How much power is enough power?

How much power is enough power?

 

As I put a studio lighting system together, I think my greed for

power is taking over:)

 

I currently have aquired four power packs. Two are Speedotron,

Browline D1204's, GN 455 (ea) and a pair of Speedotron, Brownline

D402's, GN 270 (ea). The D1204's will be hooked up to 1200ws M-11's

shooting into 60" Lastolite umbrella boxes or large Photoflex

multidome's with grids. Hooked up to the D402's will be either 400ws

MW3R's or MW3U's, also shooting into halfdomes, reflectors with 4-way

barndoors or umbrella boxes for rim, hair and/or seperation. Later I

might add a second pair of D402's and an additional pair of

Speedotron Force 10's with a GN of 540 (ea) to finish the lighting

set up.

 

I realize that seems outwardly to be a lot of total guide number but

when shooting large groups of over a hundred people (I don't want to

use the 550EX), I get the sneeky feeling that smooth even

professional lighting for large groups of a hundred to two hundred

people will demand this much energy, or more. I'm taking into

account distance to the middle of the group, twenty to twenty-five

feet, curvature from the camera position (arch) to the ends of the

rows of the grouping and light absorption of clothing, skin

characteristics as well as considering for neighboring woodwork and

cloth wall/sound hangings.

 

I'm figuring an f/stop in the f/16 - f/22 range, ISO of 100.

 

Based upon my above information; my question, not having any

experience with large group settings is; How much power does one

realistically need to get "decent" or "smooth", no harsh shadow,

professional lighting?

 

Thanks in advance.

Thomas,

 

How much flash power you might needs really depends entirely on the kind of shot you are doing and the light modifyers you are using. I've found myself using 2-4800ws Black Line packs with one head each in softboxes, shooting 4x5 film of a close table-top with considerable bellows extension having to do multiple pops of the flashes to get f 45. So it depends.

 

Most manufactures spec their guide numbers using their most efficient reflectors at 100 ISO and at a distance of 10 ft. If your D1204s have a guide number of 455 using 11" reflectors, at 100 ISO, that's f 45 at 10 ft. Move those lights back to 16 ft from the subject and you're at f 32. A greater distance of 22 ft and you're at f 22. 32 ft. from the subjects will yield f 16.

 

Put an umbrella on the heads and lose 1-2 stops, a large softbox will lose even more light. You could end up shooting at f8-11 depending on these variables.

 

So I'd say you are close to being underpowered if you have to shoot at these distances with umbrellas or softboxes.

 

Remember also with Speedotron Brown Line Flashes that their ready light comes on when the power pack is not quite at 100%. You have to wait a couple of seconds after the ready lights or your ecposures will not be consistent.

I have done large groups wherein there were 8 rows of kids, about 80 people in the

picture. And I would like to tell you that you need to elevate these people into elevated

rows if possible. Then, I would strongly advise you to use a minimum of a 6x7, and better

a 6x9 camera such as a Mamiya Super 23 with the 100mm f3.5 lens. This camera gives

sharp results and you can pick them up for about $300 on the auctions.

 

Why:

 

You need to tilt the front lens alittle bit. This will tilt the focus plane to be about the same

as your group if they are in elevated rows. You won't need any f16 or f22 to do the job,

either after you do this. You could do very well with a f11.

 

The nice thing about 6x9 is that you can get much cheaper prints. This is compared to a

4x5 film. 6x9 will crop down to 6x8 which is ideal for you.

 

If you were to rent, you might look at the Fuji 6x8 camera that has a tilting lens. It is a

huge camera.

 

I doubt seriously you will be at 25 feet here. If you were to use a wide angle lens, you

would have to be aware of lens focus plane curvature. This is not a variable I like. So, I

would be using a moderate wide angle like a 75mm on a 6x9 Mamiya Super 23 to do the

job. This is a very sharp lens, and I own it.

 

I don't know the true appearance of your group set-up. So, I am giving generic advice for

a stadium type set-up. If they are at tables, OH, MY God. I think you will be needing a

Banquet camera.

 

You should not attempt fancy "modeling" here. Just spread your lights equidistant from

one another, alittle high to the group. Place darker skinned folks in the front. Place taller

on the sides and in the rear rows.

