Methods of Triggering Firefly Slaves from Canon Digital SLR
- Thread starter footleg
- Start date
Tony_B
Member
Sorry if I'm missing something here, but can you not just fire a cheap trigger flash via the PC socket? Does this subject the camera to the same voltage as the hotshoe problem?
I know that PC connections are prone to reliability problems but I'd still favour that over some of the more complicated suggestions offered.
I know that PC connections are prone to reliability problems but I'd still favour that over some of the more complicated suggestions offered.
footleg
New member
Tony_B said:
I don't know what voltage tolerance the PC socket has, but I must admit it had not occurred to me that this would bypass the electronic flash metering problems. However I believe only the 5D has a PC socket out of the Canon EOS D cameras (at least the more affordable ones), so this still leaves the hotshoe as the only option for 300D, 350D and 400D owners.
The other advantage to using a radio slave is that you need one less flash, as you are not using one to just trigger the slaves. So for my light weight exploration camera (a little Olympus 5050) I can fit a couple of small flashes and the camera in a bag. However if I have to use one of these flashes as a masked slave trigger then I can only take single flash pictures with this set up.
DavidGibson
Member
See CREG journal 61 - September 2005*. Or go to http://caves.org.uk/flash/newsletter.html or direct to http://caves.org.uk/flash/isolator/61_16.isolator.pdfLes W said:Perhaps a project for somebody in CREG?
This article includes info on how to measure the terminal voltage of a flashgun and describes how to make a "flashgun isolator" that does not require an external battery. As usual, though, I get very little feedback. Has anyone used this circuit? Does it work under all conditions? Why wouldnt you use this? Are you waiting for me to supply you with a PCB and a kit of parts?
* Footleg - this might not be the same article you have seen. I think you saw the original in journal 60. There's an update in #61.
footleg
New member
Thanks for those links David. I had not seen that updated circuit. I've been meaning to build one for a while, but time is limited and it was quicker to buy a flash with a low trigger voltage on ebay (probably cheaper too!). So I've got a working set up now.
For some cameras it might not be as simple as using an isolator circuit. When I mask off all the pins on my dedicated Canon flash apart from the main trigger pin, the camera will not fire the flash. I can only guess that it does not close the circuit for the hot shoe trigger contact unless it detects a compatible flash gun. I expect I could work around this by using the PC socket on my camera, but not all EOS digital models have these. Either way, a dedicated flash which does NOT support the E-TTL feature works fine on my EOS digital with slave units. So I am ready to take it underground and see how I get on in Matienzo next week.
For some cameras it might not be as simple as using an isolator circuit. When I mask off all the pins on my dedicated Canon flash apart from the main trigger pin, the camera will not fire the flash. I can only guess that it does not close the circuit for the hot shoe trigger contact unless it detects a compatible flash gun. I expect I could work around this by using the PC socket on my camera, but not all EOS digital models have these. Either way, a dedicated flash which does NOT support the E-TTL feature works fine on my EOS digital with slave units. So I am ready to take it underground and see how I get on in Matienzo next week.
biffa
New member
The Canon 30D has a PC socket (and an interior thread which makes it more reliable). If I recall correctly Canon say that the PC socket can handle voltages up to 250v without damage. I've a couple of Nikon flashguns which i have taken the dedication pins out of (i.e. just left the contacts for firing) and these work fine from the hotshoe of the camera.
footleg
New member
Looks like the more heavy duty (metal bodied 10D, 20D, 30D, 40D, 5D) EOS cameras might have the PC socket then, but not the consumer models (plastic bodies 300D, 350D, 400D)? I'll see what the 350D has next week as I am helping a friend get his working with firefly slaves as well as trying out my 5D underground.
Whether individual flashes work on the hotshoe could be down to specific models of flash and camera then. My Metz dedicated flash for Canon E-TTL supporting cameras certainly does not fire when I mask off the minor pins on the hotshoe contact. But my non-E-TTL Vivitar flash for Canon non-digital EOS cameras works with the Fireflies, and only cost about ?10 off ebay.
Whether individual flashes work on the hotshoe could be down to specific models of flash and camera then. My Metz dedicated flash for Canon E-TTL supporting cameras certainly does not fire when I mask off the minor pins on the hotshoe contact. But my non-E-TTL Vivitar flash for Canon non-digital EOS cameras works with the Fireflies, and only cost about ?10 off ebay.
biffa
New member
Eventually had another chance to play with the wireless slave, http://www.flickr.com/photos/benstevens/sets/72157604327556217/ and it seemed to work well. Only problems I has were when the channel switches got knocked from the required settings whilst putting stuff into the pelicase and problems with the trigger not firing due to it not fitting on the hotshoe so well (forgot the pc sync cord).
footleg
New member
I tried mine again briefly underground, and while the little red light on the receiver flashed, the flash did not fire. I wonder if I have a flash which does not play ball with it? I need to do some more testing.
My Canon compatible Vivitar flash worked perfectly on the 5D however, and the 5D was superb underground. I protected it with a freezer bag which was secured with an elastic band round the lens. So only the lens barrel was exposed to dirt and dust. I don't think I'll bother taking my compact underground again unless I need full waterproofing. I'll post some pictures when I get time to sort them out.
