Reflection and Refraction

Correcting Misinformation 2

2011-08-31T20:52:00.001-10:00

Are you ready for the latest in my sporadic series combatting equivocal, ambiguous, or downright fallacious information that has made it's way around in the popular media about photography? Let's go…

For this chapter, I'm taking on something I heard on Photofocus podcast # 85, released on August 25th, 2011. (Photofocus is an excellent podcast, by the way…) In this podcast, professional photographer Scott Bourne and a rotating guest host (pro photographer Joseph Linaschke, in this case) take questions about photography sent to them via email or twitter. The question I'm going to tackle here is one about the best way to "expose to the right," a common technique in digital photography. "Exposing to the right" is a way to use the histogram on your camera to increase (lighten) your exposure as much as you can, to allow you to maximize the amount of information you capture without losing highlight detail. I'll describe this technique in more detail in a future post, as well as something on the basics of exposure.

The questioner asked if there was a quality difference between using exposure compensation, adjusting the ISO and changing the aperture/shutter speed combination. Scott started his answer by saying "When you start talking about ISO, then ISO should be ISO and has nothing to do with exposing to the right." Misinformation alert!

In this answer, Scott appears to be reminiscing about his days shooting film. In any photo, exposure is a combination of three factors: ISO (the sensitivity of the sensor), aperture (how wide the hole in the lens is that lets in light), and shutter speed (how long that hole stays open). In the days when film was king, you really only had control over aperture and shutter speed; while you were out shooting, you were stuck with whatever ISO film you had loaded in your camera, unless you wanted to rewind it and put in a new roll partway through a shoot. One of the advantages of digital is that you can change the ISO from shot to shot, if you want; many cameras also include an "auto ISO" feature, where you decide on the lowest shutter speed you're willing to accept and the camera dynamically sets the ISO to ensure you don't go below that speed.

So lets put this in practical terms… Say you're out shooting, and you take a shot at f/8, 1/250th of a second and ISO 100. You check your histogram, and notice you have a little bit more room for highlights, so you decide to take another shot, this time to expose to the right, and you want to increase the exposure by one stop. You could open up the aperture to f/5.6, but f/8 gave you the perfect depth of field that you envisioned for that shot… You could also change the shutter speed to 1/125th of a second, but then you might get a little motion blur from some elements of the shot that are moving around… ISO to the rescue! In this case, to increase the exposure by one stop, you could keep your aperture and shutter speed the same and increase your ISO to 200. That would quite effectively slide your exposure over to the right without changing the other artistic elements of your photo. You do, however, run the risk of increased noise with an increased sensitivity. (Didja really think you could get something for nothing? There ain't no such thing as a free lunch.)

The bottom line is that you CAN use ISO to adjust exposure in order to expose to the right. Take a look at your camera manual to see how to adjust the ISO, and go forth and photograph!

See more of my photography at http://lokahiphoto.com.
Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

Note to the Airline Traveling Public

2011-05-22T13:05:00.002-10:00

Note to the airline traveling public: I know you bought that roller bag carry-on because you can pack everything you need for your little trip in it, so you don't have to waste your time at the baggage claim. BUT… when you stand there in the aisle and try to sledgehammer and/or crowbar that ever-so-slightly-too-big bag into the ever-so-slightly-too-small overhead compartment, you're now wasting MY time, and the time of each and every one of the 200 other people on the airplane, because we can't get push back from the gate until you sit down and securely buckle your seat belt low and tight across your midsection. (Not to mention the fact that you're SCARING THE CRAP out of me because 1) you don't look like you're physically capable of lifting that thing into the overhead, and 2) the particular bin you've chosen is directly over MY head.)

So, let's say you would've spent about 20 minutes waiting for a checked bag to hit the carousel (that's probably about average, depending on the airport). That's 20 man-minutes of time, or 1/3 of one man-hour. The ten minutes you wasted trying to find an empty overhead bin and then brute-forcing the bag into the compartment, multiplied by the 200+ people on the airplane, comes to 2,000 man-minutes, or MORE THAN 33 WASTED MAN-HOURS. See where I'm going with this? In order to save yourself ten minutes on the back end, you've ended up stealing over 33 man-hours from your fellow travelers. Smart traveler? Mmmmm, no, I'm going to go with "selfish traveler." Remember, you're not the only person on the airplane.

