Ed Schlotzhauer

An artists journey

Category: Process

Depth of Insight
In a recent Medium article, Marc Overmars gave a good introductory description of depth of field (DOF) This is a technical term uniquely applicable to photography. I want to take the concept in a somewhat more philosophical direction. Maybe there is a concept of depth of insight.
Purely technical
On the surface, depth of field is purely a technical concept. it only applies to photography, because it is associated with the physics of focusing through a lens.
I went into some of the issues in a previous blog. Sorry for the math. 🙂 I know most people don’t like that. I don’t have much use for it either, and I would never use it when I’m out in the field shooting, but some level of understanding is helpful for mastery of the art.
Maybe the most challenging concept from that article, and a fundamental concept of DOF, is “circle of confusion”. The idea that there are acceptable levels of unsharpness. Very briefly, only one point in the frame is technically “in focus”. But practically, a certain amount of unsharpness can be tolerated before we would consider something blurry. The size of this allowable unsharpness is called the circle of confusion. So, when your DOF calculator gives you a distance range, those are the points where the focus becomes unacceptably blurry. The math is exact, but the concept isn’t.
Perhaps there are analogies in our understanding of what we shoot.
©Ed Schlotzhauer
Looking deeper
Let’s set the math and technical details aside for now. I can hear the sigh of relief.
I propose that there is an analogous concept concerning the sharpness of our intent when we are shooting. That is, did I just point my camera at a subject, make a decent composition, and shoot? Or was I clear in my mind why I was taking the picture and what it was really about?
I have often referenced the Ansel Adams quote that “There’s nothing worse than a sharp image of a fuzzy concept.” There are 2 reasons for that. First, it is a brilliant observation. Second, it is something I struggle with, so it is very real and close to me.
Yes, I can compose, and I can use good technique to get the sharpness I want. I can use light to my advantage, and I have a lot of experience post processing. But even so, I often look at my images in despair. Too often they are sharp images of a fuzzy concept. When I am honest with myself, I know that sometimes I didn’t have much in mind when I shot them.
©Ed Schlotzhauer
Art happens in our head
Maybe it is too obvious to state, but art happens in our head, not in the camera or the computer. As with any definite statement about art, this is a generalization. Sure, there have been many times when I was working with a scene and experimenting (e.g. playing), and things seemed to come together. That is the exception, though.
All too often I look at my images and realize they are, at best, just record shots of a place I was at. No depth of insight. Not much below the surface to give you a reason to pause over it and consider it.
The fault is entirely my own. I didn’t have anything to say, and I said it.
There is a marked contrast with the images I get when I go out to shoot a project, or ones I shoot when I feel strongly about the subject or the situation. Many more of them are strong and satisfying.
We all know this: the more we put into something the more we are likely to get out of it. Why don’t I remember it more when I am out shooting?
My excuse, other than simply laziness, is that I like to go out exploring and shoot interesting things I come across. I don’t always find interesting or “deep” things. That is just that, an excuse. Maybe it is as much that I didn’t have much to say that day. I try to remind myself of Jay Maisel‘s quote that “If you talk with nothing to say, that’s bad. When you shoot with nothing to say, that’s worse.”
©Ed Schlotzhauer
Circle of confusion
So, is there a “circle of confusion” concept for our shooting? Maybe so. If we can’t get our ideas into focus, maybe we shouldn’t shoot. Do our ideas have to be in perfect focus? No. Like the technical term, maybe there is an acceptable level of unsharpness. I hope so.
What do I mean by this? Well, sometimes I realize exactly what the scene means to me, and I can determine exactly how to shoot it. That is great. I am often happy with the result. Sometimes, though, I just have a feeling, a sense of what I am experiencing. I have learned to follow those instincts even if I cannot clearly express their meaning at the moment. If something is drawing me, there is probably a reason.
Later, while editing, I may realize what was calling me to it. Sometimes an image I was initially dismissive of emerges as the strongest of the shoot. It could be that’s just luck. I prefer to think my instincts were trying to tell me something.
Maybe I am being too hard on myself. Jay Maisel also said “You always end up with too many pictures to edit and too few that you feel ‘got it’.” I suppose the feeling is common to all photographers, but it still is frustrating.
©Ed Schlotzhauer
Projects for focus
I am learning to use projects to help me focus more clearly. A project is a chance to think deeply about something, decide how I feel about it, and then find opportunities to express it.
