I used to love my Sigma 24-70 f2.8 EX DG Macro....

but...
got ticked off when ETTL-II always was impacted while using it... so - I sold it and bought EF24-70L.... It hurts to spend the monies, but..... see for yourself....:

http://picasaweb.googl​e.com …photo#503606692​0655749266

download it from there and look at it at 100%....

WOW. Don't tempt me like this. That is DAMN sharp. You can see through the dogs eyes reflection clear as day!

Why would a lens affect ETTL?

because ETTL-II take object's distance into concideration (reads the lens'es focus distance), but it does it only for Canon lenses and not all of them. with Sigma it relies ONLY on metering the light.

with Sigma + flash my dog's fur was always light grey, this pic was taken with flash as well, no adjustment afterwards

wow. Yah, thats is very sharp. Like August, dont tempt me... I am on the verge of breaking so watch how you advertise your new toys lol.

ahh yes.......

yet another siggie homer sees the Light !

ed rader

Really? You USE TTL?

Wow. Never gave it much thought. Just set the flash computer up (if it's got one) or go by the guide number for f/8 and shutter speed (depending on light- one shouldn't mix color temperatures, but a little can be a very nice effect)

kufel wrote in post #2781576
because ETTL-II take object's distance into concideration (reads the lens'es focus distance), but it does it only for Canon lenses and not all of them. with Sigma it relies ONLY on metering the light.

I had the same problem with my brand new Sigma 17-70 but once I switched ETTL II mode to AVERAGE instead of EVALUATIVE under custom functions, I was much happier. I understand ETTL II AVERAGE mode does not use distance data from the lens to calculate flash exposures.

well, there were more reasons for upgrade, the extreme sharpnes is added bonus . i love this one now, my divorce with Sigma is for good

focal length of a lens is beingn transferred and your flash head adjusts accordingly. distance means that the camera reads how many feet or meters the lens is focused on when you hear the beep. and this is what is not being transferred from some Canon lenses and most likely from all non-Canon lenses. and it is to me the best new feature in ETTL-II since you can focus, recompose and the light metering system knows that the power of the flash needs to be adjusted for the distance to the main object (considering, of course, that the main object is the one that you put in focus )

for the record, some other features that drove me into emptying my pockets:
-double switching between AF and MF on the lens (forgetting the little switch wrecks your lens'es internals when you turn the focusing ring)
-lack of weatherproofing
-L lens fosuses faster and in lower light conditions, theoretically it should not, because they are both 2.8, but possibly Canon lens is more contrasty
-and, of course, the sharpness... my copy of Sigma was very sharp, but when I looked at my picture that is shown in the first post I almost fell off the sofa

You did no post processing on that image? Or perhaps did you take this as a jpeg and have in camera sharpening turned on? Just wondering....

???
Sigma lenses report focusing distance. I'm not knocking you for moving as all the other options (you can add a 77mm filter that will work with a lot of other lenses) add up to the better package as long as cost is ignored but honestly I haven't notice any ETTL problems due to the lens. Sharpness in truth would vary from copy to copy.

Just so people don't think Kufel is talking to himself in post #11 .

I had posted a reply after not carefully reading the entire thread and initially misread Kufel talking about FOCUS (object) distance and assumed he was referring to FOCAL length. When I discoved my blunder I skulked back into the shadows hoping no one had noticed my mistake. But to no avail.

At any rate, thanks for the clarification and congrats on the new glass.

I always take raws and always use C1Pro, contrast +10, Saturation +10, fix white balance and sharpening 170/1. the last values copied form the owner of this fine forum.

as per focusing distance - I could not find any info regarding Sigma reporting the distance to ETTL-II and I had plenty inconsistent results, so I assumed that. Nevertheless - never had problems with my 17-40L as well as with 24-70L during the tests.

Croasdail wrote in post #2784084
You did no post processing on that image? Or perhaps did you take this as a jpeg and have in camera sharpening turned on? Just wondering....