Making the Best Use of a Long Lens
There is something rather magical about a long camera lens.
It allows us to photograph a bird on the far side of a field, isolate a sailing boat from a busy background, pick out details on a distant building, photograph wildlife without approaching too closely, or compress a landscape so that distant objects appear almost stacked together.
My own interest in long lenses goes back a very long way.
As a teenager, I started photography with a Zenit E — about the most sophisticated camera I could afford at the age of 13. Compared with modern digital cameras it was extraordinarily basic. There was no autofocus, no image stabilisation, no automatic ISO and certainly no ability to take twenty or thirty frames every second and decide afterwards which one was sharp.
But there was one considerable advantage.
Occasionally I could borrow my father's 300mm f/2.8 lens.
To a young photographer, that lens seemed enormous.
Sometimes I could even add a 2x teleconverter — or "doubler", as we tended to call it — effectively turning the combination into a 600mm f/5.6 lens.
Suddenly birds and other distant objects that had previously been little more than dots in the viewfinder became possible photographic subjects.
That experience taught me something that remains true today:
Having a long lens opens photographic opportunities — but owning the lens is only the beginning.
From a Zenit E to Modern Super-Telephoto Zooms
Photography equipment has changed enormously since those days.
Today I have a much more flexible collection of long lenses, including a fast 70-210mm f/2.8 and a Sigma 150-600mm.
Like many photographers, I have gradually moved away from relying heavily on fixed focal-length telephoto lenses towards zoom lenses.
There are still excellent reasons for using prime lenses. A high-quality 300mm, 400mm or 600mm prime can provide exceptional sharpness, wide maximum apertures and excellent autofocus performance.
But zoom lenses offer something incredibly useful in real-world photography:
flexibility.
With a 150-600mm zoom, for example, I can photograph a sailing boat approaching from some distance at 600mm, then zoom back towards 300mm or 200mm as it gets closer.
With wildlife, I can photograph a bird perched some distance away and then instantly change the framing if it takes off and flies towards me.
That is much harder when using a fixed focal-length lens.
For the sort of photography I do, that flexibility frequently matters more than achieving the absolute theoretical maximum image quality.
What Does a Long Lens Actually Do?
We often describe telephoto lenses as "magnifying" distant objects.
That is a useful everyday description, but technically the important change is the lens's angle of view.
A 600mm lens sees a much narrower angle than a 50mm lens.
Because the camera is recording a smaller section of the scene, distant objects occupy much more of the image.
This produces the impression that we have moved closer to the subject.
It is enormously useful for subjects such as:
birds;
wildlife;
sailing;
aircraft;
motorsport;
astronomy;
distant landscapes;
architectural details;
sports;
events where the photographer cannot physically approach the subject.
But the narrow field of view also creates challenges.
At 600mm, finding a flying bird in the viewfinder can be surprisingly difficult.
A tiny movement of the camera produces a much larger apparent movement of the subject in the image.
Long-lens photography therefore becomes partly about learning how to control the camera.
Does a Smaller Sensor Give More Magnification?
This is one area where photographic terminology can become confusing.
If I fit my 600mm lens to a smaller-sensor DSLR, the lens itself does not suddenly become optically more powerful.
A 600mm lens remains a 600mm lens.
However, the smaller sensor records a smaller central portion of the image produced by the lens.
The result is a narrower field of view.
For example, on a camera with a 1.6x crop factor:
600mm x 1.6 = 960mm
We would therefore describe the resulting field of view as being equivalent to approximately 960mm on a full-frame camera.
That can be extremely useful for bird and wildlife photography because the subject occupies a larger proportion of the recorded frame.
But it is worth making the distinction.
The crop sensor has not changed the focal length of the lens.
It has changed how much of the lens's image circle is being recorded.
Why Long Lenses Need Good Technique
A long lens magnifies something else as well as the subject:
camera movement.
This is why photographs taken with telephoto lenses can sometimes look slightly soft even when the lens itself is extremely sharp.
At short focal lengths, a small movement of the camera might barely be visible.
At 600mm, the same movement can ruin the photograph.
Traditionally, photographers used the reciprocal rule as a rough guide:
Minimum shutter speed = approximately 1 / focal length
So with a 500mm lens, we might start thinking about something around 1/500 second.
But this is only a starting point.
Modern high-resolution cameras, moving subjects and crop sensors often mean using considerably faster shutter speeds.
For birds in flight I might prefer something such as:
1/1000 second
1/1600 second
1/2000 second
or faster.
For very fast wing movement, even 1/3200 second may be useful.
Modern image stabilisation is excellent, but stabilisation cannot freeze a moving bird.
It compensates for camera movement.
Shutter speed still has to deal with subject movement.
A Fast Aperture Is Extremely Valuable
This is one reason that my father's old 300mm f/2.8 was such an impressive lens.
An aperture of f/2.8 on a 300mm lens allows a large amount of light into the camera.
That means faster shutter speeds are possible in poor light.
It can also produce beautifully blurred backgrounds.
The problem is that large-aperture telephoto lenses require very large pieces of precision optical glass.
That makes them:
large;
heavy;
technically difficult to manufacture;
and expensive.
