# How many watt seconds do I need?



## Mach0 (Dec 26, 2013)

I don't know if this will be useful for all but I thought this video was great. Especially, for those who are trying to figure out what light to buy next.


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## Derrel (Dec 26, 2013)

Good video. The Adorama TV videos are usually pretty good. Sooooo much better than the typical one-man-band videos on YouTube.


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## Mach0 (Dec 26, 2013)

Derrel said:


> Good video. The Adorama TV videos are usually pretty good. Sooooo much better than the typical one-man-band videos on YouTube.


  I agree. It's never one sided. The profoto lights are nice. Good punch and able to turn them down super low.


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## MK3Brent (Dec 26, 2013)

Paul C. Buff - White Lightning X3200


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## Mach0 (Dec 26, 2013)

MK3Brent said:


> Paul C. Buff - White Lightning X3200


  I wonder how that works bounced and what's the guide number.

I have some PCB gear and watching that video, the Einstein didn't get that high of a reading ( I'm thinking the reflector )


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## robbins.photo (Dec 26, 2013)

Derrel said:


> Good video. The Adorama TV videos are usually pretty good. Sooooo much better than the typical one-man-band videos on YouTube.



I dunno, I kind of get a kick out of the guy playing guitar, banging cymbals with his knees, blowing on a harmonica and trying to explan aperture settings all at the same time.  Lol.. ok, probably just me again.


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## Derrel (Dec 26, 2013)

If there is a nit to pick with the video, it might be the way the "low power" demonstration was set up, in trying to achieve an f/2.8 aperture for flash portraiture; in MY experience, that is something I have NEVER wanted to do, in almost 27 years of studio flash ownership: I have NEVER, as in never,ever,ever, tried to set up a portraiture situation where I wanted to shoot flash exposures at f/2.8. Not one, single time. Again, not one,single time. And frankly, I think the reason they did that is that it shows the advantages of the most-expensive equipment available in the flash field, and negates the benefits of the low profit-margin, low-cost Flashpoints that Adorama sells.

I understand what the demo DID show, and the flip side is that it very subtly shows the value of high-priced Profoto lights for both CLOSE-in and long-range shooting. What the demo video did not tease out and highlight is that inside of 12 feet...almost ANY studio monolight gives enough power for a f/7.1 flash shot...and that the LOW-profit margin, low-cost Flashpoint lights have plenty of power at closer distances, when the goal is to shoot at f/7.1 or f/8 or even f/11, and get soft light at normal, traditional f/stops (ie,moderate to small f/stop, ranging from f/5.6 to f/22) that will give full depth of field to cover the nose, eyes, and maybe back to the ears at f/8, and definitely a full head's worth of DOF at f/22, or which WILL GIVE enough depth of field from a slightly longer camera-to-subject distance, to "cover" a group shot that is two ranks deep...

It is a good video. One of the best things it shows is the effect of the reflector on standard, Guide Number tests, and how a better reflector design can "bump up" the Guide Number.

Not to put too fine a point on it, but for people who do not really have a lot of familiarity with studio flash units, there are some subtle points that might be missed by some viewers. They are that the Model Number of a Flash, like say "Alien Bee B800" might be a gross exaggeration of the actual Watt-seconds the flash stores, while some other manufacturers (Profoto, Speedotron, Dynalite, for example) use *actual*, and not-exaggerated model numbering. Also, shown pretty clearly, was the impact that the "standard reflector" can have on a straight, unmodified, 10-foot light meter test. As they showed on the Profoto Acute 2, swapping the "old" Profoto zoom reflector, to a newer, and probably narrower beam-spread reflector can bump up the 10-foot, straight, no-modifier f/stop 1 f/stop, and if the reflector is positioned to give a tighter, more-zoomed light beam spread, gain yet another additional f/stop or so.

I thought the video showed the great versatility of the Profoto D1 1000 Watt-second and also the smaller Profoto D1 500 Watt-second unit; I'm sure Adorama would like to sell some of these three-light kits from Profoto, with one, 1000 W-S D1 and two 500 W-s D1 units, for $5,129 for the three light kit. Profoto D1 1- 1000W/s / 2- 500W/s Head Studio Kit with Air Remote 901087

I made a screen capture while I watched, showing the tested models and their f/stop readings at 10 feet with their "standard reflector" setups.


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## amolitor (Dec 26, 2013)

I will make one minor addition here, which is that if you're working in a studio space that is much too small, where your model is pressed up against the backdrop, you may wind up using wider apertures than professionals use. I've shot quite a bit of stuff in the f/3.5-f/5.6 range, because I work in an insanely small space.

In my 'studio' I am pretty much always wishing I had the ability to turn things down further. I wind up stopping down more than I would like, and then my jerry-rigged background is rather more, um, present, than I wish.


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## Derrel (Dec 26, 2013)

amolitor said:


> I will make one minor addition here, which is that if you're working in a studio space that is much too small, where your model is pressed up against the backdrop, you may wind up using wider apertures than professionals use. I've shot quite a bit of stuff in the f/3.5-f/5.6 range, because I work in an insanely small space.
> 
> In my 'studio' I am pretty much always wishing I had the ability to turn things down further. I wind up stopping down more than I would like, and then my jerry-rigged background is rather more, um, present, than I wish.



One easy fix for studio flash heads is to position a layer , or even two layers, of Neutral Density filter material over the front of the reflector, as a way to reduce flash power when the flash is really,really close to the subject. In some situations, a person can also add a honeycomb grid, or even mylar diffusing material, or the old gold standard, metal "*window screen-like*" scrim material, as a way to cut down the light's effective power.

