Round /octagonal and rectangular

Discussion in 'Lighting Equipment' started by lopezjohnston, Nov 16, 2012.

  1. Good afternoon to you all and thank you in advance for your valuable inputs...

    I would like to ask about the differences between the uses of round/octagonal and square/rectangular soft boxes.

    I read little bit about that round/octagonal diffusers provided more natural looking light spread and also were more efficient in the use of lights.. Smaller round/octagonal boxes delivered more concentrated "light beams”.

    Thank you again for your time.
     
  2. I like using the octagonal or soft soft boxes because they leave a nice catch light in the subjects eyes. Not sure about light spread...
     
  3. The real reason for the octabox is the size of the softbox. When you reach about 1 meter in the side the structure becomes less rigid than with other sizes. So the solution is to change the rectangular form to a circular one. The 8 side is the solution, it intercales one sitck beetween two of the rectangular one.

    The effect is very similar to that of the 1mx1m, but without the chance to change the rendering of the shados when you rotate the frontal plane over the light axis.
     
  4. A concentrated 'light beam' is difficult to achieve with something which is designed to diffuse light 180° - especially through a diffusion material on the front surface of a softbox.
    If your softbox or diffuser isn't working properly or you are projecting a focussed 'light beam' onto the softbox surface, then you will get a more concentrated directional 'beam' rather than a more omnidirectional 'beam'.
    The size of the softbox is the most important aspect relating to beam spread, but rather than thinking of it as a beam spread, think of it more of a beam size - where a small beam size creates a hard edged shadow and a large beam size creates a soft edged shadow.
    In an ideal world every softbox would provide exactly the same light quality, but its not an ideal world, and they don't.
     
  5. I suspect that there is very little difference in actual fall off between any of the types of soft boxes. However, I get the sense that there is a more natural "feel" to the quality of light with the rectangular shape, while glamour lighting might be better expressed with the octagonal or even round.
    The window like shape of the rectangular simply seems to be more like the light that we actually see, especially from units with a front recess of at least a couple of inches. That makes it far easier to "feather" the light and use the edge for delicate effects.
    As to the catchlight in the eyes, how many round or octagonal windows do we see where as we see rectangular windows almost all the time.? So for me, the rectangular catchlight is the norm.
     
  6. Virtually no difference, other than the shape of catchlight, all else being equal. Some octos are somewhat shallower (e.g., Photoflex) than conventional square/rectangular softboxes, which would produce slightly less even reflectance inside the octo than a deeper-welled, rectangular softbox (a notable exception being the Elinchrom Rotolux deep octos). A large octo, with the same square inches of surface area as the equivalent rectangular softbox, would give the same effect in a less bulky structure (since its corners are rounded).
     
  7. If both soft boxes are of equal size there is no difference. The difference comes to play when you add soft grids to them and now the shape of the light mimics the shape of the soft box. If you want tall and narrow you get a strip soft box. Other than that the most popular answer is the catch light in the eyes it produces.
     
  8. Dare I suggest you could fit a square or rectangular mask to an octagonal box if needed? Also the softness of light depends on the diameter or width of the softbox together with its distance from the subject. The shape has almost nothing to do with the quality of light, but obviously affects any direct reflections.
    As has already been said, if a softbox has a "beam", then it ain't really a softbox. Control of spill through use of eggcrates (grids), snoots or barn doors is something else entirely. Cutting down on spill should not change the hardness of shadows, only their depth. Shadow hardness is governed only by how much light can creep round the subject to fill the shadow thrown behind it. Light shining away from the subject doesn't affect that. And BTW you can get crates or skirts to fit octoboxes too.
     
  9. Thank you all for your valuable responses...

    Allow me please to straight something out... When I said light beam I used “---“ signs to let people know that I was expressing a metaphor for the light produced for the diffuser... It seems that my words were taken literal for some people even though I used the quote marks to communicate the idea...

    Any way... once made the point clear.. thank you ALL for your inputs... It seems to be some divided ideas (when to use round or rectangular boxes) and other common grounded ideas about the catch lights produced...

    I do really appreciate your times and knowledge..
     
  10. Your question illustrated your misunderstanding. Softboxes don't provide "light Beams". The same metaphor was used to aid your understanding - using your own language - as it were.
    Softboxes take a relative point source and convert it into a wide area array of - even - light distribution (or at least they should). If this is not what your talking about then any comparison is very difficult to judge and the differences very difficult to determine.
    In the context of "more natural looking light spread" "more efficient in the use of lights" "Smaller round/octagonal boxes delivered more concentrated "light beams”".... Compared to what exactly? Only comparing two near identical products of almost near identical design using identical materials of construction in the same location can any such comparison be made. (I'd like to know where this was written that determined these differences that you were reading).
    With "more natural looking light spread" you will be comparing to the sun wouldn't you..? Thats the only natural light source I know of. Or would it be with the sun in some modified situation you like the 'natural' look of.. or some other modified light source altogether - and not a soft box?
     
  11. Ian...

    Thank you for your input... and your time to discuss the topic.. I do appreciate it.

    About: Softboxes take a relative point source and convert it into a wide area array of - even - light distribution (or at least they should). If this is not what your talking about then any comparison is very difficult to judge and the differences very difficult to determine.

    Yes, this is what I am talking about.. It is about the concentration of the "wide area array of - even - light distribution” ( that I artificially named as “beam” to make an mental image of the light being spread into certain area... ) that square and round soft boxes produce. As I mentioned, in some forums people said that octo boxes were more efficient in projecting light than conventional square ones.. I think like parabolic antennas projecting waves.. (light is a kind of wave) . HUMMM.. I think I answered my own question... !

