Paul C. Buff, Inc. Technical Forum

Hi Paul

I'm very curious about your Zeus power packs, I really don't understand why they aren't more popular. They seem like great value compared to other brands but I don't hear many people using them or raving about them. I did see a test by Ellis Vener and it did appear that there was a larger shift compared to the other brands (http://forums.dpreview.com/forums/read. ... e=27720624) is this part of the reason?



How does the Zeus 1250WS pack with bi-tube stack up against a speedotron 2401sx?
seems like it should be better for sports strobing:

at 1250WS with a bi-tube, Zeus does 1/3000 T5 or 1/900 T1

but at 1200WS speedotron does t5 at 1/2000

am I getting this right that Zeus is actually faster in flash duration?

I'm curious why Zeus packs aren't more popular in arena lighting setups?

Probably the two biggest users of Zeus are sports photographers or those who actually need that much power in one head. For a portrait photographer, a Z1250 with two heads has several disadvantages over 2 E640/B1600/X1600's; size, weight, independent power ratios, cost, etc.

I dont know what the Speedotron specs are, but it is very possible Zeus is faster.

Thanks for the info! greatly appreciated

Hard to explain. Zeus provides more power per dollar of cubic or pound than anything on the market. It also has faster flash durations. I suppose the lack of popularity is partially because it has only two outlets and lees ratio setting capability than the more expensive packs.

I also chalk a lot of it up to the fact that that vast majority of digital camera users simply prefer monolights these days.

that is kind of what I thought

also probably the fact that people perceive all the other brands as superior

can't count the number of times i hear people saying profoto has super fast flash durations even when discussing their 600w monos and acute 2 packs

Di flash duration and color shift VS power setting are on a par with Elinchrom RX600, Bowens Gemini, AB1600 (640WS) and WL. Compact 300 and 600 are way slower and have the same color shift. Nothing touches Einstein (except speedlights) or even comes close at any price.

Sure, Einstein™ has had some growing pains and is constantly being upgraded free. Between Einstein™ and Cyber Commander™, this is one gigantic chunk of high tech technology development for a relatively small company, as is Vagabond Mini Lithium™ and PLM™.

Zeus is faster at Full power especially with Bi Tube head than anything I know of, including $10,000 packs,

Acute systems are extremely fast compared to the above mentioned. They only get fast when you switch capacitors out and operate at very low power. Look out for t.5 vs t.1, many manufacturers never mention t.1 . . . the real measure of effective duration. Profoto is the worst offender here . . . they're masters at specsmanship.

Actually I'm wondering about why lighting manufacturers list t1 and t5 settings. to me, it makes sense if they simply state the actual shutter settings (if i'm getting this right) that one would use to stop motion which is the t/5 setting. 1/516 does sound slower than 1/1336 (just as an example) but it gives a definitive measurement and capabilities of the flash in relation to the shutter.

Paul, do you know why that is?

I dont know why the t.5 spec is given. However, the t.1 time would more closely approximate an equivilent shutter speed. After the t.5 mark, you still have half of your energy left to dissipate, wich can easily cause blurring in action photos.

Fortunately, t.1 is easy to calculate from a t.5 specification on all lights that are not IGBT controlled. T.1 is typically 3 times longer than t.5. So a t.5 spec of 1/900 has a t.1 spec of 1/300.

At full power, even IGBT lights are the same way, because the IGBT's have not "kicked in". As you lower power, the tails are cut short. At some point t.1 and t.5 are virtually the same.

Absolutely. The t.5 spec is the long standing engineering term for stating power radiation, whether radio transmitter, reflectors, etc, and represents the traditional 1/2 power point. However, the t.5 1/2 power point means the the light level is only down 1f, and blur at -1f is quite visible.

In recent years, the less "hype oriented" light manufactures have concluded the the t.1 specification (the 10% power point) much more closely correlates to the effective motion stopping performance to conventional shutter speeds under continuous light. (the t.1 point correlates to the light level being down by 3.3f) I would actually argue for even a t.01 spec (-6.6f light level).

The reason some manufacturers stick with the t.5 point (Profoto being the worts offender) is that on non-IGBT lights, the t.1 point is typically 3 times as long as the t,5 point, and they don't want to make their products look bad by showing flash durations 3 times as long as they now do . . . bad for marketing. Profoto does not make IGBT units. Broncolor does (on their very high end packs), and has been the leader in converting the industry to using the t.1 standard.