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Monday, October 27, 2008

On-Axis Fill: Ring Fill Against Restricted Light

Having begun to explore fill with a ring flash, I knew there would be other ways to push light from on or near the lens axis. But before I tried them out, I wanted to learn how a ring light fill would work in combination with a more restricted key light.

Hard key light leaves hard shadows. And if you are not taking into account the ambient light (maybe the ambient light quality sucks, for instance) on-axis fill can reach into shadows and open them up in a highly controllable way.

Keep reading for two quick set-ups, and a refresher on ratio control without a flashmeter.


Swamp Thing

This summer as I was looking for any excuse to experiment with ring-as-fill, my son Ben returned from a day at camp wearing the shoes you see pictured at the top of this post.


My wife: "Do NOT come inside with those shoes. Clean them off with the hose outside."

Me: "Don't clean 'em yet! I want to shoot them. (... on your mother's great-grandma's antique cutting board, I did not say out loud...)"


Hey, we don't use the board for cooking. It is mostly used as decor against the counter backsplash. And it covers up the mess and tangled wires around the phone pretty well, too.

We only have a few minutes before dinner, so this will have to be quick. No problem, as I already have my background (secretly) picked out. I love shooting details like this for the family album, and these shoes say a lot about a well-spent summer day for a seven year-old boy.

Having seen what the ring would do against an umbrella, I wanted to play with some hard light. My thinking was, this combo will let me dial in however much texture I wanted by filling against a hard shaft of light.

But before I could make the hard key, I needed my ring flash as fill. I cranked my lens down to a very small aperture to hold focus and dropped the shutter speed to 1/250th to kill the ambient. Then, I adjusted the power output on the (manual) ring flash until I got the proper exposure.

(I was using a Ray Flash adapter fitted onto a Nikon SB-800 speedlight for the ring light.)

Now, since I was already way down on the aperture, I dropped the ISO a couple of stops to take the ring flash from being properly exposed down to a nice fill. I looked at the histogram and rear display and it looked like a nice "baseline exposure" for what would become my shadows in a moment.

This is no different than dialing down your ambient before you add in your key light, except that it was all being done with flash.

Now, for the hard fill.

Using a set of ten-dollar barn doors designed for small flashes, I closed off the spill of the key light until just a small beam was getting through from hard camera left. I used a 1/2-strength CTO gel to warm up the key somewhat to accentuate the color of the mud.

Given that my shooting aperture is set, as is the number of stops I have already dialed down my fill, the only thing left to do is to adjust the key light until the direction and exposure looks best.

No meters -- just eyeballing the relationship between the tones on the rear screen and making sure my histogram is not out of whack.

Quick and easy, and I notch another quick experience in my goal to get more comfy with on-axis fill. Honestly, the hardest thing about the shoot was smuggling the cutting board out of the kitchen (and back in) without Susan noticing.

I really like the ring-against-raking-light look on the muddy shoes. The highlights are crisp, but you can see right into the shadows -- exactly as much as I want, thanks to the lighting ratio on the fill. The ring also gives that characteristic wraparound shadow -- which looks kinda cool against the highlights, too.


Ring Against Grid

A few days before Ben's shoes, I had done a little more experimenting with ring fill and hard light, and I found myself growing more and more comfortable both with the technique itself and the key-to-fill ratios.

This portrait of Em, done in the last days of single digits before her tenth birthday, was the first time I had worked with ring and grid light. But I already had a good idea what to expect, thanks to experimenting earlier with on-axis fill and umbrella key in Dubai.

There are two ratios to consider here, and if you are into reverse engineering should be able to spot them by looking closely at the photo.

The first is the ratio of the ring (which will end up being the fill) over the ambient. You can see how far the ambient drops off by looking at the depth of the ring flash shadow (around Em) compared to the surrounding bricks in the areas of the photo not lit by the gridded key light.

The second ratio is that of the gridded key light over the ring fill light. This you can see in the shadows on Em's neck and under her nose. (These shadows are left by the key light, but are lit by the ring fill.)

Which means that in this setting, we have two control levers to adjust the contrast range of the photo. The ring flash was about a stop and a half over the ambient and the gridded key (coming from upper camera right) was another stop and a half over the ring light.

(If this shorthand exposure information doesn't make sense, take a look at this post.)

I have to say, I immediately loved the look of the ring fill against the gridded key. It was crisp and open all at the same time, and every portion of the photo was tonally legible in a controllable way.


Baseline Exposure Cheat Sheet

I was starting to get familiar with the Ray Flash, and was finding that it knocked off a little more than the one stop (vs. direct flash) advertised by the manufacturer. To be fair, after testing I found it to knock off about 1.2 stops -- if you used the 24mm throw as a bare-flash comparison.

