Lighting Q and A, 09-12-08

This week's questions are all about gels. Hit the jump for the light-sucking, color-shifting details...




James, who would tell us where he lives but then he would have to kill us, asks:

"If you gel a flash, say a full CTO for instance, does the power output of the flash alter the color thrown? (I didnt know if it had the same effect as say dimming a tungsten bulb where there is a dramatic color shift between full and almost completely dimmed.)"


James, the color of the gelled flash will remain consistent. The only thing that is actually changing as you dial down a speedlight is the amount of energy that is being discharged through the tube. The tube always flashes at (almost) exactly the same color.

For those who have not yet discovered the color shift in incandescent bulbs, take note: If you are trying to balance tungsten ambient up with a CTO'd flash, crank those ambient lights up. They only balance well at full power.

But if you want a deep, ambient red (for effect, say, in a candle-lit room) dim the lights down as far as you can stand it. Awesome colors that way. You can eyeball it, too, as you get close to low power.
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Cheryl, from Toronto, Canada asks a related question:

"How much light does my CTO filter soak up? I would like to know how much to raise the power on my flash to compensate."


Excellent question, Cheryl, and if you memorize a couple numbers, you can really help yourself.

A full CTO gel costs you 1.1 stops of light. For all practical purposes, I think of it as one stop.

Which is to say that if your flash (at 1/4 power) is giving you the proper exposure at a given distance, and you slap on a CTO gel on there, you'll either need to open up a stop or move up to 1/2 power. The partial CTOs follow the trend: 1/2 CTO costs a half stop, 1/4 CTO costs 1/4 stop, etc.

The CTBs are a little less efficient, and weirdly nonlinear: Full CTB = ~1.5 stops, 1/2 CTB = ~1 stop. And a typical fluorescent (green) conversion gels cost about 1/2 stop of light loss.

For the most part, if you remember that CTO fractions equate to lost f/stops and FL greens cost half a stop, your flash workflow will be much more intuitive. A basic familiarity with light loss numbers will help to save you lots of exposure chimping during a shoot.

You can get full light-sucking information on all of the gels made by Rosco on their site. The RoscoSun numbers, for instance, are here.

If you do not know your CTOs from your CTBs, you can get more info in the gel sections of L101 and L102.
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Tim B., also apparently from no fixed address, asks:

"About bouncing strobes off the ceiling - I did this at a recent wedding reception and the light was nice. But the ceiling was somewhat yellow. I wonder if there is a way to set custom white balance on the camera to match the color of the bounced light. Have you ever done this?"


That depends upon a couple of things, Tim. First, how much is the ambient contributing to the photo? If you are nuking the room by bouncing several big flashes into the ceilings, you can shift the whole scene easily in post-processing to compensate. This, of course, assumes your ceiling is at least reasonably close to neutral. If it is chartreuse, your screwed.

If you are shooting RAW (which for a wedding you should be) grab a bounce light shot of a grey card, white sheet of paper, bride's dress, etc. Correct that item to white in your RAW importer and use that color setting for all of the pix in that scene when you import.

But if you are mixing in ambient with the flash (which is done by your chosen shutter speed, of course) then you got problems, my friend. Because when you shift the picture to fix the off-color bounce light, you'll move your ambient color in the opposite direction, too.

Here's the best fix I can offer: Keep a full set of Rosco sample gels in your bag for each flash. Grab the color the most closely complements the color shift of the ceiling. For instance, if the ceiling was a slight yellow, you might blue your flashes just a tad. Maybe a 1/8 CTB. Then your flashes will help to compensate for the ceiling color somewhat and you will not have to correct nearly as far.

This is not en exact science. But you can set your camera on daylight and do a quick test pop or two with your flash and see how much you are helping yourself with the gels.

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Thanks for the questions. Please keep them coming in the comments of this post, or here.

Today's Special: Gourmet Speedlights Al Fresco

UPDATE: Nick was kind enough to drop by and answer some of your questions in comments. (Thanks, Nick!)

