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Sync time and flash effect

V

Valtteri

New Member
Hi!

I just made my first photoshoots with a Hasselblad H3D II 39 and got an strange problem. The sync time should work with all shutter speeds and it did, but the flash power went down quite much when I used fast shuttertimes, lets say between 125 and 800. The flash used was Elinchrom FX 400 and triggered with skyport radiotriggen set. I havent tried yet with a sync cable. Could the radiotrigger do this or is the FX 400 to slow?

br Valtteri
 
Hi!

I just tried with a "no name" studioflash and sync cable. The difference in the exposure was ovious, maybe about 2 f-stops. Havent tried yet with Elinchrom, but I guess this is not caused by the radiotrigger. Should't the exposure remain the same when shootin with studiolights in studio even if shuttertime is changed from 125 to 800?

br Valtteri
 
Valtteri said:
Hi!

I just tried with a "no name" studioflash and sync cable. The difference in the exposure was ovious, maybe about 2 f-stops. Havent tried yet with Elinchrom, but I guess this is not caused by the radiotrigger. Should't the exposure remain the same when shootin with studiolights in studio even if shuttertime is changed from 125 to 800?

br Valtteri
Click to expand...

Check the specs of the strobe units ... specifically the flash duration when used full power ... it may be that the flash duration is dropping below the 1/800th shutter speed.

For example, my Hensel Porty has a top duration of 1/125th (the newer PLUS models increased that to 1/250th), but if I use 1/250th or higher, there is a noticable difference in exposure even when I keep the aperture to shutter speed ratio the same.

Just a thought.
 
Hi!

The reason was just as you touhgt. The Elinca FX series drops the full power quite much with faster speeds than 1/250. The RX series does not drop that much. Shooting with RX 600 and shutter speed of 1/800 compared to 1/125 gives almos equal exposure, maybe a 1/2 stop drop.

br Valtteri
 
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