Camera Flashes

harish_haridas — Tue, 06 Aug 2013 10:22:34 GMT

Hi Guru's ...

need one suggestion....Does the battery maH power has anything to do with the flash response time ? battery with which mAH is suggested ? Also which is the best battery suggested for full time use for a 2hr function ?

Re: Camera Flashes

TCampbell — Tue, 06 Aug 2013 14:02:23 GMT

The milli-amp hours is the amount of power that the batter is able to store. Think of this like the gas tank on a car. One car might only have a 10 gallon tank. Another car might have a 15 gallon tank. 15 gallons means the car can store more "energy" (in the form of gas) -- but it doesn't necessarily mean that gas flows out any faster.

The same is true of the batteries.

My favorite batteries for my speedlites are Sanyo "Eneloop" rechargeable batteries. These are 1900 mAh batteries but the KEY thing about them is that they are "low self-discharge" batteries. All batteries will self-dischrage if they're sitting unused (just sitting on a shelf... they don't even need to be connected to anything). Some rechargeables will lose 20% of their power within the first 24 hours after being charged. Eneloops have a _very_ slow self-discharge rate... so slow, in fact, that when you buy them new at a store, you'll discover that they actually come charged (they do not require an initial charge like most rechargeables) and they'll be mostly full. This means that I can treat them like non-rechargeable batteries... if I let a flash sit unused for a few weeks I don't have to worry that I need to charge-up the batteries again before using it... it'll still be ready to go.

To make a flash recycle faster requires more overall amperage (amps are basically a measure of the flow-rate of energy... amp-hours is a measure of storage capacity regardless of the flow-rate). Canon makes an external battery pack for their 580EX II and 600EX-RT speedlites (not included... it's an optional accessory) called the "Compact Battery Pack CP-E4". It holds 8 AA batteries (whereas the flash internally only holds 4). You can put the system in a mode where it combines both internal and external batteries or a mode where it only draws from the external batteries). But having all these batteries significantly improves the flash recycle speed (as well as the number of flashes you can get.)

If you REALLY need fast recycle times, you can cluster speedlites. Watch this video if you want to see how this works: http://www.youtube.com/watch?v=KaALe0w992E

Note that he's using high-speed sync mode with these flashes because he has to freeze action using very fast shutter speeds. In high-speed sync, the flash has to pulse rapidly as the shutter gap sweeps across the sensor. The number of pulses required depends on how much faster the shutter speed is set above max flash-sync speed. If, for example, the shutter is set to 1/1000ths (5x the max flash sync speed of most bodies) then the flash has to pulse at least 5 times to get the exposure... meaning no single burst of light can spend more than 1/5th of the speedlites total capacity. By clustering the lights, each single light only has to release a tiny amount of stored capacity per pulse which means the cluster of them easily has enough power to handle shooting fast action via high-speed sync in full sunlight.

The point is... you can make these things fire as fast as you need them to fire -- I don't expect many of us are going to run out and buy six speedlites plus a commander, but it's nice to know HOW to get the system to do it so that IF you ever need to, the system can deliver the performance (but I think I'd probably rent the extra speedlites for the shoot.)

Re: Camera Flashes

Skirball — Tue, 06 Aug 2013 14:54:10 GMT

As a shorter answer, just get the Eneloops (the 2000 mAh version). Best battery ever.

The ultra-high capacity ones have more shots in them, but you probably wouldn’t be asking this question if you were a pro that is shooting 5-7 times a week (and thus, recharging every night). The Eneloops are Low Self Discharge (LSD – yes, that’s the acronym they chose), they can sit for a year and still have like 90% of their energy left. They’re great for weekend warriors who might have the batteries sit in their flash for a week or two without use. Totally worth slightly fewer pops. And the price is reasonable.

If you choose to go high capacity, my advise: don’t go cheap. There are no standards for battery claims and a lot of companies make claims that don’t hold true. Lots of tests out there of ‘high capacity’ batteries with lousy performance. Get PowerEx or Eneloop XX, or equiv.

Re: Camera Flashes

harish_haridas — Tue, 06 Aug 2013 15:27:44 GMT

Thank you for your suggestions 🙂 it is really helpful for an amateur like me..

Re: Camera Flashes

harish_haridas — Tue, 06 Aug 2013 15:28:02 GMT

Thanks for your suggestion...

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