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Olympus PEN & OMD Flash mod to reduce recycling time & battery

Olympus PEN OMD FLASH Mod

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#1 AYahoo

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Posted 02 December 2013 - 09:40 AM

Hi All, I just came back from a trip to the Philippines (amazing btw) and I was upset that my setup E-PL3 + 2 x YS-01 was unable to shoot faster than 5 sec between shots.

 

the main reason is that I'm using TTL, so the internal flash of the camera needs to recharge fully every time, so after thinking on many solutions, I manage to get a good working solution to shoot as fast as 1 sec between shots without loosing the TTL, on the way, I managed to save battery life of the camera, and some will say even reduce the chance of fogging since the internal flash is not heating the housing.

 

So, how did I do it? simply, we all know that we don't really need the internal flash, just the external strobes, we need the internal flash to signal the TTL, that's all, so I just lowered the flash to 1/10 of its power.

 

I'll give a small explanation to those who don't know how the flash works, if you do want and you just want to see the MOD jump ahead.

 

Ok, so I'll try to simplify all the technical details so some of the things here will be not 100% correct, but just close enough.

 

We have the flash bulb, to activate it we need power, the main problem is that to get to such a strong intensity we need strong power, and we only have a small battery in the camera, so we will use a simple device called capacitor, capacitors are devices that holds energy, so to "fill up" the capacitor with energy, takes time, the bigger the capacitor the longer the time it takes to fill it with energy, so all I had to do is replace the big capacitor with a small one, that's all. now my flash is very week (we had a 102uF capacitor, I used 10uF so 1/10 the strength [yeah yeah I know it is not linear but still you get the idea]).

 

THE MOD,

I'm using the E-PL3 that uses the same flash system as the OMD and other PEN units, but I believe it can be done to any flash.

 

Full Flash before the mod:

2.jpg

 

Full Flash after the mod:

3.png

 

our flash is FL-LM1 or the FL-LM2. if you disconnect it from the camera, you will see there are two small bolts, when you open them up, you can see the whole flash system, there are two capacitors, one is the triggering (small one, can get to 4000v) and the second one, the one that we are interested in is the big one, 330v 102uf.

 

THE FLASH:

4.jpg

 

BEFORE YOU TOUCH IT! the capacitor is charged! that means it has 330v in it, be careful, you should discharge it first (how? if you don't know better not to do it :)).

 

so you can see all you need to do is take a new capacitor, solder it to the same wires with the same connectivity, and you are done, I've checked few capacitors before I ended up with this one - 350V 10uF, (No need to go higher - 10uF works 100% I get green light on my strobes every shot) I've tried also 1uF, it was too weak, you could see the flash firing, but couldn't get TTL to work 100%, so I guess you can find a better value between 10-1 but I'm happy with the 10uF.

 

Old capacitor Vs New capacitor (smaller one is the new one)

1.png

 

So now I bought a new flash on ebay, and I have one for "land" use (not modified) and one for underwater use. Total price of the mod, 0.5$ capacitor + 35$ used FL-LM1 total 35.5$!

 

I can only give you one more tip, if you buy a new flash, buy in a different color (if you have silver camera, buy black and vice versa), so you could differentiate between them :).


Edited by AYahoo, 02 December 2013 - 09:45 AM.


#2 Yako

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Posted 03 December 2013 - 01:34 AM

Fantastic idea!!

 

I'll tray with a EM5    I'm using internal flash in manual mode (1/64)  But I would like to reduce battery consumption as much as possible.

 

I'll buy another flash spare before to do the DYI 

 

Could yo tell me how to discharge the capacitor?


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#3 AYahoo

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Posted 03 December 2013 - 01:55 AM

Well you have some options, first is just short circuiting the two terminals (don't forget to disconnect the flash from the camera). this is the simplest way, but it will make a big spark and since this is your first time I guess... it can be intimidating :)

 

the more Correct way is to use a device like this - http://dx.com/p/skil...ndicator-254651

Just touching the two ends of the capacitor will discharge it.

 

and the third option is GOOGLE IT :) many options to discharge the capacitor

 

 

.



