I just purchased a 50D and a Seatool 40D housing (as mentioned elsewhere in these forums, the 50D is identical to the 40D body so the housing needs no modificatiion). I have Inon Z240 strobes. In the past, I have used traditional sync cable and shot mainly manual. I have been playing around with the fiber optic cable which responds to flash signals from the camera. Just like the pop-up flash, the Inons will fire a burst of brief flashes while the camera is establishing focus.
Is there a way to disable the focus preflash function from the camera? I shoot a of of macro and I worry that this rapid barrage of flashing light will scare certain fish away. The 50D will attain focus in really low light with the flash disabled so Im not sure it is needed. I do need the pop up flash to fire as this triggers the external flashes.
Any thoughts/help would be greatly appreciated.
Thanks!
I have never used canon but I imagine there is a manual flash mode in the camera. Use this in the minimum power that you can to avoid battery drainage and heat/condensation.
I used the 40D/Seatool/INON combination for over 60 dives in Indonesia in May and I can't remember the rapid preflash ever occurring, even when I couldn't get a focus lock with the 100mm. Hmmmm. You already have your 50D? Have you verified this with the camera in the housing?
Needless to say, manual flash mode is not the answer unless you want to sacrifice TTL.
Mike
AFAIK, 'pre flash' is about exposure, not focusing and is indistiguishable from the main flash. In S-TTL mode the INON Z-240 puts out a very strong pre flash simultaneous with the camera's pre flash and IIRC up to 22 times stonger. Check out http://inonamerica.com/content/docs/AdvCan...ircuit2F375.pdf for the rationale.
I'd be really interested to hear of your impressions of the 50D particulary in respect of the Live View and how it compares to the 40D and 5D.
Thanks, Tim
AFAIK, 'pre flash' is about exposure, not focusing and is indistiguishable from the main flash. In S-TTL mode the INON Z-240 puts out a very strong pre flash simultaneous with the camera's pre flash and IIRC up to 22 times stonger. Check out http://inonamerica.com/content/docs/AdvCan...ircuit2F375.pdf for the rationale.
We're talking about two different things. Yes, it is true that the camera emits a pre-flash right before the main flash to assist with exposure. However, the 40D/50D also emit a series of many quick flashes on the half-press in low light (we're calling them preflashes, though perhaps you would call them something different). I honestly can't say whether this is to help set exposure or focus, but it is distinct from the preflash and main flash that accompany the release of the shutter.
Mike
Did a bit more research. I'll check to see if I did this to my camera when I get home (may have set it up this way and forgotten about it). Try going to CFIII--05, "AF Assist beam firing". Set it to Option 1, "Disable".
Good call Mike. That's what I was going to say. It's the focus assist lamp.
Cheers
James
Did a bit more research. I'll check to see if I did this to my camera when I get home (may have set it up this way and forgotten about it). Try going to CFIII--05, "AF Assist beam firing". Set it to Option 1, "Disable".
Just checked my camera and yes, in fact, it is set in this manner. While I'm at it, I'd say you might also consider setting your f-stop adjustment to be in full stop increments instead of 1/3 stop increments -- otherwise you'll be doing a hell of a lot of cranking with the Seatool rear command dial. That's my only remaining significant complaint with the housing. Everything else works VERY well!
FWIW,
Mike
Man, that was fast, the 50D out already. I am waiting to hear on something before I get my back-up/second camera but all things considered I would think it will be the 50D. Which I guess becomes my first camera. LOL
Good points Mike.
Cheers
Todd
Needless to say, manual flash mode is not the answer unless you want to sacrifice TTL.
Mike
Needed to me, Mike
as I understood Divedoc
have used traditional sync cable and shot mainly manual
so that´s why I proposed using manual flash... Sorry Doc
Thanks everyone,
Mike, you are the man I will try the settings you recommended.
Im sure that I would be very unpopular with that barrage of flashes going off every time I took a picture. I am headed to Wakatobi in a couple of weeks. The 50D arrived at my local Best Buy yesterday. They had 6 of them in stock. I dont think there wil be any major waits for those who want them. Im going to try some live view manual focus with my 100mm and some shallow water wide angle stuff with magic filters. I'll post some thoughts when I get back.