 

Listen, I had only 100 watt seconds as fill for an outdoor shot in sun of these 80 kids. I

probably used a f5.6 for these 80 kids who were in swim suits. The fill came out perfect,

and every kid was sharp! So, if I could do it with f5.6, and a tilt focus plane set-up, you

may be able to, too.

 

Unless you want to use ASA 400 film, I would not use umbrellas.

 

If you can't tilt the focus plane of your camera, then take this picture from a ladder with

the camera about 8' or more above the people. This will slightly, slightly tilt the plane of

your focus to get alittle more depth of field. This trick is never as good as just a camera

that will pivot the lens though.

 

You could buy the camera used with a 100mm f3.5 lens (black painted lens, best), then

re-sell it to someone else later. The 75mm lens does not pivot, onlyl the 100mm lens

does this function. If you really need wide angle, you need something like a Linhof or a

4x5. If you go 4x5, which is a good idea, you need a new set of lens recommendations.

 

Get yourself a tall tripod, too.

 

To know how much power you need, I need to know how these people will be arranged.

Brooks wrote<p>

 

<i>Most manufactures spec their guide numbers using their most efficient reflectors at 100 ISO and at a distance of 10 ft. If your D1204s have a guide number of 455 using 11" reflectors, at 100 ISO, that's f 45 at 10 ft. Move those lights back to 16 ft from the subject and you're at f 32. A greater distance of 22 ft and you're at f 22. 32 ft. from the subjects will yield f 16.<p>

 

Put an umbrella on the heads and lose 1-2 stops, a large softbox will lose even more light. You could end up shooting at f8-11 depending on these variables. </i><p>

 

I would expect to be using both D1204's at the same time. If I need more light, I was going to purchase and add Force 10's into the lighting mix. I figured a pair of D1204's would be quite a bit of light. The 60" Lastolite umbrella boxes are suppose to only suck up about a stop of light.<p>

 

<i>So I'd say you are close to being underpowered if you have to shoot at these distances with umbrellas or softboxes.</i><p>

 

How much, in guide numbers, do you think that I'd need in addition to the pair of D1204's. I would be using the pair of D402's for rim and seperation, so they'd be out of consideration as main lighting. Would a third D1204 and umbrella box be sufficient? The Force 10's have a GN of 540, equal to a pair of D402's @ GN 270 (ea). Would I be better off with four 60" umbrella boxes set on an arc?<p>

Thomas,

 

It's really hard for me to tell exactly how much light you might need without being there. If you have 2 1200s now, adding one more is only adding 1/2 stop more light. It's a geometric progression. Starting with 2 packs... to get one more stop you need 4, another stop and you need 8 and so on.

 

I'd suggest that you go to the location where you'll be doing this shoot and place your camera and strobes at the distance that you think you might need to get the entire group in the shot. Then place your light meter where the people will be and fire your strobes. try it with reflectors on the heads and then umbrellas or softboxes, whatever you plan on using. Then you'll know exactly what's up with your power requirements.

 

Personally I'd take 2-4800ws packs and 2 medium softboxes, one for each pack.

 

If you're shooting a smaller format like 35mm or even 6x7cm and certainly if you're shooting digital, and you're 25 ft. away from the group of people, you may not need that tight an f-stop.

 

Best thing to do is test at the actual location.

Timber wrote<p>

 

<i>You need to tilt the front lens alittle bit. This will tilt the focus plane to be about the same as your group if they are in elevated rows. You won't need any f16 or f22 to do the job, either after you do this. You could do very well with a f11.</i><p>

 

I'd be using digital. I can see about picking up one of Canon's TS lenses.<p>

 

<i>I doubt seriously you will be at 25 feet here. If you were to use a wide angle lens, you would have to be aware of lens focus plane curvature. This is not a variable I like. So, I would be using a moderate wide angle like a 75mm on a 6x9 Mamiya Super 23 to do the job. This is a very sharp lens, and I own it.</i><p>

 

I won't know the true nature of the situation venue as I'm posing a hypothetical scenerio. I'm putting the flash system together as I write and have come up against not knowing how much power I might need for the situation I listed.<p>