#4 bvanant

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Posted 03 December 2013 - 09:08 AM

I am a bit surprised that this works in TTL with the reduced flash power and would like to see the results of shooting this way using TTL. The recharge time is of course shorter but I have to think about how the camera makes TTL work in this scenario. 

Bill


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#5 AYahoo

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Posted 03 December 2013 - 11:20 AM

Well it does work, I'll try to upload a video & sample photos, I haven't had time to dive test it yet, but it should be the same underwater.

 

If you go the logical way, there is no way for the camera to know the guide number of the flash that it attached to it, it can be the FL-LM1, or the bigger FL-14 or the bigger FL-300R or the bigger FL-600R... and actually any hot-shoe flash that is capable of TTL signaling. so why not smaller? the whole idea is for the camera to measure the "flash system" (can be many flashes together...) result, and calculate the intensity accordingly.

 

if the modified flash is firing a pre flash, so does the two external flashes, so the camera is picking up the light from all 3 flashes (in my setup, 1 internal + 2 x external), and calculates the output accordingly, so since the camera has no idea what flash is connected to her, and how strong it is, it shouldn't mind...

 

but again, i'll try to upload some images during the weekend.

 

P.S.

I'm stating to obvious, I'M NOT RESPONSIBLE TO ANY DAMAGE YOU MAY CAUSE TO YOUR CAMERA, OR YOURSELF, DO IT ON YOU OWN RISK :)



#6 Jock

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Posted 04 December 2013 - 02:18 AM

... if the modified flash is firing a pre flash, so does the two external flashes, so the camera is picking up the light from all 3 flashes (in my setup, 1 internal + 2 x external), and calculates the output accordingly, ...

 

 

Hi,

 

but what if the camera calculates that you need a really strong flash? (f/22 with the infamous black frogfish...) The (unmodified) camera-flash must fire at say 95% max. power to give the correct trigger signal to the external strobe.

 

My theory: If you use the modified strobe (10% of the standard capacitor) it cannot deliver this power, and you will get an underexposed picture. 

 

If you haven't already done so, maybe you could set up a test where a correct TTL-expusure is achieved with almost full power of the unmodified strobe, then use your modified strobe.

 

If TTL still does work, my theory needs to be adjusted!

 

Jock


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#7 AYahoo

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Posted 04 December 2013 - 07:20 AM

 

Hi,

 

but what if the camera calculates that you need a really strong flash? (f/22 with the infamous black frogfish...) The (unmodified) camera-flash must fire at say 95% max. power to give the correct trigger signal to the external strobe.

 

My theory: If you use the modified strobe (10% of the standard capacitor) it cannot deliver this power, and you will get an underexposed picture. 

 

If you haven't already done so, maybe you could set up a test where a correct TTL-expusure is achieved with almost full power of the unmodified strobe, then use your modified strobe.

 

If TTL still does work, my theory needs to be adjusted!

 

Jock

 

Hi All, I will do a better testing soon when I will have more time, but for now I think your theory is wrong, I'm only guessing since I wasn't able to find the TTL algorithm anywhere online :(, so my explanation is this:

 

the camera doesn't know what flash system is connected and what is the "maximum" guide number that it can output, so it fires the pre flash, lets say 1/50,000 pulse and gets 20% lighting, so for 100% it will need 5 times more power, your theory that the camera controls the intensity of the flash, but you are wrong, it controls the duration of the pulse, so let assume that the algorithm is linear, then 5 times more duration is 1/10,000 sec pulse, so it will fire 1/10,000 sec pulse and quench the power after 1/10,000 sec. so you will get the correct exposure, also for your example it needs the strongest flash, so it will give the maximum duration of the flash that will be without quenching the power, so I think it will still work, but again I"M ONLY GUESSING :)

 

When I'll have time I will test it more, and will update here.

 

 



#8 AYahoo

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Posted 04 December 2013 - 07:28 AM

PS, I think if you want to test the theory and you have time, just put a tape on the flash, something that will block some of the light, and see if it still output the correct exposure from the external strobes :)



#9 Jock

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Posted 04 December 2013 - 08:10 AM

 

... so it fires the pre flash, lets say 1/50,000 pulse and gets 20% lighting, so for 100% it will need 5 times more power, 

 

Yep. I know that the intensity of the flash is determined by how long the flash is "burning".

