How to achieve natural light effect with studio lights?

[Leonardo Boher]

Well... That was the only way I could fiugure the question.

I would like to know what should I buy in order to achieve this looking. This picture was taken with natural sun light, but I want to achieve the same thing with flashes. I have tried hotshoe mounted in 1 umbrella, but doesn't work.

Image taken using ambient light (no raw process, nor Photoshop either):

Surely, you will suggest using the flash model 736XGS-9YI, or something like that. I have no idea about studio flashes, if you can attach a picture showing what the 32947-AKjd7 flash model can do, I will really appreciate it.

PS: I do not have the money to buy, try and buy again, so your help will be really appreciated!

Thanks!

Leo

 

[Asher Kelman]

Hi Leonard,

The issue with the umbrella is one of size and how well the light is distributed and how close it is. The thing to so is to bring the light close but trim it with card to only allow a shaped window to be used and you must block light coming back behind it. According to how much light gets reflected to the rest of the room from behind the umbrella, that's what will illuminate the rest of the subject. All this can be done with a single electric light and the same umbrella. You could be shooting at about 1/30 sec at 160 ISO.

Asher

 

[Per Ellström]

Several factors has to be kept in mind when trying to simulate natural light.

Direct sunlight will create dark, hard edge shadows. Depending on time of day both color an contrast will change. This is paralell light.

A cloudy day will produce almost no visible shadows, as the clouds function as a giant light modifier, like a neverending softbox =) This light is diffused, ( not paralell ) it comes from a lot of directions.

The you have to take the location of the subject into account. Generally its said tha window lights is good for portraits, but that of course depends on the weather. I f the window faces the direct sunlight and you just put your model there it would be the same as having her in direct sunlight ( exept for som fill from walls, ceiling and such ).

So for direct sunlight, a undiffused camera flash will be good. For a cloudy day you need like a white sheet with light behind it.

Heres an example of simulated sunlight. ( they are composites , model shot in my living room )

And heres one with with simulated room light from window.

 

[Leonardo Boher]

Hi Leonard,

The issue with the umbrella is one of size and how well the light is distributed and how close it is. The thing to so is to bring the light close but trim it with card to only allow a shaped window to be used and you must block light coming back behind it. According to how much light gets reflected to the rest of the room from behind the umbrella, that's what will illuminate the rest of the subject. All this can be done with a single electric light and the same umbrella. You could be shooting at about 1/30 sec at 160 ISO.

Asher

Hi Ahser, long time without getting connected

I tryed putting the umbrella outside my flat (in the backyard and in the night), so the flash light pass through the window like the sun did in this pic. I tryed shooting the flash through the umbrella and pointing to the subject and also, bouncing the flash light toward the umbrella. I also tryed putting the umbrella closer to the window and a bit away from it, but the result was almost the same. Not a bit close to the result by using the sunlight. I was trying to mimic the same contrast ratio obtained by using the sunlight and I did it (kind of), but the transition among ratios still too hard.
I have heard that: "The wider the diffussor, the smother the shadows", so I applied that concept too

 

[Asher Kelman]

Simulating natural light!

And heres one with with simulated room light from window.

Per,

Great ideas. However, it's not clear how you actually setup this lighting. What do you mean by, "Simulating room light from a window"?

Do you mean,

• simulating room light by a strobe behind the window?
  
• simulating room being lit from light naturally coming from a window?

In any case, her face is bright and the distribution of light appears to be coming from the front.

Asher

 

[Leonardo Boher]

Hi Per,

Yes, I know about lights, I'm not a pro, but I know the basics (I also saw the Nikon's DVD's about flashes).

I'm pretty amazed about your pics. I wouldn't believe the first pic was taken inside an studio if you don't say it. I didn't know such quality of light could be done inside an studio.

I would really need to know if the example I posted here can be achieved by using flash and what kind/type.

I'm also wondering about the bounced light because the bigger the flash the more bounces, the more "fill" light. And fill light is something I don't want to certain pics like nudes. I don't have an studio and my flat is quite small, so bounced light will ocurr. However, for some strange reason, the sunlight which comes from the window, falls off pretty fast and the camera doesn't recognize the bouncing light but doing exactly the same with the flash and the umbrella, the fall off of the light is almost non existent, meaning there is lot bounced light, even if I put the flash outside my flat, in the backyard and also quite far from the window. I have tryed several distances, directions and potences and the result never gets a bit similar to the one obtained by using sunlight (keep in mind I'm not using direct sunlight and the weather is clear, the sunlight comes from a bigger backyard, so bluish tint is not present).