Real-world (50mm throw) I would call it close to two stops. But that is still plenty powerful to use as a beautiful fill light at portrait distances outside.

Having experimented in a darkened room, I tested it to see how much light it would throw in a given ISO and power setting. To help me learn get faster at future setups, I stuck my standard cheat sheet on the Ray Flash:


The numbers:

1/2 power -- ISO 400 -- 10 Feet -- f/8


From there, I could quickly interpolate differences in any future setups to get a starting point for my power setting in manual.

Comfortable with the tests, I was ready to try ring light as fill on an assignment -- confident that I probably would not screw it up completely.


__________

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22 Comments:

Blogger stefanogiovannini said...

i think on axis / on camera flash can be great.
and 2 dimensional is great too.
graphic and patterns!
http://ngm.nationalgeographic.com/2008/11/tarahumara-people/kendrick-photography.

I like the setup of the shoes. in the portrait of the girl the shadow bothers me - I would like more on axis flash.
Anyway I like some setups i see here - but i feel sometimes bidimensionality is shunned.

I like a colorful wall and flat lighting - you see more of color / patterns faces. you can try different ways to frame with more freedom to move. it has a place.

October 27, 2008 2:10 AM  
Anonymous Anonymous said...

This might be a good place to point out that the light output of the rayflash adapter varies quite a bit with the zoom setting on the flash. You get much more light at 105mm.

Another thing is that I sometimes find the Rayflash too powerful. I often have to use 1/128 power when the key flash fires through an umbrella and I'm close with the camera.

-Marin

October 27, 2008 5:34 AM  
Anonymous Anonymous said...

Any filtration on the ring flash for the shoe shot? You know, ala Pete McArthur.

October 27, 2008 6:30 AM  
Anonymous Anonymous said...

I think you have stock in ring lights LOL

October 27, 2008 9:29 AM  
Blogger David said...

Anon @5:34- Really? Thanks much for the tip. I will check it out.

Anon @6:30- No gel on the RF for the shoes or for the portrait. I think I had a 1/4 CTO (my standard keylight gel) on the grid flash on the portrait.

Anon @9:29 - I wish. Boy, do I wish.

October 27, 2008 9:48 AM  
Anonymous Anonymous said...

"Two-Step" I get it :)

October 27, 2008 10:06 AM  
Anonymous AlanS17 said...

What's the inside diameter of the barn doors you're using? I've read through all the linked posts and reviews, but I can't find that simple figure. That would really help for people using off-brand and less popular flashes.

I currently have an SB-600, and I'll have an SB-900 (yes, I'm a sucker) arriving later this week. I'd like to know how well either one will fit. I think the SB-600 might be prohibitively small and the SB-900 may be flat-out too big.

Thanks in advance!

October 27, 2008 11:33 AM  
Blogger Monty said...

David

On July 15 you mentioned the upcoming Orbis Ring Flash adapter.

Is there any news yet about this. These days 3 months can seem like forever.

I loved trying out YOUR ring flash at the park meetup and knew I wanted my own. I have been playing with a DIY ring flash for months now. But I would like to start using something a little bit better.

Ron M.
http://CaneBayPhoto.com

October 27, 2008 3:34 PM  
Blogger David said...

Monte-

I am waiting right along with you. Apparently, there were samples at Photokina, but that is the last I have heard. (No sign of them in the US, including at Photo East last week.)

-D

October 27, 2008 4:08 PM  
Anonymous Anonymous said...

There's a sub-genre happening here: Strobist Shoes.

http://www.flickr.com/photos/off_camera/sets/72157605915989127/

http://www.flickr.com/photos/bbxjai/2673919162/

http://www.flickr.com/search/groups/?q=shoes&w=71917374%40N00&m=pool

October 27, 2008 5:22 PM  
Anonymous Micheal Hall said...

It's interesting to see how the off axis main light adds detail, gives relief and a sense of texture and how the on axis fill, in contrast, flattens and removes depth from those areas not struck by the main light.

I haven't particularly cared for any of the previous examples where the on axis light gets "too strong" (my opinion of course), but this image is an interesting one. I think the key is that the main light is restricted.

The ring light adds a subdued shadow around the shoes, that doesn't match at all with the directionality of the main light. That makes the visual cues a little "confusing" but attention grabbing.

Neat.

October 27, 2008 5:29 PM  
Blogger Ryland said...

Quick question:

If the SB-800 with the Ray Flash is mounted on the camera's hot shoe, thereby excluding the using of a PW and blocking the CLS function of the master flash, how are you triggering the second flash?