    About: In the context of "more natural looking light spread" "more efficient in the use of lights" "Smaller round/octagonal boxes delivered more concentrated "light beams”".... Compared to what exactly?

    According to what I have read.. compared to square/rectangular ones of the same size (diameter of the round diffuser compared with same side length of a square). I read this in a questions/answers site of photography.. Sorry I do not remember the link..

    About: With "more natural looking light spread" you will be comparing to the sun wouldn't you..? Thats the only natural light source I know of.

    Yes.. I think so.. Those forum did not pointed to what they were calling “natural” Sun light is always the point of comparison regarding to natural light... It is more regarded to mood and light quality for portraits provided by windows. The articles mentioned that square boxes provided more like a kind of window light effect .. and octo boxes provided more like outdoors lighting effect because how the octo make the like to fall around to subject..

    The discussions I have read are about ROUND Vs square/rectangular softboxes only.. so no other kind of "modified situation you like the 'natural' look of.. or some other modified light source altogether"

    Again.. I appreciate your time.. and your thoughts...
     
  12. J.C, by "efficiency" I would interpret the modifier puts out very near the amount of light energy the strobe/light put in. I wonder if you are thinking of comments about parabolic modifiers. My silver AB parabolic umbrella reflects a high percentage of the light from its silver lining and also, because of the umbrella design and correct placement of the strobe on the umbrella shaft, it produces parallel light beams, so more of the light hits the subject rather than scattering it over a wide area. My first test had me checking and rechecking because at the distance of 18 feet, I couldnt believe the f stop I was getting at a low power setting. As to use of round vs rectangular, I prefer, and this is just my taste, a round catch light on head shots and head and shoulders when I am shooting something with a soft feel. The straight edges and corners of a rectangular catchlight are somewhat contrary to the over all feel of the shot and catchlights are a larger element in tight shots. I see it as a specular of the sun and as Tim points out, the rectangular as a window specular. Will most clients notice it, no, but I do so try to keep at least one round modifier hung at all times I dont take down the 7 footer, life is too short. As to a natural look, first, sure the sun is a hard source, but yesterday it was raining here and it was really soft light. Natural. But then, I dont strive to reproduce precisely what is in front of my camera. Shape is also a function of control for me. I feel I have a more precise control of the straight edge of a rectangular box for some purposes. For example, placing a kicker highlight on the side of a face or even on the main. Sure, I could use a flag, but it takes longer, but I will use a flag to control the edge transfer. Size matters as well. I really like the 7' octa not only because of is fabulous softness, but also because of the ability to feather it to create one light chiaroscuro or to otherwise control bg tonality. On the other hand, I prefer the egg crated rectangular boxes when trying to eliminate contamination of the bg to achieve pure black or accurate saturated gel color. May even combine them with flags to knock down the contamination. I shoot in a relatively small space so control is at a premium. Here's a coupletest shots with a cutter in front of the eggcrated soft box and subtractive at left and below Julius (I thank Tim for teaching me that technique). I like being able to precisely roll the cutter forward backward to place the edge and left right to control the shadow edge transfer. With a real subject would add one more light, an eye light to produce a catch light for his R eye. Saw "Lincoln" last night and they must have gone through a few bulbs for the eye light on his constantly dark sunken eye sockets.
    00b2hm-504795784.jpg
     
  13. Here's the set up
    00b2hn-504795884.jpg
     
  14. Oh, goal of the shot was a setup that was slimming from both the short and broad side and also gave a good rimmed profile (move the subtractive at left). One setup, 3 flattering shots.
     
  15. Light being reflected from a parabolic umbrella in a parallel or columnated direction and then diffused by a cover should provide the most efficient use of the light possible. With an equivalent surface area of the round parabolic on a square or oblong softbox similarly optimised - there would be no difference in efficiency. The same quantity of light spread evenly over the same surface area will provide the same luminance level and the same light quantity on subject. You would benefit slightly from an oblong softbox in having two options for shadow gradation, with the parabolic being in between, but the different results being barely noticeable between all modifier variations with them having the same surface areas.
    In relation to your "compared to square/rectangular ones of the same size (diameter of the round diffuser compared with same side length of a square). I read this in a questions/answers site of photography.." ...then you will understand that you are comparing apples with oranges there.. As just pointed out, the surface areas of those two samples are unmatched.
    "The articles mentioned that square boxes provided more like a kind of window light effect .. and octo boxes provided more like outdoors lighting effect because how the octo make the like to fall around to subject.. " Window light effect - would that be full sun streaming through a window acting as a point source.. or would that be an even cloud cover evenly illuminating the aperture towards the light that the subject is in? They are.. completely different. And would the room be white, grey or black.. again, the results would be completely different.
    In comparisons, its best to compare like with like, or to specify the objective of your comparison.
    When it comes to cost, convenience or preference then compromise comes to effect and can be wholly decided by what you have and whether you like the effect or not.
    Looking natural can divide many different opinions.
     
  16. A lot of thinking going on here..too much for me. lol Ian said it best.. We need to know the objective in order to compare properly. What is it you are trying to do? You may like the look of one soft box over the other or the way it sets up. I personally don't like to rotate so I go for the octa style. I own both but i don't pull hairs over all what is being discussed here about this. I make beautiful images soft and hard light. If you were to say which is the best for head shots then I would say both. There is no difference other than the catch light shape. As far as one being more efficient than the other? Again it depends what the objective is. Otherwise they are both the same. They both diffuse the light equally if they are the same size. What is more important here is for you to do a comparison yourself and see which one you like better. Everyone here has there own opinion and only you can make the final decision. You need to explore this creative path on your own.
     

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