Thanks a lot for your illustrative help!

Leo

 

[Bart_van_der_Wolf]

I'm also wondering about the bounced light because the bigger the flash the more bounces, the more "fill" light. And fill light is something I don't want to certain pics like nudes. I don't have an studio and my flat is quite small, so bounced light will ocurr. However, for some strange reason, the sunlight which comes from the window, falls off pretty fast and the camera doesn't recognize the bouncing light but doing exactly the same with the flash and the umbrella, the fall off of the light is almost non existent, meaning there is lot bounced light, even if I put the flash outside my flat, in the backyard and also quite far from the window.

Hi Leo,

There is no reason that natural light gives a different result than artificial light, but only when the character is the same. Natural sunlight consists of either direct light from the sun (in an angle pointing down), or reflected/scattered light from the sky (inherently more diffuse), or ambient light from the outside scenery/garden (also diffuse but in a more horizontal angle), or a combination of those with a certain ratio. The more diffuse and horizontal, the more it will produce fill light by bouncing off of walls/ceiling/floor/furniture. Diffuse light also falls off less with distance, compared to a more point-like source of light (although the distance of the light source from the subject does play a role).

If you want to increase contrast, you'll have to avoid light from reaching the walls/ceiling/etc., and/or absorb the light before it bounces back as fill light. You can try to hang some dark cloth near your subject on the shadow side.

Bart

 

[Leonardo Boher]

Hi Bart Van Der Wolf (such a heavy mood you have in your name! Sounds like the name o a king).

Now I'm having things a bit more clear.

1) Sunlight can be reproduced by using flashes.
2) Now I understand better the Asher's point.

But I don't get the "Diffuse light also falls off less with distance". It's because my English is not so good. Do you mean Diffuse light falls off "faster" with more distance? Meaning the fall off radius will be smaller or bigger?

I will try the thing adding some black sheets. I think that's important.

Well... Things are becoming more clear!

Will wait to read more comments!

Thanks a lot for your explaniations, Bart Van Der Wolf.

Leo

 

[Bart_van_der_Wolf]

Hi Bart Van Der Wolf (such a heavy mood you have in your name! Sounds like the name o a king).

Hi Leo,

LOL, in some cultures the "van der" part, being separate lower case words, indicate nobility/royalty indeed. Unfortunately (?), I'm just a normal guy (all be it with some very distant (mid 1500's) statesman bloodline, through one of my grandmothers, so I have been told).

But I don't get the "Diffuse light also falls off less with distance". It's because my English is not so good. Do you mean Diffuse light falls off "faster" with more distance? Meaning the fall off radius will be smaller or bigger?

A small, point-like lightsource has an intensity that decreases with the square of the distance. The intensity at e.g. 1 metre from the lightsource, is reduced to 1/4th at 2 metres, to 1/9th at 3 metres, 1/16th at 4 metres, etc. A larger lightsource has a more gradual reduction of intensity with distance, so it can penetrate further into the room and cause fill light reflections, which further reduce the fall-off of intensity.

Also, a larger (diffuse) lightsource causes a more gradual transition between light and shade on the subject. A large window will probably be more like a large diffuse lightsource, especially if it has some transparent curtaining.

Bart

 

[Asher Kelman]

For a point light sources or a group of point light sources on a light box, the fall off at depth, is great when the light is close to your subject and very little when you move the lights far away. This is a consequence of the inverse square law where doubling the distance gives a 1/4 of the light. Still when you do that an object say 10 inches behind your subject, might, (if the distance to the light is great enough) be little less in power, (or Flux) from your main subject.

However as one moves the light towards your subject, the power of the light, or incident light flux on a surface will start to drop off precipitously. A wider source will decrease this gradient. It's that effect which one can see in using a very large softbox close to a subject. The fall of will be gentle and the shadows soft and feathered.

Asher

 

[Leonardo Boher]

Well... I'm replying to both.