 

Current lense selection for this situation would be either a 16-35, 20mm or 28-70. Later, as I posted earlier above, I'll add a tilt-shift lense if need be. Either of the listed lenses will probably be going on the yet to be announced, 1Ds replacement:)<p>

 

<i>I don't know the true appearance of your group set-up. So, I am giving generic advice for a stadium type set-up. If they are at tables, OH, MY God. I think you will be needing a Banquet camera.</i><p>

 

I'm figuring bleacher style standing position.<p>

 

<i>You should not attempt fancy "modeling" here. Just spread your lights equidistant from one another, alittle high to the group. Place darker skinned folks in the front. Place taller on the sides and in the rear rows.</i><p>

 

Will keep that in mind.<p>

 

<i>Unless you want to use ASA 400 film, I would not use umbrellas.</i><p>

 

I'll be using digital and the 1Ds can easily do ISO 400 but would be expecting to be shooting at ISO 100 or 200.<p>

 

<i>If you can't tilt the focus plane of your camera, then take this picture from a ladder with the camera about 8' or more above the people. This will slightly, slightly tilt the plane of your focus to get alittle more depth of field. This trick is never as good as just a camera that will pivot the lens though.</i><p>

 

My plan was to set the camera on the middle/middle of the group, use enough light for a big f/stop of about f/11 or f/16, depending on what the sensor defraction limits out at.<p>

 

<i>Get yourself a tall tripod, too.</i><p>

 

Already go that one covered:) Picked up a Bogen/Manfrotto 3258:) The sucker is huge. Not going to Sedona with this puppy:)<p>

 

<a href="http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=getItemDetail&Q=&sku=5551&is=REG&si=spec#goto_itemInfo">Bogen/Manfrotto 3258 tripod specs. B&H Photo web site</a><p>

 

<i>To know how much power you need, I need to know how these people will be arranged.</i><p>

 

I can only give a generic church like scenario and describe what I currently have, what my plans are to purchase next and hope your experience will be able to tell if the amount of power listed is sufficent Vs the power an experienced one might feel they'd need to bring to the party to get the job done right and list the short commings of what I listed. This way I'll know how much to budget for future powerpack/monolight purchases.<p>

 

I just dropped a small bundle on a PocketWizard Max, another pair of receivers, an additional trio of lights stands, 9' boom arm and some other doo dah:)<p>

 

I'm having to do this in little bitty financial steps:) Order some gear, pay the gear off. Order some gear, pay the gear off. Kinda like a tide cycle:)<p>

 

I haven't shot with lights since 1978 and decided to jump off the cliff of sanity on this one and I'm putting together, sort of sight unused, the system that I couldn't get back then:)<p>

 

Thanks to both you and Brooks for your answers.<p>

I think you need to do some testing to see if your camera can capture enough detail so that every person in a large group will be recognizable.

 

Norman McGrath once had to photograph the New York Philharmonic with the requirement that every person be recognizable. He used an 8x10.

Steve wrote<p>

 

<i>I think you need to do some testing to see if your camera can capture enough detail so that every person in a large group will be recognizable.<p>

 

Norman McGrath once had to photograph the New York Philharmonic with the requirement that every person be recognizable. He used an 8x10.</i><p>

 

We're both safe. I doubt the NY Philharmonic will be speaking to me let alone asking me to capture an image of their combined orchestra:)<p>

 

The above being said, I'm strickly focusing on power requirements and power requirements alone and the question of how much power is needed.<p>

 

Doing the math, based upon Speedotron spec sheets, a 4803CX has a GN of 1000. A pair of Force 10's has an equivalent GN of plus 1000. A pair of D1204's has a combined GN of 910. Four D402's has a combined GN of plus 1000. If one were to use a pair of Speedotron 4803CX's, then all numbers would, of course, be doubled.<p>

 

To me GN is the most reliable indicator as the efficiency of any unit is then automatically taken into consideration.<p>

 

