Tuesday, September 4, 2007

Off-Photographer Camera

Five-foot-eight Matt Adcock (who is still taller than me) apparently loves his babies Canons more than does digicam-tossin' Mike Larson, as Matt opts for the camera-on-a-stick method of getting those overhead shots.

The difference, of course, is that Matt is still rockin' the off-camera flash. He has a voice-activated light stand toting a synched speedlight.

Can you see the second flash, which is actually in the photo? Hit FlashFlavor.com to see a bigger pic, and learn more about how Matt does it.

(When he is not running like a mama's boy from a little hurricane, that is.)

(Shot of Matt by Matt's Better Half: Sol Tamargo)

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Smartflix Adds 'Dean Collins Live' Video

If you never got a chance to catch lighting guru Dean Collins lecturing live, you can now rent Dean Collins: Live at Brooks Institute of Photography 1991 on Smartflix.

(Well, you probably can't right now, because other readers from this site probably just beat you to it and soaked up all of their copies. But you can get in line.)

I am a huge fan of Collins, who also has a "Best of Finelight Video" 4-DVD Set [review] that totally rocks. The clothing and hairstyles may be passé, but the first-rate lighting info is timeless.

You can purchase the video through Software Cinema, here. You can watch a preview of Collins talking about his Chromazones theory there, too. Check it out.

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Lighting 102 - 3.1 Balancing Light: Twilight

For the available-light photographer, the idea of exposure is a fairly simple and static concept.

There is a correct exposure for a given ambient light scene. Sure, you can tweak it, say, half a stop up or down. But go much beyond that, and you move beyond "artistic license" to "I screwed up."

But what is the correct exposure when your photo can have as many different zones of varying light levels as you have flashes? The correct exposure is what you say it is. And you say it by establishing a zone of (traditionally) correct exposure on your main subject using the flash.

If you are looking for a touchstone in this process, that's it. Establishing a correct exposure on your primary subject allows you to do whatever you want with the exposure levels in the rest of the frame. And you can go far beyond the "correct exposure" range of an ambient-only, evenly lit scene. And look like you knew what you were doing.

In short, "screwed up" becomes "artistic license" when you have established an exposure reference point with your light on your main subject. (More after the jump.)

To really understand the concept of balancing light, many of you will have to expand your concept of a so-called proper exposure. After all, you are creating a scene that has precisely the tonal range that you want it to. You can use this ability to compress the tonal range of a photo, or to expand it. It's up to you.

Take this scene photo which includes long-time Strobist reader Ryan Brenizer. Exposing for the model, the sky is washed out. Exposing for the sky, the model would be too dark.

But with flash, you can expose correctly for both. By adjusting the shutter speed and aperture to get exactly the desired tone in the sky and then filling the model with flash sufficient to raise her exposure to the aperture you happen to be using, you get this:

In addition to turning the water into diamonds with his flash, Ryan has compressed the tonal range of this scene to where everything fits in the histogram rather nicely, thank you.

So, is Ryan shooting at the correct exposure? Yes. Or no, depending on exactly how he wants the background to look.

Ryan shot this photo at 1/250th at f/3.2 at ASA 160. He could easily open his shutter speed up to, say, 1/125 and lighten the background. Or, he could up the power on his flash by a stop, close his aperture down a stop (to f/5.0 - a partial stop between f/4.0 and f/5.6) and reset his shutter to 250th to darken the background.

How does that work? Let's look more closely.

The background is lit by ambient light. It is controlled by a combination of the aperture and the shutter speed. The model is exposed by the flash. (She would be significantly underexposed without the flash.) So as long as the model is receiving the correct amount of light from the flash, the background can be placed at whatever tone the photographer wants.

What if Ryan cranked up the power on his flash 2 and 1/3 stops to where it lit the model to f/8? (He would then set his aperture to f/8 to correctly expose her.)

But what about the shutter speed? The new shutter speed to get the same effect on the background would be 1/50th of a second. (We simply open up the shutter 2 1/3 stops to neutralize the fact that we closed down the aperture 2 1/3 stops.) Thus, the exposure on the background has not changed.

