For good portrait photography, there has to be a connection between me and the person during the time of the shoot. That connection has to be prepared. I can't just jump out of the car, walk up to a complete stranger, and say, “I'm going to take your picture now.” First, I have to establish trust and, above all, create a relaxed atmosphere. That requires at least a brief conversation—not anything profound; perhaps the person is a vendor from whom I first buy a small item, or the owner of the workshop where I just had my motorcycle repaired, or an elderly Mongolian woman whom I meet in front of her yurt and with whom I talk about the universal topic of the weather. That's why, in countries whose language I don't speak, and where I have to assume that the locals know neither English nor French, it's helpful to have a local driver who can interpret, or an additional translator.

Once the first hurdle has been overcome, I can introduce myself as a photographer and ask whether I may take a portrait. It took me years of practice, and even today it's not easy for me to ask for a portrait, because even though you wouldn't notice it when I'm on stage speaking effortlessly in front of a thousand people, I am fundamentally a shy, reserved person. Every now and then, someone turns down my request for a portrait; in those cases I don't insist, but in most cases people agree.

Then, for example, I kneel in front of the elderly Mongolian woman, who is now sitting on her bed inside the yurt. I take a camera body out of my camera backpack—fortunately, in the age of digital photography, I no longer have to worry about whether the right film is in the camera or whether there are enough frames left—and I have to decide whether to use a zoom lens, which allows me to vary the framing but, because of its maximum aperture of 2.8, won't separate the woman well from the background. “Separating” the subject means that the face, and perhaps the upper body as well, are sharp while the background is blurred. Or whether I should use a standard zoom and, if so, one that lets me include the bed in the picture and then, with a twist of the zoom ring, capture only the woman's head. Next, I make a few preliminary settings, such as the shutter speed, because during that time the woman remains relaxed. While doing so, I continue talking with her, asking, for example, how many children and grandchildren she has. Only then do I raise the camera to my eye.

Interestingly, outside Europe people rarely smile when they are being photographed, quite unlike us, where almost everyone immediately puts on a camera smile. In many other cultures, a portrait is a serious matter. And I grant people that. The saying that a picture reveals more about the photographer's character than about the person being photographed is quite true. It depends on me as the photographer: that I respect the people I photograph, that I preserve their dignity, but also that I portray them accurately—that I show, for example, a simple shepherd or a tribal chief as exactly that, without reading anything into them or leaving anything out.

Only now do I press the shutter. Once or twice. In between, I glance at the monitor, zoom into the image on the screen to check whether the focus is right and whether the subject happened to blink. I may press the shutter a third and, rarely, a fourth time, because in portraits facial expressions often differ considerably from one frame to the next, whether because of blinking or changes in expression, and because I've found that the person being photographed often relaxes once they think the photo session is over. But I never use burst mode for portraits. It's more pleasant for the people being photographed to hear the click a few times than to hear twelve clicks per second. Sometimes I pause briefly, make eye contact again, or say, “You have a beautiful smile,” thereby giving positive feedback about the pictures. When I myself am being photographed for press photos, I notice that this does me good as the subject. Every now and then I also ask for something—for example, to turn the head just a little or look slightly in a different direction.

Three of my portrait photographs remain especially memorable to me to this day. I had always wanted to photograph a Tuareg man with an indigo-blue cheich and striking eyes, like the famous photo by Pascal Maître that GEO used in advertisements for years, but I never found one quite so extraordinary. Pascal Maître's subject was almost too beautiful to be true, which is why I always suspected that the image had been enhanced a little. At some point, somewhere in Mali, I met a photogenic Tuareg man by the side of a dirt track—not as conventionally handsome as Pascal Maître's subject, but with a very distinctive, expressive face. At that time I still wasn't particularly practiced or skillful at asking for a portrait, and I was still considering the best way to make my request when I noticed that the man kept casting longing glances at an empty gasoline can I was carrying. So I offered him the can in exchange for a photograph—and finally got my long-awaited portrait of a Tuareg man, a picture that still fills me with joy and pride today.

Without the man's consent, I could never have taken that close-up. In the years that followed, I became increasingly adept at approaching people and cautiously making contact before I even thought about taking photographs. Since I frequently returned to the same regions of the Sahara at the time—the Aïr Mountains and the Ténéré in Niger, or the Niger River in Mali—I gradually got to know more Tuareg people and their families. I gladly accepted their invitations into their mat tents or mud houses, because many of the nomads had already settled down. From there, I was often passed on to other families within the extended family circle. Once I had been introduced to a family, it became much easier to photograph family members in the tent, the head of the family during the tea ceremony, or—my second special portrait—a boy during a visit to a Quran school.

