Studio Light Output Comparison

Good Morning all.

I thought that maybe I can begin a thread on comparing light outputs

from various systems (I have been inspired by Garry Edwards' last

contribution). I was thinking that we can all test the systems that

we use and post our results/comments on F/stop output at

10 feet/ISO 100 using a barebulb or standard reflector at full power

as our standard.

 

For example: I use White Lightning X3200s.

My results were as follows: @ 10 ft/ISO 100 using a Minolta

Autometer IVF.

 

Barebulb: F/16.9, Standard Reflector: F/32.2, 11"Reflector: F/45.2

 

This is in no way to look down on any particular system. There are

many other factors that are important when purchasing a lighting

system such as portability, flexibility, accessories...

 

Of course, I know that the environment in the room may also be a

factor. Such as light from outside sources, natural light, the color

of the walls perhaps. But I thought we could use a very basic

standard just using distance and ISO.

 

I thought that this could be an interesting theme that could be

helpful for those looking to invest in a system.

 

I welcome your comments...

 

Best Regards to you all.

This is a good idea, he closest comprehensive series of tests I've seen were done several

years ago by Chimera in their studio. I have also done a limited amount of testing with a

few units (see below).

 

But to be accurate all different systems would need to tested in the same space, in the

exact same circumstances, with relatively new flashtubes in all heads and with the same

meter set to the same ISO and shutter-speed. In other words as many variables as possible

need to be eliminated or negated and if you are testing in a small room room, size of

room, height of ceiling, color of walls, ceiling and floor will skew the results sometimes

significantly.

 

I did a limited version of this with the gear I had access to a couple of years ago, I tested A

Norman P2000X pack with a standard Norman head; the same pack with a Speedotron

102A head (connected using a custom built conversion cable); An Elinchrom EL1000

monolight; a Balcar A2400 pack with a standard Balcar U head; and the same Balcar A2400

pack with a cable modified Elinchrom head.

 

here was my testing procedure; A Minolta Flash Meter IV set to 1/60th and ISO 100

mounted on a stand 6 feet away from the flashtube, or in the case of using an Umbrella (a

Photek Goodlighter II) & Softbox (same softbox for all: a Plume Wafer 100). from the light

emitting surface. I tested the following configurations: baretube, standard 7" reflector, 10

inch "normal" reflector, baretube pointing away from the meter position, softbox, and

umbrella. For the umbrella I defined this as the outer edge of the umbrella and for the

softbox, the diffusion screen. Matching up reflectors as every manufacturer makes slightly

different variations. Since the Balcar pack has a maximum capacity of 2400 watt-seconds

and the Norman pack 2000 watt-seconds Power settings on the Balcar was adjusted as

closely as possibly to match 2000 watt-seconds. I took either 5 or 10 readings for each

head /modifier combination. The tests were done at night and the flash tubes &

electronics were warmed up by firing several times before being tested. The Flash meter

IV was used as an incident meter with the dome pointing directly at the light source and

was set to cordless mode. The stands were heavily sandbagged to keep distances fixed. A

Pocketwizard Max set was used to trigger the lights. The flashes were given plenty of time

to recharge and "settle down" between measurements: My recollection as I write this is

that this was either 20 or 30 seconds.

 

Without recounting actually f-stops, in all circumstances the Norman + Norman

combination was consistently around (within +/- 3/10ths of a stop) a stop less efficient

than all other pack + head combinations. The Elinchrom EL1000 monolight was roughly

equal to the Norman + Norman combination.

 

Other factors do need to be considered when doing up a comparison between different

brands: native color temperature (and the difference between anti-UV coated and non

-coated flash tubes or flashtube covers, flash duration at different setting, maximum

modeling light strength. power setting/output range, and true light fall off from the center

using different reflectors or with heads like the Balcar zoom, all Profoto and the

Speedotron 202 heads, with the reflectors "zoomed" to different positions.

 

I will be willing to help do these tests again with different units, if you we can coordinate

everybodies schedules and you live in the Tampa Bay area.

Both Alien Bees and White Lightning post similar information on their website. If you overlook the initial specs about watt/seconds and effective watt/seconds and click on the link that says "full specs", you get good information about measured f/stop and distance with different reflectors and modifiers. They post their testing methodology, so I'd believe that the figures are pretty accurate.

 

In fact, they quote an f/stop of f/32 2/10 for the standard 7" reflector on the X3200 at 10 feet - exactly what you showed!

 

Hope this helps!

