Since there is a thread going discussing some of the benefit's and downfalls of the EOS 3, I thought it might be interesting to hear some of your thoughts on the new Speedlight 550ex that Canon is introducing with the EOS 3.

Specifically, I think the wireless flash ability of mulitple 550ex's is outstanding. But one of the best features I think is the new "FP" high speed sync it offers, this will allow the flash to sync at all shutter speeds the camera is able to handle which is 1/8000. What are your thoughts on this feature...

-- Bill Meyer (william_meyer@stortek.com), September 22, 1998

Answers

High speed sync is useful for outdoor fill, and a few other situations. The problem with it is that unlike having a fast X-sync speed on your camera it effects the guide number of the flash. I have the 380EX, which of course was Canon's first flash with this feature. At 1/4000 sec. the guide number at the 105mm zoom setting is only about 15 feet. In other words, if you are trying to use the flash as the main light at f8, you have a maximum range of about 2 feet. Of course at slower speeds it isn't as bad, but it just isn't all that useful for anything but fill in most situations. Since the 550 is a lot more powerful it may be more useful though.

As far as the wireless capabilities, it is about time! The drawback is that it only works with other 550ex's so far, and they will probably cost $350-$400 each. Even so, I think this feature will be far more useful than FP mode.

-- Brad (reloader@webtv.net), September 22, 1998.

Brad - FP sync is really intended for outdoor fill. After all why would anyone want to shoot a full flash portrait at 1/4000 and f8?? I can tell you that it's really useful for fill flash outdoors, especially when shooting with fast lenses wide open to blur the background. Though the power does drop as the shutter speed gets faster, it's still more than adequate (even on the 380) for doing its intended job.

Actually you don't lose all that much distance over conventional flash. Say you are shooting in bright sun at ISO 100. You'll be at f16 and 1/125 for conventional flash with a 1/125 sync speed. Though GN drops as you go to faster speeds, you are opening up the aperture at the same time and the two effects partly cancel each other out! For example with the 380, at f16 and 1/125 you can shoot full flash out to 2.4m with a GN of 38. Under the same ambient lighting conditions you get the same exposure at f2.8 and 1/4000, and you can shoot full flash out to 1.7m though the GN has dropped to only 4.7. So you've only lost 30% in distance.

-- Bob Atkins (bobatkins@hotmail.com), September 22, 1998.

That is exactly what I thought it would be useful for, outdoor fill flash. Canon claims the E-TTL is superior to their old A-TTL, can anyone explain what makes this a better metering system?

-- Bill Meyer (william_meyer@stortek.com), September 22, 1998.

Please forgive my ignorance, I ran a search on the photo.net Q&A and found an answer to the differences between A-TTL and E-TTL, though it's a bit vague, I think I understand. If anyone feels like giving a better explanation, please do...

-- Bill Meyer (william_meyer@stortek.com), September 22, 1998.

Bob,

I would not want to do full flash portraiture at 1/4000. As I said, FP mode is useful for fill flash. However, I remember when it was new to me, and I didn't understand the real usefulness, and wanted to be sure no one got the idea I had when I first got mine. I wanted to photograph my parakeet in flight at about 1/1000 to try to stop motion. I found out that it wasn't intended for such things, and was just trying to let others know ahead of time that this was the case.

-- Brad (reloader@webtv.net), September 22, 1998.