I love letting the new submissions to the Strobist Flickr Pool build up for a few days, so I can spend a few hours looking through the thousand or so photos that have dropped in since the last edit.

That's a lot of images to look at in one sitting. But every now and then a photo really jumps out and grabs you. Such was the case with UK-based photographer Nick Turpin's series of portraits of thriller writers, shot for Arena Magazine.

They are sophisticated, stylish and bathed in pools restricted light. And they were done entirely with a few SB-800s and voice-activated light stands.

More, including Nick's video and links, after the jump.
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I hope you enjoy this movie as much as I did -- I probably watched it half a dozen times. Take a look, and then keep reading for some of the thought process behind street shooting with multiple SB's as light sources.




Nick says that began as a pure street photographer, and then started evolving his look to include small flashes. The street has since become his impromptu studio, and he is free to choose his settings on a moment's notice. He is now shooting magazine work and advertising campaigns, using gear that would be right at home at a Strobist meetup.

My guess is that he often is able to work without location permits because he is not setting up stands or tripods. And from the look of this video, this series was shot over the course of a single day.


When shooting outdoors in the daytime and using small flashes, there are three things to consider: Ambient level, balance and lighting direction(s).

It is helpful, though not mandatory, to work in shade. This keeps the ambient light at a manageable level. Still you'll want to start out at you highest normal sync speed speed, to give yourself a reasonable aperture.

Take a "properly exposed" photo and look at your frame. It will probably look okay. But likely a little boring, too.

Next, keep your shutter speed where it is, and start to underexpose your ambient light by dialing down your aperture and chimping the back of the camera. This will set the mood and contrast range of your photo. What you are doing is basically setting an ambient "floor" on your overall exposure via your chosen aperture.

How far down should you go? One stop? Two stops? Five stops? That is entirely up to you and depends on the look you are trying to achieve.

Now, bring in your lights. You will have to dial them up to a power level sufficient to properly expose your subject at the aperture you have chosen in the last step. Nick is using multiple SB-800's, snooted and aimed (via the VAL's) to create multi-directional pools of light on his subjects.

This is where it gets more difficult. Nick's eye for narrative (and humor, if you look at some of his other work) is what defines where he places his subjects and his lights. Sometimes he motivates the light with objects on the set (i.e., the lamp post) and sometimes he goes for pure, seemingly random whimsy. Your photos probably will not look like Nick's because you will bring an entirely different eye to your settings, body attitude and light placement.

But however you do it, cool things start to happen when you balance multiple hard lights against soft fill. It is as if your subject wandered into an area of interesting, mixed light. Texture happens. Depth happens. Interestingness happens. Sure, the light from the strobes is hard, but the shadows are only as deep as you set them with your baseline ambient exposure. So it is all under control.

What are your thoughts? Were you as surprised as I was to find the photos were done with speedlights and VALs? I found myself thinking back to Gregory Crewdson, mostly because of the sense of place defined by those pools of light.

Pretty amazing, when you think of the comparative amounts of gear being brought to bear on the shoots.

I love that VAL street lamp boom. To be honest, I love all of the photos in this series. It's amazing how he can be at once both sophisticated and mobile.

You can the whole series of portraits of thriller writers at Turpin's website. (More projects, and another video, here.)

Speedlnks: Sept. 8, 2008

Quickie batch of bonus speedlinks for Monday morning, after the jump:
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• PDN ran a piece on Tim Kent's amazing car photography, thus justifying Ken Brown's subscription for the next ten years. Don't miss the companion OA-style sidebar, too.

• If you live in eastern Canada and are a fan of Martin Prihoda, you may wish to check out a big-lights seminar he'll be doing in Toronto later this month.

• My bet is most of us get a steady stream of requests to shoot photos of friends and family. This is how you might do it if you were contributing SI shooter (and current cover boy) David Bergman. If that SI thing does not work out, Dave, you would make a heckuva yearbook photographer...