Correcting Misinformation 1

2011-04-01T01:41:00.002-10:00

In this first installment of "Correcting Misinformation," I'll take on what I think is a common misconception about legal considerations involved in selling your photography. And now, the standard disclaimer: I am not a copyright attorney, I don't play one on TV, and I didn't stay at a Holiday Inn Express last night. The opinions expressed here are exactly that: opinions. If you are in need of actual legal advice, you should find someone qualified to provide it, and that person is not me.

In the March 16, 2011 episode of the "This Week in Photo (TWIP)" podcast (which is an excellent podcast, by the way), the assembled panel discussed a recent brouhaha about Lady Gaga demanding the rights to photos taken during her concerts. The conversation meandered a little, and along its course, one of the panel members said:

"I don't know the ins and [outs] of copyright laws, but… Anytime that you are selling images, you have to have a model release if it's not for editorial use, meaning used for journalism."

Copyright law is murky at best, and if you ask any copyright question to a roomful of lawyers, you're likely to get a roomful of different answers. Then they'll start arguing about who's answer was right, which is why they can charge so much money. That being said, I believe the above quote is not quite true, in a pretty important way.

The internet has a wealth of information about model releases and luckily for us, some of it is even correct. The key issue here is the way in which the image is used. In general, "commercial" use of a photograph with a recognizable person in it (use that implies endorsement or approval of a product or service) requires a release; "editorial" use (primarily to inform the public regarding something "newsworthy") does not. There's another important case, though… What if you want to sell a print of a photo you have taken that has a recognizable person in it? A portrait, for example? According to the more authoritative sources I have seen (including the website for the American Society of Media Photographers), you do not need a model release to sell that print. If there is no advertisement or other commercial business use, you can sell a print of your photograph with a recognizable person without having obtained a model release.

What's the safer course of action? Obtain a model release for any photograph you take with a recognizable person in it. When you trip the shutter, you don't really know how you might want to use that photo in the future; getting a release will enable you to sell or license it for commercial use even if that wasn't your original intent. But even if you didn't get a release, realize that you still have options to monetize that photo, if that's what you want to do. And if you need legal advice about photography, speak to an attorney. Like Carolyn Wright, for example.

See more of my photography at http://lokahiphoto.com.
Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

New Feature: "Correcting Misinformation"

2011-03-31T20:14:00.002-10:00

I, like a lot of photographers, listen to photography-related podcasts and read photography-related blogs, trying to improve my knowledge and my craft. In these media, the "listener question" format is very popular, where a portion of the show or blog (or even the entire show, as with the Photofocus podcast) is devoted to answering questions submitted by the show's listeners. The vast majority of the time, I find the answers to be interesting, helpful and accurate. Occasionally, however, the hosts/authors just get one wrong. And that bothers me. I know there are a lot of people out there listening to these podcasts and reading these blogs that may know even less about photography than I do (and that's saying' something!). I hate to see them be misled by bad information provided in good faith by otherwise excellent photography experts.

This has inspired me to start a new feature in this blog, which I'm going to call "Correcting Misinformation." Creative, right? In each "Correcting Misinformation" post, I'm going to highlight something I've heard in a photo podcast or read on a photo blog that didn't sound quite right, and that upon further research, I found to be confusing, misleading, or just downright incorrect. Now, I'm not some technical or photographic genius, so whenever I can I'll try to include references from my research that back up my point, and where you, Dear Reader, can maybe find more information about the topic at hand.

I'm writing these blog entries in the spirit of trying to increase the overall knowledge level in the photographic community, not as an attack on any particular show, blog, host or author. In keeping with that spirit, I welcome your critiques if you think I've gotten one wrong as well… You can either leave them in comments, or e-mail me at tim@lokahiphoto.com.

Thanks for reading, and stay tuned...

See more of my photography at http://lokahiphoto.com.
Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

Open Letter to People Who Don't Shut Off Their Cell Phones On Airplanes

2010-10-13T19:45:00.007-10:00

[rant]

I had an experience today that moved me to actually write a blog entry, and that is a truly rare and special event. Basically, I've finally had enough, and I can't take it anymore.

