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

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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:

post-37057-0-02866200-1386005750_thumb.jpg

 

Full Flash after the mod:

post-37057-0-41368500-1386005592_thumb.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:

post-37057-0-42649200-1386005752_thumb.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)

post-37057-0-85773300-1386005573_thumb.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

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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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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/skiliwah-repair-tools-sparkpen-capacitor-discharge-pen-w-buzzer-led-indicator-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

http://www.youtube.com/watch?v=yC6Va8nLVS0

 

 

.

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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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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 :)

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... 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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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.

 

 

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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 :)

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... 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

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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:

post-37057-0-42599700-1386180239_thumb.png

 

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

post-37057-0-41319000-1386180233_thumb.png

 

1/160 f22 EXTERNAL STROBE ON TTL:

post-37057-0-41246900-1386180220_thumb.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 :).

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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

post-5673-0-93725900-1386245833_thumb.jpg

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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

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I have ordered the discharge tool -:)

 

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

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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.

post-25106-0-92227100-1386478988_thumb.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

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

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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.

post-37057-0-31684900-1386706426_thumb.jpg

post-37057-0-98032300-1386706432_thumb.jpg

post-37057-0-43402900-1386706439_thumb.jpg

 

Also about the preflash that we've talked about:

NO TTL, full flash:

post-37057-0-58824300-1386706760_thumb.jpg

 

TTL ON:

post-37057-0-80495600-1386706755_thumb.jpg

 

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

 

33uf NO TTL, full flash:

post-37057-0-97748300-1386707912_thumb.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!

 

 

 

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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

 

 

post-25106-0-83042700-1387832916_thumb.jpgpost-25106-0-70056500-1387832901_thumb.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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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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I just discovered this thread and it is a nice brain-teaser forcing you to think about how flashes and TTL operate. It reminded me of the flash trigger recently released by Nauticam but that one does not support TTL. However, after some thought I either don't understand how flashes work or there is a problem with this approach.

 

On my EM-5/Nauticam housing 100% of the strobe light comes from the external strobe as the camera strobe is blocked by the housing. My understanding is that flash light output under TTL is determined by controlling flash pulse duration. So if we need a given amount of light for our scene then we need a certain pulse duration. In turn that means that the pop-up flash on the camera needs to fire for that same duration. The way I see it, the only manner to reduce the energy consumed by the camera flash is to reduce its light intensity. I don't think using a smaller capacitor does that very effectively beyond perhaps lowering the average voltage over the pulse duration.

 

The oscilloscope images shown above seem to work but are misleading because they are "full flashes" that dump all the energy in the capacitor. This is not a fair comparison because the larger capacitors actually produce a proportionally stronger flash. In a real shooting situation where you need a fixed, non-maximal, flash output all capacitors are drained by the same absolute amount but different relative amounts. In other words if the shot requires a "25uF drain", the 100uF capacitor will have 75% of its juice left, while the 33uF capacitor is almost empty and the 10uF capacitor ran out of steam prematurely giving an underexposed image. This can explain the report where the smaller capacitor gave reasonable exposure in some situations but not others if shooting conditions affect the required strobe output (ISO, aperture, subject distance/color, ambient light, etc). Reality may be a bit more complicated because the smaller capacitor will lose voltage faster as it drains but if I am correct then I don't think this approach will work satisfactorily. What is needed is a different light source that can handle the voltage coming off the capacitor but has a light output just enough to trigger the external flash. I read on wikipedia that "A photoflash capacitor is an electrolytic capacitor used in flash cameras, professional flashes, and also in solid-statelaser power supplies." A tiny laser that directs its light right into the fiber optics would need a tiny amount of energy but I have no clue if cost, size or other limitations prevent that from working.

 

Bart

 

PS: looking at the Nauticam flash trigger it seem they use either a laser or more likely a LED, which is somewhat related to a laser.

Edited by Glasseye Snapper

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Hi Guys, I was a little bit busy lately, but I'll try to answer some of the questions...

 

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 :-)

 

My bad, the Y is V (each div is 50v) and the X is time (ms).

 

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

...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?

 

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

 

Cheers

/O

 

I think you are semi right about the "loose out one the maximum possible duration" assumption, since the camera doesn't know the size of the flash installed, and the size of the strobe setup (can be 10 external strobes working together) this is the key feature that you are missing, I can install a very big flash on my hotshoe and still get a correct exposure of the image. so I think the Olympus Eng. deiced to use the size of the capacitor that will get a good coverage of daily use, since we are not using the same setup as they predicted (external strobes), we don't need that big of a capacitor, I did many tests will all kind of capacitors, I think that the magic number is around 30-50uf, I've used the 30uf and during the test only one extreme situation was under exposed compared with the original (f22 1/160) with big distance to the object, so I've ordered the same brand and same specs as the original capacitor but 50uf to test and check (I will update when I will get it).

 

Regarding the pins, I was also interested, but I didn't get there, I still have it disassembled and I might have time in the next few days to check it.

 

Other than that, I will try to update soon, but I took my friends RX100 MK2 and disassembled it completely, it had two capacitors 1x48uf and another 33uf connected in series, so 81uf total, again tried many settings ended up with 1uf capacitor to only trigger the external strobes, NO TTL! but we managed to take 2-3 photos per sec compared with 1 photo every 4 sec with the original, so about x10 faster. (didn't check battery consumption but I'm sure it will be much better).

 

Last but not least, I've tried to trigger a led, to check if I can get better results, but I had some success but not enough time to investigate it properly.

Edited by AYahoo

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Hi,

 

Just picked up on this and it is a very interesting idea.

 

I have a hunch that when you use a flash-specific capacitor you may no longer get the results we desire.

I think that the reason this is working is that the standard-grade capacitors you are using have a slower maximum discharge speed due to higher internal resistance.

This is causing reduced flash intensity and so allowing the same duration of flash for less power as the standard size capacitor.

With a proper high-speed flash capacitor you will not be able to achieve this any more.

 

Lets see if your next test bears this out or not.

 

My concern is that if this is the case and you need to use standard-grade capacitors to achieve this effect then you run the risk of overheating the capacitors as they are really designed for use in power supply smoothing applications not high-speed discharge.

However this makes me wonder if there is an alternative mod we could do using the standard capacitor but increasing the series resistance slightly. Have you tried this on your test bed? EDIT - though this would limit the charging speed too so not a great idea

 

Simon

Edited by simonknee

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My electronics knowledge is very dusty but aren't they two separate circuits. You can charge the capacitor without it being "connected" to the flash light, so if you put the resistor after the transistor, or whatever controls the connection between the capacitor and light, then it will only affect the discharge.

 

Still the ideal situation is to use a light with higher resistance/lower wattage and that focuses its lumens into the fiber optic rather than spreading it out over a broad area. So I am very curious about the test with triggering a LED.

 

Bart

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Possibly Bart, though I am aware that adding resistance to any part of a working circuit without a proper understanding of what the designers intended might just render it useless.

I too wonder about led, from a quick Google hunt it seems that there is success as a trigger but not as a ttl.

Retro fitting a lower output xenon is another option. Not sure how to source such a thing mind. Most suppliers of xenon tubes want to advertise how bright theirs are!

Sent from my Nexus 4 using Tapatalk

Edited by simonknee

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