Does size matter?

Discussion in 'Photography Beginners' Forum' started by o hey tyler, Sep 10, 2010.

  1. o hey tyler

    o hey tyler Been spending a lot of time on here!

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    Most would probably say yes in any given situation...

    However, this question is not "junk" related, it's about umbrellas.

    I've been asked by my neighbor to do senior photos and a family photo for him and his oldest son. I say, "Wonderful! Time and place?" He says 'some time in the next few weeks when our schedule's don't conflict'.

    Well, that's great. So I could be shooting outdoors at a forgiving time of day, or it could be during the harshest sunlight of the hour, who knows? So what I am thinking is, I should invest in an umbrella to assist in the lighting of the shots.

    I have a 430EX II, and I will have a pair of Cactus transmitters by the time of the shoot. What I am wondering though, does the size of the umbrella and the output of the flash have a direct effect on the quality or direction of the light? Should I just get a larger umbrella for the future? Or should I start with a small one until I get a more robust flash unit?

    I've been wanting to get into off camera lighting more, and now I will finally get my feet wet.
     
  2. Derrel

    Derrel Mr. Rain Cloud

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    Smaller umbrellas give slightly "crisper" light at normal working distances. Umbrellas in the 30-inch size for example, look great in B&W conversions, where a crisper, more-contrasty and higher-ratio lighting look is appealing. Umbrellas in the 40 to 43 inch class are probably the best overall,total compromise for use with speedlight flash units; they are affordble,portable, and a speedlight can "fill them up" when set to around the 35 to 50mm flash zoom setting. Speedlights do not work that well with 60 inch umbrellas...the light beam spread needed to "fill up" a 60 in cher is too great for a speedlight to efficiently fill...60 inchers outdors are also asking for trouble...imagine a nice kite with a $459 flash attached...that's a 60 outdoors...think sandbags, guy wires, turf spikes, C-stands.

    I like reflecting umbrellas with solid, non-transparent black backs. Photoflex makes good umbrellas. The Photoflex convertible is one of my favorites. It used to be called the RUT,as I recall. They have a good web site. Speedotron's super silver is also a very,very nice silver "metalized" umbrella that has been made for years. Paul C. Buff's brand new PLM or Parabolic Light Modifier is an incredibly efficient "large-area" umbrella,capable of lighting up a HUGE swath of real estate with about 2 f/stops' worth higher efficiency than a Photoflex 60 inch white, according to Rob Galbraith's extensive testing and use of both. Rob and his crew have moved to the PLM's for lighting up huge team shots outdoors in bright sunlight, previously having used the Photoflex giant whites for many seasons.

    Umbrellas only soften the light when they are relatively large in relation to the subject size/light-to-subject distance, so the mid-sized 40 to 43's are pretty soft when up to eight feet or closer to your subject. For single-person shots, the 40-43's are pretty decent.
     
  3. o hey tyler

    o hey tyler Been spending a lot of time on here!

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    So maybe a 42" PLM with a black outer shell? That's not asking my neighbor for too much. It's actually pretty reasonably priced for the high tech sounding name it has.

    Silver 42” 16 Rib Parabolic Umbrella $39.95
     
  4. mrmacedonian

    mrmacedonian TPF Noob!

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    Thank you for this post. I will be looking into 1-2 umbrellas soon and these look like they can change from reflective umbrellas to shoot-through am I right? (if not blame google). I would like to explore the utility of 1-2 of these umbrellas for taking indoor, real-estate type shooting, which is my immediate focus as its actually creating a revenue stream!

    Any other suggestions/directions are of course welcome and appreciated. Thanks again for the info.
     
  5. flea77

    flea77 TPF Noob!

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    Soft light is dictated by the apparent size of the light source. In theory, the larger the light source, the softer and better the light. In practice you have to have something you can actually fill with light for it to work.

    The sun would be an excellent soft light source because of it's size. Unfortunately it is so far away that it's "apparent size" is quite small, and therefor the light it gives off is quite harsh.

    An umbrella works the same way. Close up they work wonderful, far away and they do very little. Following that logic you want the largest umbrella you can fill with your flash (no more than about 45") and you want to get the surface of the umbrella as close to the person as possible without putting out an eye.

