Using a 430EX II

timfenton

timfenton

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Tim
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Hi all,

I have an issue that is probably me being incredibly dense but need your intellect to point it out to me.

I have a Canon 550d which I am trying to use a 430EX II flashgun with. If I set the camera to 'P' I am given both speed and aperture by the camera. If I now select 'AV' and set the aperture to that previously given in 'P' I am given a shutter speed way slower than before. The same with 'TV'. Flashgun is set to ETTL.

I have tried different lenses (18-55mm, 70-200mmL IS, Sigma 30mm). All show the same trait.

For example, using the 70-200 'P' gives me 1/60 and F/4 and 'AV' gives me 0"8 and F/4. On the 30mm, 'P' gives 1/60 and F2.8, 'AV' offers 1/4 and F2.8.

I've looked through the settings in the camera and flash. Reset everything to default and read through the manuals but am no wiser so I'd appreciate any advice.

Many thanks,
Tim
 
In 'P' mode with the flash enabled, the camera is metering for flash exposure, i.e. it's treating the flash as the primary (possibly only) source of light.

In 'AV' or 'TV' modes, the camera meters in "fill flash" mode, whereby it meters for the ambient light and then fills in with the flash, so if it's dark your shutter speed will plummet.

Have a read here: http://photonotes.org/articles/eos-flash/ It's quite long but worth looking at as it explains how flash works on Canon cameras.
 
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I've got to ask the obvious but are you telling it to use the flash? The slow shutter speed leads me to believe that the body is assuming an 'available light only' shot. There is a small "flash" button to the left of the lens mount (camera pointing away from you)...pressing it should then show a flash icon in the viewfinder and the exposure will compensate accordingly.

Bob

Edit....page 64 in your user guide
 
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Canon Bob said:
I've got to ask the obvious but are you telling it to use the flash? The slow shutter speed leads me to believe that the body is assuming an 'available light only' shot. There is a small "flash" button to the left of the lens mount (camera pointing away from you)...pressing it should then show a flash icon in the viewfinder and the exposure will compensate accordingly.

Bob

Edit....page 64 in your user guide
Click to expand...

Never knew the flash button could do that, had a quick try on my camera, and in doing so found out that it seems that in P mode it is using slower speeds (1/60 @ 2.8) but as soon as I go to AV no matter what I choose, it fires at 1/200. I've got a 430EX II also, perhaps the way they operate with our camera bodies is different.
 
shogran said:
Never knew the flash button could do that, had a quick try on my camera, and in doing so found out that it seems that in P mode it is using slower speeds (1/60 @ 2.8) but as soon as I go to AV no matter what I choose, it fires at 1/200. I've got a 430EX II also, perhaps the way they operate with our camera bodies is different.
Click to expand...
The cameras will operate the same but your settings or the ambient lighting may be different. The 1/200th is the max sync speed so the flash power (if used in ETTL) will reduce accordingly.
In the auto modes then the camera is a little like your mother and sorts everything out for you. Switch into creative mode and it becomes a wife....you need to specify and explain everything you want in the smallest detail.

Bob
 
As I said above, 'P' meters for flash whilst 'AV' or 'TV' meter for ambient light.

shogran, in your case when set to 'P' it's metering for flash and locking the shutter speed at 1/60th, whilst in 'AV' mode it'll be metering for ambient light, of which I assume there is enough to warrant a shutter speed of 1/200th or above - you'll be limited to this if it's the maximum flash sync speed of your body. Try enabling HSS (high speed sync) mode on the flash and you'll find the shutter speed will probably go higher than 1/200th, correctly metering for ambient light.
 
Canon Bob said:
In the auto modes then the camera is a little like your mother and sorts everything out for you. Switch into creative mode and it becomes a wife....you need to specify and explain everything you want in the smallest detail.

Bob
Click to expand...

:lol::lol::lol::lol:
 
A prophetic (and bold) statement from one who is three weeks away from his 30th wedding anniversary :(
 
Canon Bob said:
The cameras will operate the same but your settings or the ambient lighting may be different. The 1/200th is the max sync speed so the flash power (if used in ETTL) will reduce accordingly.
In the auto modes then the camera is a little like your mother and sorts everything out for you. Switch into creative mode and it becomes a wife....you need to specify and explain everything you want in the smallest detail.

Bob
Click to expand...

Now that......is bloody funny:clap::clap::clap:
 
Thank you all for the responses though my wife is unimpressed having just read Canon Bobs comments over my shoulder!

Regarding the flash button, I thought this was only for the built in flash. I do get the flash symbol by default in any setting and the flash fires. the button doesn't seem to do anything with the 430 in place.

It seems Vertigo1's link gives the answer but I need a clearer head to understand it fully. I can set the speed and aperture in manual copying the 'P' settings and achieve the same exposure though the camera is telling me it will be underexposed.

I therefore take it that in order to be able to set my own aperture to give me a desired DOF I need to use full manual but won't know if the exposure will be correct beforehand. I'm just relieved that my camera and flash are not faulty and I just need to learn some more.
 
Flash still baffles me at times, the best thing to do is just experiment :)
 
D'oh, me being silly earlier! Makes sense now! Bob, you are a comic genius.
 
timfenton said:
I therefore take it that in order to be able to set my own aperture to give me a desired DOF I need to use full manual but won't know if the exposure will be correct beforehand. I'm just relieved that my camera and flash are not faulty and I just need to learn some more.
Click to expand...

In full manual mode as long as the flash is set to E-TTL the camera will adjust the flash power to give you a correct exposure as long as the subject is in range of the flash.
 
If You are hitting the sync limit at 1/200 then set 'H' with the lightning bolt symbol on your 430, thats high speed sync and shutter speed can now be faster, usually for an outdoor scene where there is plenty of light but you want good fill.
 
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