A quick question about my lens or flash(Underexposing in ETTL)

Okay I have a Tamron 28-75 2.8 and a Canon 580ex II flash. When I use my flash on my 50mm 1.8 it never underexposes the picture in ETTL, but with my tamron 28-75 it underexposes until I press the *(fel) Whats up with this problem? Thanks in advance

Sample pictures
both of these were in ETTL

hmmm...

i should try this with mine

Canon E-TTL flash photography is extremely poor. I'm surprised you don't have the same results with your 50.

Let me give you a $1,000 flash tip: turn off E-TTL on your Canon when shooting flash indoors. Set your E-TTL metering to AVERAGE and your 2-3 stop underexposure will stop.

Nikons don't have this problem, they easily shoot perfect flash exposures.

BestVisuals wrote in post #11806096
Canon E-TTL flash photography is extremely poor. I'm surprised you don't have the same results with your 50.

Let me give you a $1,000 flash tip: turn off E-TTL on your Canon when shooting flash indoors. Set your E-TTL metering to AVERAGE and your 2-3 stop underexposure will stop.

Nikons don't have this problem, they easily shoot perfect flash exposures.

you serious or being sarcastic?

BestVisuals wrote in post #11806096
Canon E-TTL flash photography is extremely poor. I'm surprised you don't have the same results with your 50.

Let me give you a $1,000 flash tip: turn off E-TTL on your Canon when shooting flash indoors. Set your E-TTL metering to AVERAGE and your 2-3 stop underexposure will stop.

Nikons don't have this problem, they easily shoot perfect flash exposures.

I've never had any problems with ETTL using 580EX or 430EX speedlites..I find they are very accurate..

yogestee wrote in post #11806136
I've never had any problems with ETTL using 580EX or 430EX speedlites..I find they are very accurate..

I generally find that mine underexposes by about 2/3rds when bounced, but that's just me.

TheBurningCrown wrote in post #11806157
I generally find that mine underexposes by about 2/3rds when bounced, but that's just me.

This can happen if you don't set your flash up properly.. With a little FEC adjustment, open up your lense or increase ISO you should be OK..

Downs Photography wrote in post #11806105
you serious or being sarcastic?

ive noticed setting it to average on my 5d2 helps it.

and nikon ettl and flash metering is a lot better. i also use a d700 w/ an sb-800 and its much much more consistent no matter the condition im in

yogestee wrote in post #11806180
This can happen if you don't set your flash up properly.. With a little FEC adjustment, open up your lense or increase ISO you should be OK..

I'm not saying that it's an issue, I'm just saying that I default to +2/3 FEC to get a properly exposed image most of the time.

Well, once you hit FEL, you are bypassing ETT-L, so both photos aren't E-TTL so the photos don't tell the story. FEL meters the focus point which is like 3% of the frame vs. ETT-L which is metering the entire frame more or less. You're can get pretty different results between E-TTL and FEL unless the subject is very low contrast.

What it looks like to me is that since the frame is made up of high contrast with little in between, E-TTL weighted more towards the blanket leaving the baby, the subject, under-exposed. Once you hit FEL, it meter the baby, which I assume is the focus point, so now the baby is properly exposed and the blanket is a bit over-exposed.

E-TTL is no different that any other auto setting on the camera; it doesn't know what your subject is, it's just going to try to make everything look as uniform as possible.

That said, that can explain these two photos, but have you experienced this under-exposure in different conditions? Because the most logical explanation for these two is that the E-TTL just missed. At worst, the 580 II can bracket flash, so you can experiment and find out where you need to dial the compensation with that lens.

FEL performs spot metering in the center, not at the AF point you are using. But of course, with a 5D Mark II, the point you use is often the center one.