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01/09/2008 10:34:25 AM · #51 |
yes, for this particular application (long lens outside)
When I shoot macros, I also need the preflash off in order to not scare away very fast bugs ... but I'm in manual everything for that, so it hasn't been an issue
Originally posted by Gordon:
Is your motivation for not wanting pre-flash to reduce the recycle time ? |
Message edited by author 2008-01-09 10:34:48. |
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01/09/2008 03:20:57 PM · #52 |
funny...when I read my flash manual last night it said to select Av or Manual mode on camera when setting the flash power manually. I guess it thinks if you are setting the flash power manually, the flash will be the main light source (at least in Av mode).
I guess we need to buy 1DMarkIII's and 580EXII's!
-drew |
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01/09/2008 03:34:50 PM · #53 |
I bet the 40D (which is DIGIC III based) works the same way as the Mark III.
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01/09/2008 03:39:36 PM · #54 |
this thread has had me thinking for two days now, trying to get the logic straight in my head. this is what I came up with.
In Av mode and the flash on low-speed sync, you can set the aperture and the shutter speed with automatically adjust to what the metering tells it. I would guess that outside, at a large aperture (guessing that's what you want to do to get nice OOF backgrounds), the shutter speed must be much less than the sync speed (usually 1/200 or 1/250, instead of the 1/500 or faster the light situation calls for). So what happens is that the shutter speed pegs at sync.
So, naturally, you'd instinctly set the flash to high-speed sync, so you can get faster shutter speeds, yes? The problem is that with the flash on high-speed sync, the shutter speed is always set at that really fast speed.
Kind of a conundrum that I don't think can be solved with the flash connected via the hot shoe (getting all the electronic data transferred betwen camera and flash).
Have you tried to use a small aperture where the required shutter speed would be longer than the slow-speed sync? I'm guessing that will work, but is not good for your blurred backgrounds.
So... one possible fix is to use those cheap e-bay triggers (which have only a single pin trigger contact). I think the camera would be fooled into thinking that there's no flash attached, and the Av setting will work as we think it should. Flash power is set manually of course, but that should work out fine since you are just trying to use it to get a catchlight, and not get a pre-flash.
I haven't tried this out yet, but I might tonight, unless someone who has those triggers can try it out first. |
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01/09/2008 04:04:55 PM · #55 |
Originally posted by brownsm:
Have you tried to use a small aperture where the required shutter speed would be longer than the slow-speed sync? I'm guessing that will work, but is not good for your blurred backgrounds. |
If you put the flash on the camera, leave the lens cap on and switch to Av mode and put the flash in manual mode, the camera sets the shutter speed to the sync speed (1/250 or 1/200s in normal sync, depending on camera, or 1/4000s or 1/8000s in high speed sync, depending on camera)
At that point, the camera has given up doing any metering - Av mode with a manual flash attached essentially disables metering - it lets you set aperture only and uses the max possible sync speed (which is what you'd actually want to do for a flash or strobe only exposure)
I suspect if there is anything electrically attached to the hot shoe, it'll do this, unless it can control the flash via E-TTL.
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01/09/2008 04:09:01 PM · #56 |
Originally posted by brownsm:
Have you tried to use a small aperture where the required shutter speed would be longer than the slow-speed sync? |
Just tried this and no matter the aperture, when the camera is in Av and the flash set manually, the shutter is 1/200th or 1/4000th (high speed sync on).
Originally posted by dwterry:
I bet the 40D (which is DIGIC III based) works the same way as the Mark III. |
I would be interested to see what happens on a 40D, as that is the next camera I am looking at purchasing.
-drew
edit:spelin!
Message edited by author 2008-01-09 16:18:50. |
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01/09/2008 04:11:50 PM · #57 |
Originally posted by drewbixcube:
Originally posted by brownsm:
Have you tried to use a small aperture where the required shutter speed would be longer than the slow-speed sync? |
Just tried this and no matter the aperature, when the camera is in Av and the flash set manually, the shutter is 1/200th or 1/4000th (high speed sync on). |
with no flash connected, would the correct shutter speed be longer than 1/200th, like 1/100 or so? On my 5D, I use Av mode with flashes and in low light situations, it works just like we'd expect.
