First ETTL Flash

Totally understand Wilt. Ok, did you see my test samples in my post? Same camera, same settings... please explain how the exposure vary so differently between V660c and 580EXii.

I have my theory but I'd love to hear your take on it.

With used 430EX and 550EX units being so affordable, I have no idea why people buy Chinese knockoffs.

Taylor, I am not opposed to spending money, but I am opposed to spending more money than I have too. I looked at a new Canon 430 which swivels right/left, and up/down for $249. I bought my Yongnuo 565 for $140 at the time, now they are around $100. Yes you could buy a used 430 for a little more than a new YN 565. But again, I have found my YN to be just as good as providing light for less money than any of Canon's OEM offerings for flash. So I choose to buy what I can for the price I am willing to spend. I am not the kind of person who will see two products side by side and just pick the name brand simply because they think they can pull the wool over my eyes. I did the comparison of the two devices and I still think I have better gear for less price and will continue to do the same until the YN brand somehow lets me down. And to this point, that has not been the case.

EmaginePixel wrote in post #17190388
Totally understand Wilt. Ok, did you see my test samples in my post? Same camera, same settings... please explain how the exposure vary so differently between V660c and 580EXii.

I have my theory but I'd love to hear your take on it.

I would tend to think that the V660c pre-flash puts out too bright a light, relative to its full power output, so when it is told "flash at power X " by the ETTL command from the camera, the light that is output is too weak by perhaps -0.5EV. Therefore, with that weak start, saying FEC +1 gives 'a bit brighter than correct exposure' (rather than +1EV brighter) and FEC -1EV gives -1.5EV

Exactly Wilt. That's my theory as well. Therefore, that being said, the faulty exposure would have to lie with the 'FLASH'.

Yes, it may sound as easy as applying +1 FEC but that doesn't work. My sample is in a controlled and static environment. But in real life, 90% of the time my flash is bounced or feathered one way or another. And that will exponentially affect the real output.

EmaginePixel wrote in post #17190483
Exactly Wilt. That's my theory as well. Therefore, that being said, the faulty exposure would have to lie with the 'FLASH'.

Yes, it may sound as easy as applying +1 FEC but that doesn't work. My sample is in a controlled and static environment. But in real life, 90% of the time my flash is bounced or feathered one way or another. And that will exponentially affect the real output.

I hear what you're implying, about the faulty exposure lying with the flash itself, but I'd also complain that the nature of ETTL is also to blame...I know that putting a modifier on a ETTL speedlight can lead to bad flash results, too -- even though bounce ETTL works fine! The nature of ETTL is NOT to measure light at the time of exposure (as it is done with film TTL flash), but to 'predictively' command the flash to a predetermined amount of light (resulting from measuring preflash) and HOPE that it is right in the exposure.

gonzogolf wrote in post #17189767
The 430ex is fine. Unless you plan to expand into the canon radio system the 600 is overkill. YN makes some highly regarded ETTL flashes but I dont have any personal experience with them.

HSS is a flash feature, to accommodate the fact that fast shutter speeds do not expose the entire sensor at the same time, but rather becomes a moving slit, the flash fires a series of pulses designed to emulate a brief continuous light. You lose a lot of power in going to HSS so its not a miracle cure. It can be useful for baee flash fill on a bright day fairly well.

I agree with the above regarding the 430EX (and 430EXii) being just fine for the purpose, especially when modified with a reflector/diffuser (I use the Joe Demb Flash Diffuser Pro) and when mounted on a bracket which will keep the flash above the camera and pointed in the correct bounce position when the camera is switched from horizontal to vertical position (I use the Stroboflash camera flip bracket). I like to use a Canon Off-camera Sync Cord because using the buiolt-in 7D flash for a trigger is chancy outdoors...

The HSS capability allows you to use a shutter speed in excess of the maximum sync speed for your camera (the max sync speed for my 7D cameras is 1/250 second). You are perfectly correct in that the HSS loses a bit of exposure. However, when you are increasing the shutter speed, you are also using a larger f/stop, so the actual loss is not that great - about a total stop...

IMO, HSS is essential when shooting out doors because you will want to use a wide f/stop (especially in portraiture). Using a wide f/stop normally requires a faster shutter speed. In order to achieve that faster than normal sync shutter speed is the reason for HSS...

BTW: When you have HSS selected on most Canon hotshoe flashes and your shutter speed dips to at or slower than the maximum sync speed, the flash automatically reverts to normal sync...

I have found my Yongnuo 565s and 568s to be every bit as reliable as my Canon 420s, 550s and 580s in ettl mode. However, ettl has never been as consistent as manual mode (duh!!) or auto thyristor mode (which I use for weddings and event/candid work). My ideal flash is a Metz which allows me all three modes: ettl, auto, and manual.

Bob Kupecky wrote in post #17192674
I have found my Yongnuo 565s and 568s to be every bit as reliable as my Canon 420s, 550s and 580s in ettl mode. However, ettl has never been as consistent as manual mode (duh!!) or auto thyristor mode (which I use for weddings and event/candid work). My ideal flash is a Metz which allows me all three modes: ettl, auto, and manual.

^^^
and only film SLR TTL has been even better than Metz' Auto (photosensor) mode, in certain circumstances.