OP - No, they don't need a special charger. AAs are small batts so a slow charge will be kinder to them than a fast charge i.e. they will run for longer and last longer.Most chargers will charge NiCd and NiMH batts and you will get the longest life from your batts if you get a decent charger/discharger.
It is possible to find lithium AA batteries which would seem the obvious choice in 2016 but they are not yet widely available in the way NiMH batts are. This may be a transport/postage/airline issue but certainly worth looking into as they should outperform NiMHs in every way.
Riddell - Panasonic cells are well regarded. Many batts for pro applications are made using them and so Eneloops are similarly well regarded. The best? That's hard to say. The 3 main elements of a battery are capacity, lifetime and shelf life. The first two ate linked by the proportions of chemicals in the cell, thus standard Eneloops advertise 4 times the operating life of Eneloop Pros but at the cost of reduced capacity. I don't consider shelf-life important as I would not go out on a shoot without having freshly charged batteries. So there are also excellent batts available from Duracell, Energiser etc. but whether the performance difference is worth the research, I doubt. On the basis that they will get lost, stepped on, inadvertently thrown away, I would get the highest capacity, shortest life.
Having said that, I've gone back to alkaline. Not very eco but at £20 for 100 with a shelf life of several years, they are definitely ever ready!
Can someone give me the technical details of why eneloops are so much better over other rechargables? What is it about them that is perceived to be so good? I hear several photographers saying they are the best, but no one can give me a real reason why.
You can leave Eneloops for 2-3 years and they still hold most of their charge. Standard NiMH batteries will typically lose their charge after a few weeks.
Obviously for a professional like yourself who will use the batteries regularly it's not an issue, but for many of us amateurs who can go weeks/months or even years without shooting it's comforting to know the batteries are always ready and are more chemically stable (as allowing natural discharge often damages batteries).
Eneloop pro, the black ones are high capacity batteries which once fully charged will keep 85% of that charge for a year. During wedding season we run about 26 AA at every event, eneloop are my favourite and I never need to swap a set out for drainage ( but could easily from flash gun to transceiver unit if I needed the extra kick) the real beauty of them is that when the full compliment are charged up and you're shooting both days of the weekend, you're reassured that each set will have avoided the drain factor of some other rechargeables.
lots of suppliers on Amazon - does anyone have a recommended supplier? The difference between Panasonic eneloops and Sanyo eneloops ? And what does 3rd generation 4th generation mean? Thanks
Sanyo were the original manufacturer of the Eneloop battery trademark. Since their introduction Sanyo have merged with Panasonic and obviously somewhere along the line the decision was made to brand them as Panasonic (since they are trademarked they will be the genuine thing although other other manufacturers have since brought out similar technologies but they cannot call them 'Eneloop' ).
As for the 3rd / 4th generation... the 4th generation ones are obviously a newer design (being a generation ahead of 3rd generation), simple really.
Obviously keeping the charge for years is of very little interest to myself, I'll probably get through 2 or 3 sets in a day sometimes.
What would be more of interest (and price doesn't really matter much) Is are there any better batteries for pro use?
I see industrial batteries which claim a higher Mh output, but what is it like when used in a flash that constantly needs to keep draining in a stop start fashion. Need a fast recycle rate for this reason.
Also how do they tail off? Slowly or just suddenly die?
And what would be the quickest chargers?
I'm not totally convienced that rechargables re the best option, but I'm spending a fortune on Duracell ultra, which I find are the best in a flash gun.
Keeping charge is of use, then when you charge a load up you can leave them ready to go and grab however many sets you'll use that day. Gives you time to charge them when you're not so busy and store.
If your needs are higher output and longer duration of use, you'd be better to consider an external battery pack rather than individual rechargeable. I can rely on a set of black eneloop for a whole wedding, though in winter might make a change during the evening for safety sake.
Eneloop are 2-3 seconds recycle before firing not much difference in the short term between the 200mah and 2500mah but with extended use the extra power does show up and they last longer, becoming a little faster than the 2000's as time passes. The difference isn't massive so you'll want to do a cost/benefit thing perhaps. Tail off is gradual as recycle time extends towards the point they give up. You might note eneloop rated at 1.2V, but they charge at 1.5 or above.
I dispute the results in this test in terms of recycle time, but it is useful comparatively. The chaps says seven seconds, I count three, sometimes less with white or black eneloop. From SLR Lounge https://www.youtube.com/watch?v=cueMf2tj4HY
For charging, I like these type, they are avaialble under various brand names https://www.youtube.com/watch?v=Vzxmd5LbQhg