PC Sync

[msvadi]

I plan to attend a studio photography workshop. One of the requirements is a camera with a PC sync socket. It turns out, my DRebel does not have one (another advantage of a 10D over a DRebel). I'm looking now for a PC Sync - hot shoe adapter. One can get it cheap from the ebay($11 plus $4 shipping):

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15215&item=3828921 907&rd=1

My only concern is the level of trigger voltage. Is there a risk of the damage to the camera circuitry?

[msvadi]

I just received an email from the instructor. he says, that one can use even a built-in flash to trigger studio flashes. I guess, I should not worry about an adapter, but I'm curious if E-TTL is going to be a problem. I understand, that studio flashes may have a built-in slave, which triggers them when any other flash in the area is fired. But, in such case, a studio flash will fire on a pre-flash, right?

[Jon]

Yes, but . . . you can turn off the red-eye pre-flash. You won't be able to get E-TTL with slaved studio flashes anyway. There'll presumably be enough light that you won't need to use the flash as a focus assist. You'll probably want to use an external flash at minimal power setting, and possibly directed away from the subject, instead of the pop-up in this case, so as to not mess up the lighting you're setting up.

[msvadi]

thanks for the response, but the pre-flash has nothing to do with the red-eye. the pre-flash is due to E-TTL, and it lets the camera to meter the scene. I would like to turn the E-TTL off, but, unfortunately, it's impossible with the buil-in flash or 420EX that I have.

Yes, but . . . you can turn off the red-eye pre-flash. You won't be able to get E-TTL with slaved studio flashes anyway. There'll presumably be enough light that you won't need to use the flash as a focus assist. You'll probably want to use an external flash at minimal power setting, and possibly directed away from the subject, instead of the pop-up in this case, so as to not mess up the lighting you're setting up.

[Jon]

Put the camera in manual mode - you're not going to get E-TTL with the studio strobes anyway. Calculating exposure using those big boys is part of what you're going to learn anyway (i hope, or you're going to be disappointed). If you want/need to use E-TTL in a studio situation, you'll have to buy a pack of 550s, 420s and maybe an ST-E2.

[msvadi]

are you sure that the M mode cancels the E-TTL? I remember that how the G2 worked: the flash always fired at the full power in the M mode. But, for some reason, I thought that with the DRebel it's always E-TTL. I guess, I have to check the camera manual again.

Put the camera in manual mode - you're not going to get E-TTL with the studio strobes anyway. Calculating exposure using those big boys is part of what you're going to learn anyway (i hope, or you're going to be disappointed). If you want/need to use E-TTL in a studio situation, you'll have to buy a pack of 550s, 420s and maybe an ST-E2.

[Jon]

The 420 has a manual mode too, and can be cranked around so it points at one of the studio strobes, thus reducing its impact on the studio light setup. You could also just pick up an el cheapo vanilla hot-shoe model flash that's too dumb to mess around with things like pre-flash.

[evilenglishman]

the preflash will always fire on the built in flash. buy a wien safesync that attaches to the hotshoe - mine has a pc connector built into it

[Conk]

As Evil said, buy the Wein safe sync. Unless you know for sure the studio flash puts out 6v or less you'll fry your camera using the $11.00 sync adapter. Unless of course you are using Alien Bees in the studio which put out 5.6. Or was it 5.8?
In manual mode with a 420, if there is a preflash, it is so damn fast it is very difficult to detect. I have had no problem using the 420ex to trigger my Bees in manual of course.
Example;
http://images2.fotopic.net/?iid=y3lfg3&outx=600&noresize=1&nostamp=1

[msvadi]

thanks guys, that's what I thought - there is always a pre-flash. I'll try to find out if the studio strobes we are going to use produce safe voltage. I was thinking about getting a safe adapter, but I'm not sure how often I'll use it after the workshop. Also, I already have a 420EX, so, I'm not sure if I want to spend more money on a flash that does not understand ETTL.

Conk: do you mean that in the M mode a pre-flash is not a problem with optical slaves?

[tracyh]

I've done mutliple tests trying to figure out the preflash on my D60/ST-E2 transmitter/550/420 combo used with some background and hairlight strobes (the background and hairlight are studio strobes, not Canon flash units). I have never been able to "see" the preflash (it must be lightning fast!), but I believe it still exists... even with the camera and my 550 in manual mode. I believe it because in my test shots, although the background strobes appear to flash simultaneously with my flash, the light is "off" when they appear in the picture (i.e. it appears that they fired prematurely). And, when I turn off the background lights and shoot again, everything looks exactly the same (i.e. no lighting difference).

I originally thought that perhaps it was the ST-E2 that kept forcing me into ETTL, so I took that out of the equation... as well as the 420. So, even with just the 550 (in manual mode at full power) and my camera set to M, it still appeared that ETTL was kicking in somehow. The other reason I believe this is that the flash output seemed to always adjust to my settings (even with the shutter open for 2 seconds at full open, I couldn't get anything to overexpose... and the shot appeared just like the one I shot at f8 and shutterp speed of 90).