You see, when I get on an airliner, I'm one of those "weirdo" passengers… You know the type; we're the ones who actually look at the safety information card, who pay attention to the safety briefing, and who say "please" and "thank you" to the flight attendants as they try to make our shared misery a little less miserable. Am I a goody-two-shoes? Maybe. Do I realize that the flight attendants really ARE there first and foremost for our safety, and that knowing how many rows of seats are between me and the overwing exits could come in handy in a dark and smoke-filled cabin? Yes. Do I know that when the flight attendants tell you to sit down, buckle in, hang up and bring your seat back and tray table to their fully upright and locked position, they aren't acting out some personal vendetta but are simply trying to enforce federal regulations designed to help get us all to our destination in one piece? Absolutely, I do.

So this morning, I boarded a flight between one major international airport and another, less-major-but-still-international airport. I took my aisle seat and shortly thereafter a young man found his way to my row and occupied the window seat. He seemed nice enough, apologizing profusely when he made me get up so he could get into the overhead compartment to fetch the food he had brought for the trip. No one took the middle seat; this was shaping up to be a pleasant flight. The flight attendants conducted their usual preflight routine and soon enough, it was "that time"… "We're ready to close the boarding door, so please turn off and stow all cellular telephones and any other electronic equipment. Flight attendants, prepare the cabin for departure."

Mr. Window Seat, in mid-cell-phone-conversation, continued his discourse. I gave him a slightly-longer-than-normal look… Longer than the "something caught my eye so I looked over for an instant" glance but not as long as the "what the hell are you doing over there" glare. He made brief eye contact, but didn't seem particularly discomfited by the fact that he was ostensibly committing a federal offense by failing to comply with flight crew instructions. As the flight attendants walked the aisle to check seat back positions, seat belts and electronic-equipment-stowage, he…

…shut off his phone and securely stowed it? No.

…hung up and held onto his phone? No.

…hid his still on, still connected phone underneath the jacket he had placed on the middle seat between us? Ding ding ding! Winner, winner, chicken dinner!

So, after the flight attendant passes, HE RETRIEVES HIS PHONE AND CONTINUES HIS CALL. Surely, this must have been a conversation of overriding importance, right? One with dire national security implications? Or maybe he was a crack surgeon, talking a lesser doctor through a complex procedure on a critically ill infant?

Nope. "We're about to take off, so I'll have to call you when I get there, babe… No, I put the money in your account… Mumble, mumble, mumble…"

So that's the critically important conversation you couldn't have had five minutes earlier, before you got on the airplane? This was the point at which I had 1) had enough, and 2) couldn't take it anymore. OK, it's on. It's on like Donkey Kong. You know it… Time for the full-up "what the hell are you doing over there" glare. After a few seconds of this treatment, he looked back at me and said…

"Oh, did they tell us to shut these off?"

"Uhhh, yep."

Now, I can hear what you're saying out there:

"Maybe he didn't hear the announcement."

"They've done studies and such like that, and they proved that cell phones don't affect any airplane stuff."

"People use their cell phones on airplanes all the time, and nothing happens."

"Quit being such a goody-two-shoes."

OK, if he didn't hear the announcement, why did he hide the phone when the flight attendant walked by?

And, so, you're telling me, with your aerospace and electrical engineering background, that there's NO WAY that the radio frequency energy your phone is emitting could interfere with any of the literally thousands of systems on a modern airliner?

And, sure, on 99,999 flights out of 100,000, maybe nothing happens. Do you want to be on that one flight on which something does happen? I don't.

And, finally, it's a federal regulation. If trying to comply with federal regulations designed to keep us all safe makes me a goody-two-shoes, then so be it.

So, here's where it is… If I'm on your flight, and you insist on talking on your cell phone after you've been instructed to shut it off… or getting up out of your seat while the airplane is moving on the ground… or just generally giving the flight attendants a hard time…

Expect the "what the hell are you doing over there" glare. And, if that doesn't get your attention, maybe a a conversation about federal regulations and interfering with a flight crew. Because, despite what you might think, you're not the only passenger on that airplane, and you're not any more important that anyone else. So, SIT DOWN, BUCKLE IN, HANG UP, AND BRING YOUR SEAT BACK AND TRAY TABLE TO THEIR FULLY UPRIGHT AND LOCKED POSITION. Thank you.

