Old SLR Flash Gun

H

hobbsidt

Suspended / Banned
Messages
12
Edit My Images
Yes
Hello,

I wonder if any of you can help. I am fairly new to using a DSLR and having bought a 400D I have been trying to master the basics. My dad recently gave me an old flash gun (a Miranda CTB 24) which he used to use with his old film SLRs. I have experimented & managed to get some results that weren’t too bad (more luck than judgment!) This morning I tried to find a instruction manual on the web & I found a site suggesting that an SLR flash should never be used with a DSLR.... Is the writer trying to cover themselves or have I messed up my new pride & joy?! Any thoughts would be much appreciated.

Paul
 
A test must be made on the trigger voltage of this flashgun. It has to be low voltage, but things are getting better now. Fuji are saying "Our cameras are ok for up to 400 volts. Canon are saying "Ours are ok for 250 volts but only for use with the sync socket, not the hotshoe"
 
Many thanks for you help. I have found on the net someone has tested this unit as haveing a trigger of 11.5V but has also warned that this is no good for EOS cameras. - Doh!

In my 400d instruction book it states ' do not attach a high-voltage flash unit on the camerasd hot shoe. It might not work' Does this means the camera is design to protect its self?
 
To measure the trigger voltage, turn the flash on and let it charge up. Measure the voltage between the two primary contacts on the hotshoe with a multimeter set to the highest DC volts range you can.

http://www.botzilla.com/photo/strobeVolts.html this page carries a list of known voltages, unfortunately yours isn't listed but one model of miranda flash does give out a very high trigger voltage, so it might be best to check.

If yoiu're keen to use the flash and are worried it might damage your camera, you can buy a Wein Safe Sync to go between the two but they are expensive typically (£40-£50)
 
what the high voltage does is burn out the camera hotshoe
so best avoided!
 
Just tested as 11.7V

Not bothered about using again just want to make sure I haven't damaged anything yet! What do you think? On the net limits seem to be 6v or 250v but theres alot of difference here!

Only used about 30 times
 
I'd take a guess that it's probably fine but stop using it now and keep your fingers crossed.
 
Bad info here I'm afraid. The 400D is safe to 250 volts. It has no sync socket and even if it did the hotshoe is one the same circuit, so if it's too much for the hotshoe it's too much for the sync port.

11 volts is easily safe. I've used all manner of flash guns on my previous 400D and my current 40D and had no problems.

The warning about 6v is for early EOS models. The 300D could only handle 6v.
 
martinsmith99 said:
Bad info here I'm afraid. The 400D is safe to 250 volts. It has no sync socket and even if it did the hotshoe is one the same circuit, so if it's too much for the hotshoe it's too much for the sync port.

11 volts is easily safe. I've used all manner of flash guns on my previous 400D and my current 40D and had no problems.

The warning about 6v is for early EOS models. The 300D could only handle 6v.
Click to expand...
Sorry you are incorrect saying they are one and the same. Canon 5d states The PC socket must not use a higher than 250 volts input. Also "do not connect a high voltage to the cameras hot shoe".
 
Thaks for all the help.

I'm now fairly sure I havent fried anything! but will stop using it just in case.

Canon should really state the tollernces in the manual!

Thanks again.
 
I'm sure yours will as well, not that it matters since you know now anyway :)
 
classcams said:
Sorry you are incorrect saying they are one and the same. Canon 5d states The PC socket must not use a higher than 250 volts input. Also "do not connect a high voltage to the cameras hot shoe".
Click to expand...
NO I AM NOT INCORRECT!

The PC port and hot shoe are on the same circuit. If it's unsafe on one it's unsafe on both. Look at a wiring diagram. JEEZ!
 
You have a wiring diagram for a flashgun? Please send it post haste, I have never seen one. I shall have to check my guns. I feel quite safe using my 5D on sync socket straight to the studio flash , but I would not use the hotshoe even if the studio flash is only 20 volts
 
martinsmith99 said:
NO I AM NOT INCORRECT!