If you had a thirty foot front row face, with twenty people on the front row. And you had ten rows, a foot and a half per row or fifteen foot deep and the camera was thirty feet from the front row, you'd have rounded ® 38' distance to center or a r 34' to the end of the people arc from camera position. At thirty-eight feet, light absorption, not taken into account, I'd have one half stop variation between the front row and the back row. If you included a half stop for light absorption, there'd be about a half stop variation from center to front and center to back or a total one stop variation from front to back.<p>

 

To get even lighting I would set on an arc, three lights, not counting rims and seperation lighting, midway up the climb (center row height). For a f/10, I'd need three lights equal to GN 380. For a f/stop of f/11, I'd need 1/3 stop more light or three lights equivalent to GN r 500 equal to the GN light output of three Force 10's at full power. So carrying that to a more desirable f/16, all numbers have to be doubled to R GN of 1000.<p>

 

The way I read my math, I'd need three Speedotron 4803CX power packs with SP206VF heads attached and I'd need to bring in some seven foot Lastolite umbrella boxes to smooth the lighting out, at best; realizing that I'm twenty to thirty feet outside ideal numbers of one to one and a half times the diagonal of the softbox.<p>

 

<a href="http://www.lastolite.com/umbrella.html">Lastolite umbrella box</a><p>

 

Do I need to put four smaller fills in-between the three mains; the ends and between the mains?<p>

 

As to recognizable faces, I'd be expecting to capture the images with either a next generation 1Ds, the yet to be announced Canon 1Ds MkII or a currently announce but unreleased Kodak DCS Pro Slr/c; 16 megapixels.<p>

 

<a href="http://www.dpreview.com/news/0403/04031802kodakslrc.asp#press">DPReview, Kodak press release</a><p>

 

Based upon what I've read, this should be sufficent megapixels to get recognizable faces in group shots of a hundred and fifty to two hundred people. Tests will show otherwise as I'm currently focusing my consideration on power requirements for lighting purposes.<p>

 

How off am I in my lighting thoughts, or am I on the money in my thinking? For me, that's a lot of light and a lot of money to budget for a lighting scenario.:)<p>

 

Thanks for taking the time to look over the math.<p>

I'm sorry, it seems that it get worse not better as I realized that I left off a stop of light for the umbrealla boxes.

 

Oops!

 

So that would knock me back to f/11 and the need for a tilt-shift lense to improve DOF.

 

My! This exercise is getting expensive:)!

A friend of mine was involved with converting the strobes off a B-52 for studio work. They were working with a line voltage problem and were blinded everytime they set the strobes off so they put them in a card board box. They set the box on fire after about two flashes.

 

I also say a documentary on Edgerton where he held a sheet of newspaper about 2' from a strobe and fired it, and the newspaper burst into flames.

 

So if you can't set things of fire, you're not there yet.

I was joking with my wife that I was needing enough power to set city hall on fire and with enough reserve to get all the storage buildings.

 

From what you just commented on, it seems my joking wasn't far from the truth.

 

aaaaaaaaaaaaaaaaaaaaahahahahahahaHAHAHAHAHAHAHAHA!!!!!!!!!!!!!!

 

Oh my! :)

You need enough power to get the f-stop you want.

 

If your present kit gives you f11 and you want f16, you have to double it. If you want f22, multiply times 4.

Unless you are going to use the kind of power and number of

heads/modifiers that you're talking about on a regular basis, it

makes no sense to purchase that much gear. Buy only what you

need to reliably cover your needs most of the time, and rent (or

borrow) what you need on the relatively rare occasions that's not

enough. There's a huge difference between planning to shoot

groups of 100+ people every week and actually booking those

jobs.

A Canon digital camera may have a "shift lens", yes, but "tilt"? I don't like the small

format. I think you should cut these people up in smaller groups, then paste it together in

Photoshop. Then you could do more modeling of light and you would get better

resolution of their faces. 10 rows is very, very deep. I am worried that at 25 feet, you will

have tiny faces in the rear compared to the front row faces. Therefore, you should, for

quality purposes use a slight telephoto, as difficult as that sounds. I think you should re-

design the rows and make them perhaps 4-5 deep only, then paste the picture together.

 

I think you should be using a 4x5 or better for this; and as Steve says, an 8x10 is

comfortable. I would give up on the umbrella useage, use distance to even out the light.