The way the camera is supposed to work is get a metering for the background, and that sets the shutter speed, then it worries about the flash to properly expose the subject (assumed to be in the foreground).
Message edited by author 2008-01-09 16:12:19. |
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01/09/2008 04:17:42 PM · #58 |
Originally posted by brownsm:
with no flash connected, would the correct shutter speed be longer than 1/200th, like 1/100 or so? On my 5D, I use Av mode with flashes and in low light situations, it works just like we'd expect.
The way the camera is supposed to work is get a metering for the background, and that sets the shutter speed, then it worries about the flash to properly expose the subject (assumed to be in the foreground). |
Yeah, but you are probably using the flash in ETTL mode (Automatic), not manual. In automatic, it works just as you described, but when the flash is set to a manual mode (say 1/2 or 1/64 power) the camera automatically picks the sync speed as the shutter speed. This is where all the confusion started. |
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01/09/2008 04:24:42 PM · #59 |
Originally posted by brownsm:
with no flash connected, would the correct shutter speed be longer than 1/200th, like 1/100 or so? On my 5D, I use Av mode with flashes and in low light situations, it works just like we'd expect. |
yes - like I said - this happens even with the lens cap on. Av mode, flash in manual, the camera forces the shutter speed to the appropriate sync speed. |
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01/09/2008 04:37:55 PM · #60 |
I don't know if this matters or not, but this does NOT happen when using the Sigma EF500 EG Super. If I leave the lens cap on, flash in manual, and Av mode the camera wants 30s (which is right). FP mode does not force any kind of change either. It still meters for ambient and lets you deal with flash exposure.
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01/09/2008 05:51:49 PM · #61 |
like it ought to be !!
they don't even mention how it works in the canon manuals i don't think
Originally posted by SamDoe1:
I don't know if this matters or not, but this does NOT happen when using the Sigma EF500 EG Super. If I leave the lens cap on, flash in manual, and Av mode the camera wants 30s (which is right). FP mode does not force any kind of change either. It still meters for ambient and lets you deal with flash exposure.
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01/11/2008 02:31:32 PM · #62 |
last little bit of follow up:
//photography-on-the.net/forum/showthread.php?t=44018
One person suggests the camera "locks" the shutter speed as a way of indicating the camera will not auto expose when the flash is in manual mode. Apparently, the same situation happens in Tv mode (smallest lens aperture locks in) when the flash is switched to manual.
Gordon, in response to something you said before. I tested turning the FEC all the way down to achieve "rapid fire" - didn't work. The flash will only fire in succession when in manual mode.
damn aliens
Message edited by author 2008-01-11 14:31:40. |
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02/11/2008 12:56:08 PM · #63 |
| I think your problem is that you have Custom Function 3 on the camera set 200 fixed. |
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02/11/2008 01:25:54 PM · #64 |
Originally posted by GW:
I think your problem is that you have Custom Function 3 on the camera set 200 fixed. |
Originally posted by hopper:
edit to add: custom function 3 is set to 0 (which is auto, not fixed to max shutter speed) |
I'm pretty sure there's no "problem" at all ... canon just didn't design it to work the way I want it to. |
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11/14/2008 02:24:27 PM · #65 |
Hey guys, I've got the same problem with my 430EX II and 400D.
But luckily I've got a stupid solution, that I have a cheap radio wireless flash trigger that does not have the 4 communication pins on the hotshoe, obviously the camera doesn't know I have my flash on wirelessly, and I can have my flash on manual and while the camera can still work with metering on in Av/Tv mode. I believe that if you put a tape on the 4 pins, it would solve the problem too, but I haven't try that yet.
Back to the problem itself, I think obviously this is a bug rather then things like "if you put the flash in manual, you're saying the flash is the only light, so that shutter speed isn't a matter, and it locks on X sync" because, in Tv mode, it is stupid enough to lock my aperature to my smallest f/22. And also, if that was the case that "shutter speed isn't a matter, it locks on x sync" why do I not use the manual mode??
As I was reading the first page on this topic, I wished I could see the solution on latter pages, however there are none :( Shouldn't us email Canon and ask for an explaination for that, and probably a firmware fix?? I don't want my newly bought expensive 430EX II to behave so stupid like that that I have to tape off the 4 pins everytime I wish to go manual mode on the flash!!! |
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