Now I get it. The wider the lightsource, the smaller the fall off. BUT! The larger source also has more steps/divisions of decay, making somekind of sine-like curve decay (with an more loose slope) while the point-like source has less steps in the decay and also, larger divisions and a more triangle-like decay curve. Let me know if this drawing is right:

If that's right, I should buy an studio flash.

 

[Daniel Buck]

hm... not entirely sure what you mean by "steps" of falloff. I think you may be thinking about something else. Light falls off the same with distance, no matter how big the light source. A smaller light source (or a large one that is far off, like the sun) will look more "harsh" because the shadows are more crisp and the highlights have a tighter definition.

 

[Leonardo Boher]

hm... not entirely sure what you mean by "steps" of falloff. I think you may be thinking about something else. Light falls off the same with distance, no matter how big the light source. A smaller light source (or a large one that is far off, like the sun) will look more "harsh" because the shadows are more crisp and the highlights have a tighter definition.

Hi Daniel,

I'm getting help about flashes. I want to achieve the same sunlight effect by using flashes, but I don't know what kindof flashes should I use and I also think a big light source (like a soft box) will also spread too much light, bouncing all around the place. Asher and Bart have done a difference between point-like light and wide source light and also, explained how they work individually (both kind of lights explained in the graphic I did in order to see if I'm understanding all this stuff).

As much as I understand, they say the fall off of a big light source light will be shorter in the trayectory crossed by the light than the fall off of a pointing-like light source but, the big light source will also have more "shades of gray" or "steps" when falling off. Instead, the pointing-like source light will have less "steps", therefore, the light has more constant intensity through its trayectory till absolute fall off ocurr. That's what I've understood.

Thanks a lot for your approach, Daniel

Leo

 

[Cem_Usakligil]

....As much as I understand, they say the fall off of a big light source light will be shorter in the trayectory crossed by the light than the fall off of a pointing-like light source but, the big light source will also have more "shades of gray" or "steps" when falling off. Instead, the pointing-like source light will have less "steps", therefore, the light has more constant intensity through its trayectory till absolute fall off ocurr. That's what I've understood...

Hi Leonardo,

The light fall of is inversely related to the distance. In other words, twice the distance will reduce the luminousity by x4, 4 times the distance by x16, etc. It has nothing to do with how big the light source is. It also has no discrete gradations like the 16 shades of gray on your computer monitor, it is continuous regardless of the size of the light source. The other variable is the total luminousity of the light source at the point of origin. That is linearly related. Twice the luminousity of a source, twice the luminousity at the destination/target. When you take single light source and divide it into many smaller ones because of scattering such as when one uses a soft box, the total luminousity at the target will be less because the indirect light will have a longer distance to travel to the target.
Coming back to the "shades of gray" what you are referring to is the change of the luminousity across your subject. The more the change, the higher the contrast. If you take a subject and illimunate it from the side with a light source, the luminousity difference across the subject will become less if you move the subject further away from the light source, hence the contrast will be less. The sun is at almost an infinite distance so the fall off of the luminousity of the sun rays across a subject is negligable compared to a fall of caused by a spotlight which is only a few meters away from your subject. HTH,

Cheers,

 

[Daniel Buck]

As much as I understand, they say the fall off of a big light source light will be shorter in the trayectory crossed by the light than the fall off of a pointing-like light source but, the big light source will also have more "shades of gray" or "steps" when falling off. Instead, the pointing-like source light will have less "steps", therefore, the light has more constant intensity through its trayectory till absolute fall off ocurr. That's what I've understood.

a larger (or closer and larger appearing) light will wrap around your subject more than a smaller (or smaller away) light will, because it's coming from a larger area than just one point. This "wrapping around" will give you a broader range of tonality, but the falloff with distance is the same.