[/rant]

See more of my photography at http://lokahiphoto.com.
Looking for more great photography related info? Check out the PhotoFocus blog and podcast and the This Week in Photography blog and podcast.

Sorry... I'll try harder.

2009-08-23T19:53:00.002-10:00

First off, an apology. I know I haven’t been posting here as often as I had promised, and certainly not as often as I would like to have been; for that, I would like to say a deep and sincere “sorry” to all of my follower. (And yes, I use the singular form advisedly…)

I’ve been busy, and unfortunately, I haven’t even been busy making photographs But I’m going to try to change that. Iknow you’ve heard that before (in part because I know I’ve said that before), so let’s see how it works out this time.

So, for now just a quick post to let you know that I’ve posted some new photos at http://lokahiphoto.com/events/lanterns2009. This Memorial Day, I was lucky enough to be able to watch a beautiful tradition as thousands of lanterns were released into the waters surrounding Magic Island in Honolulu, in commemoration of lost loved ones and in hopes of future lokahi (harmony) for the world.

I’ve also got some that will be coming soon of a beautiful fall morning in Taylor’s Falls, Minnesota; they’ll be in the Landscapes area. Next up on the editing block are some photos I made in Alaska earlier this year as I was hanging around Anchorage between temporary duty trips. Hopefully I’ll be able to get to (and through) them fairly quickly.

Thanks for stopping by, and check back often!

See more of my photography at http://lokahiphoto.com.

Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

The Power of a Photograph

2009-07-11T17:07:00.002-10:00

I recently had found myself pondering the power of photography, and of photographs, in our personal lives.

I’m not talking here about the iconic images you see of major news events, like Eisenstaedt’s shot of the sailor and the nurse kissing in Times Square on V-J day, or the frame that captured one of the aircraft headed for the World Trade Center on 9/11.

Neither am I talking about those photos of strangers that seem to offer a glimpse into the human soul, like Dorothea Lange’s “Migrant Mother.”

I’m talking about pictures of the people around you: your friends, family and other loved ones. And I’m talking about pictures of you.

You see, my father passed away earlier this year after a battle with cancer. I flew back to be with my family, to help with arrangements and to attend his memorial. The days leading up to the funeral were hectic to say the least; I’m grateful for the assistance provided by the wonderful and tremendously helpful folks from hospice and from the funeral home. Even with all their help, however, it was a very busy time, especially for my mother.

So what struck me about this process? How much time my family and I spent… looking at photographs. Looking at, reviewing, and arranging photographs, and building several poster board collages we displayed at the memorial review.

I knew we had quite a few slides that catalogued our family experiences as my siblings and I grew up and explored our world, but I was a little overwhelmed by the sheer volume of images we had that I didn’t even know existed… Hundreds, perhaps over a thousand, slides and prints. Images of my father, my mother, their relatives and friends, how they grew up and explored their world. Prints that showed my Dad as a kid in south Minneapolis, in his Marine Corps recruit platoon, and shipping out to Korea during the war. A record of his life. A record, in the beginning, intertwined with that of his parents, relatives and friends. Later, a record intertwined with that of his children, nieces and nephews, and their friends. As a photographer, it struck a chord in me.

So I want to say a couple of things about the power of a photograph; not pictures that are going to win a Pulitzer, but the pictures of you and the people that have surrounded you throughout your life.

First of all, photographs provide a “trace” of our existence. Those we love, and those who love us, will never forget; but a photographic record reinforces those memories and provides a great emotional resource once we’re gone.

This next point applies to everyone, but it especially applies to my fellow photographers out there. It is very important that we have GOOD photos of those we love, in groups of two or more. Individual formal portraits are great, but the pictures that really hit me were the ones of my Dad with his friends and relations. The pictures that show those social interactions emphasize how many lives he touched, and how privileged we were to know him. So, photographers: make those pictures! I know how people can get annoyed by having their picture taken again and again at those family events; do it anyway. They’ll thank you later. Also, photographers: give that camera to someone else every now and then, and make sure YOU appear in some of those pictures. Seriously.