We did this step to get away from our 1/250th of a second sync speed, and give us some "playing around" room with the shutter speed.

So now, imagine you are Ryan, wading in the water, shooting at 1/50th at f/8 and getting the same tones as we see above. Now, say you drop the shutter to 1/100th. What happens?

Model lady does not change. She wants f/8 from the flash and that is what she is getting. But the background gets one stop darker. You have just increased the contrast range of the photo. Darker, moodier and looking completely different. And I'm thinking those water diamonds are really popping now.

Drop the shutter down to 1/200th. Darker still -- but not black yet. Completely different feel to this photo than with the other two.

Which is correct? They all are -- just different. "Correct" is determined by the exposure on the model -- and that is set by the flash (and choosing the corresponding aperture that makes her look well-exposed.)

But the sky? That's up to you. Airy, normal, moody, black -- it's all good. And it is all available to you.

What you have is two different photos -- each with its own exposure -- being compressed into one scene. There is a flash exposure, which happens instantaneously and is controlled with the aperture. Then you have an ambient exposure which happens over time and is controlled by a combination of the aperture and the shutter speed.
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Now, You Do it

Our first light balancing exercise will be very similar to Ryan's setup, except that you will probably stay dry and you probably won't have a beautiful model to work with. (If you want to stick a gorgeous model into the water to do this, knock yourself out.)

Drag a partner out to an area where you have a fairly low horizon and a view of the western sky. Go out at about sunset and wait for the twilight sky to meter (continuous light level) at your sync speed (probably a 250th) at f/5.6 at a reasonable ASA (ASA 200 or 400.)

Now shoot a photo of your model using the correctly exposed twilight sky as a backdrop. He/she will be too dark.

Next, light your subject with a flash so that he/she is correctly exposed at f/5.6. You can do this with hard or soft light, on-camera or off-camera light -- I don't care. We are working on balancing light here.

Shoot a few frames of your subject this way. Talk with them. Tell them how good they look. Show them the images on the back of the camera. You are doing this to (a) build rapport and (b) to keep them around for a few more minutes.

Pretty soon the twilight background will drop to 1/125. Adjust your shutter and keep shooting. Next it'll go to 1/60th. Adjust your shutter and keep shooting.

But now, also shoot some frames at 1/125, to underexpose the background by a stop. And try a few at 1/250th to underexpose by two stops. You should see a very different feel in these photos, but they should all look okay, as does the underexposed sky in this photo, by Jonathan Shears.

When the background drops to 1/30th instead of opening up the shutter to compensate, turn the power on your flash down by one stop. (If you were shooting at 1/4 power, move to 1/8.) Now, instead of opening up from 1/60th at f/5/6 to 1/30th at f/5.6, you're opening to 1/60 at f/4 and adjusting your flash to compensate. This buys you more shooting time before you get into the "Hail Mary" range of shutter speeds.

The next time the sky drops another stop in exposure, power down your flash another stop and move to f/2.8. if this sounds difficult, it is not. Try it.

As your light drops lower still, keep opening up your shutter. Play with different speeds to see the effect on the background. But remember to choose the correct aperture to expose your subject correctly with the flash.

You will soon have too little light to focus. But before that happens, you'll have a lot of cool photos, with a range of background looks.

If you want to post some, tag them:

Strobist
Lighting102
Balance
Twilight


You can see the tagged photos here. If you would like to talk about it, I have set up a thread here.

There's lots more coming on the light balancing front, so no need to get fancy yet. Next week, we'll be looking at how to do this kind of thing in full daylight.
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Related post:

:: On Assignment: Custom Backdrops Delivered Daily ::


NEXT: Crosslight: Balancing With the Sun

What is That -30- Thing?

WIth the new "read more" tags, I have moved portions of some of the longer posts off of the front page. This allows more items on the front, while keeping page load times down for the dial-up users. But in my template, the tags show up on every post, whether there is a jump portion or not. (Still looking for a workaround on that.)

