question about flash


maisatomai1

New Member
Dec 26, 2013
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Singapore
Hi I am using yongnuo 468 which is a TTL flash.

I set sync speed to 1/200 and realise that my shutter speed is 1/200. I am using AV mode and I set the aperture to F8, and the auto ISO show ISO of 400. I then set aperture to F5.6 and realise that the ISO is still 400 which is kind of strange.

I then tried setting aperture to F32 and ISO to 100 and tried shooting. It is strange that the metering in my camera still show 0. But when I shoot, the picture came out to be totally dark (as expected). Why didnt the camera warn me that my photo is underexposed? Thanks in advance
 

My guess is that you are using Canon.. For some reason, once you put the flash on, in Av, Tv, Manual, your auto ISO will be kept at 400.

No clue regarding the metering.
 

My guess is that you are using Canon.. For some reason, once you put the flash on, in Av, Tv, Manual, your auto ISO will be kept at 400.

No clue regarding the metering.

so the only way is to manually set iso right? i usually keep it at 400 anyway...(for flash conditions)
 

so the only way is to manually set iso right? i usually keep it at 400 anyway...(for flash conditions)
First of all: please confirm or correct the assumption about Canon. Which model?
Check the Auto ISO settings in the camera manual, especially for flash. It should be possible to change this to anything else than 400. (Sometimes you need to read also the footnotes and remarks, certain details are only mentioned there.)
 

is it possible for you to un set the sync speed? you didn't mention what shutter you're getting in av mode.

however you should still be getting a non black image (however under exposed ) at aperture f11 and wider if you're not attempting sky bounce and there is something to reflect the flash into the lens.

at very narrow aperture the flash incident on your sensor may be to little for correct exposure

in any case logically the camera will aim for correct exposure through TTL metering so the meter would logically read zero and any change make you in aperture would be set off by adjustments in flash output energy
 

If you are using Auto ISO, and you attach a TTL flash, the ISO will usually default to base ISO X 4.
 

Hi I am using yongnuo 468 which is a TTL flash.

I set sync speed to 1/200 and realise that my shutter speed is 1/200. I am using AV mode and I set the aperture to F8, and the auto ISO show ISO of 400. I then set aperture to F5.6 and realise that the ISO is still 400 which is kind of strange.

I then tried setting aperture to F32 and ISO to 100 and tried shooting. It is strange that the metering in my camera still show 0. But when I shoot, the picture came out to be totally dark (as expected). Why didnt the camera warn me that my photo is underexposed? Thanks in advance

You ask a similar question before (2 yrs ago): http://www.clubsnap.com/forums/showthread.php?t=965404
 

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