open at the same time. Above this speed the shutter works as a moving slit so that part of the image on the sensor plane will be blocked by the shutter when the strobe fires.

 

It is possible to use speeds above synch speed using a special mode that is only available with dedicated strobes, e.g. Canon strobe with a Canon camera. There are limitations here - consult your camera's instruction manual.


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#3 Pavel Kolpakov

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Posted 15 September 2018 - 12:37 AM

       Tom is right. Normal Sync Speed (shutter window is fully open) is determined by the camera, not the strobe. Underwater strobes work only with fully open camera shutter, because they produce flash mono pulse only. Underwater strobes don't support HSS. 

 Mechanical shutter of modern DSLR cameras has sync speed about 1/200 s. This is fast enough for 99% of underwater shooting tasks. Don't forget that flash duration is just 1/1000 by itself, it freezes moving underwater objects very well.

 

       If you need more fast sync speed with underwater strobes for any special aim, then use cameras equipped with electronic-mechanical shutter. For example, one of my cameras Nikon D50 has sync speed up to 1/500. But believe me, for normal cases this is not necessary. I used sync speed 1/500 with underwater strobes only 1 time for all years of underwater shooting. Don't forget that camera has other controls as well, for getting desired exposure.

       If you need a speed more fast than 1/500, than use land strobe in the housing. This case High Speed Synchronization (HSS =40 khz flash flicker) is available, for speeds up to 1/8000.


Edited by Pavel Kolpakov, 15 September 2018 - 01:49 AM.


#4 Barmaglot

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Posted 15 September 2018 - 01:42 AM

Another option is to use a compact camera with a fixed lens - they typically come equipped with a leaf rather than curtain type shutter, which is free from flash sync speed limitations. I believe Sony RX100 and Canon G7X series cameras sync with flash at up to 1/2000s.



#5 gdiver25

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Posted 16 September 2018 - 06:13 AM

This is excellent information!! Thank you all. I'm shooting with a Nikon D500 and was hoping to use the higher SS to freeze frame the likes of Mako sharks.



#6 ChrisRoss

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Posted 17 September 2018 - 01:24 AM

The D500 max sync speed is 1/250, at higher shutter speeds the frame is not fully illuminated by flash.



#7 gdiver25

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Posted 17 September 2018 - 05:39 AM

Thanks Chris



#8 tursiops

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Posted 17 September 2018 - 07:42 AM

This is excellent information!! Thank you all. I'm shooting with a Nikon D500 and was hoping to use the higher SS to freeze frame the likes of Mako sharks.

If you've got a fast-moving subject, there are only a few things you can do to keep the image unblurred:

1. Fast shutter speed, no strobe. (Typical sports photography). This can require high ISO, wide-open lens aperture, and not worrying about the color.

2. Pan the camera so the subject is not moving in the frame....the goal is to have the subject sharp, and not worry about the background now being blurred.

3. Use a strobe, and let its quick flash stop the motion. This also requires a shutter-speed/f-stop combo that does not allow the ambient light to produce a blurred subject with a sharp subject (from the flash) superimposed on it, i.e. the flash fires as the camera shutter opens or just before it closes. 

 

For sharks, it is rare they are so close a strobe has much effect.







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