So take those pictures. Take those old slides and negatives you have, and get them scanned. Catalog them in whatever way makes the most sense to you, but keep the memories… It’s important.

See more of my photography at http://lokahiphoto.com.

Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

Canon PowerShot G-10

2009-05-17T22:41:00.002-10:00

OK, I know I promised to post my thoughts about the Canon PowerShot G-10 high-end point and shoot camera ($499 US MSRP; street price $469.95 at B&H Photo/Video), and I know it’s been a while since I made that promise; I’ve been busy. I’m sorry. But as they say, “better late than never.”

Unlike the Panasonic Lumix LX-3 (which I talked about in this post), I have laid hands on a G10. On the surface, it has all the minimum requirements that I wanted in a “take everywhere” compact digital camera: major manufacturer, minimum 10 megapixels, raw capture capable, raw file support in Apple Aperture, takes video. Like the LX-3, however, I had some reservations about the G10 that ultimately led me to a different choice for my everyday shooter. Details? OK.

Once again, I’ll start with the good. The G10 is the follow-on to the impressive G9, which had been very popular with pro/serious amateur photographers. It comes in at 14.7 effective megapixels, the highest resolution of the three cameras that were in the running. It also sports a zoom lens with a 28-140 35mm equivalent range, going out slightly longer than the Nikon Coolpix P6000 and significantly longer than the LX3. Its LCD monitor is a spacious 3 inches diagonally, the largest of the three. Overall, clearly a very capable camera.

The bad… Really, not much, but enough to be a deal-breaker for me. I’m not a huge fan of Canon’s control layouts. Honestly, if I had grown up shooting Canon, I’d probably be fine with their setup, but I didn’t, and that factor loomed large in my decision-making. Combine that with the fact that the G10 is kind of big for a compact (larger in every dimension than the P6000; almost a full half an inch taller), and it became obvious to me that this camera didn’t provide the level of convenience I was looking for. After all, a camera could have the best lens, sensor, and on-board processor in the world, but it does you absolutely no good if you didn’t bring it along because a) you don’t like working with its controls, or b) it won’t fit in your pocket!

By now it should be obvious that I went with the Nikon Coolpix P6000 as my everyday, everywhere camera. I’ve had it for a couple of months now, and have developed some initial impressions. Stay tuned for them; I’ll do my best to get them posted a little more expeditiously. I promise.

See more of my photography at http://lokahiphoto.com.

Looking for more great photography related info? Check out the PhotoFocus blog and podcast and theThis Week in Photography blog and podcast.

Panasonic Lumix DMC-LX3

2009-03-24T22:22:00.009-10:00

Let me be up front about this... I have never handled a Panasonic Lumix DMC-LX3 (MSRP $499.95, street price $429.95 at B&H Photo and Video), so these impressions are based on information I've gathered from elsewhere. For those of you thinking "How can you review a camera you've never seen in the flesh," here's how: I'm NOT reviewing the camera. I'm summarizing what I know about it, and telling you why I didn't pick it as my "take everywhere" camera. In the interest of full disclosure, I also own several Nikon cameras; two film SLRs, two DSLRs and a point-and-shoot. (I also have two Sony digital point-and-shoots and a Kodak Easy Share digital point-and-shoot that my kids use, and an old manual focus Minolta X-370 film SLR with several lenses. Some people I know might call me a Nikon fanboy...)

First up, the positive... I've heard good things about the LX3's lens, and since it's a Leica, I'm inclined to believe them. The focal length ranges from 5.1mm-12.8mm (35mm equivalent 24mm-60mm), which is nicely wide at the short end. The maximum aperture is f/2.0 at the wide end and f/2.8 at the telephoto end for exceptional depth of field control. Panasonic also shows they haven't been seduced by megapixel madness: the LX3 sports a sensor with a modest 11.3 total (10.1 effective) megapixels, the lowest megapixel count of the cameras I'll be discussing. It also appears to have the lowest "pixel density" (pixels per square inch) of the three, which can have a positive effect on noise. Like all three high-end point-and-shoots I'll talk about, it offers custom white balancing; full-auto, aperture priority, shutter priority, and manual shooting modes; and RAW image recording. Sounds nice...

