The Metz 45CT has a GN of 45 meters; the 54MZ has a GN of 54 meters. But the 54MZ (and 58AF1) have deceptive GN just like ever other zoom head flash unit!!! If you put the 54MZ at the same 35mm coverage angle as the 45CT, the 45CT still has a GN of 45 but the 54MZ has a LESS powerful GN!!!
All zoom head flash manufacturers overblow the 'power' simply by quoting what it does when zoomed to 105mm coverage angle! Deceptive BS
I've noticed that German flash guns manufacturers quoted guide numbers tend to be more accurate than others because they have to conform to D.I.N. standards.
Rechargeable batteries need to be fully charged and fully discharged regularly if they are constantly topped up they loose capacity until eventually they will hardly accept a charge at all. I don't use flash all that often and find that ordinary AA cells are fine, because rechargeable s if they aren't used often loose their charge.
I use rechargeable NiMH AA batteries of the "new generation". Their selfdischarge is very low (the capacity is still around 80% after six months), and they don't have to be fully discharged before charging them. I use GP ReCyko 2100, but there are others too like Varta Ready2Use ans Sanyo Eneloop.
[QUOTE=frotog;980450](I like to utilize the 1/4-20 receivers on the bottom of the power supply to maffer clamp the heavy batteries to the legs of a c-stand) they can be extremely versatile for location work.... If you plan to use them this way it's best to power with a 220 Ah 6 volt golfcart battery (thanks to Mike Wilde for this tip!) as the factory power supply is a measly 4.5 Ah.
I don't go quite the 220Ah, but it would work.
My CT2 pack is now modified to allow the internal battery to still be used ( mine is a $30 5Ah replacement UPS gel cell battery, that fits by shaving some spacers off of the bottom of the battery compertment, and folding its terminal tabs back to match the dryfit pad locations)
I have removed the second power cord socket (It went to rehab the power socket on the handle, that had become unreliable due to arcing), and filled the spare socket with a pair of recessed male quick disconnects that parrallel the internal battery.
There is an external 6V power cord that can be plugged into these male panel mount connectors. The female connectors are fully insulated and polarity marked. The other end has two sets of push on spade terminals that can link to external gels cells; I am presently using 2x 5Ah gell cells for shoots where the internal battery may start to recycle slow.
With external battery cords, and paralleling batteries in general, make sure that you observe polarity, and make the spade leads up of different lengths so that short circuits are a much less a likely accident. These batteries are powrerful and should be treated with some respect.
Moving the battery and the charging circuitry to the separate power pack results in a large but light flash head. The relatively heavy power pack hangs easily either on a shoulder, or from a light stand, where it adds stability.
Weight wise, and from my old Metz catalog, the 60CT4 without the battery pack weighs 22.9 ounces whereas the CL4 weighs 24 ounces without batteries. It's only carrying the pack that adds the weight and from what I hear there is a belt clip available. Now I'm not a big fan of Nicads. If you don't run them out on a shoot your screwed. I have a drawer full that are bad so I'm thinking that a power pack is the way to go even with the 45CL4, and although double A's are fine, being available anywhere, their expensive in the long run if shooting professionally. Really tho, the most important thing to me is manual control. There's no real number in the catalog about this, but from what I have read and if I remember right the 60CT4 can go to 1/128 or 1/256. I don't know about the CL4? Maybe someone can clue me in.
The dry lead acid battery used in the Metz 60 series doesn't lose much power when not in use. You should charge it as soon as you've done using it. Lead acid battery doesn't like to be in the discharge state for a long time.
Just to toss something into the pot, I recently acquired a well-used 45 CT-1 and was surprised to discover in testing with a flash meter that it didn't seem to throw out any more light than my Canon 199a or Sunpak 422d. I'm not sure why that is (use of alkaline batteries?), or how likely it is, but it's something to look out for I suppose.