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SMALL flash for Q3


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  • 2 weeks later...
On 3/29/2024 at 4:30 PM, Ad Dieleman said:

I bought the Godox Lux Junior yesterday. It doesn't play well with the Q3. It looks like the Q3's shutter fires too slowly relative to the flash. Manual mode at 1/64 output or Auto used close-up makes the unit generate very short flash durations and that results in very dark pictures, giving rise to the suspicion that the light burst is over by the time the shutter opens. Going to manual mode at 1/4 output or shooting in Auto with subjects at 2 m gives the desired results.

I tried all flash-related combination of settings under "Flash Settings" in the menu, nothing made a difference. I guess things like "Flash Mode" = "Slow Sync" and "Flash Sync" = "End of Exp." only are effective when a compatible flash is mounted; the Godox only has a center pin for firing the flash and that's it.

This Godox flash works perfectly when mounted on my Sony A7R4, even at its maximum sync speed of 1/250 s the pictures are evenly and correctly exposed.

I tried a vintage flash with the classic Auto mode with a sensor on the flash unit, the Minolta Auto 200X. That works flawlessly with the Q3, so it seems that the Godox is very quick to fire, quicker at least than that Minolta flash. Puzzling it is.

Too bad, the Godox Lux Junior is a very nice fit on the Q3, light and small. Now looking for an alternative.

As I am (a.o) an electronics engineer, I decided to do some measuring and experimenting and I established that a resistor with a value between 1.7 kΩ and 9 kΩ in series with the hot shoe center contact would make the Godox Lux Junior flash operate correctly with the Q3. Guarantee be damned, I opened the flash and inserted a 2.7 kΩ resistor in series with the center contact. Presto, works! Both Auto and Manual operation now deliver good output, even with the maximum 1/2000 s shutter speed. So there's obviously an incompatibility between the Q3 and this Godox flash.

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1 hour ago, Ad Dieleman said:

As I am (a.o) an electronics engineer, I decided to do some measuring and experimenting and I established that a resistor with a value between 1.7 kΩ and 9 kΩ in series with the hot shoe center contact would make the Godox Lux Junior flash operate correctly with the Q3. Guarantee be damned, I opened the flash and inserted a 2.7 kΩ resistor in series with the center contact. Presto, works! Both Auto and Manual operation now deliver good output, even with the maximum 1/2000 s shutter speed. So there's obviously an incompatibility between the Q3 and this Godox flash.

Interesting... How did you discover this? I will get one and have a go: they are cheap enough. what wattage did you use for the 2k7 resistor?

David

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Posted (edited)
1 hour ago, David Wien said:

Interesting... How did you discover this? I will get one and have a go: they are cheap enough. what wattage did you use for the 2k7 resistor?

David

I have a bunch of hot shoe adapters and PC cables, so I put together something with a potentiometer to determine what was the maximal resistance that the flash needed for firing. Then I connected that same setup to the Q3's hot shoe and found that the resistance needed to fire was much lower. It appeared that the input of the Godox flash behaved like a 90 nF capacitor. So inserting a  resistor might delay the flash's firing which was what was needed.

I took the smallest 2.7 kΩ resistor I had, probably 1/8 W. The Godox offers an EMF of 3.08 V so in theory 3.3 mW is the maximum dissipation possible and that only momentarily. The 1/8 W resistor easily fitted on the hot shoe board of the flash, but 1/16 W would be easier still. On putting the flash back together I disregarded the positioning of the button for the S1/S2/Off switch, so that one doesn't work anymore, the button would have to be engaged correctly when re-assembling. I don't care, I'm not going to fix it.

Edited by Ad Dieleman
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2 hours ago, Simone_DF said:

If you don’t want to work for money, do it for free. For “the community” 😀

I get the idea, but not open to that either. However, I will gladly share my knowledge with anyone up for this. Please note I managed to break the switch for slave operation settings...

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50 minutes ago, GREG PLAT said:

I searched but i cant find it new the Leica SF 24D. Not second hand. Its out of production. Does anyone know where we can find it?

 

 

I read somewhere that the SF24D is not compatible with the Q3.

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Posted (edited)
On 4/19/2024 at 2:58 PM, SrMi said:

What kind of flash is being used here on Q3?

 

Its not a flash, its an LED light he is probably using as fill light for when he records video.

 

 

https://www.amazon.com.au/ULANZI-Portable-Photography-Lighting-Rechargeable/dp/B0B5SRVZQ9?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&smid=A3ILOTR74HEDWF&th=1

Edited by AussieQ
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4 hours ago, Dave777 said:

I am using an old Fuji EF-X20 with my Q3, works very well given the limitations.

These cost a small fortune - around 500€ - and have been discontinued a few years ago. Not really a good solution for anyone looking to buy a flash

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1 hour ago, Dave777 said:

I purchased mine second-hand for GBP 160 a few months back. I definitely wouldn't spend 500€ on one.

You got it for a “cheap” price. But the little Godox mentioned in the thread go for 60-90€ brand new

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