You'll never be able to assemble enough umbrellas to make a partial light tent; so use

'distance' , and the rule of inverse squares to reduce light fall-off.

 

In large groups I have seen, such as a picture of about 60 cooks in an academy here, the

photographer was very high in relation to the group. This evens out the issue of nearer

faces to farther faces. You need height. Then, when you solve the problem of height,

maybe being 15-18' high, you can more easily accept pasting them together as everyone's

face will be similar in size.

 

Are for using Guide Numbers, remember that Speedotron has varible focus heads and

their best numbers may be a result of using the variable focus head to "zoom" setting.

Then, there is the factor of a need for 1/2 f stop for overexposure just to pick up detail in

the dark suits. Then you have the front to rear difference in exposure of about 2/3 to 1- f

stop for such a deep row'd group. At 10 rows deep, this could be 15 feet right there!

 

While you are worrying about light power, I don't like all the other specifications. I think

with one 4800ws unit, 2 heads and umbrellas, you can have a f8 at 25' ASA 100, no

problem. But I don't like 25', I don't like the 35mm digital camera, I don't like a lack of a

tilt lens, I don't like a mere 8' tripod.

 

I would like to see your lights back to 40' or 50', no umbrellas. I would like to see a

minimum of a 4x5 and you using at least 9,000ws of power.

If the room has a white ceiling, I would try at least one shot bouncing from the ceiliing to

more evenly light this group. Of course, you need a fill, but you would add this. If the

ceiling is dirty white, you have a problem for more power.

 

If I had such a white ceiling, I would use Speedotron's 16" "sports reflector" to telescope a

bright spot on the ceiling. By the time this light gets to the ceiling, it will likely be 3-4

feet wide and therefore act like an umbrella up there. If the ceiling is 16' or more high, I

know this would be effective. And maybe you could stick some white plastic from TAP

plastics (about $5) to the ceiling to give you a white spot to aim at. I was just over there

this morning and I handled some. You could also suspend some strings from each wall to

carry a large piece of plastic to bounce from. This would create a false "ceiling" to bounce

from. They have these in our symphonic hall to bounce sound around. The plastic is light

weight, and string is light weight. All you need are some stands to push it up there.

 

 

If the ceiling is 8', this will not work for such deep rows.

Speedotron's GN reference uses a 35-90 degree coverage rating. Therefore, you need to

re-consider these figures. Go to www.speedotron.com

Mike wrote<p>

 

<i>Unless you are going to use the kind of power and number of heads/modifiers that you're talking about on a regular basis, it makes no sense to purchase that much gear. Buy only what you need to reliably cover your needs most of the time, and rent (or borrow) what you need on the relatively rare occasions that's not enough. There's a huge difference between planning to shoot groups of 100+ people every week and actually booking those jobs.</i><p>

 

Good advice but I'm not being rational on this one Mike:) I'm going to put the foundation of a decent lighting system together and then park the whole thing on a shelf in the garage:) Seriously! I might not pick up the larger umbrella boxes and will stop with the 60" models. But I expect to complete the set up this winter.<p>

 

I'm just not too sure how much power, I should put on the shelf. Do I add a pair of Force 10's or a pair of 2405CX pwr paks with 202VF heads from e-Bay?<p>

 

The rational is there, it's just not a rational many would understand or agree with. The wife understands and is good to go with this idea that's being put together. Think of "Noah's Ark" and you'll have a pretty good idea of what I'm up to:)<p>

Timber wrote<p>

 

<i>I think you should be using a 4x5 or better for this; and as Steve says, an 8x10 is comfortable. I would give up on the umbrella useage, use distance to even out the light. You'll never be able to assemble enough umbrellas to make a partial light tent; so use 'distance' , and the rule of inverse squares to reduce light fall-off.</i><p>

 

I'll give the LF cameras a consideration, after I've had time to read tests on the 16mp sensor bodies that have just come out or will be announced in the next few months.<p>

 

As you alluded too with the distance problem with umbrella boxes, I have to agree with you that I'm too am in serious doubt that it would work but am willing to try and see in test situations.<p>

 