 

Sheldon

I just checked my Calumet Travelties (750 WS) at 10 ft, with 6" reflector....f22, and it gave the same reading with bare bulb at that distance. I'm using a Gossen Luna-Pro F as my meter.

Photogenic PL2500:

 

Bare bulb: f16.5

w/standard 8" reflector: f45.1

 

Seconic L508 meter

ISO 100

Here's a couple of quick measurements from a Profoto Acute2 2400 pack and single head, with head in A socket and set to full power.

 

Flash meter and distance: Sekonic L-558 set at ISO 100, shutter speed 1/250th second sync speed and using dome "up" in incident mode at 10 feet from front of flash tube cover.

 

Barebulb -> f16.8

Zoom Reflector at 10 setting -> f16.9

Zoom Reflector at 4 setting -> f32.3

Zoom Reflector at 7 setting -> f22.0

 

-------------------------------------------------------------

 

Next are measurements with softbox with internal baffle in place.

 

Softbox used Photoflex Q39 White (i.e. not silver) 36"x48" with internal baffle/diffusor in place.

 

Flash Meters and distance: Sekonic L-508 and Minolta Flash Meter V both set to ISO 100, 1/250th sec sync speed with dome up on Sekonic and using incident mode on both meters. Meter incident dome placed in center of beam (if you can call using softbox a beam) at 5 feet from the front of the flash tube cover, not the front of the softbox, don't ask why, I can't remember. I think to match the Chimera results so many years ago. If I remember correctly, this is how they measured the light with various heads also. Or ... it could have been the published results Calumet used to have in their paper catalogs years ago. I can't remember, but it did it this way for some reason to match some published readings from somewhere else.

 

Anyhow, now for the results:

 

Single head set to full power on pack. Head in socket A on pack.

 

Full power (i.e. 2400ws/joules on pack) on single head (baretube) in softbox results in f45 on both meters.

 

I have other readings at lower settings if anyone is interested with the Acute2 flash head and pack set at different settings with the same softbox and same criteria.

 

BR

Juice

Barebulb -> f16.8

 

 

Zoom Reflector at 10 setting -> f16.9

 

 

Zoom Reflector at 4 setting -> f32.3

 

 

Zoom Reflector at 7 setting -> f22.0

I would sure like to see a comparison of speedotron pack and head and a Dynalite pack and head system, just because these are the two that I am looking at purchasing in the next few months.

Bernard,<br>An interesting idea!<br>Here are a few of my figures, this is not by any means a scientific test, but here goes....<p>

 

 

Elinchrom 1500 HS generator = f22.2<br>

 

Elinchrom 2400 Generator = f32.4<br>

 

Elinchrom 1200 Mono = f22.4<br>

 

Elinchrom 6000 Generator = f64.2<br>

 

Stobex 2400 Generator (824 Location Pack) = f22.1<br>

 

Stobex 5000 Generator (City 5000 Pack) = f45.6<br>

 

Bowens Estime 3000 Generator = f22.8<br>

 

Courtenay 400 Mono = f11.5<br>

 

Courtenay 800 Mono = f11.9<p>

 

Each head was tested bare, i.e. with no reflector, but the objectivity goes to pot a bit because all units except for the Strobex have a small built-in reflector which pushes some light forward. The Strobex are totally bare bulb, so some light goes behind.<br>The Strobex <i>seem</i> to be much brighter than they actually measure, probably because they are very high voltage with physically large tubes and a long flash duration.<br>As a matter of interest, I also tested the Elinchrom 1200 Mono fitted with a Chimera medium softbox. It read f16.7, which was higher than I expected at this distance.

Thank you all so far for your time and inputs. I am super honored that both Ellis and Garry considered it a good idea, WOW Thanks!

Garry, you have a lot of fire power there! I have never really heard of Strobex, must be UK. It would be nice to get some readings from Speedotron users and Dynalite too.

 

Keep them coming! Best Regards to all.

This is a really cool idea and my compliments to all you contributors as I have been thinking about a home studio setup in the future. Just bought a couple of 285's to experiment with (the price was right) multiple flash in my living room. My question is in regard to the AB's spec...what does the 2/10 mean? Thanks!

2/10 means 2 tenths of a stop. Like dividing an F stop into 10.

 

For example: if you get a reading such as F/22 or lets express it this way F/22.00. As you increase power you get F/22.1, 22.2, 22.3, and so on to F/22.9 until you get to F/32.

 

I hope this helps.

Bernard, Thanks for the info. That was just too simple. So the spec AB is publishing is f 32.2 at 10 feet. I thought it was a separate number that meant something. Duh.