question about flash


Dec 26, 2013
11
0
0
Singapore
#1
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
 

SkyStrike

Moderator
Staff member
Nov 29, 2010
3,444
11
38
Somewhere
#2
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.
 

Mar 14, 2013
265
1
0
Singapore
#3
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)
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,515
30
48
Pasir Ris
#4
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.)
 

Shizuma

Senior Member
Mar 19, 2012
2,557
25
0
#5
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
 

daredevil123

Moderator
Staff member
Oct 25, 2005
21,652
66
48
lil red dot
#6
If you are using Auto ISO, and you attach a TTL flash, the ISO will usually default to base ISO X 4.
 

shierwin

Senior Member
Dec 29, 2008
3,457
10
38
East Coast
#7
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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