<i>In large groups I have seen, such as a picture of about 60 cooks in an academy here, the photographer was very high in relation to the group. This evens out the issue of nearer faces to farther faces. You need height. Then, when you solve the problem of height, maybe being 15-18' high, you can more easily accept pasting them together as everyone's face will be similar in size.</i><p>

 

I'll keep your above in mind as a helpful solution to the problem of near/far faces.<p>

 

<i>Are for using Guide Numbers, remember that Speedotron has varible focus heads and their best numbers may be a result of using the variable focus head to "zoom" setting. Then, there is the factor of a need for 1/2 f stop for overexposure just to pick up detail in the dark suits. Then you have the front to rear difference in exposure of about 2/3 to 1- f stop for such a deep row'd group. At 10 rows deep, this could be 15 feet right there!</i><p>

 

You above pretty much mirrors what I wrote in a more math specific post, a few posts above this post of yours. I was seeing a +/- 1/2 stop for a total of a 1 stop difference. I also, as you suggested have decided that ISO 100 may not be fiscally obtainable and will have to shoot at ISO 400 but this will give me the f/16 that I'm wanting. The smoothness of ISO 800 is very surprising in the currently being released models by Canon.<p>

 

<i>While you are worrying about light power, I don't like all the other specifications. I think with one 4800ws unit, 2 heads and umbrellas, you can have a f8 at 25' ASA 100, no problem.</i><p>

 

Working with your above and adjusting my thinking according to what you and others have posted here, I'll expect to use an ISO of 400. Things are coming into focus as to my needs. Each main head will need to have a GN of about 500 and that all seems to be easily do able. With the addition of either a pair of 2405CX's and 202VF heads or Force 10's for mains, with three D1204's w/M11 heads for fills and a pair of D402's on (2 ea) MW3U's/MW3R's for rims and seperation lights, I'll be pretty much good to go.<p>

 

What's not to like? :)<p>

 

<i>But I don't like 25', I don't like the 35mm digital camera, I don't like a lack of a tilt lens, I don't like a mere 8' tripod.</i><p>

 

Oh! Well! What else is there not to like? :)<p>

 

<i>I would like to see your lights back to 40' or 50', no umbrellas. I would like to see a minimum of a 4x5 and you using at least 9,000ws of power.</i><p>

 

Oh!<p>

 

Well the good news is, I have a wonderful 12' folding ladder I'm use to standing on. Based on a previous post, I'd expect to have the lights and sensor body back at about about 38'-40' from center row and will expectedly be using for mains and fills about a total of 8400ws for the two mains and three fills to the sides of each main if I use a pair of 2405CX's. Now I just need to budget for the large sports reflectors you suggested in a post after this one that I'm responding to.<p>

A lot will depend on the reflectors you use on the Speedotrons. But Having lit the

Houston Symphony orchestra a few years ago with high intensity "long throw"

reflectors and using 6,000 watt-seconds of Speedotron and Elinchrom equipment,

and struggling with getting good depth of field at f/8 + 1/2, no I don't think you have

enough power. Light s to center of stage distance was about 50' to 60'. Wat those

distances there was virtually no fall off from the front edge ofthe stage to the back

riser. the long throw reflectors let me tune the light across the group for evenenss. I

was using ISo 100 film and shooting with a Pentax 6x7 (loaded with B&W)and a

6x9cm back (loaded with color on a 4x5 camera. Both cameras were fitted with 90mm

lenses. The largest size the final image was printed at about 20" x 30" and that was

really pushing the resolution of the image. I would have been much happier at f/16

bu that wouls have required about 24,000 watt-seconds (If these had been Norman

packs I would have needed about 48,000 watt-seconds to get f/16)

 

Using anything less than the Canon EOS 1Ds or the Kodak Pro SLR/n or SLR/n

cameras will work against you -- you just won't have enough resolution to see

everyone clearly. And you don't need view camera movements -- in fact using tilt may

even work against you in this situation.

<i> I'm not being rational on this </i><p>

 

That's true.

What distance?

 

What film?

 

What f-stop?

 

It's easier if you don't use a mixed bag of equipment.

 

Or, do as I plan to do on an upcoming shoot: set up every hot light and flash I have and fire away.