My Canon compatible Vivitar flash worked perfectly on the 5D however, and the 5D was superb underground. I protected it with a freezer bag which was secured with an elastic band round the lens. So only the lens barrel was exposed to dirt and dust. I don't think I'll bother taking my compact underground again unless I need full waterproofing. I'll post some pictures when I get time to sort them out.
footleg
New member
Finally got some of the photos I took online, so as promised:
Straw Curtain http://www.flickr.com/photos/footleg/2972773148/
Formations on Balcony http://www.flickr.com/photos/footleg/2971926281/
Chamber containing both the above sets of formations http://www.flickr.com/photos/footleg/2972774546/
Straw Curtain http://www.flickr.com/photos/footleg/2972773148/
Formations on Balcony http://www.flickr.com/photos/footleg/2971926281/
Chamber containing both the above sets of formations http://www.flickr.com/photos/footleg/2972774546/
I have a Canon EOS 400D and a Canon specific Jessops flashgun and I always used to have the problem of the preflash setting off the firefly's too early. I normally use it with a Canon off-camera sync lead so as to keep the flash as far away from the camera as possible.
The solution I found was to use an old Nikon off-camera sync lead. This fires the flash straight away without any of the pre-flash and works fine with the old style firefly's. I guessing this is because only the main firing pin is connected and all the other little Cannon specific connections are ignored. The only downside is that for close up type shots the picture is sometimes over exposed as the flash always fires at full power as it doesn't have the pre-flash to calculate what power to use.
Hope this helps.
Greg.
The solution I found was to use an old Nikon off-camera sync lead. This fires the flash straight away without any of the pre-flash and works fine with the old style firefly's. I guessing this is because only the main firing pin is connected and all the other little Cannon specific connections are ignored. The only downside is that for close up type shots the picture is sometimes over exposed as the flash always fires at full power as it doesn't have the pre-flash to calculate what power to use.
Hope this helps.
Greg.
footleg
New member
Sounds like my Metz 'Canon compatible' flash. Just has an on-off switch on the back, so no way to turn off E-TTL which uses a pre-flash. I tried masking the contacts apart from the firing pin, but then the flash was not triggered at all. So I can't get that one to work with the Firefly 2 slaves. But what we have found is that EOS film camera compatible flashes which only support TTL mode work fine. These are often advertised as 'not compatible with EOS Digital cameras just to confuse matters. But what this really means is they do not supported the automated E-TTL metering system of the EOS digital cameras. But for cave photography with Firefly 2 slaves they work great.
I've been asked so many questions by people around this issue that I have started writing a blog to capture all the information I learn as I use Canon EOS digital cameras underground. I've written about the E-TTL issue and lot more about what flashes work here: http://canon-cave-photography.blogspot.com/
Hopefully this will be a useful resource for people using these cameras underground.
I've been asked so many questions by people around this issue that I have started writing a blog to capture all the information I learn as I use Canon EOS digital cameras underground. I've written about the E-TTL issue and lot more about what flashes work here: http://canon-cave-photography.blogspot.com/
Hopefully this will be a useful resource for people using these cameras underground.
francis
New member
I just read through your blog - it was very interesting, and contained lots of good photos .
I noticed that you say that canon dSLR's can only stand <= 6V trigger voltage. I was sure I had read 250V for some Canon models on one of the Norwegian camera forums I read, so I checked for the 5D which you are using.
From the manual (page 102):
Francis
.I noticed that you say that canon dSLR's can only stand <= 6V trigger voltage. I was sure I had read 250V for some Canon models on one of the Norwegian camera forums I read, so I checked for the 5D which you are using.
From the manual (page 102):
Francis
footleg
New member
Glad you found the blogs of interest. I would write about Nikon flashes if I had the same knowledge and experience of them that I do of Canon. Please feel free to add any information via the comments option to my blog if you have any to share. Once you have sorted out the camera connected flash to trigger the slaved flashes, the rest of what I am planning to write about on there should be relevant to any make and model of camera which has manual control. But I have a lot to write and not so much time so it is early days for the blog.
Remember PC sockets tend of be voltage protected, unlike hot shoe trigger contacts. I cannot vouch for all models of EOS cameras (and I have not read my 5D manual in as much detail as maybe I should), but I have read that the later EOS film SLRs were only rated up to 6V on the hot shoe, and also that burnt out flash trigger circuits were the most common repair done by Canon service engineers. I also read that high voltage flashes cause slow gradual damage to the circuit in the camera, and so may appear to work fine at first but eventually trash the camera. So while I can't claim to have first hand experience of any of these problems, I would rather not risk my camera.
On a lighter but still relevant note, I have found high voltage flash trigger contacts tend to upset assistants when they touch them with wet hands underground and get a big shock through their fingers! So lower trigger voltage flashes have other advantages.
Remember PC sockets tend of be voltage protected, unlike hot shoe trigger contacts. I cannot vouch for all models of EOS cameras (and I have not read my 5D manual in as much detail as maybe I should), but I have read that the later EOS film SLRs were only rated up to 6V on the hot shoe, and also that burnt out flash trigger circuits were the most common repair done by Canon service engineers. I also read that high voltage flashes cause slow gradual damage to the circuit in the camera, and so may appear to work fine at first but eventually trash the camera. So while I can't claim to have first hand experience of any of these problems, I would rather not risk my camera.
On a lighter but still relevant note, I have found high voltage flash trigger contacts tend to upset assistants when they touch them with wet hands underground and get a big shock through their fingers! So lower trigger voltage flashes have other advantages.
