bdazel 0 #1 February 18, 2009 Does anyone know what this thread size is? It's not the standard 1/4-20. Canon support has been very unhelpful - and seems incapable of providing the information. The only application I've found is for the SB-E2 bracket sold only in Europe. So I presume it's a metric size. Quote Share this post Link to post Share on other sites
Icon134 0 #2 February 18, 2009 I'm not sure I understand what you are talking about from what I can see there isn't a mounting hole on the bottom of the 580EX II?Livin' on the Edge... sleeping with my rigger's wife... Quote Share this post Link to post Share on other sites
PhreeZone 20 #3 February 18, 2009 There is on the side under a flap. Its for mounting directly to a studio stand with a bracket. It would work well for mounting a flash in portrait orientation directly to a helmet. Its a fine thread but I don't know what it is.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
bdazel 0 #4 February 18, 2009 QuoteI'm not sure I understand what you are talking about from what I can see there isn't a mounting hole on the bottom of the 580EX II? It is under a rubber tab, on the base, opposite the battery compartment. Small shallow hole with very fine threads. Canon says it is strong enough to be used for mounting purposes, but they don't know what the thread size is. Go figure. Quote Share this post Link to post Share on other sites
swilson 0 #5 February 18, 2009 M6x1.0 is just a touch smaller than than 1/4"-20NC, is the equivalent of 25.4 threads per inch, and is a standard metric thread. Could this be what you are seeing? I haven't actually handled this flash... Quote Share this post Link to post Share on other sites
BMFin 0 #6 February 18, 2009 Quote Small shallow hole with very fine threads. Canon says it is strong enough to be used for mounting purposes, I would recommend reinforcing the mount with something else also. It maybe strong enough for studio mounting, but not necessarily strong enough for freefall photography.. Quote Share this post Link to post Share on other sites
bdazel 0 #7 February 18, 2009 Very true. The magnitude and direction of forces are much different. I plan to use it only as one of three attachment points. But I still need the thread size... Anyone? :) Quote Share this post Link to post Share on other sites
PharmerPhil 0 #8 February 18, 2009 Not that this answers your question but,... If the flash is not mounted on the camera, you will need Canon's flash extension cord. That does have a 1/4-20 mounting screw hole in the bottom center. Maybe you could just use that? Otherwise, find a local hardware store (not a big home improvement center). Most have a great selection of standard and metric machine screws, and you can just bring your flash in and match it up. I just got back from my locally-owned True Value franchise and picked up all sorts of stainless machine screws/washers/etc. for a helmet project. Reason enough to patronize this place for paint and other stuff so they're still around when I need them. Quote Share this post Link to post Share on other sites
bdazel 0 #9 February 18, 2009 Thanks for the advice. I plan to use both the hot shoe and the bracket mount. I'll try the hardware store next, although someone in another forum told me that he couldn't find a match at the hardware store. Maybe it's a proprietary thread size? Would Canon do that? Unfortunately, Canon's support is dodgy and not at all helpful. I repeatedly attempted to extract this information from them. The responses I got were the following: "It's in the manual" - not true. "It's a standard tripod mount size" - not true. "I don't have that information" - not helpful. When I asked where I could go or who I could talk to to learn the info they ignored the question and regurgitated one of the above three responses. Very disappointing. Some Canon engineer has the specs written down somewhere, and the thread size must be in a drawing for the thing to even be made. I'm shocked that they won't even make an attempt to find out, especially considering the $1000s I've spent on Canon equipment. Quote Share this post Link to post Share on other sites
billvon 2,990 #10 February 18, 2009 >Maybe it's a proprietary thread size? Would Canon do that? I've never seen that. It may be an odd size (like a 12-24 or something) but it's very unlikely that it's proprietary. What I do when faced with such a situation is to go to Marshall's (hardware store that has every bit of hardware known to man) and just try bolts until I find one that works. Quote Share this post Link to post Share on other sites
kai3fly 0 #11 November 5, 2010 QuoteIn any case, I had a good rummage through the odd-ball tap drawer today, and I found a 6mm x 0.75 bottom tap. It ran right into the mystery thread, no fuss. So there it is, gang: the Canon bracket mount screw for the 580exII is a M6x0.75 fine thread. from http://www.dgrin.com/showthread.php?t=153972 Quote Share this post Link to post Share on other sites