So...instead of spending $1,900 for one,single Profoto flash head, a guy could spend $30 for a couple of wire scrims from a professional lighting supply maker, like Matthews...Mathews makes single, double, and triple-intensity reducing wire scrims...

Matthews Studio Equipment Wire Diffusion / Scrims - Matthews Studio Equipment


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## Mach0 (Dec 26, 2013)

Derrel said:


> One easy fix for studio flash heads is to position a layer , or even two layers, of Neutral Density filter material over the front of the reflector, as a way to reduce flash power when the flash is really,really close to the subject. In some situations, a person can also add a honeycomb grid, or even mylar diffusing material, or the old gold standard, metal "window screen-like" scrim material, as a way to cut down the light's effective power.  So...instead of spending $1,900 for one,single Profoto flash head, a guy could spend $30 for a couple of wire scrims from a professional lighting supply maker, like Matthews...Mathews makes single, double, and triple-intensity reducing wire scrims...  Matthews Studio Equipment Wire Diffusion / Scrims - Matthews Studio Equipment



What about if you used it in a soft box?


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## Derrel (Dec 26, 2013)

A wire scrim cuts the same amount of light no matter where it is used.

But from a practical standpoint, the issue becomes, "How does one mount the scrim and mount the light to the softbox." I have for example, a really useful speedring for softboxes; it is the Chimera brand "Speedotron Brown Line speedring." It is a standard metal, and super-strength polycarbonate speedring with the normal, four corner holes for the softbox rods. The difference with it is that the speedring mounts to Speedotron Brown Line M90 or MW3-series light units, which have an 8.5 inch, or roughy a 5-inch for the MW3 series units, non-removable reflector that has an umbrella mounting hole that is drilled through the bottom edge of the reflector. this particular CHimera speed ring has an aluminum rod that has been screwed onto the bottom on the speedring, so that the light head's reflector goes "inside the softbox", and the ring mounts using the umbrella shaft opening on the light. In other words, *the speedring mounts to the light unit as if it were an umbrella's shaft!

*That leaves the entire front of the reflector un-touched, so you can tape/clip/clamp/wrap any gels, diffusers, or other do-dads onto the front of the reflector.
*
Chimera Non-Rotating Speed Ring for Speedotron 2350

*As with most things in lighting, the key is having the right "tools" to do what you want to do, reliably and easily. I believe this speed ring will work with a good many studio flash units.


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## amolitor (Dec 26, 2013)

Yep. A weak point in my personalized jerry-rigging techniques is good, reliable, ways to soak up flash output in predictable ways.

Interestingly, taping over the head itself is nearly useless. The light seems to bounce around and get out through the smaller hole pretty much OK. It's reduced, but not a lot. You have to tape over like 3/4 of the face if the thing to get much reduction. Mopping it up after it's left the flash head works a lot better, but needs more thinkin' than I have put in to it.


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## Derrel (Dec 26, 2013)

The whole "How many Watt-seconds do I need? " answer for single-person portrait shots (head shots, bust, or half-body shots) with the camera at ISO 1-- to 320 is, "Probably not as many Watt-second as you might think." I took this two-light, one reflector portrait using two lights, each one with 100 Watt-seconds of light. The main light is camera right, and is a Photoflex 36 x 48 inch softbox just off to the right of the subject. The hair and separation light for the shoulder is an identical Speedotron Brown Line M11 light unit, with  a deep-dish, 11.5 inch grid reflector that throws a 50 degree beam spread on its own, but fitted with a snap-in 20-degree honeycomb grid, so it would put out a very much toned-down, softer, more-directional light. I added a set of 2-way barndoors to this light, and also added a Speedotron snap-on mylar diffuser. The combo of the grid reflector, plus the 20 degree grid put in place AND the milk-jug-like, tough mylar diffuser in front, and the barn doors, allowed me to aim the light right at her shoulder and hair from  about 8 feet back.

Now, normally, at 8 feet, with 100 Watt-seconds, a big parabolic reflector like this would create REALLY "hot" light that would totally,totally blow out the hair and shoulder; but the grid + diffuser, + the barn doors narrowed down allowed me to aim very soft light right where it was needed, to just create a subtle hair light, AND light the off shoulder. Look very closely at the crown of her head, and also look at the rim light that just barely separates her shoulder from the black background. I have not retouched this image AT ALL; this is 2007...from *the era before Lightroom for me*...this is the way I learned to shoot,and to light...straight out of the camera, with the light coming from "the lights", and not from layer masks, adjustment brushes, and highlight/shadow recovery...today, I would probably clone out the flyaway hairs on this, and I was NOT fond of her hairstyle, with the deliberate "in the eyes bangs" look that was so trendy that season...but if you look, this is what one softbox, one big reflector, and one light with grid + diffuser + barn doors looks like at ISO 100, and f/5.6. at 100 Watt-seconds





If you look closely at this shot on a calibrated monitor, you will see that the background has a very,very subtle gradient...it's NOT pure, jet-black from edge to edge, but behind her is a very,very subtle "halo" that's lighter in the center. That was done in-camera, by opening the right-hand side of the 2-way barn doors, and allowing some of the light to bounce off of the left flap, which was constricting the light and confining it to her head-top and shoulder, and also keeping my lens from flaring--AND, *at the same time*, bouncing a little bit of light over and to the background,some eight feet behind her head. The falloff at the bottom of the frame is totally pre-vignette for me..that is the actual,natural fall-off of that softbox, and the way it was aimed and positioned. Overall, I was trying to get a really good, realistic,naturalistic, 3-D look that would look "classical" and not "trendy" or dated. No airbrushing, no post-processing tricks, just SOOC lighting with two, 100 Watt-second flashes and a reflector and what I consider essential light-shaping tools: honeycomb grids, mylar diffuser material, and 2- way or 4-way barndoors.


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