• If you are willing to give up your email address -- and can read German -- California Sunbounce is giving away 450 day passes to Photokina.

• Finally, in case you haven't seen it yet: Vincent Laforet takes a video stroll through Pocket Wizard heaven at the finish line of the 100m sprint at the Olympics. (Patrick Smith, if you are reading this from a public computer, you might want to put a pillow over your lap before you watch it...)

Los Angeles Lighting Seminar Registration Opens

UPDATE: Both seminars, Saturday and Sunday, are sold out. You can jump straight to the discussion thread, here. Please check that thread periodically, as the latest info will be there.

-DH
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Registration for the October 4th and 5th lighting seminars is now open sold out. Continue reading after the jump for details on the seminars.


LOCATION:

We will be at the Culver City Courtyard by Marriott, at 6333 Bristol Parkway in Culver City, CA. You can get a Google map of the location here.




WHAT WE'RE ABOUT:

With these seminars, my goal is threefold: To refine your approach to creating light, to fill you with as many ideas as possible in a day's time and to have fun doing it. We'll start with a roadmap for the day, which I will do my best to keep us on. But each session will take on somewhat of a life of its own. Which is a good thing.


Our Anticipated Schedule

Morning check-in/setup: 9:00 a.m. - 9:30 a.m.

Please plan to arrive between these times, as we will still be setting up before then and still waiting for the caffeine to kick in.


Morning session: 9:30 a.m. until approximately 12:30 p.m.

We'll talk about gear (I'll have a good gear selection there for a petting zoo) and take an extended, integrated look at what is essentially the Lighting 102 material in it's entirety. If you have seen the lighting DVDs, this is the roadmap we will follow for the day. There have been some new example photos added (I am always trying to evolve the material) but the general course structure is the same. Afternoon shoots are always improvised, so they are always different.

The focus will be on taking all of the things we talk about on the site in a day-to-day sense and integrating them to gain more of a holistic approach to lighting. Everything really is interrelated.


Lunch Break

On your own, approx. one hour, and we'll be looking for your nearby suggestions in the Flickr discussion thread related to this seminar.

We get a special all-day parking rate of $6.00, but no in-and-out privileges. There are several nearby restaurants listed here, including some within easy walking distance. The hotel has the typical hotel restaurant onsite.


Afternoon Session:

~1:30 p.m. - 5:00 p.m.

Assuming we have finished the theory stuff, we'll move into the practical/demo session. (Sometimes we go into a little overtime on the theory.) We'll get into some real-world lighting exercises photographing some models I will have cleverly hidden around the room disguised as ordinary attendees.

This is basically a lighting version of "Whose Line is it, Anyway?" with a focus on improvisational lighting based on available gear, the room, found objects, lighting mods, etc. I never know what ideas we will come up with, which is what keeps me equal parts interested in and petrified of the afternoon session. It's a good thing.

Shortly after each shoot, we will view each setup and discuss the results onscreen. This instant feedback in a group environment is a wonderfully efficient way to drive home the thought and technique process. We can read and write all we want. But for photographers there is nothing better than "monkey see, money do."

The goal will be to incorporate lighting theory, room environment, assignment constraints and our available gear to create a photo that seeks to produce an photograph that is an appropriate response to our situation.

Working within that framework will allow us to concentrate on better freeing ourselves in the other areas: Creativity and subject/photographer interaction.

The entire day will be a nonstop flow of ideas and techniques, punctuated by spur-of-the-moment Q-and-A. I want you to bring lots of questions, and to feel free to voice the ones that pop into your head throughout the day. In fact, if you do not ask me enough questions, I will start throwing some questions at you.

You might want to bring a notebook and pen. (I will have a URL to download the presentation, so you don't have to spend all day scribbling.) And please bring a camera if you want to shoot the setups as a visual reference. And dress is exceedingly casual, so you won't feel out of place if I show up in shorts.