    Now think about this for a second. "As close to the person as possible". If you use a reflective umbrella the closest you can get is to put the shaft of the umbrella lets say six inches from the person's eye (not smart, but it will work). Assuming a shaft of about two feet that means your light source is two feet six inches from the subject. Using a shoot through umbrella you can put the surface of the umbrella six inches from the person's eye (much safer anyway) and so your light source is 1/5th the distance from your subject as it would be if you used a reflective umbrella.

    Not only would a shoot through give you a larger apparent light source and consequently be better light, but since you reduced your working distance the power required is massively reduced (or your ability to overpower the sun is massively increased).

    Allan
     
  6. Mustlovedragons

    Mustlovedragons TPF Noob!

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    Yes, size matters. If it can be afforded, in time, space and finances, it's a good idea to have various sizes.
     
  7. Derrel

    Derrel Mr. Rain Cloud

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    Unfortunately,theory and practice often diverge, especially where theory fails to accounts for the laws of physics...placing an umbrella "as close as possible" to the subject sounds good in theory, but what actually happens is the inverse square law rears its ugly head, and you get HUGE drop-off in light intensity from one side of the face to the other,because at very close light-to-subject distances there can be a tremendous loss of light across a span of just four inches...with the light farther away at a "normal" distance of say four to eight feet, the inverse square law assures you of fairly even lighting. In practice, the light output of a shoot-through umbrella versus a purpose-built is negligible,and in the cae of the PLM umbrella, and most other quality "reflecting" umbrellas, the output is quite high.

    There is no "massively reduced" output using a reflecting umbrella...in fact, the shoot-through umbrella design throws away a large percentage of its light output...perhaps half goes through (ie 'shoots through'), and a substantial percentage of light goes the opposite way, away from the subject...which indoors leads to huge amounts of what is called ambient spill when using shoot-through umbrellas. A quality reflecting umbrella however, does NOT waste light...ALL of the light is reflected and goes in one direction, instead of half going through and the other half bouncing back and scattering all over the place...
    __________________
     
  8. flea77

    flea77 TPF Noob!

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    I understand your points I just happen to disagree. If you check out the Strobist blog, and their video series, you will see exactly what I am talking about. David Hobby (I believe that is the gent's name who did the videos) explains that he too used to use reflective umbrellas and switched to shoot through because of exactly what I stated.

    I am glad you brought up the inverse square law. If the typical person's face runs about 6" deep (nose to ear, actually I think it is more like 5-5.5") and the umbrella is 6" away from the side of the face, the ear and nose are separated from the cheek by 3", or 1/2 the total distance. Using the inverse square law that has a fall off of .5 * .5 or about 2.5 times as dark maximum, or 1.25 stops. In real world shooting it shows much less (I have LOTS of examples if you want to see them). In addition, most portraits are shot with at least two umbrella's, one on each side, which further reduces the loss. Lastly, in my portraits at least, I do not want every square mm of the person covered in exactly the same light, it makes for a very boring portrait.

    Once again, following the inverse square law, a light source at 6" is 1/5 the distance of one at 2.5', which means 5 times the distance to the reflective umbrella, or 5x5=25 times the amount of light needed for the same exposure (you brought up the inverse square law, am I applying it correctly?). If 25 times more light needed does not mean "massively reduced" to you, well I am sorry, but it sure does to me. I can overpower the direct light of the sun on a hot Texas summer at noon with an SB-600 on 1/2 power and a shoot through umbrella.

    Continuing on, apparent light size drastically decreases as distance increases. This is one reason a shoot through at 6" will always give softer light than a reflective at 2.5'. The other reason is the same reason we use soft boxes for product photography, the shoot through does a better job of diffusing the light (yes, at a penalty of absorbing some of the light, abliet minimal in my tests). If that were not true, everyone would use mirrors instead of shoot throughs, soft boxes, etc etc.

    If you still disagree, I suggest you get a copy of the Strobists workshop DVDs and watch them. David not only tells you what I just did, he actually shows you with actual models and images. You will see right there on your screen the advantages of using a shoot through at point blank range. Once I tried it, I got rid of my reflectives and went shoot through only from that moment on and have never been more satisfied with the images I got.