The negative: The controls look a little obtuse and fiddly to me. It also has an external lens cap that I've heard can become an annoyance; it comes with a lanyard, but it can certainly be a pain to have a lens cap flopping around on the end of string when you're trying to create art, and if I didn't put it on the lanyard, I'd be GUARANTEED to lose it. And now, the big one.

Like all digital cameras that offer RAW file capability, the LX3 has a RAW format that is unique to this camera model. (ALL cameras' RAW formats are unique; since they all have different sensors/electronics/recorded metadata, no two are alike.) The problem is that the LX3's RAW format is not supported by Apple's Aperture imaging program, which happens to be my RAW workflow solution of choice. (This information is current as of the time of writing; Apple may offer LX3 RAW support in the future, but that ship has already sailed as far as I'm concerned.) Why? I don't really know, although I've heard it may have to do with the fact that Panasonic's own RAW conversion software (SilkyPix) allegedly applies distortion correction to RAW files without any user input, a "feature" of which I'm not a big fan. RAW data is supposed to be just that: unprocessed, uncorrected information directly from the sensor. Adobe Camera RAW and Adobe Photoshop Lightroom both support RAW files from the LX3, but I'm just not willing to include a different RAW workflow to accommodate my point-and-shoot.

Despite the good things I've heard about the LX3, the RAW format issue was a deal-breaker for me. It may be a great camera, but the LX3 was just not the camera for me.

Next up: Thoughts on the Canon Powershot G10.

See more of my photography at http://lokahiphoto.com.

Looking for more great photography info? Check out the "This Week in Photography" blog (http://www.twipphoto.com) and podcast (iTunes; elsewhere). Need help managing your digital life? Everything you need to know at http://mydl.me!

The First Rule of Photography

2009-03-24T18:08:00.008-10:00

Some years ago, I ran across an old truism about gunfighting: "The first rule of gunfighting is... have a gun."

It was intended to illustrate the point that even if you buy the latest new whiz-bang firearm for self-protection, it isn't going to do you a lot of good if you don't have it available when you need it. Lately it occurred to me that the same idea can apply to photography: "The first rule of photography is have a camera."

The underlying point here is the same. The latest, greatest whiz-bang DSLR with a zillion megapixels, and lenses you had to mortgage your kids to buy won't do you any good if they're sitting at home when you see that once-in-a-lifetime shot. Between listening to photo-related podcasts and trolling online photography forums, I've lost count of the number of times I've been told that if I want to improve my photographic eye, I should always have a camera with me.

"But Tim," I can hear you saying, "who wants to carry fifty (or fifteen, or even five) pounds of camera gear around with you everywhere you go?" Nobody, that's who. But how else are you going to be able to do justice that shot-of-a-lifetime you happen to run across, if you don't at least have a DSLR with a decent zoom?

High-end, raw-shooting compact cameras to the rescue! Several manufacturers have introduced point-and-shoot style cameras that include good lenses, a wide range of manual controls, and the ability to shoot in the raw format (which is really what you need if you want to get the most from your pictures). In a series of upcoming posts, I'l talk briefly about three that have gotten a lot of press lately: the Panasonic Lumix DMC-LX3, the Canon PowerShot G10 and the Nikon Coolpix P6000, and tell you which one I settled on for my "always with me" camera.

Stay tuned!

See more of my photography at http://lokahiphoto.com.

Histograms 101

2008-12-21T15:08:00.012-10:00

Got a digital camera? Do you use Adobe Photoshop? (or Photoshop Elements, or Nikon Capture NX, or Lightroom, or Aperture, or just about any other digital image editing app?) Then you’ve probably seen a histogram, whether you know it or not. If you’ve read any blogs or forums about digital photography, or listened to any podcasts about digital photography, you’ve probably heard that you should “check your histogram” or “keep an eye on the histogram” to get an idea of how good your exposure was. If you’re like me, right about now you’re probably wondering just what the heck a histogram is and what you should be looking for when you “keep an eye on it,” but you don’t want to ask. Not to worry; I’m here to help!

So, what’s a histogram? Here’s what Dictionary.com has to say about it:

“–noun Statistics.

a graph of a frequency distribution in which rectangles with bases on the horizontal axis are given widths equal to the class intervals and heights equal to the corresponding frequencies.”

