Flash Modifications

David Holden

David Holden

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Has anybody modified a standard auto / manual flash to allow turn down of power?
I have read somewhere that you can replace the ligh sensor with a variable resistor.
 
David Holden said:
Has anybody modified a standard auto / manual flash to allow turn down of power?
I have read somewhere that you can replace the ligh sensor with a variable resistor.
Click to expand...

Hi Dave,

Most flashes have the option of turning the output down, can you elaborate or be little more specific? Are you referring to onboard/built in flashes with dSLR's or point and shoot camera's, or flash guns and speedlights? :shrug:
 
There's one of the Vivitar flashes that you can hack using a paperclip to dial the power down, but I'd need to try and remember which one it was :thinking:
 
Maybe email the guy who has done the mod and ask?

It's all a bit over my head when it comes to re-wiring or mods like that. I wouldn't mind knowing how to do it as we have a couple of similar vivitar units knocking around.
 
Id be very interested in this, id always thought something like this should be fairly simple to do :D

Might try and buy a few scrappy ones off Ebay for a few quid and see what can be done with them.

Im guessing the light sensor is just a LDR that increases or decreases the resistance depending on the amount of available light. So if you can match a VR to a similar range of values that the LDR produces from pitch black to direct sun, you should be able to adjust the output manually.

Hmm ive got myself thinking now lol.
 
That's me :)

I've done a Vivitar 283 (not posted the photos/ how-to yet) in a non-destructive way and the 2800. The 2800 mod should work with any Vivitar that uses the same type of thyristor.

Happy to help if I can. Message me here or Flickr. Or on the thread :)
 
I'm game to have a go at this as I have a 330 EZ thats no good to me, I'm an electronics student too so I think I should be able to work it out (a practical alternative to revision this easter).
So basicaly work out what the thyristor (ie increase/decrease - maybe calibrate new circuit) does then build a circuit to let you do that with a switch. Should be quite doable potential to give yourself a fair belt though.

ake sure you discharge the capacitor before you play ;)
 
Flash In The Pan said:
Ahh, here's the hack I was thinking about, it's for the old Vivitar 283...
Click to expand...
Just checking the HiViz circuits I knew it would come down to how much?. I perused the circuits, and they do not seem to be suitable for measuring the flash duration. The only way is to measure the duration is with an osciloscope.
 
I tried this. Unfortunately the sensor was mounted on a printed circuit boad, and it is beyond my skills to remove and replace with a potentiometer. So they stay at full power.
 
I have an issue with the 330EZ where the board is attatched to the case, and I can't work out how to remove it, so haven't even had a crack at analysing the sensor
 
Turning down the power of the flash - ANY flash, is easier than all that messing about.

Simply put a white handkerchief in front of the tube, hold it in place with a rubber band....job done, power reduced and softened at the same time.
 
There are two sides to this question. Using a cloth in front of the flash the flash still operates at full power. Turning down the power you conserve power.
 
Lensflare said:
Turning down the power of the flash - ANY flash, is easier than all that messing about.

Simply put a white handkerchief in front of the tube, hold it in place with a rubber band....job done, power reduced and softened at the same time.
Click to expand...

Yep, I understand that, and you can use ND gells in the samle book from Lee Filters, but you are still using up battery power and increasing the recharge time.
 
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