 

In your example, the camera flash will will need to have five times more power  so it can trigger the external strobe to give five times more power. Right? (If not, forget my idea)

 

 But what if your modded strobe can only supply three times more power, because of its small capacitor? That was my question...

 

As I said, a field test will give the answer!  :)

 

Jock


Edited by Jock, 04 December 2013 - 08:11 AM.

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#10 AYahoo

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Posted 04 December 2013 - 10:09 AM

OK, so I was very curious about the solution... so I made some time to test it, this is not 100% test yet, but here are some of the results:

 

I did not image editing other than re-sizing

 

1/160 f22 NO EXTERNAL FLASH:

P1015118.png

 

Set the camera on 1/160, but camera limitation changed it to 1/100 f22 EXTERNAL STROBE ON MAXIMUM POWER (SLAVE):

P1015117.png

 

1/160 f22 EXTERNAL STROBE ON TTL:

P1015116.png

 

VIDEO OF THE FLASH SHOWING TTL SIGNAL (Green light is TTL was ok).

 

I still didn't check to see if I can get the FULL POWER of the strobe but I wiil :).



#11 Jock

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Posted 05 December 2013 - 04:17 AM

Hi, thanks for your tests. 

 

Whatever the green TTL Signal may say - IMHO the photo is underexposed. See also snapshot with histogram.

 

Did you use spot metering? Matrix? ESP? Maybe a larger, non-reflective object and spot-metering will give more significant results? 

 

Greetings,

Jock

Attached Images

  • histogram.jpg

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#12 AYahoo

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Posted 05 December 2013 - 05:30 AM

You are right, this is the reason I said I will test some more... I want to wait until I will receive my second flash (I modified the original the second one is still on the way), than I will be able to make a comparison test & I have somewhere a digital osc, I could measure raise time, pulse length & charge time.

 

So, I will update you all :)

 

P.S for anyone who want's it to work without TTL it is still very good solution, for the TTL, I have to check more.


Edited by AYahoo, 05 December 2013 - 06:29 AM.


#13 Yako

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Posted 05 December 2013 - 06:39 AM

I have ordered the discharge tool -:)

 

And I'm looking for a cheaper FL-LM2 flash unit without luck (:-


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#14 ProfF

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Posted 07 December 2013 - 09:04 PM

As an E-PL3 owner, I thought I will give it a try. I modified one of my two strobes, and indeed got a much weaker light. To test the effects on TTL, I did a semi controlled test (see attached pictures). My conclusion is that there is little difference between the two strobes when using an external strobe in TLL mode. The differences are mainly at the extereme ranges of apartures.

 

Setup:

 

E-PL3, Olympus 60mm lens, T 1/160 throughout.

 

External strobe YS-D1, set on TTL with the TTL dial on 0. The strobe was on the right of the camera facing so that the edge of the beam was on the object. The strobe was connected with fiber optic cable. I was holding the other end of the cable about 2cm in front of the camera strobe. I checked that the hand blocked any light from that strobe (you can also see that from the shades in the images).

 

I varied the strobe setting of the camera and aperture, as noted in the attached picture. I converted the images from raw to jpeg without any adjustments.

 
 
Untitled-1.png

 

 

My conclusion is that the camera changes output by modifying duration of the flash. The modified strobe had slightly lower exposures throughout the test. 


Edited by ProfF, 07 December 2013 - 09:08 PM.

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#15 Jock

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Posted 08 December 2013 - 01:36 PM

Hi ProfF,

 

is there something wrong in your settings? With camera flash set to "Fill" and the YS-D1 to "TTL" there should not be such a big difference between f/4 and f/22, exposure should be almost the same - that's why you use TTL!

 

F/4 looks good, the other ones to me seem underexposed.

 

Jock


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#16 ProfF

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Posted 09 December 2013 - 06:14 AM

Jock,

 

I am not sure. Actually, I was surprised to see this. I just revisited the YS-D1 manual (I usually don't shot TTL, so never checked this option), and it seems that maybe I should have used the Slave-TTL rather than the normal TTL mode (which assumes preflash). I don't think the E-PL3 pre-flashes.