It is basic psychology that when you are concentrating on something you are more attune to it. A simple example: a friend was thinking about buying a Nissan car. I don’t think about there being many of them around, but after that conversation it seemed like every other car I saw was a Nissan. I was more attuned to them.
A somewhat more relevant example is from a recent trip to France. It was a family trip, not a dedicated photo expedition. But I didn’t want to come back with just random tourist shots. So, I created a few projects to keep in mind to focus my thoughts and energy. One of them I called Sacred Places. It helped me be much more aware of cathedrals, of course, but also monuments and memorials and standing stones. Even a small village celebration of their liberation in WWII. I felt it helped me to see more opportunities, and I looked deeper at the occasions I found.
If I don’t see it, why should you?
Circling back to Jay Maisel’s quote: “If you talk with nothing to say, that’s bad. When you shoot with nothing to say, that’s worse.” If we can’t focus our feelings and experience, are we shooting with nothing to say? Just taking a sharp or well composed picture isn’t enough. If you can’t participate in the experience I felt, then I’m not bringing you anything other than an “I was there” picture. Maybe it is pretty, but there isn’t much to feel or remember.
Perhaps I do not have to be able to precisely express what I was feeling at that moment. Maybe there is a “circle of confusion” associated with our understanding of the image we are creating that gives us some margin for imprecision. But the circle of confusion in focusing helps discuss a range of acceptable sharpness, not permission to be out of focus. Maybe there is a range of acceptable understanding of our feelings leading to making an image. But little or no understanding is out of range. With no real understanding or feeling, there is little interest for viewers. Have something to say.
I am starting to concentrate. much more on depth of insight than depth of field.
©Ed Schlotzhauer
Head image
I mentioned having Sacred Places in mind and encountering a memorial celebration in a small village in France. The image at the top was a result of that. We happened, by accident, to be there on the day of their annual celebration of liberation in WWII. They still remember and memorialize it to this day. That is heartwarming.
This flag display was presented while local dignitaries and military officials made speeches. I didn’t understand enough French to follow it, but it was moving.
Having the Sacred Placed project in mind made me more attuned to this. We stayed for all of it and loved being there. When they discovered that we were Americans I barely avoided having to give a speech at their village celebration afterward.
I hope a little of the dignity and solemnity of their memorial comes through.
October 1, 2025
What You See Is What You Get
This is a well worn cliché with many meanings. I would like to attach a new one to it. What you see is what you get is also a description of our photography process.
History
You can predict that I like to get into the background of things. The phrase seems to have originated in the mid 20th century. It was popularized by Flip Wilson in the 1960’s show “Rowan and Martin’s Laugh In”. Anyone remember that? I have to confess that I do.
I will talk about meanings of the phrase, but one historical meaning was also special to me. “What you see is what you get” (abbreviated WYSIWYG) became a theme for personal computers back in the 1980’s. Before that, computers were terrible at dealing with fonts and layouts. Along came the Apple Macintosh and things changed radically. Thank you Steve jobs! But that is a topic for another time.
Conventional meanings
The normal usage of the phrase implies things are exactly as they appear, simple, no hidden meaning or content, clear.
For example:
“On a side note, with Jake, what you see is what you get; he’s always upfront.”
“In this political climate, it’s refreshing to see a candidate for whom what you see is what you get.”
“The website builder offers a what you see is what you get editor, making it easier for non-technical users to create professional-looking sites.”
We all know what we mean when we say the phrase, at least if you speak colloquial English.
©Ed Schlotzhauer
In our photography
I am proposing a new facet for this old phrase. As photographers, we have to see something to photograph it. So, what we see, is what we get.
That sounds blindingly obvious, but think about it a moment. In today’s world, the ability to notice things is getting to be a rare and precious talent. We live in culture of distraction. Every tech device in our lives is fighting for our attention.
But you are a photographer. I assume it is different for you. You have developed the skill of noticing things. To do that, you have to look and be aware. In order to even do that, you have to have the discipline to disconnect from most of the distraction that is keeping other people in addiction.
It seems like it is the goal of people today to have the least contact with the outside world they can. Almost like they want to live in a Matrix-like simulation.
Distraction
Next time you walk around in your city pay attention to what the people around you are doing. How many are looking around, seeming to take in what they are seeing? Compared to how many are glued to their phones or isolated with headphones. If they are looking around, is it with their phone camera in front of them to record everything they see so they can post it on social media? Do they have to get a selfie in front of that pretty sight, rather than actually looking at it?
