How many watt seconds do I need?

Discussion in 'Lighting and Hardware' started by Mach0, Dec 26, 2013.

  1. Mach0

    Mach0 TPF Supporters Supporting Member

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    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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  2. Derrel

    Derrel Mr. Rain Cloud

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    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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  3. Mach0

    Mach0 TPF Supporters Supporting Member

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    I agree. It's never one sided. The profoto lights are nice. Good punch and able to turn them down super low.
     
  4. MK3Brent

    MK3Brent No longer a newbie, moving up!

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  5. Mach0

    Mach0 TPF Supporters Supporting Member

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    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 )
     
  6. robbins.photo

    robbins.photo Yup, It's The Zoo Guy Supporting Member

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    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.
     
  7. Derrel

    Derrel Mr. Rain Cloud

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    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.
    $Flash Output with Std Reflectors 10 feet.jpg
     
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  8. amolitor

    amolitor TPF Noob!

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    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.
     
  9. Derrel

    Derrel Mr. Rain Cloud

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    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
     
  10. Mach0

    Mach0 TPF Supporters Supporting Member

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    What about if you used it in a soft box?
     
  11. Derrel

    Derrel Mr. Rain Cloud

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    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.
     
  12. amolitor

    amolitor TPF Noob!

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    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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