I just ordered some Alien Bee units in the hope that using these via the included pc cord will eliminate any ETTL/preflash concerns (taking the ST-E2, 550, and 420 out of the mix) and all of my lights will fire at the same time.

I'd sure like to have someone tell me that I'm right... or tell me what the heck it is that I'm doing wrong--- just for peace of mind, if nothing else!

[HJMinard]

Nice shot Conk ... and a beautiful dog. Just curious - and sorry about going off topic - but it looks very similar to my German Shorthair Pointer ... what breed is it?

[Conk]

Conk: do you mean that in the M mode a pre-flash is not a problem with optical slaves?
It doesn't seem to be. I have looked closely for preflash and it is so fast that it is hard to tell if it even fires.
The way I see it, if my images are turning out ok, then preflash away.

Nice shot Conk ... and a beautiful dog. Just curious - and sorry about going off topic - but it looks very similar to my German Shorthair Pointer ... what breed is it?

Thanks
She is a German Shorthair Pointer, (with a tail). :D

[msvadi]

I got another message from the instructor. He says, most likely, our strobes have more than 6V. So, cheap adapters are out.

I posted the same question to the dpreview forum:
http://forums.dpreview.com/forums/read.asp?forum=1031&message=9629041

And one guy there (Mark Marshall) has a little trick to fool ETTL. One can use Flash Exposure Lock (FEL) to cancel e-ttl. After you press FEL button, there is no E-TTL for about 16 seconds. The flash will fire, when you hit FEL, but, hopefully, 16 seconds is enough time for the studio strobes to recycle. He says, it's also possible to cover the flash, so it won't trigger the strobes during FEL.

tracyh: may be you can use that trick to test your set-up.

[tracyh]

Thanks. I'll give that a shot. Shot... ha ha :lol: Okay... maybe I'm getting a little loopy over this problem....!

[Jesper]

I did a portait and model photography course last year, in which I used my 10D and my EOS 30 (Elan 7E).

The built-in flash of the EOS 30 does not emit an E-TTL pre-flash, so I was able to use it to trigger the studio strobes.

Unfortunately, the built-in flash of the 10D (and most likely also the 300D) *does* emit the pre-flash and I could not use it to trigger the strobes. Note, we almost exclusively used our cameras in M mode, so even in M mode it didn't work well. So I used the PC socket on the 10D and that worked.

Get the Wein safe sync, it's the safest solution for your camera and you can be sure it will work.

[evilenglishman]

And one guy there (Mark Marshall) has a little trick to fool ETTL. One can use Flash Exposure Lock (FEL) to cancel e-ttl. After you press FEL button, there is no E-TTL for about 16 seconds. The flash will fire, when you hit FEL, but, hopefully, 16 seconds is enough time for the studio strobes to recycle. He says, it's also possible to cover the flash, so it won't trigger the strobes during FEL.



This is a well known bypass, however it is mostly unusable as it means having to fire your lights 2 times for each shot and holding down the fel button. Try it when you are shooting 500 photos.

[Cordell]

And one guy there (Mark Marshall) has a little trick to fool ETTL. One can use Flash Exposure Lock (FEL) to cancel e-ttl. After you press FEL button, there is no E-TTL for about 16 seconds. The flash will fire, when you hit FEL, but, hopefully, 16 seconds is enough time for the studio strobes to recycle. He says, it's also possible to cover the flash, so it won't trigger the strobes during FEL.

tracyh: may be you can use that trick to test your set-up.

Would this actually work considering FEL gives your flash readings that are locked in? Or is this to say the locked in flash reading is picking up the light from the strobes too??

[Jon]

If you're using studio strobes, you'll usually be setting exposure manually or via a flash meter. You're usually not going to be using direct head-on flash as any significant part of the lighting setup.

[tracyh]

Just as an fyi.... I tried the FEL button trick to disable the preflash. The interesting thing (and perhaps this is normal and makes sense) is that with the camera in manual mode and the flash in manual mode, hitting this button did nothing (i.e. no flash was fired). So now, it's got me wondering about this whole thing again. Maybe I'm *not* getting a preflash... and there's something odd in the timing of the studio strobes such that they're either firing prematurely for some other reason OR maybe AFTER shutter release? It all appears to be simultaneous... but I would expect to see the flash from the strobe in the picture if it was.

[msvadi]

What flash do you use? You can try with the built-in flash (or 420EX), it has to fire when you hit the FEL, even in the M mode.

[slin100]

That is very odd. Do you have 2nd curtain sync enabled? If so, try switching back to 1st curtain sync. Perhaps the studio strobes are triggering after the 2nd curtain has closed.

[evilenglishman]

also, it may be a stupid question but are you using the 'x-sync' shutter speed?