If you click through, you will get the entire post, plus any comments that have been published. But if you are already at the end of a short post, you'll see a "-30-" which is a journalism convention signifying the end of a story. The origins of the symbol are not clear, but it dates back to the US Civil War. (If you are a journalist, you almost certainly know the term.)

Clicking through after seeing a "-30-" will still allow you to see the comments, if there are any. But you see a -30-, are already at the end of the post.

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Monday, September 3, 2007

Just Look at You.

I just spent two hours going through the Strobist Flickr pool, checking out your stuff and tagging faves. To put it bluntly, you all are getting to be a pretty intimidating group to blog to.

Check you out here.
(Swimmers by Chad Coleman.)

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Feed Your Flash Ni-MH's

One of the perks of shooting for a newspaper is that your day-to-day supplies are usually taken care of for you. You get issued a bag of daily equipment -- the stuff that goes with you everywhere. You also have access to a "pool" room, full of more exotic gear (600 f/4, anyone?) that would make the typical amateur drool with envy. And you have a battery drawer.

Our battery drawer at The Sun was full of industrial Duracells. The supply never seemed to go away.

Oh, we used them by the case. It was only that Jeff, our Gear Guru, made sure the battery box was pretty much bottomless. Did some of the batteries find their way into R/C cars, or maybe baby monitors? Maybe -- I'm not sayin'.

But when we started going through them too quickly Jeff would occasionally remind us that we did not, in fact, have to replace the batteries in our flashes every day. We got the message.

It is against that backdrop that I'll tell you that I stopped using the "free-for-me" alkaline batteries about a year ago. It was after reading some of the reader responses to this post, where we talked about some of my preferences exterior power options for speedlights. I got an earful in the comments and in emails.

What started out as a little battery experiment has led to a wholesale change of approach when it comes to how I power my flashes.

Nickel-Metal Hydride (Ni-MH) rechargeable batteries and your flashes are a match made in heaven. I have long-since abandoned the company-supplied alkalines to switch to the more expensive batteries, which I had to buy out of my own pocket.

Why? They are so much better than alkalines, it is a no-brainer. In fact, they are better for your flashes in just about every way.

(More after the jump)
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Ni-MH's: Cheaper

Technically, my Duracells, were free -- for me. But for the sake of argument, let's assume that alkalines cost you 50 cents each and Ni-MH's cost $2.00 each. (Which is pretty close to being correct as of today.)

Ni-MH's can be recycled hundreds of time if you care for them correctly. Which takes the cost down to less than couple cents per cell over time. Sure, it costs some money for the power to charge them. But that is negligible compared to the cost of replacing an alkaline battery.


Ni-MH's: More Convenient

But there are more to cost than just purchase and recharging costs. Time is a cost, too. And if you don't get by the office very often (a practice I employed for a variety of reasons) you can find yourself having to schedule a "supply run." That bites.

Ni-MH's can be bought in packs that include 4 AA's and a 1-hour charger that can be plugged into the wall (easy enough) or plugged into your 12v cigarette lighter jack in your car. Which means you can top off between assignments any time you like, even when shooting on location or in your car heading to the next shoot.

That is about as convenient as it gets. And any choice that keeps me out of an unnecessary trip to the office is a good thing.

I even ran a 12v line (only powered when the car was running) back to the trunk for easy swaps when I was putting gear back into the car. So in terms of both money and timed saved, NiMH's kick butt.


Ni-MH's: Faster Recycle Time

None of this would matter if the batteries were crap. Fortunately, that's not the case.

At 1.25 volts for each Ni-MH battery (compared to 1.5 for alkalines) you'd think that NiMH's would be sucking wind when it came time to recycle your flashes. After all, 4 NiMH's (connected together in series) only have 5 volts, compared to 6 volts for alkalines.

To be sure, Ni-MH's are at a disadvantage in the voltage department. But voltage is not the only thing that matters in recycling a flash. When that flash is chirping away and you are waiting for the little light to turn red, what a flash needs is current. And NiMH's deliver current in spades.

