K50 and Sigma EF-500 DG ST fires before shutter opens

telum · 12-20-2018, 01:56 AM

Hi Guys

I have an old Sigma EF-500 DG ST flash which I have used earlier in PTTL-mode where it worked fine (overexposed a bit, but whatever).

I have not used it for some time, and now I simply cannot get it to work. It is registered by the camera and the flash fires, but the images are very dark. It simple seems to fire too soon for the shutter to open. It happens both in P-TTL and manual mode. I am sure this is the case, as I take a picture within 30cm that is almost pitch black even when the flash fires, so it is not just underexposion.

I have not changed anything in my setup, but using AAA-batteries since last time I used it.

It is probably me who is doing something wrong, so I hope you guys can guide me in the correct direction

Unregistered User 8 · 12-20-2018, 03:34 AM

Hi telum, can you post some images with the EXIF data attached to give us some clues to be able to help you.

telum · 12-20-2018, 04:49 AM

I fiddled a bit around and think I found the reason - it worked after I had moved that piece of plastic you can pull down in front to diffuse the light, forth and back. A sound came from the flash and now seems to work most of the time with PTTL. However with the diffuser part down it does not work. Guess the old software is not really stable with my K-50.

Not a Number · 12-20-2018, 08:37 AM

Maybe there is a sensor switch linked to the diffuser that is broken?

12-20-2018, 01:56 AM	#1
telum Junior Member Join Date: Feb 2015 Posts: 45	K50 and Sigma EF-500 DG ST fires before shutter opens Hi Guys I have an old Sigma EF-500 DG ST flash which I have used earlier in PTTL-mode where it worked fine (overexposed a bit, but whatever). I have not used it for some time, and now I simply cannot get it to work. It is registered by the camera and the flash fires, but the images are very dark. It simple seems to fire too soon for the shutter to open. It happens both in P-TTL and manual mode. I am sure this is the case, as I take a picture within 30cm that is almost pitch black even when the flash fires, so it is not just underexposion. I have not changed anything in my setup, but using AAA-batteries since last time I used it. It is probably me who is doing something wrong, so I hope you guys can guide me in the correct direction

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12-20-2018, 03:34 AM	#2
Unregistered User 8 Closed Account Join Date: Mar 2015 Photos: Gallery Posts: 8,694	Hi telum, can you post some images with the EXIF data attached to give us some clues to be able to help you.

12-20-2018, 04:49 AM	#3
telum Junior Member Join Date: Feb 2015 Posts: 45 Original Poster	I fiddled a bit around and think I found the reason - it worked after I had moved that piece of plastic you can pull down in front to diffuse the light, forth and back. A sound came from the flash and now seems to work most of the time with PTTL. However with the diffuser part down it does not work. Guess the old software is not really stable with my K-50.

12-20-2018, 08:37 AM	#4
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Maybe there is a sensor switch linked to the diffuser that is broken?