October 27, 2008 6:34 PM  
Anonymous Anonymous said...

I think it's great that DH tried so hard to sneak the antique cutting board out of the kitchen and back in without his wife noticing, then posts that he did it to literally millions of people online.

October 27, 2008 6:39 PM  
Blogger David said...

Ryland-

The Ray Flash will pass the CLS pulses right through when used as a master. Range is a bit reduced -- not a prob in a ring portrait environment, tho.

In these situations, tho, I am using the RF in manual and slaving the key light.

-D

October 27, 2008 6:44 PM  
Anonymous CW said...

David,
Seems like the RF can't work with a PW, unless you can also use a cable for the PW when the hot shoe is also used? Kind of messy though. Have you noticed any LOS impairment with CLS?

October 27, 2008 7:02 PM  
Anonymous Anonymous said...

I've got to try the ring flash technique for on-axis fill. I'm work on a DIY "ray-flash" adapter from my own camera, but I stumbled upon a really cool Fiber optic ring-flash for use with the built-in flash seen here:

http://fuzzcraft.fuzzphoto.eu/ringlight4-0.html

This is really a great idea and I may look into designing one for my speedlight.

Thank you for the great post again David! I'm addicted to this site!

October 28, 2008 10:50 AM  
Anonymous Joe said...

The 'thin shadow' around the shoes from the ringlight can be reduced by spreading out the on-axis fill... the wider the ring light, the less-distinct that shadow will appear.

One way to do this when using a ring light would be to cut a larger doughnut-shaped sheet of diffusion material (Rosco gel backed w/ thin plexi for stiffness)to suspend off the front of the ringlight (which becomes cumbersome in practice).

A better way to overcome this rim-shadow is simply to set a 60" or larger umbrella behind the camera (and yourself) to serve the same on-axis-fill-light purpose. This will also save you $300, and it's intensity will not vary as you move the camera closer and/or farther from your subject (as the ringlight's intensity varies tremendously when moved in or back).

Ringlights are best used in combination with a zoom lens, to change your framing w/out having to constantly readjust the ringlight's power setting whenever the camera is moved even slightly.

October 28, 2008 12:03 PM  
Anonymous Anonymous said...

I've learned one thing from this. A very ugly pair of shoes makes for a very ugly photograph. Regardless of the lighting.
Garbage.

October 31, 2008 5:03 PM  
Blogger Blake said...

Here's my attempt at a similar shot, just with a Gary Fong LightSphere II instead of ring light (link with full setup details).

November 06, 2008 12:58 AM  
Blogger Lola said...

Can someone please explain this part to me: "The ring flash was about a stop and a half over the ambient..."
I know how to measure the ambient (take a reading on auto, although in a darkened room this is going to give a really slow shutter?) so if my flash is on manual how do I measure it in stops in relation to the ambient reading?

January 11, 2009 6:27 PM  
Blogger Shane Poppleton said...

Hi David,

I have only been following strobist for a month or two, but started right back at the beginning and working my way forward in time, post by post. There is a lot to digest, and I can understand your shorthand notation OK, but am having trouble doing it in practice.

When you say you underexpose ambient by 2 stops, does that translate to.

"Zero out the meter in manual and then (if using 1/3 stops), close down the aperture 6 clicks, or faster shutter speed by 6 clicks, or use a combination, i.e. 1 full stop smaller aperture and 1 full stop quicker shutterspeed."

I think I have that down, but then when you bring it back up with the flash, how do you know that you have brought it up to a perfect exposure, do you just check the histogram, and chimp?

Also if using 2 lights, and they are different guide numbers and different distances from the subject how do you dial in your second light to be 2 stops hotter than your fill? Is it just by feel, or do you have to get out the calculator?

October 18, 2011 8:41 AM  
Blogger Shane Poppleton said...

Hi David,

I have only been following strobist for a month or two, but started right back at the beginning and working my way forward in time, post by post. There is a lot to digest, and I can understand your shorthand notation OK, but am having trouble doing it in practice.

When you say you underexpose ambient by 2 stops, does that translate to.

"Zero out the meter in manual and then (if using 1/3 stops), close down the aperture 6 clicks, or faster shutter speed by 6 clicks, or use a combination, i.e. 1 full stop smaller aperture and 1 full stop quicker shutterspeed."

I think I have that down, but then when you bring it back up with the flash, how do you know that you have brought it up to a perfect exposure, do you just check the histogram, and chimp?

Also if using 2 lights, and they are different guide numbers and different distances from the subject how do you dial in your second light to be 2 stops hotter than your fill? Is it just by feel, or do you have to get out the calculator?

October 18, 2011 8:41 AM  

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