Oh, that’s all it is? Right. Got it. Perfectly clear now.

Not.

Let’s see if I can untangle that a little bit for you. As it pertains to a photograph, a histogram is a depiction of the relative brightness levels of the pixels in the image. That probably didn’t help, did it?

OK, let’s try an example. Here’s a simple black to white gradient:

And here’s the histogram that goes with it:

As you can see, the histogram is almost completely flat, and extends all the way from left to right. That’s because there are an equal number of pixels at each brightness level in the image it represents. Now, look at this gradient, in which I’ve shifted the midpoint to the right, so it has more dark pixels than light:

Here’s the histogram for this gradient:

You can see that it “piles up” at the left side, at the lower brightness levels, reflecting the fact that there are more dark pixels in this gradient. Here’s a gradient with a left-shifted midpoint, which increases the number of light pixels:

And here’s the corresponding histogram:

Now the graph “piles up” on the right side since there are more light pixels than dark.

Here’s a picture I recently took in Japan of some trees after a fresh snow lit by the rising sun:

And the histogram for this shot:

Based on what we now know about histograms, what can we tell about this image? Well, we can see that there are quite a few dark pixels (evidenced by the peak at the left end of the graph), not too many in the medium-dark range, and quite a few in the medium-light area. Also, the fact that the peak on the left-hand side piles up against the edge of the graph indicates that there are areas of the photo in the shadows that have completely lost detail (they’ve gone entirely black, commonly called "blocked-up shadows"). On the other hand, since there’s no peak on the right end of the graph there should be details visible in all the highlight areas. Since there’s some “room” at the right end of the graph, it shows that I could have increased my exposure by about half a stop or so without losing much detail in the highlights.

That’s enough for now; in the future, I’ll get into some more details about how you can use a histogram to make adjustments while you’re out shooting and increase your chances of getting that “perfect shot!”

See more of my photography at http://lokahiphoto.com.

Looking for more great photography related info? Check out the This Week in Photography blog and podcast.

Quick Tip #1 – Polarizing Filters

2008-11-09T23:11:00.001-10:00

A lot of people will tell you, with so many powerful image-editing software packages available, that filters are unnecessary. (Just to be clear, I'm talking about the kind of filters you attach to your lens, not the kind you find in Photoshop.) That’s true… to an extent. You can pretty well replicate the effect of many popular filters with a click or two in your favorite image editor. Split neutral density, graduated neutral density, and color correction filters, as well as many “special effects” filters have awfully good software equivalents, but there are a few filters you can’t replace easily (or even at all). One of these is the polarizing filter. Keep reading, and I’ll tell you why you want to keep one of these in your bag and how to make the best use of it.

Polarization is a physical property of light. The easiest way to explain it is to think of wiggling a rope to make waves travel along it; if you move the end of the rope up and down, the waves will be vertical:

If you move the rope side to side, the waves will be horizontal. Un-polarized light has both kinds of waves, while “perfectly” polarized light has waves that oscillate in only one direction. A polarizing filter does to light kind of like what a picket fence would do to your wiggling rope. If the rope runs through a picket fence, only waves in one direction will pass through and waves in the other direction will be cancelled out. The polarizing filter is like that picket fence for the light going into your lens; light oscillating in one plane passes through and light oscillating in the other plane is blocked. Put two polarizing filters together (two picket fences), with their “slats” turned ninety degrees to each other, and ALL the light is blocked and NO light gets through.

Now here’s the photography part: light can get polarized in different ways. Light reflected from a non-metal surface (think glass or water) gets polarized; light passing through the glass, or the surface of the water, remains non-polarized. Put a polarizing filter on your lens and rotate it to the right angle, and you block the light reflected from the water or the glass, i.e. you block the contrast- and saturation-robbing glare you get from those reflections. Ever seen pictures of the ocean where you can see right through the water’s surface to the fish swimming beneath? Probably shot with a polarizer. Likewise photos of shop windows where you can hardly see the glass. Need to kill reflections? Throw on a polarizing filter and fire away. How do you know what the “right angle” is, you ask? Easy! Compose your shot and then rotate the polarizer until the reflections are minimized.