The goal of most people seems to be to isolate themselves from the world around them. A 24/7 always on stream of TikTok, YouTube, Facebook, music, or movies provides an exciting alternative to the seemingly boring, mundane life and surroundings people have in their daily lives.
If people are on mass transit, they are plugged in and doing their best to block out the world around them. If they have to walk a few feet from their car, they are already checking email or Facebook. My state even felt the need to make it illegal to as much as pick up a cell phone when we are driving. It was that big of a problem.
And then there is the self imposed distraction of always being in a hurry. We rush and try to multi-task. Many people now do not even take all of their vacation, because we are too busy and afraid of falling behind. But that puts blinders on us. In our frantic hurry, we do not see much of what is around us.
I am in no place to give any kind of judgment about people’s desire to block out or deal with the world. Everyone gets to choose their path. That doesn’t make all choices equally beneficial. If we are artists, that puts us in a different context.
©Ed Schlotzhauer
Mindfulness
A theme I can’t help coming back to frequently is mindfulness. Not in any kind of Zen practice, with painful poses and mantra chants. I don’t bend that way anymore.
Like most great ideas, mindfulness is very simple and extremely complicated.
From the viewpoint of photography, It is simple, because at its core , it is just about being aware of where you are, what is around you, possibilities of interesting colors and patterns and compositions and movement and subjects.
Just being aware. Training yourself to be in the habit of looking. Turning down the volume of distractions and looking around with an open mind. Being willing to think about things around you. Being willing to slow down some.
It is complicated, because it is exactly the opposite of what most of the world is trying to get you to do. Instead of closing into your little cocoon you have to open up to experiencing outside stimulus. This means consciously fighting against distraction that are trying to capture you.
Crazies
I love a quote from Lee Ann White I found recently. “If you make photographs when no one else does, you get photographs no one else does.” Simple and obvious. I think it was part of what inspired me to describe this idea of what you see is what you get.
I’m not suggesting taking the idea of being where no one else is to extremes. My friend Dean is an example of doing that. He is full on crazy (IMHO). For example, he goes solo trekking in wilderness areas of the Colorado mountains for days at a time in the worst winter conditions. And seems to enjoy it. And gets unique shots to prove it. That’s extreme even by my standards.
As a matter of fact, I know a lot of fairly crazy photographers. But that is not a requirement for doing good work.
This mindfulness I am recommending does not require existential danger or major travel ventures. It just requires us to be aware. To look around and see more than most of the people around you are seeing.
©Ed Schlotzhauer
Give it a try
Look at everything you see as a picture. What is the interest here? How would I frame and compose it? What should I do with the lighting? What depth of field should I use? Is there a better viewpoint?
We can be going through that thought process without even getting out our camera. I hope, though, that it compels you to make the picture. I want you to get so excited about what you are seeing that you have to give it a try.
Have you ever stopped on the way to work because something caught your eye in a new way? Even after driving the route every day for years, today you saw something different. I have.
Just 3 days ago I was driving my normal route that I have done for thousands of times and I had to pull off in a cemetery. In the many years I have been by it nearly every day I have stopped less than a dozen times to actually go in and see it. That day was one. It was a bitterly cold day with a beautiful layer of hoar frost covering the trees. It compelled me to turn in. I’m glad I did.
What you see is what you get
If we do not see it, we will not photograph it. If we are not mindful and paying attention we will not see it in the first place. Just making the effort to look is a necessary first step. Mindfulness is a habit, a thought process. It is something we can learn through practice.
Even then we will not get the picture unless we give ourselves permission to stop and take the picture. Without taking the action we will never have it or the joy of the memory. Be one of the few who is paying attention.
I’ll wave at you when I see you pulled off on the side of the road shooting pictures of something i can’t even see. Looking a little crazy. And happy.
See it. Do it.
You see what you think, you see what you feel, you are what you see.
If with a camera you can make others see it – that is photography.
Ernst Haas
The featured image
I thought it would be good to describe the image at the top of this article. It is exactly a “what you see is what you get” as I describe here. My wife and I were staying in a hotel downtown Denver for some reason. Probably a weekend away.
This was a scene looking right out our balcony. It is not composited or edited other than normal color and sharpness. The reflections were exactly this. I was fascinated and still do not understand how such diverse scenes could be captured on the windows. And I loved the distortions. I’ll take it. I’m glad I looked out and noticed it.
