Am I gonna hurt myself? - DPChallenge Forums

08/14/2007 11:31:19 AM · #26

In case it is of interest, I bought a cheap ring flash kit that does a pretty good job and, importantly, does not look home made (I posted about it here).

The results I get are pretty good - this is the only image I have handy:

Spork99

Canon EOS M6 Mk II

Canon EF-M 22mm STM Lens

08/14/2007 11:34:27 AM · #27

I'd leave it alone and try to figure out a way to get what you want without disassembling the flash unit, there are things in there that can really hurt you.

As one example, I've seen a screwdriver used to discharge a capacitor from a disposable camera flash have serious pits in it from one discharge. If it can melt a hole in metal, imagine what it could do to your finger.

If you remain foolhardy and determined, whatever you do, have someone there that knows CPR and first aid with 911 on speed dial.

To answer your original question about hurting yourself: You might not, but, given what you're planning and your demonstrated level of knowledge, in all likelihood that answer is probably a yes.

Message edited by author 2007-08-14 11:41:09.

08/14/2007 11:37:04 AM · #28

Originally posted by Spazmo99:

If you remain foolhardy and determined, whatever you do, have someone there that knows CPR and first aid with 911 on speed dial.

And a camera - no pics, then it didn't happen...

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

08/14/2007 11:40:04 AM · #29

Originally posted by Matthew:

Originally posted by Spazmo99:
If you remain foolhardy and determined, whatever you do, have someone there that knows CPR and first aid with 911 on speed dial.

And a camera - no pics, then it didn't happen...

And ofcourse another flash for lighting the event :-)

SamDoe1

Canon EOS-350D Rebel XT

08/14/2007 11:47:40 AM · #30

Not sure if this such a great idea. Have any friends that know how to safely work with high voltage/high current circuits? If not, I'd stay away from taking the flash apart.

This right here is my personal favorite out of an article I found:
"Also, high microfarad low voltage capacitors can vaporize a screwdriver and spray metal in your eyes."

You can probably find some good articles online about how to safely discharge a capacitor, but sometimes discharged capacitors need to be replaced since they "bleed to death".

Good luck and wear some safety glasses.

08/14/2007 11:51:55 AM · #31

Never mind all the downsides - what's the upside that would make this worth doing ?

The fresnel lens on the flash is going to distribute the light pretty well anyway.
It's doubtful you'll get much more light by disassembling the flash - the head is going to be in the same place in the ring light, in its housing or not.

If you don't disassemble it the flash is usable normally and in the ring flash.

If you do disassemble it, it can only be used in the ring flash.

So what's the advantage of taking it to bits ? A very small power gain ? (I'm ignoring the fun of ripping stuff apart and building new things, which has its own allure though)

Message edited by author 2007-08-14 11:52:18.

08/14/2007 11:59:17 AM · #32

Wow guys, I think you 're overeacting. The jolt from the capacitor may be unpleasent, but it wouldn't harm you (much less kill you) under any circumstances. We used to shock each other for fun using a disposable camera. Ok, smaller flash, I know, but still.... don't worry

08/14/2007 12:04:16 PM · #33

30 volts DC can kill you if it travels through your heart. If it catches it in the right place in the beat, it takes even less.

Proceeding things with "I did this as a kid" doesn't exactly validate its safety.

Edit: typo

Message edited by author 2007-08-14 12:06:35.

_eug

Nikon AF Nikkor 50mm f/1.8D

08/14/2007 12:16:27 PM · #34

Originally posted by fotomann_forever:

Proceeding things with "I did this as a kid" doesn't exactly validate its safety.

What if Art we're to precede his story with, "This one time at band camp?"

SamDoe1

Canon EOS-350D Rebel XT

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

08/14/2007 12:20:01 PM · #35

Originally posted by fotomann_forever:

Proceeding things with "I did this as a kid" doesn't exactly validate its safety.

Similar to "hold my drink and watch this!"

08/14/2007 12:28:16 PM · #36

Originally posted by hsolakidis:

and your qualifications to make this assertion are ?

FWIW, disposable cameras use much lower capacitance devices than a portable strobe (~100uF or so) The voltage is the same, but the energy storage and hence current is much less on a full discharge.

300V DC can certainly kill in the right (wrong) circumstances. It would be unusual, but not impossible, particularly if you don't handle it with some respect. Nasty shocks/ burns are very likely.

Message edited by author 2007-08-14 12:43:23.

08/14/2007 12:31:28 PM · #37

Originally posted by Gordon:

and your qualifications to make this assertion are ?

Originally posted by hsolakidis:

We used to shock each other for fun using a disposable camera.