Think of two hoses, with the first having a little more water pressure than the second. But the first one is a garden hose, and the second is a fire hose. The fire hose may have slightly less water pressure, but it can still deliver more water per second. Ditto the Ni-MH battery with current.

Example: My SB-26's take 6-7 seconds to recycle a full-power, manual shot with good alkalines. But with fresh Ni-MH's, they recycle in 3.5-4 seconds.

That lower-voltage/faster-recycle thing is counterintuitive, but true. And to be honest with you, if they were slower than alkalines I would still be mainlining the Duracells.


NiMH's: Greener

Finally, Ni-MH's are greener than alkalines, if that kind of thing matters to you. An old friend of mine (who I just found out happens to read this site from Cairo) once told me that environmentalists make pain-in-the-butt neighbors, but great ancestors.

The green thing is not the end-all for me. (I am getting greener -- I now proudly recycle 100% of my bad jokes.) But as icing on the cake, it's pretty cool.

For instance, if your spouse is a serious treehugger, you may completely forget to mention that Ni-MH's are faster, cheaper and more convenient for you. Instead, you might offer that you did this just for her, as a gesture to her environmental sensitivities. After all, what maters to you matters to me...

(Now, can I please watch the Florida football game next Saturday instead of mowing the lawn? Thanks, honey. You're the greatest.)


Ni-MH's: Selection, Care and Feeding

Driving Ni-MH's are a little different than alkalines. So there are a few things you'll want to know.

First, "mAH" matters. mAH stands for miliamp-hours, and it tells you how much power the little guys can hold. All things being equal, go for the higher number. In fact, I would say get at least 2500 mAH batteries. Unless you see 2750's, in which case buy them. They are so cheap over the long haul that you may as well buy yourself more capacity.

Second, resist the temptation to get the 15-minute chargers. They work, but are very hard on the batts. Best for them is the overnight trickle chargers, but that could cramp your style. (I like to rotate shooting an charging sets on location.) The 1-hour, or 1.5-hour chargers are a very good compromise.

Third, think about your batteries as being a quartet. They like to sing together. Batteries that are charged and discharged together over time perform better and last longer. I like to label my sets with a number or letter. (My first idea, to label them as sets with a woman's name, was completely misunderstood and I am not going to talk about that further except to say not to do it if you are married.)

I have two sets of batteries (and one, four-cell charger) for each flash. This works just great, as I can charge the "B" sets on location faster than I can shoot down the "A" sets. Essentially, you have unlimited power.

There is one blemish on the record of Ni-MH's. They self-dischage faster than alkalines. Which means two things to consider. First, I tend to top them off (no memory - top them off any time) within a couple days of when I am going to need them. Basically, I am just always shooting and rotating them through chargers, which they really seem to like.

It is for that reason that I still use Ni-MH's in my Pocket Wizards, which are so stingy on power that I have to try to remember when the last time I changed the batteries was.

Some people swear by the new Ni-MH "Eneloop" batteries (by Sanyo) which reportedly self-discharge more slowly. I have not tried them yet but plan to. If you use them, please report on them in the comments.


Where to Get Them

There are several websites that specialize in rechargeables. Amazon sells them, too. But to be honest, I have been very happy with my sets from local discount stores. Wal-Mart, specifically. (I know. Sorry.)

For $18, I get a set of 2700 mAH's and a 1.5-hour charger that works on US A/C, car battery or in A/C in Europe. I get the "B" set of batteries for each flash (no charger needed) for another $8.00. This is an instance of when you would want to buy local -- or at least in your country. It does you no good to get a set and a charger with a US and Euro plug if you are in the UK.

Wherever you get them, do yourself a favor and switch to Ni-MH's if you haven't already. There's a lot to like about them.

Sunday, September 2, 2007

Coming Tuesday: Light Balancing Unit

This week we'll be starting light balancing in the Lighting 102 series. It is, IMO, the most enabling of all of the lighting controls. But it is also a little tough for some people to get.

You might want to scan the related Lighting 101 material as a review in the next couple of days.

:: Balancing Flash with Ambient, Pt. 1 ::
:: Balancing Flash with Ambient, Pt. 2 ::

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