March 19, 2025
Staying Creative
Since you are reading this, you probably call yourself a “creative”. That is great. But creativity seems to be cyclic. Staying creative is a continuous process. Some would say a struggle.
Cycles
Creativity is not a constant level. We experience creative peaks where exciting new work seems to burst from us. But we also have low points. In those troughs we don’t feel like we can generate any creative ideas. It is depressing and scary.
The encouraging reality is that this is normal. We do not and cannot operate at a peak of creative output all the time. We empty the tank. The reserve has to be refilled. It can’t be predicted or planned, but at some point it seems to dry up. But keep in mind that we really do not know what creativity is.
We know it is cyclic. And we know it will come back at some point. But when we are in that valley it can seem like a time of doom and gloom. Will it ever come back? Have I used up all the creativity I had and now I will never have any again?
You have thought these things. Admit it. I’m not the only one with these fears.
©Ed Schlotzhauer
Forcing creativity
So what do we do? At some point we often resort to forcing it. We are determined to regain our creative highs, so we try to make our self create.
How does that work for you? Probably as poorly as it does for me. Sure, we can do some good work, even very good work. But we can’t kid ourselves that it is up to the level of our best.
Whatever it is in us that generates creativity operates on its own schedule. It is not sympathetic with our wishes. We can be welcoming and encouraging to it, but it does not operate at our command.
Do something
Now I will seem to contradict what I just said, but I do not believe it is a conflict. We will get through a creative valley easier and probably faster if we work through it. I used the idea of “emptying the tank” of our creativity. I believe practicing our craft and following our curiosity are very good behaviors to help refill it.
You may not be inspired with amazing new creative ideas, but go out and see what you can find. Explore. Do not expect to do your best portfolio work. Taking that pressure off will help you relax and lean into it. But doing something is better than sitting around moping.
It is a wonderful time to learn new skills, take some courses or watch some videos. Pick out some new technique you have been curious about and learn it. Practicing it now without all those creative bursts getting in the way is a good time to learn. It is a great time to explore some of those dark, scary corners of Photoshop that have intimidated you for a long time.
Like most of life, doing something is better than doing nothing. Don’t sit feeling sorry for yourself, thinking you are useless and have no more creativity. Fill. your time with learning, exploring, practicing, experimenting, even catching up with cataloging your images. And always follow your curiosity.
The word “create” is a verb. Be active. Go make things. Make dinner, make a drawing, make a fire, make some noise, but make. If all your attempts at being creative consist of passively consuming, no matter how brilliant what you consume is, you’ll always be a consumer, not a creator.
Scott Berkun, in The Myths of Innovation
©Ed Schlotzhauer
Relax
When creativity seems to slip away, when the muse no longer is with us, relax. It does not mean it is gone forever. Like waves, there are highs and lows. It will come back.
Even when we are not feeling inspired, we can keep on working and learning. Do not be passive and waste your time. Be preparing for the rush of creativity when it comes.
We are not a failure when it seems we cannot create astounding new things on command. We are recharging. Accept it. Go do your work anyway.
Have you done creative work you are proud of? Then you should be able to do it again when you are ready. Creativity is not a limited resource that is used up. When you are feeling it, pour it out on everything you do.
Let it flow
Being in a flow state is a great feeling. But it is not exclusive to feeling creative. Anytime you are immersed in applying your skill to a difficult and challenging problem you can be in flow.
Flow and creativity, then, are not synonymous. We can do great work even when we are not riding the crest of creativity. Don’t stop working.
Curiosity is the thing that pulls us along through life and through our art. It does not come and go like creativity. In that way, it is more powerful than creativity.
The cure for boredom is curiosity. There is no cure for curiosity. – Dorothy Parker
I like that idea that there is no cure for curiosity. I don’t want to be cured of it.
We can develop our curiosity by asking questions and wondering about things. Give yourself permission to follow your questions. Find the answers. Try things. See what happens. This healthy attitude will carry us through the ups and downs. Creativity may come and go, but our curiosity goes on and gets stronger.
So, even if you feel that your creativity has evaporated, trust that it will return again, just like it has in the past. While you are waiting, keep photographing, learn, practice, experiment, and especially, feed your curiosity. You might find that the extra kick of creativity is actually just an incremental boost to the power of your curiosity.