Are there other situations where a polarizer can come in handy? Absolutely! Have you ever seen a landscape with a beautiful, dark blue saturated sky? Chances are there was a polarizer involved there, too. As sunlight is scattered by the atmosphere, it also gets partially polarized. By using a polarizing filter, you can block some of the polarized light, which will darken and saturate that blue sky. There’s a catch, though; the whole sky isn’t polarized equally. Some areas of the sky are more polarized, and therefore more susceptible to the effect of a polarizing filter, than others. You’ll get the maximum darkening effect if you point your lens ninety degrees to the path of the sun through the sky. Put more simply, keep the sun off one of your shoulders for the maximum effect. If the sun is directly behind or directly in front of you, you won’t get nearly as much out of your filter. Also, be careful using a polarizer with a wide-angle lens. The large angle of view you get means the sky can end up lighter at one side of the frame and darker at the other side, which can look pretty funny. The bright side is that you see the effect of the polarizer through the viewfinder, so you can catch this gotcha before you trip the shutter if you’re paying attention.

How much would you pay for this magical filter that can cut glare and give you gorgeous saturated blue skies? Don’t answer yet! There’s more! Many kinds of leaves have a waxy coating that polarizes reflected light. By cutting that reflected glare with a polarizing filter, you can nicely saturate the greens of summer foliage or the beautiful golds and reds of fall leaves.

There are a couple of things you’ll want to keep in mind about polarizing filters, though. First of all, there are two types available, linear and circular. Which do you want to buy? If you have an autofocus camera, get a circular polarizer. Autofocus cameras may be unable to focus with a linear polarizer mounted. I have also heard that evaluative metering systems in newer cameras may not work properly with a linear polarizer. Another caveat: regardless of what kind of polarizer you use, you’ll lose about one stop of light; for example, say you shoot a scene without a filter and your aperture and shutter speed are f/4 and 1/1000 of a second for the desired exposure. Add a polarizer and you’ll need to use either (about) f/2.8 and 1/1000 or (about) f/4 and 1/500 to achieve the same exposure. Not necessarily good or bad, just something to be aware of.

So do you need a polarizer? Like so many other questions in photography, the answer is a definite “it depends.” It depends on the kind of shooting you do and what effects you want to achieve. I will tell you this, however: a polarizer can do things for you that are very difficult, if not impossible, to do in software-based post-processing.

Visit my photography site at http://lokahiphoto.com.

Looking for more great photography info? Check out the This Week in Photography blog and podcast.

Will photograph for food...

2008-10-13T20:56:00.001-10:00

Aloha!

I’ve been kicking around the idea of starting a blog for some time, but, until now, I’ve just never pulled the trigger. Every now and again the idea would find its way into my mind; each time, it was immediately followed by this pesky fact: I just don’t have anything interesting to say.

Then I came to the realization that if “interestingness” was a prerequisite for starting a blog, 99% of the blogs that now pollute the "internets" would never have gotten past the idea stage. Couple that fact with the completely self-serving desire to drive more traffic to my photography business’s site (http://www.lokahiphoto.com/), and here we are!

For me, photography started as an off-and-on hobby. The technical side of photography appeals to my predominant “left-brained” nature, and it provide me the artistic outlet that I believe everyone needs (left-brained people probably more than most!). Since I’m otherwise pretty much a talentless hack, you can see how photography captured my imagination and quickly became a passion. And along with that passion naturally comes an insatiable need to acquire more photographic equipment. Now, listen close, because I’m going to let you in on a dirty little secret about photography: camera gear is expensive! REALLY expensive! Well, in addition to being a geek, one of my other character flaws is that I’m an unrepentant capitalist. So I says to myself, “Self, some people out there sell pictures for money. If you could do that, you could buy more camera gear, with which to take more pictures, to sell for more money, to buy more camera equipment…” And thus, Lokahi Photography was born!

Luckily, I happen to live in one of the most photogenic locations on the planet, the beautiful Hawaiian Islands. A poorly trained monkey with a camera could produce some stunning images here; I’m only slightly less capable than a monkey, but I think I’ve got a few winners, so please take a look at my work. If you like what you see, leave a comment; if you really like what you see, buy a print (or several)!

Looking for more great photography info? Check out the This Week in Photography blog and podcast.