Not enough proof for ya Gordon? LOL

_eug

Nikon AF Nikkor 50mm f/1.8D

08/14/2007 12:35:53 PM · #38

Originally posted by Gordon:

Originally posted by hsolakidis:
Wow guys, I think you 're overeacting. The jolt from the capacitor may be unpleasent, but it wouldn't harm you (much less kill you) under any circumstances. We used to shock each other for fun using a disposable camera. Ok, smaller flash, I know, but still.... don't worry

and your qualifications to make this assertion are ?

I'm with Gorgon on this one. Just because you were lucky enough to pick a smallish cap to zap yourselves with doesn't mean that ALL capacitors are that forgiving. It's possible to build or buy capacitors that will carry several thousand volts charge.

08/14/2007 12:41:09 PM · #39

Originally posted by Gordon:

and your qualifications to make this assertion are ?

MEng Digital Systems Engineer. But that's not the point. The point is that 4 puny AAs can't deliver the current required to kill you. Voltage may be high(ish), but that alone can't hurt you.

08/14/2007 12:44:04 PM · #40

Originally posted by hsolakidis:

Originally posted by Gordon:

and your qualifications to make this assertion are ?

MEng Digital Systems Engineer. But that's not the point. The point is that 4 puny AAs can't deliver the current required to kill you. Voltage may be high(ish), but that alone can't hurt you.

Then I suggest you should have paid more attention in your high voltage electronics classes.

08/14/2007 12:46:45 PM · #41

Sarcasm really doesn't help Gordon. If you think that 4 AAs can kill you (even fully draining them to charge a capacitor) then it's you who needs to be educated.

08/14/2007 12:48:04 PM · #42

Originally posted by hsolakidis:

Sarcasm really doesn't help Gordon. If you think that 4 AAs can kill you (even fully draining them to charge a capacitor) then it's you who needs to be educated.

Its the 300V capacitors that are the issue, not the charging mechanism. Just because you shocked yourself with the caps in disposable cameras has no bearing on the caps in a portable strobe. 300V shocks are certainly painful, and potentially lethal if you are careless and unlucky. Disposable cameras typically have about 100uF caps, portable strobes are easily up to 10x that.

I wasn't being sarcastic FWIW.

But if you are comfortable risking your career on giving advice that it's safe, have at it.

It isn't that dangerous to work with these devices if you take reasonable precautions and know what you are doing, but the OP doesn't appear to. This all ignores the various risks of UV exposure due to removing the shielding, potential for the tube to explode and so on too.

Message edited by author 2007-08-14 13:36:09.

Canon EF 70-200mm f/2.8L IS USM

08/14/2007 12:50:29 PM · #43

Originally posted by Gordon:

Originally posted by hsolakidis:

Originally posted by Gordon:

and your qualifications to make this assertion are ?

MEng Digital Systems Engineer. But that's not the point. The point is that 4 puny AAs can't deliver the current required to kill you. Voltage may be high(ish), but that alone can't hurt you.

Then I suggest you should have paid more attention in your high voltage electronics classes.

yep - a single 9v battery has the power to kill if applied to an open wound: blood is an excellent electrolyte, so as soon as the charge gets a route to your heart past the insulator that is your skin, it can kill. Bad news if you cut yourself on a live component such as while handling a charged capacitor.

KevinRiggs

Canon EOS-1Ds

08/14/2007 12:51:28 PM · #44

Danged and this had been so funny. I understand the desire to do something like this on the "oh, it'd be cool to tear that apart and make something else" angle and I hope no one gets hurt trying any of this but I laughed my butt off over the first 20 posts. Now its down to arguing electronics and voltage and whatnot and its back to being business as usual.

hsteg, good luck with however you go on this one. Gordon thanks for the info and all you other smartasses (yeah, Leroy, you) thanks for the laughs.

Now back to pix or work or whatever preceeded this I s'pose.

KevinRiggs

Canon EOS-1Ds

Canon EF 70-200mm f/2.8L IS USM

08/14/2007 12:52:18 PM · #45

By the by, anyone know what batteries are used in those portable defibrillators?

08/14/2007 12:55:05 PM · #46

Originally posted by KevinRiggs:

By the by, anyone know what batteries are used in those portable defibrillators?

I would guess that they have large capacitors - hence the charging time (from a standard ish battery) to capacitors ("beep" on charge) to be released on the press of a button ("clear!").

08/14/2007 12:55:21 PM · #47

Anyone wanna take a shot at how much voltage/ampage the batteries in a implanted defibrillator produce? It's not much, I assure you.

It doesn't take much to induce atrial fibrillation. It's not a matter of how much, but when and what path. Those caps in the strobes have the juice, you just have to be unlucky enough to get the juice at the right time and place. The odds are significantly higher than winning the lottery if you wanna play the game.

_eug

Nikon AF Nikkor 50mm f/1.8D

08/14/2007 12:57:02 PM · #48

Originally posted by KevinRiggs:

By the by, anyone know what batteries are used in those portable defibrillators?

Duracell?

(That's what the TV ads say!)