The artist is nothing without the gift, but the gift is nothing without work. – Emile Zola
©Ed Schlotzhauer
Staying creative
So, as far as staying creative. You won’t always be at your peak. Sometimes you may feel way down in the valley. Don’t panic. It will come back. In the meantime, there are things you can do to improve yourself as an artist and a person and to entice the creativity back. Work on your curiosity. Explore new ideas and techniques. When you feel the creativity flowing again, you will be even more ready to use it.
But no matter what, keep working.
Today’s image
Sunset downtown. I turned my view down to the parking lot instead of out at the glowing buildings. Is this creative? Or is it just following my curiosity? I don’t know. I will leave that for greater minds to decide. Either way, I was letting it flow.
January 29, 2025
Don’t Show It All
Not like that. This is a follow up to my last post on portfolio selection. A simple, overarching principle to keep in mind is: don’t show it all, or even most of it. Actually, not very much of it.
We’re proud of our work
A blessing and curse of digital photography is that we now shoot thousands of images. Of course, we’re pretty good, too. Everybody should like to see 500 pictures of my cat. After all, they are all different poses. And that big trip we enjoyed so much, here are the very best 900 pictures from that great trip to France. They’re all worth seeing.
We fall in love with our own pictures. This is a fact of life. Each one is special because it was exciting, memorable, unique for us. We remember what we experienced at the time. It makes it significant to us. To us, each one of those 900 pictures from France is worth showing to other people.
And when we are too attached to our pictures we tend to overlook problems that are obvious and distracting to others. The telephone pole growing out or your kid’s head is not seen. After all, it is a really cute expression. And we overlook all those people in the foreground of the beautiful picture of Chambord. Just look at how spectacular that Chateau is. It is too easy to convince our self that that tilted horizon is not a problem, or the poor composition, or the bad color balance.
But we have to be adult. Part of that means being very aware of the actual quality of our work and of what is appropriate for the situation. And in most situations, less is more.
Other people generally don’t care
I don’t want to pour cold water on your enthusiasm, but other people are not excited about what you have. That is a hard reality you have to learn.
They weren’t there. They did not experience what you did. None of these images have the same meaning or impact for them. It wasn’t their vacation, or their family, or their cat. Call up your pictures of France and hand the phone to someone to page through. If they are good friends, they will fake interest and flip through a lot of them. But even they will probably not look at any image for more than 1-2 seconds.
When they look at your pictures, they don’t see it the same way you did. They can’t and never will. Understanding this is a key to getting our images viewed by other people.
It gets much more challenging when we are wanting strangers to view our work. They do not know us, they were not there when the image was taken, it may not be anything they are interested in. But here, look at my pictures. Thanks, but I’ll pass.
©Ed Schlotzhauer
Context is key
The context where we are and where and when we are presenting our images makes a huge difference. Is it to friends or strangers? Is it one-on-one or a public venue? What is drawing people to pay attention to your photos?
Pushing pictures on social media is a main venue for many of us. The audience is friendly if it is our network. They will politely scan through a few of the pictures. A few of the viewers may even give us a thumbs up to make us feel good. But did they actually see them or care? We can’t tell. And we won’t know.
And how often have we been cornered by friends who have “a few” pictures to show us? They hand us their phone, sure we will love the 50 pictures they took of the great sunset last night. It is one of those “just shoot me” moments. But if they are a friend, we have to be polite. Back in the film days it was a common joke theme to go over to a friends house only to have them get out the slide projector to show “a few” pictures of their trip. After the first few hundred we want to fake a heart attack to get away.
Up to here we are only bothering captive audiences. We can get away with little editing and selection. It will make us look foolish, but our friends will forgive us – eventually.
But perhaps we decide we’re pretty good and book a booth in an art fair. Now the audience has no connection to us and no inherent reason to look at what we have. We will get a glance as they walk by. People will only pause to give a second look if we present something that captures their attention. They will only come in to look more closely if we show them something exceptional.
Now take it to the big leagues. We get an opportunity to show our portfolio to an art director or gallery manager. That is a tough audience. These are professional art viewers. They look at huge numbers of pictures and it is their job to reject almost everything. What are you showing that will capture their attention? It better not be 100 of your best cat pictures.
How many?
How many images are in a portfolio? There is no hard rule for this. It depends on what the portfolio is for.