 

[Leonardo Boher]

Hi Leonardo,

The light fall of is inversely related to the distance. In other words, twice the distance will reduce the luminousity by x4, 4 times the distance by x16, etc. It has nothing to do with how big the light source is. It also has no discrete gradations like the 16 shades of gray on your computer monitor, it is continuous regardless of the size of the light source. The other variable is the total luminousity of the light source at the point of origin. That is linearly related. Twice the luminousity of a source, twice the luminousity at the destination/target. When you take single light source and divide it into many smaller ones because of scattering such as when one uses a soft box, the total luminousity at the target will be less because the indirect light will have a longer distance to travel to the target.
Coming back to the "shades of gray" what you are referring to is the change of the luminousity across your subject. The more the change, the higher the contrast. If you take a subject and illimunate it from the side with a light source, the luminousity difference across the subject will become less if you move the subject further away from the light source, hence the contrast will be less. The sun is at almost an infinite distance so the fall off of the luminousity of the sun rays across a subject is negligable compared to a fall of caused by a spotlight which is only a few meters away from your subject. HTH,

Cheers,

Hi Cel,

I see... So I should put the light source quite far from the subject in order to mimic the sunlight effect shown in the photo I posted here? Should I buy a softbox? How big? What kind of flash? I personally like dramatic ratios and somehow, emphatized contrast like in the pic I posted, but not the contrast generated when using direct flash toward the subject. That's too hard for my taste, even bouncing the flash is too hard.
I have another umbrella here which is like a closed umbrella, like an octodome, but I cannot use it because the flash cannot be mounted on it. That one may produce softer shadows.

Thank you very much for your reply!

Leo

 

[Asher Kelman]

Replicating or simulating sunlight for photography without costly gear!

Leonard,

Two ideas:

For open direct sunlight, you can put a small electric light/strobe in an empty coffee can 20-30 feet away and the light fall off will be gradual but the light will be harder, like open sun. Remove any paper or outside label. You can also use an new 1 gallon pain can or even a new metal bucket. The larger the better! Treat the inside with a solution from the hardware store which creates a black dull surface. (It contains dilute phosphoric acid, so be careful.) Just rinse out afterwards and you have a black surface that can't catch fire. Depending on the brightness of your strobe or electric light, you'll have to use a wider aperture and maybe a 1/30 second but that's fine for a portrait. The closer you "sun" the faster the light will fall off from the front to the back of your scene.

For cloudy overcast Let's say you cannot afford a huge soft box and/ an electronic flash. Well you can have an even larger soft source of light. It just needs no interference by your housemates/wife!!

You need three 4'x8" (white on one side, black on the other) foam core cards, obtainable from your photographic supply or art store, some electric lights and several sheets and string. Oh yes, a roll of 2 inch wide black "Gaffer's" tape.

Set up a 4'x8' white foam core card, facing your subject. That's you reflector. From the periphery and 2 feet away, shine obliquely 6 small electric lights on to the 4x8 white face card from 6" aluminum reflectors, (from the builder/Home Depot supply yard, $5-6 each). In front of that string across a crumpled white double/ Queens size sheet, (your diffuser). In from of that a second white sheet, smooth, or Tough Spun.™ Voila, soft broad light for pennies. Stand 4x8 cards to each side to block light from escaping to the room and adjust position to alter indirect light ratio in room.(I score the foam core card, (white one side, black the other), and bend it to a V, so it will stand on its own. I then reinforce the seam on the black side with black gaffer's tape.

Color temp can easily be accounted for by using a grey card. For B&W, no problem anyway!

Asher

Warning! Keep in mind that electric lights can generate heat and so keep sheets at a safe distance from light. In this scenario, using small lights, especially todays fluorescent lights aimed from the periphery to the white card, means that the aluminum housing stands between the hot bulb and the sheet. Still, remember to keep an eye of the sheets for developing brown spots! Never leave lights on when you leave the room! You may get distracted and forget! I have a fire extinguisher but never set one off since high school, but then I got caned, LOL!

 

[Bart_van_der_Wolf]

a larger (or closer and larger appearing) light will wrap around your subject more than a smaller (or smaller away) light will, because it's coming from a larger area than just one point. This "wrapping around" will give you a broader range of tonality,

That's correct. It's also important that, as you mention, the distance to the 'large' lightsource also matters. When a large lightsource is placed at a larger distance, its effective angle of illumination of the subject gets narrower, and the chance of relections functioning as fill light increases (unless precautions are taken to avoid that).

but the falloff with distance is the same.

That's not correct. The intensity of a point light source that radiates in all directions, reduces whith the square of the distance:
http://hyperphysics.phy-astr.gsu.edu/HBASE/vision/isql.html#c1

A larger surface radiator has a different characteristic, its intensity falls off with less than the square of the distance. For a flat radiating surface, known as a lambertian, the intensity falls off as the cosine of the observation angle with respect to the surface normal.