    Allan
     
  9. Derrel

    Derrel Mr. Rain Cloud

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    Yes, I knew you were referring to the David Hobby blog vis a vis positioning an umbrella six inches from a person's face; he's about the only person I've ever heard of doing such a ludicrous thing.

    Your math and your application of the inverse square law are not squaring with the reality of HUGE light fall-off at extremely close light-to-subject distances.

    A shoot-through umbrella a 6 inches will not give softer light than a reflective light at 25 inches...the shoot-through at 6 inches will have a roughly 3 f/stop fall-off from the bright side to the dark side...leading to very high-contrast lighting...again, THEORY is not squaring with practice.

    I'd like you to illuminate something with a shoot through 6 inches from a subject, and then with a reflective umbrella 25 inches from the same subject. Compare the light fall-off pattern, and also, please, look at what awful light a shoot-through produces when it is a foot from a subject the size of a person. Yeech!

    We're talking about umbrellas for senior portraiture...you need 4 to 8 feet between the subject, for posing flexibility, and decent lighting. I'm pretty familiar with Hobby's fascination with cheap, shoot-through umbrellas. They're nice for slam-bang,sloppy lighting where loads of light bouncing off the back of the umbrella,adding to ambient spill, can help create fill lighting in indoor environments. Honestly though, I think shoot-through umbrellas produce sickly, awful-looking light. I started with shoot-through umbrellas 29 years ago, and switched to reflective and enclosed designs 10 years ago.
    But then again, I prefer to shoot with "real" flash units and 200,400,800 watt-seconds of power, no 60 watt second speedlights, so it's much easier to get professional effects with more lighting power and no hindrances from a light that's so weak it can barely shoot through the fabric.

    Again, an umbrella six INCHES from a subject...not very practical. PITA to work with. "The advantage of a shoot through at point blank range?" Are you kidding me??? That is an "advantage". WTF???
     
  10. flea77

    flea77 TPF Noob!

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    You are 100% correct, close in shoot through umbrella lighting is horrible and looks like garbage:

    [​IMG]
    two shoot throughs, middle of the day in the shade, one camera left for fill at about 2', one camera right for main at about 1'. Looks horrible doesn't it? Yech!

    [​IMG]
    Single shoot through camera left, terrible shot. Note that until her forehead curves away from the light, the fall off is minimal, how could that be?!?!?!

    [​IMG]
    Main shoot through camera right, camera left has one at 1/4 the power of the one on the right just to soften the shadows (inside with no other lights), can't imagine why she was happy with this one.

    You talk about a 3 stop fall off from the light side to the dark side, what? Where? ANY light you put on one side of a person and feed it enough power will cause dark shadows. For example:

    [​IMG]
    That is a shot with a 5'x4' 400ws softbox, you know, "real" flash units? That is what happens when you have no fill light on the left and a light source 6' from the subject on the right. Note that the fall off you are referring to is MUCH worse than any of the images above it where the umbrella(s) are MUCH closer, wonder why that is?

    All I know is that if I move the shoot through in close I get light like in #1 and I like that. If you think it stinks, fine, I still like it, my customers still like it, the subject liked it, so I am sticking with it no matter how much you think the inverse square law is wrong.:lol:

    Allan

    PS. In #1 and #2 there was 0% ambient spill as there was absolutely nothing behind the umbrellas to bounce off of. Well, I guess in #2 the light could have bounced off the ocean onto the clouds and back again, but since I was not using "real" lights I doubt I had enough power:lmao:
     
    Last edited: Sep 11, 2010
  11. supraman215

    supraman215 TPF Noob!

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    Which of these had one strobe?
     
  12. supraman215

    supraman215 TPF Noob!

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    I have to say, I did some experimenting with my 43" shoot through umbrella and distance from the subject. For whatever reason as I moved the umbrella closer to the subject the light did get a lot softer and wrapped around the subject a lot more. Closer to the subject = further from the ceiling. This was indoors, could be related to the bounce of the flash off the back of the umbrella and the ceiling. But as I moved it further away the shadows were more sharp and I'm inclined to think this has to do with the relative size of the umbrella with respect to the subject.
     

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