The PC port and hot shoe are on the same circuit. If it's unsafe on one it's unsafe on both. Look at a wiring diagram. JEEZ!
Click to expand...

sure theres not an optoisolator or something similar in there as it does specifically state that the 5d has a 250v pc port and a non HV shoe?
 
hobbsidt said:
In my 400d instruction book it states ' do not attach a high-voltage flash unit on the camerasd hot shoe. It might not work' Does this means the camera is design to protect its self?
Click to expand...

martinsmith99 said:
The PC port and hot shoe are on the same circuit. If it's unsafe on one it's unsafe on both. Look at a wiring diagram.
Click to expand...

There is a lot of nonesense spoken (and written) about this. Especially the bit about high voltage being o.k. on the sync. socket but not on the hotshoe.

I think the reason for the hotshoe warning is that manufacturers are worried about someone sliding a fully charged flash into the hotshoe and having the centre pin momentarily touch one of the other pins causing damage.

In reality, the connection to the hotshoe trigger pin and the sync. centre pin will either be a direct connection or identical circuitry.

In older cameras the flash was triggered with actual metal contacts. Now it is done with an opto triac (or SCR). It is not possible to buy one of these only rated to 6 volts (the commonly quoted maximum) and most would be rated to at least a couple of hundred volts.

The 6 volt warning seems to sit well with the worries of shorting the centre pin to a TTL pin as I stated above.

Anyway, read your camera manual. Most DSLR manuals have stated a 250 volt maximum for many years.


Steve.
 
Steve Smith said:
There is a lot of nonesense spoken (and written) about this. Especially the bit about high voltage being o.k. on the sync. socket but not on the hotshoe.

I think the reason for the hotshoe warning is that manufacturers are worried about someone sliding a fully charged flash into the hotshoe and having the centre pin momentarily touch one of the other pins causing damage.

In reality, the connection to the hotshoe trigger pin and the sync. centre pin will either be a direct connection or identical circuitry.

In older cameras the flash was triggered with actual metal contacts. Now it is done with an opto triac (or SCR). It is not possible to buy one of these only rated to 6 volts (the commonly quoted maximum) and most would be rated to at least a couple of hundred volts.

The 6 volt warning seems to sit well with the worries of shorting the centre pin to a TTL pin as I stated above.

Anyway, read your camera manual. Most DSLR manuals have stated a 250 volt maximum for many years.


Steve.
Click to expand...

^^^ Really helpful post Steve :thumbs: Thank you very much for that :)

An explanation that actually makes sense of this confusion. I know somebody who will instantly save £35 on unnecessary radio triggers as a result. Cheers bud.
 
HoppyUK said:
^^^ Really helpful post Steve :thumbs: Thank you very much for that :)

An explanation that actually makes sense of this confusion. I know somebody who will instantly save £35 on unnecessary radio triggers as a result. Cheers bud.
Click to expand...

You can buy a buffer/safety device that fits between the hot shoe and the flash too. Not sure where I saw the link, but shouldn't be too difficult to find.
 
Checked on my Canon cameras, it is impossible to make the centre pin touch the logic pins. The Japs know what they are designing.
 
classcams said:
Checked on my Canon cameras, it is impossible to make the centre pin touch the logic pins. The Japs know what they are designing.
Click to expand...

I know it's not really possible but I still think it's the only reason for the low voltage flash in the hotshoe rule.

Think about it logically. If you were a digital camera designer, why would you design a camera which was incompatible with and could be damaged by every flash already made?


Steve.
 
classcams said:
Checked on my Canon cameras, it is impossible to make the centre pin touch the logic pins. The Japs know what they are designing.
Click to expand...

Perhaps it is to protect the camera from somebody shoving a Nikon flash in to their Canon/Sony/Olympus/xyz camera? :thinking:
 
You must log in or register to reply here.
Back
Top