Light modifiers will change the characteristics of the light, and will create a fall-off with distance that's somewhere between the 2 above extremes.

Also remember that light itself doesn't lose intensity (unless it's absorbed e.g. in the atmosphere, or reflected). It's the solid angle in the direction of the subject and it's distance that dillutes the energy, it's spread thin as it were.

Bart

 

[Daniel Buck]

A larger surface radiator has a different characteristic, its intensity falls off with less than the square of the distance.

Hm... I'm not entirely sure that I buy that. I've never heard of that before. I'd gladly be educated though! Have any links to papers that show this?

 

[Andy Haynes]

Don't have a paper handy but here's the why

So Apparent lightsource width = Light Source Width x Cos Observer Angle
And observed intensity is proportional to observed width if each part of the source contributes equally to the light output.

This assumes the source behaves as an infinite number of small sources all similar to a point source but radiating through 180 degrees.

This is therefore approxiamtely true for sources with well distributed intensity, such as a softbox, but certainly not true for things that are not flat, such as umbrellas, nor for directional light such as a strobe with a grid or snoot.


Observed intensity is thus:

I = Width x Cos Angle x Distance x Distance

Which is also only true if distance is much bigger than light source width. When distance is near equal to width then it's much more complicated...

I'll try to find a good paper or reference.

 

[Bart_van_der_Wolf]

So Apparent lightsource width = Light Source Width x Cos Observer Angle
And observed intensity is proportional to observed width if each part of the source contributes equally to the light output.

Yep, that's the reason, and agian; light intensity itself doesn't fall off with distance (unless absorbed/scattered on the way). A point lightsource emits radiation in 'all' dimensions so, as distance increases, the solid angle and thus intensity is reduced. A flat Lambertian surface emits evenly in all directions in every point of its surface and effective output is multiplied by the visible surface as seen by our objects or our eyes. From an angle, the apparent surface becomes smaller when observed from a more oblique angle, compared to head-on / perpendicular to the surface.

Such a diffuse surface can be restrained a bit by adding a honeycomb grid, to reduce ambient reflections from the side surfaces/objects.

Umbrellas can have different surfaces, where a glossy (silver/gold) surface gives harder shadows than a matt white surface, or it can be translucent (which requires more power for an equal exposure). When a refelctive umbrella is shaped as a parabola, and the lightsource is positioned in its parabolic focal point, then there is less risk of reflexions to the side because the emitted light is more parallel/collimated. That can produce a very large and uniform lightsource (no hotspot) and produces non-intrusive highlight reflections, and still somewhat contrasty directional light (despite its size).

Here's an example of the different effects (but size and distance are still variables):
Silver-white umbrella reflector
Octobox
Combined modifiers

I'll also look for some other reliable sources on the internet.

Bart

P.S. Here are some instructional video's for the OP.
http://www.graspr.com/videos/Studio-modifiers-part-1
http://www.graspr.com/videos/Studio-modifiers-part-2

 

[Leonardo Boher]

I was wondering about the fall off because a photo I took using the light of 1 candle. The candle light fall off is very similar to the sunlight coming through the window, because it falls pretty quick too. At that point I asked myself why the ratio is so strong, and I figured something about intensity, meaning that the candlelight intensity is too high at the beginning, but falls off pretty quick, so I wondered that other kind of light may be less intense in the center of emitions but more wide in range.

Some knowledge from the stone age lol!

 

[Per Ellström]

What do you mean by, "Simulating room light from a window"?

Do you mean,

• simulating room light by a strobe behind the window?
  
• simulating room being lit from light naturally coming from a window?

In any case, her face is bright and the distribution of light appears to be coming from the front.

Asher

Sorry for responding so late, I had no subscriptio on the thread.

The light is actually coming from two different directions other than the "window" light. Thats how I would light it if I had been in the "room". The "front" light being the light in the ceiling lamp, hence the nose shadow.

I used umbrellas for the back lights and two bare flash in front ( clamshell ).

To simulate cloudy days ( soft light ) I use a room divider with a white sheet ( porr mans softbox ) that is 8x8 feet. That also gives an unusual catchlight, like a 3-part window. Heres an example where I placed the model at a bus top in post.