Peter Eastway, the publisher of Better Photography Magazine, has a nice little ebook titled “Creating a Portfolio“. It is worth reading if you can get a copy. He tries to address this and many other considerations of putting together a portfolio.
In his Australian humor, he says “The number of photographs in a perfect album is 12. Or sometimes 8. Or maybe 24.” In other words, it depends. No rules. But the number is probably much lower than you thought, and whatever you put in needs to be the best. No filler. Nothing that’s there because you want to show some variety to widen the interest.
Peter gives an interesting test. He says do not put an image in your portfolio unless you think you will still be proud of it in 12 months time. That is significant to me. I often am enthusiastic about an image, only to find I cool off toward it with time. My filtering process has built in delays. It take months for me to elevate an image to “one of the best” status. I do that intentionally to let the initial enthusiasm be replaced with a more objective evaluation.
In general, between 12 and 20 for any collection of images in a project or portfolio works for me. I would feel free to violate my own rule if I were doing a documentary or a book. Or for a multi-year project that had significant importance to me. But I would have to make a very conscious exception.
©Ed Schlotzhauer
Less is more
I advocate that we take a mindful “less is more” attitude. Always take out images until it hurts. Then take our a lot more.
Remember, your audience has a short attention span compared to your view of your portfolio. Any weak image will loose their interest. They may even abandon looking at that point. I have heard it said that you will be judged by the weakest image in your portfolio. I believe it. It is human nature to find the worst as a way to critique the whole.
I consider building a portfolio kind of like an athletic contest. Teams have to compete in and survive multiple rounds of playoffs to be chosen the champion. Hopefully the best emerge. Same with our images. It is a brutal, hand to hand contest.
If you are evaluating coolly and objectively, every one removed makes the remaining set stronger. Remember, when you remove one, you are not saying you don’t like it or it is a bad image. You are just acknowledging that it does not hold up against the competition of the rest of the group. That is good. But hard.
It is very hard for me. If I want to select a project with max 20 images, I may pull at least 60-80 very good candidates. Doing the first cut is only a little painful. Maybe that gets me down to 50. I try to toughen up and go slashing again. Now maybe I have 35 left. OK, I swallow hard and cut some more and get it down to 30. Still a long way from 20.
The trouble now is that I really love every one of the 30 candidates that remain. The pain of eliminating any of then is extreme. Remind myself over and over that taking one out is not saying I don’t like it. It would be a lot easier to relent and let myself use all 30.
You would think it would get easier now. After all, I think all of them are great. But the reality is that there is a rank order to be discovered. Some are better than the others. That is what I still have to resolve. Eventually I get there. It is painful and lengthy. But a funny thing happens. I love the set that survives, and forget about the pain of the ones that didn’t make it.
The optimum number to show people is fewer than you think. When we learn that we don’t have to show it all, we can build stronger portfolios.
If you’re not your own severest critic, you are your own worst enemy.
Jay Maisel
November 20, 2024
Out of Focus
A few months ago I wrote about being in focus, both technically and mentally. I want to go a little deeper into how technical focus happens in modern cameras and an an experience I had recently where what I did was out of focus.
What is focus
Technically, focus is simple when the lens is adjusted so that the part of the subject you are most interested in is sharply defined. Your lens has a focus ring to use to manually focus. Most of us probably use the camera’s built in auto focus capability. This is much more precise than my old eyes. And a lot faster than most of us can do manually.
Focusing physically moves one or more of the lens elements inside the lens barrel. This is required to adjust the focus point.
I will let you argue whether focus is an absolute, precise point or just an acceptable range. I will just say that I am swinging away from being adamant about absolute technical perfection and leaning more toward artistic judgement and intent. Set your own values you will live by.
Whether we manual focus or use auto focus, we observe in the viewfinder the image moving from a fuzzy blob a crisp, detailed representation of the scene before us. Unless we have a very old piece of technology in our camera with something called a split image viewfinder. I had this in my first SLR. It was magic and awesome for most of the subjects I shot.
The split image viewfinder showed the image sharp regardless of focus. The image was divided into 2 pieces in the central circle. The pieces were offset from each other when out of focus. Use the focus ring to bring the 2 halves into alignment and the image was sharply focused. Magic. Enough trivia, though.
Little did I know this was a type of and precursor to what we now call phase detection auto focus. Let’s get a little deeper into the technology.
How does it work?
