Sigma EF-500 Super for Canon TTL Flash or 420DX & Canon G6

I already decided for a G6.
Now I am in doubt between the two flashes above.
I know the right one to compare with the Sigma would be the 550DX or
the 580DX but I excluded them for the price.
The 420DX is Canon branded, affordable, but lacks flexibility as
compared to the Sigma.
I feel inclined toward the higher power of the Sigma and plenty of
manual settings.
On the other hand I have a doubt: could it be too powerful for portrait
picture?(or any kind of close to subject picture)
I can remember, back in the fifties, whem my father bought a wonderful
pre-pro Braun flash. It was so powerful that family photos looked like
washed by light. A very bad outcome.
Is this a non-issue nowadays ? (with the auto ttl metering)
Thanks in advance for your valuable support.
Jorge
PS: Without this group it would have bee a hard task to select my
equipment.

 

Canon speedlites are 420EX, 550EX and 580EX - I assume those are what
you are asking about. The Sigma 500 EF Super has some problems,
primarily that it doesn't remember any setting after being turned off.
The Sigma is not as well-built as the Canons.

Since all 4 flashes mentioned are E-TTL, too much power is never a
problem - the flash output is controlled and adjusted according to need.

-Dave

 

No. Canon lights have a reputation for under-exposing, infact.

However, I'd advise against spending money on a 420EX - the ETTL-only will
be much more expensive in the long run if you ever want to add more lights,
and manual is a lot more consistent anyways.

 

Dave and Eric,
Many thanks for your points. The units I am referring to are Canon EX
indeed.
The lack of memory of Sigmas are of some concern but my use will be 99%
auto.
There is some value, however, for the flexibility being there.
Also, it is good to know that auto takes care of exposure to a large
extent.
Regards, Jorge