I travel with cameras, projector, lights, stands, mods and clothing, which pretty much maxes out my baggage allowance. So if you happen to have a collapsible-type of background, feel free to bring it with you. More options is always better.

As with my philosophy for the website there will be no secrets and no posturing. This stuff is not rocket science. It's light. And the first step in learning to light is to realize that anyone can get very good at it.

We will plan to wrap up at about 5:00. But if we are still going (and they don't kick us out) who knows. Normally, a fair number of people come back to the hotel bar after dinner, where we discuss lights, darks, ambers -- whatever. Always fun.

If, for some reason, you require a cancellation after booking, refunds will be granted up until September 25. After that time, you would be responsible for transferring your seat to another attendee.

Very Important: If, through events beyond my control, I am unable to present this seminar, refunds will be limited to the ticket price. As I already have airfare, hotel room and our venue rental paid in advance, I do not anticipate this happening. But I just wanted to cover all of the bases, in case I get run over by a bus tomorrow, or one of those Big Macs finally catches up to me.

Bases covered, I would note that I am very much looking forward to this trip and especially to meeting many of you. As I do more of these seminars, I find that each session develops a vibe of its own. You put a few dozen photographers who are all eager to learn in a room, and what starts out as a simple stack of talking points turns into a rich, organic discussion that ends with everyone - including me - having a head swimming with new ideas.



Feedback from Previous Seminars

London:
Post-seminar thread | Extended report

Seattle:
Post-seminar thread | Extended report

Paris:
Post-seminar thread | Extended report

Northern California:

Extended report I | Extended report II

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Registration Details

The cost for either seminar is $159.00. The two seminars cover the same material, so you would register for either day, but not both.

To register for either seminar (with any major credit card) please click on the link at the bottom of the post, which will take you to PayPal. A PayPal account is not required to register.

VERY IMPORTANT: If you are in the process of registering and the seminar sells out, your fee will be refunded by the end of the day -- usually within the hour.

Please leave your name and phone number (and a working email if different from the PayPal address) in the info box on the PayPal page, in case I should need to contact you.

I look forward to seeing you there. The discussion thread for this seminar is here. Please save either your PayPal receipt or your confirmation email and bring a printout on the day of your seminar.


UPDATE: Both seminars are sold out.

Strobist Lighting Seminar: Los Angeles - Oct. 4th and 5th

Just a quick note that I am finally getting out to L.A. Just scheduled myself for a nose job (and a quick Botox touch-up) to better fit in with the locals next month at the Oct. 4th and 5th lighting seminars in Los Angeles.

We will follow the same setup as in this previous seminar in Phoenix. So read through that if you want more info, links to reviews, etc. Registration opens on Sunday at 8:00 a.m. local (LA) time -- watch this space. We'll be at a hotel (TBA) near LAX.

More details and full registration info then.

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TTD Video: How They Roll in Belgium

Thanks to Didier Jouret, who sent me a link to this video from a Pieter Van Impe "Trash the Dress" -type shoot.

This one is not so much about lighting, but it does include all of the typical stuff: Beach, sunset, trippy beats, happy couple, some champagne, a little nipple pinching, a kite-mounted Canon G9 for overheads, ... wait, WHAT?

Dude, I so want that G9 kite mount. He uses the G9 on a monster light stand, too.

Related links:
:: Pieter Van Impe ::
:: Tom Museeuw ::
:: Bridseye Kite Aerial Photography ::
:: Didier Jouret :: (Videographer)

Dustin Snipes on Quality and Quantity

Quick, what's the first image that would pop into your mind if you were assigned to go to a basketball camp and shoot seventy portraits in two days?

Picture day in seventh grade? I Love Lucy at the cake factory?

L.A.-based shooter Dustin Snipes shows not only that it can be done, but it can be done with quality and style. Check out his blog post for the details. And dig around for several more OA-style posts he has for you, too.
(Thanks, WSP! | Photo ©2008 Dustin Snipes)

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