Auto focus in a DSLR or mirrorless camera is complex and requires many precise components. But it works so well now that we tend to take it for granted.
There are 2 basic technologies in modern cameras. The older one is called contrast detection and the newer and better one is called phase detection.
I have written on histograms, a subject I consider vitally important to photography. Histograms and their interpretation are the basis of contrast detection auto focus. It is brilliantly simple in concept and in process as what we do when we are manually focusing.
If an image in the viewfinder is out of focus, the pixels are blurred together. Kind of like looking through a fog. A result is that in the histogram, the values are clustered in the center. This is an indication of low contrast. But when an image is sharp, there is a wider range of brighter and darker pixels. This illustrates it:
From https://digital-photography.com/camera/autofocus-how-it-works.php
Focus process
So conceptually, the system moves the focus a little and measures again to see if the histogram got more narrow (more out of focus) or wider (sharper) . If it got more in focus, continue moving that direction and measuring until the peak contrast if found, But if it got more out of focus, move the focus the other direction and continue the process. It is a hunting process to find the optimum focus point. Just like we do to manually focus.
Unfortunately, this process is slow. It can take seconds to arrive at the focus. This is why phase detection auto focus came to prominence.
In phase detection auto focus, some of the light coming through the lens is split off to a separate sensor. Like the split image viewfinder I mentioned above, it is further split into two paths. Through some brilliant engineering, they can determine in one measurement how far off focus is and in what direction. The focus moves there quickly. Note that in mirrorless cameras all the light goes directly to the sensor, so these auto focus sensors are built directly into the sensor.
I said that phase detection is “better” than contrast detection. That is true as far as being very fast. Actually, contrast detection can achieve more precise focus. There is a kind of system called hybrid the combines the strengths of both. I will not discuss that or go into the bewildering variety of focus areas or focus modes.
Out of focus
This is all great as far as technology goes. It works quite well in the cases it is designed for. We are lucky to have it.
But all of these systems rely on the sensor having enough light to see some contrast. It doesn’t work in the dark. Yes, there is another variation on auto focus that is called active auto focus. It shoots a red beam from the camera to illuminate the focus area. This has a very short range and does not help the scenario I’m about to describe.
Recently I was in Rocky Mountain National Park, over on the west slope where there is little light. It was full dark on a moonless night. The mountains all around provided lovely silhouettes. The stars were astonishing. Beautiful. I had to stop and get some star images.
A trailhead parking lot provided a great and convenient place to set up – wondering if those occasional sounds I heard in the dark were bears. I guess not. It was perfect. Except. There was not enough contrast to focus, even at 6400 ISO. And the viewfinder image was too noisy to be useful for manual focus. I did not have a powerful enough flashlight to cast enough light on the nearest object, over 100 yards away, to allow the focus system to work.
Adding to the problem, the lens I brought on this outing did not have a focus scale (a curse of modern zoom lens design). Normally, in low light, I switch to manual focus and set the lens to infinity for a scene like this. I guessed, but missed badly for a big section of the images. They were uselessly out of focus. I am ashamed to show an example, but like this:
©Ed Schlotzhauer
Experience is a great teacher
I write frequently advocating that we study our technology to become expert with it. And to practice, practice, practice to know how to use our gear, even in the dark. I failed. I encountered too much dark and a lens I had never tried to use in low light. The combination tripped me up. I am ashamed to admit I did not follow my own advice well enough.
But every failure is a learning opportunity, right? It can be a great motivator and reinforcer. I did some research and discovered a “hidden feature” I never knew my camera had. It should save me the next time I do this.
My Nikon camera has a setting I had never paid any attention to called “Save focus position”. When On (the default) it remembers the focus position of the current lens when the camera is turned off and restores it on wake up. But when Off – this is the brilliant part – it sets the lens to infinity on wake up. Now I will have a known infinity focus setting, even in total darkness! This setting is now in my menu shortcuts so I can access it quickly.
I would never have learned about this feature if I had not failed so spectacularly. Experience really is a great teacher.
So dig into those obscure settings you never bother with. There sometimes is gold there.
Keep learning and failing!
The featured image
That night’s shooting was not all bad. I nailed the focus on this star shot. It was purely of the stars and had no foreground. This foreground has been substituted from another blurry image that night (actually, redrawn by hand).
This is artistic expression rather than literal reality. I do that a lot. As photography progresses and matures, I believe that is more and more the norm.
October 30, 2024