The third of my favorite portraits shows three boys in a guelta, a natural waterhole in the Sahara. At forty degrees Celsius, in the (nonexistent) shade, they lured me away from a car repair with the call, “Piscine! Piscine!” and led me to their “swimming pool.” Photographing children is easy and playful and usually arises naturally from the situation, yet this image remains one of my favorites to this day.

In my early years as a photographer, it was absolutely taboo for me to photograph women. I didn't want to do it secretly, and I didn't dare ask them. It wasn't until the 1990s that I was able to take my first portraits of women, and even then only because I had someone by my side who gave me access to them: my young daughter Gina or my travel companion. On top of that, I discovered that the women had a great interest in photographs of themselves. That was perfectly understandable, because they often didn't own a single picture of themselves. So I started taking an instant camera with me on my travels and offered the women an instant photo in exchange for my photographs. The problem, however, was that then the sister, the mother, and the cousin also wanted a picture of themselves, and of course so did the father and the uncle and everyone else. The only thing that saved me was the fact that a pack of instant film contained only ten shots. It was important that I first took the pictures with my “real” camera and only afterward with the Polaroid, otherwise the women would have been so fascinated watching their likeness slowly appear that they wouldn't have spared me and my camera another glance.

Not only with women, but in general, for a long time a Polaroid picture was the best currency a photographer could offer anywhere in the world, because people simply didn't have a picture of themselves—or at least not a current one—and I, as a traveling photo studio capable of providing pictures immediately and free of charge, was highly attractive. Nowadays, I can't entice anyone with that anymore. When I took a Polaroid camera to Mongolia again in 2018, people pulled out their smartphones and showed me the pictures they had taken themselves. Even so, some people still like to receive my photographs, and with today's technology that's no problem. Then I send them via Bluetooth, WhatsApp, or whatever method works.

If I meet an individual and want to photograph them, I ask that person directly for permission. With groups, I obtain general permission to photograph from the respective “head” of the group. That might be the head of the family; if it's churchgoers standing together after a service, the pastor; if it's schoolchildren in the schoolyard during recess, the teacher... That way I can take several portraits, full-body shots, or, in the case of a family, photograph the whole family, the yurt, and the animals.

Even in the past, I very rarely thanked people with cash; today I never do. If I've already paid for a tire repair in a workshop or for lunch in a pub and want to photograph the mechanic or the innkeeper, I simply leave a better tip. And if there's no such occasion, I express my gratitude with small gifts: a pack of cigarettes, or perhaps just a single cigarette, staple foods such as flour or sugar, or other things that are always welcome in the remote regions where I mostly travel, such as kerosene or flashlight batteries. I buy all these things in small local shops because that brings business to the stores and the people are familiar with the products. For example, they wouldn't know what to do with instant soups from Knorr or Maggi. Nor do I give children balloons or sweets from Germany, because that would only create expectations. I also don't make a big fuss about it; instead, I might simply place my gift of thanks next to a tent pole.

Another issue is the right to one's own image. If I want to publish a photograph of a person, then theoretically, according to Western legal understanding, I need their written permission—a model release. Incidentally, such permission would also be required for a photograph of someone else's property (a property release), whether it's a private villa, a school, a museum, or a lion in a zoo—theoretically, because the old saying applies: where there's no plaintiff, there's no judge, and I'm not aware of a single case in which a travel photographer got into trouble because of it. Strictly speaking, I should have every person I photograph on my travels—whether in Niger, Peru, or Afghanistan—sign a model release. The problem is that many of my subjects can neither read nor write, and such a form would only arouse suspicion. So I do without it.

I must admit, however, that for lack of official permission to photograph, I don't publish some pictures in books or magazines—for example, the photos of children sniffing solvents that I took in Aboriginal communities, settlements marked by severe poverty. When selecting images for the book The Deserts of the Earth, I left them out because photography in those communities is permitted only with special authorization—which I didn't have—since the conditions there don't fit the image of harmonious coexistence between cultures that the Australian government likes to portray. I do show the photographs during presentations, however, because they are part of reality, and there I can remove them at any time if the Australian authorities should object. That's much harder to do with books; under certain circumstances, the entire print run would have to be destroyed.