 

Nir


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#17 AYahoo

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Posted 09 December 2013 - 12:28 PM

Hi Nir, the E-PL3 does output pre-flash, I have it tested, and I will post some of the findings later.



#18 AYahoo

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Posted 10 December 2013 - 12:40 PM

OK, so I finally had sometime to check what is going on with the TTL.

 

I thought that the problem was that the capacitor is not big enough to supply the "full" duration of the pulse needed, so I setup a small test to verify it.

 

I will not upload all the info & data, since I don't think it will interest anyone, I'll cut to the results (if anyone want the full report, contact me).

 

This is the setup:

A small circuit board with 4 capacitors on it, Original 102uf, 10uf, 22uf, 33uf, A small dip switch to select the current capacitor.

And a OSC connected to see the signals.

IMG_20131210_215652.jpg

IMG_20131210_215702.jpg

IMG_20131210_215725.jpg

 

Also about the preflash that we've talked about:

NO TTL, full flash:

102Full.jpg

 

TTL ON:

102FullTTL.jpg

 

You can see the small pulse before the flash, this is the preflash.

 

33uf NO TTL, full flash:

33Full.jpg

you can see the fast charge time.

 

OK, so if I cut to the chase, I've tried all the capacitors with different settings on the camera, the 10uf was always underexposed.

the 22uf worked well until the f18, this was the maximum that I was able to achieve with the correct exposure.

and the 33uf gave exactly the same results as the 102uf.

 

if we compare timing (charge to full):

10uf: 350ms

22uf: 1662ms (or 1.6 sec)

33uf: 1277ms (or 1.2 sec) (I think the difference here is due to different manufacturers, you would expect this to be longer than the 22uf).

102uf: 3796ms (or 3.8 sec)

 

I can upload the images of the test if anyone wants.

 

Conclusions:

I think that if you wish to use TTL than cutting down from 3.8 to 1.2 is good enough preserving the TTL signal, I'm sticking with the mod for now :).

 

If you don't use TTL (god know why) than you can go even lower than 10uf, I think even 1uf, this will give you very good results: super fast & low battery usage. (on second thought you can use 1/64 flash, so maybe 10uf is enough).

 

I'll soon be testing it on RX100 ii that my friend is asking me to MOD to allow faster shooting, I'll update you all.

 

Have fun!

 

 

 



#19 ProfF

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Posted 23 December 2013 - 01:10 PM

I am not sure if I understand the graph, but I assume the y-axis is capacity and the x-axis is time (it would help to have a scale :-)

 

Anyhow, just wanted to report that after ~12 dives with the modified flash I have many TTL shots that came perfect on and some that did not. I am not sure if this is due to my errors (e.g., positioning of the strobes) or due to the flash output capacity. I did not hold a careful comparison.

 

Here are two examples, shot with TTL with the 10uf mod and two external strobes (Sea & Sea YS110a + DS-Y1, both set on TTL). Didn't change the exposure in development from RAW

 

 

PC120586.jpg PC131061.jpg

 

In some cases I had to set the exposure higher in Lightroom. So the mod might be under-exposing in some situation.

 

Regarding my earlier comparison, I did repeat a similar test with a full housing, and it seems that having the fiber-optic cable in the right positioning helps... and the results are better. 

 


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#20 oskar

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Posted 28 December 2013 - 04:16 PM

Thanks for the test and info, I saw your thread only now but it is very interesting.

 

I can confirm your findings that:

 

1 electronic flashes controll power by time by quencing the flash.  On a strobe i have the time(power) ranges from 1/20000s  to about 1/800s

2 if you limit the energy of a flash by the capacitor, you will loose out one the maximum possible duration (power)

 

 

I'm interested to know how the electronics of the flash looks like and what pins they are using if you have any pictures?

 

I made a microstrobe for my previous compact camera using the standard mid pin. this gave a 1ms pulse.  I used this to trigger a little laser.  This gave only manual control which I am happy with, and about 5000 triggers on one battery :-)

 

Now I just got a EM-5.  I'm curious on the efficiency of the standard strobe at 1/64, and I am thinking of making a micro strobe for this one too.

 

However your TTL experiment is interesting, As well a quenching the flash tube, the camera can quenche a LED or laser.

 

Cheers

/O

 

 

 







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