How many watt seconds 580ex

I've grown accustomed to listening to the whine of the charging flashes - I can audibly tell when they are at full power and know when the batteries are nearing the end of their charge. I definitely like the new, very-professional quiet charging, but I need to relearn my flash-ready indicators.

I'm told "they switched the voltage boost oscillator to an ultrasonic frequency". I should note that the flash is not sound-free as the zoom flash head still makes noise. The flash head zoom noise is higher-pitched. I wouldn't call it louder, but it is possibly more noticeable sometimes. The EX II sports a more-rugged build quality with a metal foot being one of the most noticeable changes. Bad in that it will still be the part that breaks, but good that your camera likely will not be the part that breaks a broken flash beats a broken camera any day from my perspective.

The long-time standard plastic foot is shown above left - the new metal EX II metal foot is shown above right. Visible dust and water resistance indicators denote another update this flash has received. This is Canon's first weather-resistant flash.

Dust and water resistance is a feature that is going to be in heavy demand from sports and photojournalism photographers. Users of older and non-sealed bodies will not get this final sealing protection, though the rest of the flash is sealed.

A little tape can probably remedy this issue for older weather-sealed bodies. Rubber covers seal the external ports - for external power and the new, greatly needed receive-only PC terminal - Pocket Wizard RF remote users know what this port does for them. The PC terminal is located just above the foot on the flash's left side. The long-time standard large round foot locking screw above left has been replaced with a very nice lever lock above right. Simply thumb slide the lever from left to right until it clicks into locked position.

Feet lower to tighten the flash solidly onto the hot shoe and the locking pin is lowered. A lock release button is located just to the right of the lever making unlocking easy. The new lever is faster to use - I like it. To get to this menu setting requires the zoom button to be held for 2 seconds - I could change the old switch in much less time than it now takes just to pull up the menu setting.

Newer Canon DSLR bodies have the ability to control the flash from their menus - this becomes the easier method of controlling this flash option. Note: the adhesive Velcro shown on the original EX above left is an accessory used to hold certain flash modifiers in place. Small changes include a repositioned wireless slave sensor and a reconfigured AF assist beam emitter - which now includes a small round hole containing the Auto and Manual External metering sensor.

The EX II weighs 1 lb 2. The EX II sports a new power switch design - this one rotates instead of sliding. The new one is a little nicer and likely easier to seal , but the physical change is not significant from a user perspective. The flash body finish is slightly more-textured than that of the EX. Those of you familiar with Canon's recent flashes will correctly recognize Auto and Manual External metering as being new. The built-in meter measures reflected light and turns off the flash when the proper amount is detected.

Compatible cameras will pass the ISO and aperture to the flash "auto"matically. Other body users can still use external metering, but will need to use the External Manual "EM" mode which requires the camera settings to be manually entered into the flash.

Metered off a gray card manual flash is also available. A custom function menu setting is used to select the external metering modes. High speed synch is not available and no preflash is fired in the external metering modes. My comparisons showed external metering, even from a 1D Mark III, to be significantly underexposed typically 1.

This is Canon's very easy-to-use automatic flash. Some people love it and some don't I personally like it very much. This flash also passes color information to the camera. I primarily shoot with my camera in M mode or Av mode.

With the camera in M mode, the flash will provide the light necessary to get a proper exposure. Forums New posts Search forums. Gallery New media New comments Search media. Members Current visitors New profile posts Search profile posts.

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Active Oldest Votes. From Wikipedia , The lumen symbol: lm is the SI derived unit of luminous flux, a measure of the power of light perceived by the human eye. I've looked around for a lumen-second rating of the ex II, but can't seem to find one. Improve this answer. Evan Krall Evan Krall And of course there's not much point in quoting on the minus side. Wouldn't a Watt-second be a joule?

Watts is joules per second. I think some of the higher-end units have ways to avoid this firing at the same intensity or not at all , and I'm fairly certain that some units at least do a better job of being uniform than others.

But why would a lumen, which apparently measures human visual perception, be appropriate for an electronic sensor? For a sensor with linear response and equal sensitivity across the visible spectrum, it seems we should be interested in actual light flux without any adjustment for our vision.

In fact, I think it's worth making a special note because I think he happens to be right on manufacturer-stated guide numbers. That is, although not everything he says is correct, not everything he says is wrong either.

May be the stuck-clock-twice-a-day effect, but still. Show 12 more comments. Marco Marco. But what if you don't have both lights available to do this e. Essentially, you're rejecting the use of standard units. I have both a EX and a Uni I'll test them against each other if you're interested but you need to tell me how to set up the EX zoom setting. The Uni is normally used with a modifier and the EX is used in varying ways, so it will be hard to compare in actual use.

Wow, I was under the impression the UniJr is true ws. Thanks for the offer to test these units, Nadine, but there's no need to do that. I have them both, but I am just too lazy to do it myself!