Inaccurate exposure with Canon flash unit

[Luval]

looks fine to me, exposure wise..

 

[mrchua]

I don't see anything very wrong with these shots.

You expect your flash to penetrate thru' human bodies and reach ALL THE WAY to the distant background???

Secondly, you have this person in white in your second shot and expect the flash to do the thinking for you?

Thirdly, do you know how to use aperture and ISO to control background, shutter speed to get your handshake under control, and let the flash take care of your foreground?

I bet if you and your friend switch systems, he'll get things right while you will still be struggling with 'poor' shots.

don't be too harsh..if he knew, he'd be using manual mode for the flash already instead of relying on ETTL. some of the pics don't look tack sharp possibly due to handholding. TS, forget ETTL or iTTL on Nikons. no technology is perfect, even autofocusing can be inaccurate at times. what you see with your eye is what is most accurate, and only manual mode does that as it gives you total control.

 

[TYM]

I don't see anything very wrong with these shots.

You expect your flash to penetrate thru' human bodies and reach ALL THE WAY to the distant background???

Secondly, you have this person in white in your second shot and expect the flash to do the thinking for you?

Thirdly, do you know how to use aperture and ISO to control background, shutter speed to get your handshake under control, and let the flash take care of your foreground?

I bet if you and your friend switch systems, he'll get things right while you will still be struggling with 'poor' shots.

aiyo why you so harsh to him? teach him how la, not humiliate him la. This is a forum to share and learn right?

Anyway, finally the photos are up. I think the camera may be confused with the "white" of the groom. The room is small, so i guess your 580EX output shld not be a problem. So i think it has to be with the metering of the scene. Perhaps you can either compensate the flash as needed, or manually fix the flash outpout at a certain value so that the exposure is constant regardless of metering for that venue. Thus dun have to worry whenever the handsome "white" groom (or brides gown for the matter) comes into the picture.
Thanks for sharing this is a good learning discussion for myself

 

[alternatve]

IMO, all the shots are slightly underexposed, even your "good" example.

You can try to lower your shutter speed a notch (1/30) or increase your ISO speed to let in more ambient light. Remember, you are trying to get two exposures in one frame, one by the ambient light in the background, the other by the flashgun in the foreground. I hope you weren't trying to use the flashgun to illuminate the background as well! That would have blown your foreground to little white bits. The fault wasn't with the E-TTL, in fact it worked perfectly in this situation.

The problem was you didn't control the flash properly (guy at the left wearing the white jacket overexposed), expected the flash to light up the background (impossible without a secondary flash unit without blowing the foreground) and didn't know the technique enough to compensate for the underexposure. Also, I won't follow my friend's settings exactly, but only use it as a gauge for my own settings. ISO standards differ from camera to camera and make to make and the technologies involved is different too, making it unwise to follow the other guy.

Please do inform me if you have any objections with my opinions. I hope through this, the TS and all of us will learn something new. I certainly did!

Samuel

 

[alternatve]

One example...

Technical Details: 70mm, 1/30, f/8, ISO 640. Slight tweaking of image on LR.

Now I won't say this is a perfect shot, but I did manage to get the person with a nice tone and without blowing anything. Picture is a tad under but the place was pretty dark (lited only by candles and some ambient light from the sides!) so I did what I could. Plus I didn't want to fire my flashgun at full power as it was an old folks event.

What I did do was to lower my shutter speed - aperture - ISO range till I got a suitable background light level then proceeded to ignore the settings and cookie cutter the shots, only varying the flashguns' (I'm using a 430ex!) head direction for maximum reflection and adjusting power. If you're using a bounce card (I wasn't!) and am shooting at place with a constant ceiling, it would be much much easier, with you adjusting only the flash output to give the foreground (and a little of the background) more or less light according to your needs.

Hope it helps.

Samuel

 

[Gizmore]

I don't see anything very wrong with these shots.

You expect your flash to penetrate thru' human bodies and reach ALL THE WAY to the distant background???

Secondly, you have this person in white in your second shot and expect the flash to do the thinking for you?

Thirdly, do you know how to use aperture and ISO to control background, shutter speed to get your handshake under control, and let the flash take care of your foreground?

I bet if you and your friend switch systems, he'll get things right while you will still be struggling with 'poor' shots.

is there a need for such harsh reply? This is not really very constructive to begin with.

 

[calebk]

The truth hurts. :bsmilie:

I concur with doodah, and in addition I have this to say. TTL does not mean you have a magic bullet of a flash. You still have to understand the scene and dial in compensation accordingly, or perform flash exposure lock.

Like what TYM pointed out, TTL flash is easily fooled by black or white objects (especially in large amounts; if there are both in the same frame, happy day) in the frame. For instance, shooting a dinner and dance event, where everyone was wearing black or dark coloured jackets, one has to dial in -2/3EV flash compensation so as not to blow out the skin tone. Either that, or one can perform a flash exposure lock over the skin tone.

Understanding your system, its quirks, its flaws and its strong points, is key to getting good results. Technological advances still have to go hand in hand with a user understanding of those same advances. One cannot solely blame the flash, nor oneself.

 

[acitinium]

err ... the exposure seems okay to me.

anyway the 3x photo taken is not under same light conditions, which is shootin at different places.

or is it your monitor cotrast/brightness is set too low?
its not possible to get the whole room (both foreground and background) lit up with same exposure, as the function room is using 'spotlights'.

Hi everyone,

Thanks for all the contributions so far.
I figured since im the TS, I should at least post some sample shots for viewing.
I was hoping to get some shots from my friend as a comparison, but he is too busy now that its the peak period, so i shall just post 3 of my shots for sampling.

Slightly under exposed both front and back

Subject is slightly under like 1st pic but background is almost in darkness

The better exposed shot among the 3, both foreground and background

Used the same settings for all 3 shots, under same lighting condition and distance.
But got 3 different results.

 

[digital601]

I'm a newbie in flash, but the photo exposure look ok to me.
WB abit off, maybe custom WB with Expo disc could correct the lighting!
People near camera wearing bright clothing tends to overexposed especially white!
Bouncing the flash off ceiling helps as it is low.
Just my 2cents...
And lens f2.8 or lower..

 

[CYRN]

Hi everyone,

Thanks for all the contributions so far.
I figured since im the TS, I should at least post some sample shots for viewing.
I was hoping to get some shots from my friend as a comparison, but he is too busy now that its the peak period, so i shall just post 3 of my shots for sampling.

Used the same settings for all 3 shots, under same lighting condition and distance.
But got 3 different results.

Are you using a diffuser? :think:

From exif.. your last pic aperture different. that might be one of the factor.