Sometimes one could notice those people, probably tourists, that go around in the streets of placid small towns with a photographic camera hanging from his neck with an enormous and heavy telephoto lens, as if they are going to shoot the jerks of a cheetah in a photographic safari or who knows what other sensational sighting.
I have discovered the existence of a directly proportional relationship between the obesity of the photographer and the focal length of the lens he uses as a custom. Clinical studies have confirmed that the use of telephoto lenses, especially of the zoom kind, are the main cause of overweight, obesity, circulatory and cardiac diseases for the photographers. As a confirmation of this fact, it must be noticed that on the contrary the slim photographers prefer the wide-angle lenses.
Obviously i am joking, anyway not much.
Everyone surely know that a telephoto lens draws closer the distant subjects. But if this is the only reason why you have one of them, then throw it away, because you are simply a lazy person!
Oh people of lazy-bones photographers! Move the legs, summon your courage, jump through the ring of fire and face closer your subject, reach it and shoot it with a normal lens!
The greatest photographers have always realized their own masterpieces standing in direct contact with the scene, also in presence of danger.
Become yourselves the most powerful tele and zoom lens that ever existed!
On the artistic field, the use of the telephoto lens is determined firstly by a creative choice.
Yes, sure: the telephoto lens allows a closer shooting of those subjects otherwise impossible to reach physically, as for example an eagle in the nest, the privacy of a notorious personage, the moon in the sky, sporting competitions or the flames of a fire accident. However, apart these particular needs, sometimes the use of the telephoto lens is just a synonymous of idleness. Obviously, if idleness is for you a lifestyle, then you can even not to read this article.
But if you do not have any idea of what else are the issues when photographing with a telephoto lens, then this article can be interesting for you.
First of all let us clarify what a telephoto lens is. Somebody confuse them with the "zoom" lenses, thinking that these are telephoto: not necessarily; "zoom" does not mean "tele", but it defines a lens with a variable focal. The majority of us all, with the verb "to zoom", intends to draw closer the subject magnifying it with the lens; instead to zoom means, more precisely, to vary the focal, therefore also the opposite of magnifying, that is to say to zoom back to the wide-angle. In few words: wide-angle or normal (medium) lenses can also be zoom.
It is defined medium or normal the lens that has optic features similar to those of the human eye, and therefore it renders verisimilar normal pictures.
The characteristic of the telephoto is to have a focal length approximately longer than 100 mm (for the most diffused format by now: the frame picture of 35mm). Obviously the tele can also be zoom, or with variable focal, for example 80-200mm, 100-300mm, 200-600mm. They also exist focals longer than 1000mm: enormous, bulky, heavy and expensive lenses for professionals (for example those lenses that are used by the sporting photographers).
The use of the telephoto could seem only a matter of comfort, but it is not this way. The photographs taken with the telephoto lenses are very different from those taken with a normal objective, and also different it is the wide-angle. To know how to make a full use of the features of the various lenses, means to know how to creatively manipulate the scene to shoot.
The telephoto lenses have certain characteristics that influence the appearance of the photographs; these characteristics can be creatively utilized otherwise can make the photographs unpleasant. Let us see what they are.
Compression of the planes
The first big difference in comparison to the normal lens defined "medium", it is the compression of the planes.
The various perspective planes of a photograph realized with a telephoto are all drawn one near the other.
Let us make an example: we want to photograph a scene with a man in the foreground and another one far away; in the photograph realized with a medium objective, the distant one will be smaller than the near one; instead in the photograph realized with a telephoto the difference in size between the two will be smaller; this effect will be more noticeable as longer is the focal of the telephoto.
The lenses with the most long focals, over 500mm almost nullify the distances between the different planes, making the photograph very flat, almost axonometric.
Ahead in the article you will find some explicative pictures.
It is obvious that this levelling of the planes can be a great expressive tool if used with good sense, but it can make a photograph horrendous when used unwittingly.
Blurring of the background
In a way strictly tied to the effect of the compression of the planes, also the blurring between the different planes of focusing is greater as longer it is the focal of the telephoto.
Many people know that depending on the opening of the diaphragm, one can blur the background behind to a subject focused in the foreground. With a telephoto this blurring is much more remarkable, so much that often one has troubles even to focus the same subject that one wants to be sharp. To focus with extremely long telephoto lens can be very difficult.
Also the blurring of the planes is an expressive technique that is normally used to make the subject to stand out, separating it from the context. If we have the intention to realize photographs with the whole subjects in focus, then practically the telephoto is not usable; that is to say the telephoto lenses have a limited depth of focusing, or selective.
In the example pictures you can ascertain also this issue.
Besides there is a particular kind of telephoto lens, called catadioptric, that gives to the blurring a certain aspect, that is well visible when in the scene there are spots of light: these become blurred like rings or small circles. Also these telephoto lenses can be used creatively, but the main reason for which they are built is because they have a weight and an encumbrance almost halved in comparison to the traditional ones, and often this peculiarity of them to alter the blurring is considered by many photographers an unacceptable defect.
Examples of compression and blurring of the planes
Five prints have been photographed placing them on a table and arranged in a line of nearly half a meter of distance between one and the other. The focal lengths are inherent to the classic 35mm format.
800mm telephoto lens
The prints have similar dimensions.
The focus is only on the church.
The prints seem very near one to the other.
400mm telephoto lens
The difference in size of the prints starts to change.
The tree and the buildings are a little sharper.
140mm telephoto lens
The difference in size increases.
The focusing is wider.
The near subjects now tend not to overlap those in the back.
50mm normal lens (medium)
This is more or less what the human eye sees.
28mm wide-angle lens
The size of the prints are now very different.
The focusing covers almost everything.
The nearest subjects go away to the side.
The sensation of distance between the prints is stronger.
Then there is another factor to take into consideration when one uses the telephoto: the so-called atmospheric perspective, or that fading of the distant subjects caused by the poor visibility.
Surely you had noticed that a mountain at the horizon is usually more faded in comparison to a nearer one; this is caused by the water vapour or other particles suspended in the atmosphere, which limit the visibility as soon as the subjects become more distant.
Therefore if we photograph a subject from a greater distance, thanks to a telephoto, this phenomenon will be more visible.
Obviously this effect can be pleasant or unwanted, it depends on your expressive intent: if you want saturated and bright colours but the sky is not perfectly clear, then it is better to avoid the use of very powerful telephoto lenses, preferring to get closer to the subject. On the contrary, if you want to get an pastel effect, the use of the telephoto can be considered in a particularly damp and misty day.