Ellis wrote<p>

 

<i>"...Having lit the Houston Symphony orchestra a few years ago with high intensity "long throw" reflectors...</i><p>

 

Not familiar with "long throw" reflectors. I'll look for them over on B&H's web site.<p>

 

<i>and using 6,000 watt-seconds of Speedotron and Elinchrom equipment, and struggling with getting good depth of field at f/8 + 1/2, no I don't think you have enough power.</i><p>

 

Based upon what's been written here by you and others, the total ws will be some 10k ws but I'm looking at GN as opposed to overall ws.<p>

 

<i>Light's to center of stage distance was about 50' to 60'. With those distances there was virtually no fall off from the front edge of the stage to the back riser.</i><p>

 

That's an interesting observation.<p>

 

<i>The long throw reflectors let me tune the light across the group for evenenss.</i><p>

 

I'm under the impression from past reading that grids or louvers will help both control spill and even the lighting intensity out front to back.<p>

 

<i>I was using ISo 100 film and shooting with a Pentax 6x7 (loaded with B&W)and a 6x9cm back (loaded with color on a 4x5 camera. Both cameras were fitted with 90mm lenses. The largest size the final image was printed at about 20" x 30" and that was really pushing the resolution of the image. I would have been much happier at f/16 bu that wouls have required about 24,000 watt-seconds (If these had been Norman packs I would have needed about 48,000 watt-seconds to get f/16)</i><p>

 

Just a thought; if one uses 48k ws's worth of energy, do they need to have both an electrician on site and do they need a fire permit:)<p>

 

<i>Using anything less than the Canon EOS 1Ds or the Kodak Pro SLR/n or SLR/n cameras will work against you -- you just won't have enough resolution to see everyone clearly.</i><p>

 

Kodak just announced a Pro SLR/c for those with Canon lenses. It should start shipping in a couple of months. Expectedly, based on first reports, it will give the 1Ds a run for it's money at the lower ISO ratings of a 100-200. At ISO 400, the noise starts to tear the image up a bit. It's coming out in the $5,000.00 range and should give Canon's pricing of the 1Ds fits:) This is a good thing.<p>

 

Thanks for the experienced input.<p>

Steve wrote<p>

 

<i>What distance? What film? What f-stop?</i><p>

 

Not being snippy in my comment. I tried answering all these question further down the thread. A couple of reponses down from the original question in the thread, I did a more detailed breakdown.<p>

 

The executive version, 38' at f/11 or f/16 using a Canon 1Ds set at ISO 100-400.<p>

 

<i>It's easier if you don't use a mixed bag of equipment.</i><p>

 

Won't be using a mixed bag of equipment. All lighting equipment would be Speedotron with PocketWizard slaves.

 

<i>Or, do as I plan to do on an upcoming shoot: set up every hot light and flash I have and fire away.</i><p>

 

That's a bit of a novel approach:)<p>

 

If you check out a few of my responses, they should fill you in on what I'm wanting to do, with what and why. Thanks for checking in.<p>

You guys are out of my league, but as I read the Canon 1Ds versus LF camera with tilt/shift debate, I couldn't help thinking of that Cambo gizmo <a href="http://www.shutterbug.net/test_reports/0104sb_cambos/">Reviewed here.</a> I know you're still up against a 35mm-sized sensor, but you could at least "scheimpflug the faces" going up the bleachers. Good luck!

Hi Thomas,

 

With regards to using GN, you wrote:

 

"Doing the math, based upon Speedotron spec sheets, a 4803CX has a GN of 1000. A pair of Force 10's has an equivalent GN of plus 1000. A pair of D1204's has a combined GN of 910. Four D402's has a combined GN of plus 1000. If one were to use a pair of Speedotron 4803CX's, then all numbers would, of course, be doubled.

 

To me GN is the most reliable indicator as the efficiency of any unit is then automatically taken into consideration."

 

It may be that I misunderstand your comment, in which such case I apologize for stating the obvious, but be careful when using GNs for such comparisons. First, a doubling of the power, with all other things kept constant, will NOT double the GN but will increase it by a factor of about 1.4. Second, a GN that gives a good result in a relatively small, light colored/highly reflective room will not give the same result outside or in a very large, dark room.