There is a considerable physical difference between producing a 300mm f/2.8 lens and producing a much smaller-aperture 300mm lens.
The front element alone gives a clue to what is required.
A rough relationship is:
Aperture diameter = focal length / f-number
For a 300mm f/2.8 lens:
300 / 2.8 = approximately 107mm
That helps explain why fast professional telephoto lenses become so physically large.
Teleconverters: More Reach, But Not for Free
A teleconverter can still be extremely useful.
A 2x teleconverter doubles the effective focal length.
So:
300mm becomes 600mm
400mm becomes 800mm
600mm becomes 1200mm
But there is a price.
A 2x teleconverter normally costs about two stops of light.
So:
300mm f/2.8 becomes approximately 600mm f/5.6
The converter may also reduce autofocus performance and slightly reduce image quality.
Whether it is worthwhile therefore depends upon the lens, camera and subject.
With a high-quality fast prime lens, the result can be excellent.
Putting a teleconverter behind an already slow or relatively soft lens may be much less successful.
Why 150-600mm Zooms Are So Useful
For many photographers, the modern 150-600mm zoom occupies a very interesting position.
It gives enormous photographic reach without entering the cost, weight and specialist nature of the very large professional prime lenses.
At 150mm I can still frame a fairly large subject.
At 600mm I can photograph something much further away.
That range is particularly useful when photographing unpredictable subjects.
Imagine photographing sailing.
A boat might be hundreds of metres away as it approaches a mark.
At that point, 500mm or 600mm might produce the photograph I want.
A few moments later the same boat could pass fairly close to the camera.
Now perhaps 200mm is more appropriate.
With a zoom I can follow the action continuously.
That is one of the reasons zooms have become such practical working tools.
Do Not Automatically Use the Longest Focal Length
One of the easiest mistakes is assuming:
"If I have 600mm available, I should use 600mm."
Not necessarily.
Sometimes 400mm will produce the better photograph.
Sometimes 250mm will.
The important question is not:
"How much focal length have I got?"
It is:
"What composition am I trying to create?"
A bird completely filling the frame may make an excellent identification photograph.
But a smaller bird surrounded by reeds, branches or water may make a much more interesting environmental portrait.
Similarly, a photograph of a yacht filling almost the entire frame can be impressive.
But sometimes including the river, competing boats, spectators and surrounding landscape tells a better story.
The lens should serve the photograph rather than dominate it.
Long Lenses Change the Appearance of Perspective
Telephoto lenses can also create a very distinctive visual effect known as perspective compression.
Strictly speaking, perspective itself is determined by the photographer's position.
But because we normally stand much further away when using long lenses, objects at different distances can appear much closer together in the final image.
A row of sailing boats may appear tightly packed.
Hills behind a town may appear dramatically large.
The Moon near a building can appear enormous.
A distant bridge may seem surprisingly close to the subject in front of it.
This is not simply about photographing distant things.
It can be an important creative technique.
Atmospheric Conditions Become Part of the Optical System
There is another limitation that buying a more expensive lens cannot solve.
The atmosphere.
At very long distances, we are photographing through a considerable amount of air.
That air may contain:
water vapour;
dust;
pollen;
pollution;
turbulence;
heat gradients.
On a warm day, heat shimmer can destroy fine detail.
You may have an extraordinarily expensive lens perfectly focused on a distant subject and still obtain a slightly wobbly-looking photograph.
The problem is not the camera.
You are effectively photographing through moving layers of air with slightly different refractive properties.
Early mornings are often better for extreme long-distance photography because the atmosphere tends to be cooler and more stable.
This is particularly noticeable with wildlife, aircraft, landscape and astronomical photography.
Supporting the Lens Properly
A 150-600mm lens is not something I particularly want hanging unsupported from my hands all day.
There are several possibilities.
Handheld
Modern stabilisation makes handheld super-telephoto photography surprisingly practical.
It also provides enormous freedom for tracking birds and moving subjects.
Good posture makes a significant difference.
Keep the elbows relatively close to the body.
Support the lens under its centre of gravity.
Avoid holding your breath for long periods; instead, settle your breathing and release the shutter smoothly.
Monopod
A monopod is one of my favourite compromises.
It removes much of the weight while still allowing the camera to move quickly.
That can be ideal for sport, sailing and wildlife.
Tripod
For static subjects or very long periods in one location, a tripod becomes extremely useful.
Heavy long lenses benefit particularly from a gimbal-style head because the camera can remain balanced while still moving freely.
The key is not simply preventing movement.
It is making the entire camera-and-lens combination comfortable enough that I can concentrate on photography.
Finding the Subject at 600mm
Anyone who has tried photographing a bird in flight with a super-telephoto lens will know the problem.
You see the bird.
You raise the camera.
You look through the viewfinder.
Nothing.
At 600mm the field of view is so narrow that it is surprisingly easy to point the lens slightly to one side of the subject.
A good technique is to initially locate the bird at a shorter focal length.
Perhaps start around 200mm or 300mm.
Acquire the subject.
Then zoom towards 500mm or 600mm while continuing to track it.
With practice, locating subjects becomes much faster.
But it is a learned skill.
Autofocus Settings Matter
Modern cameras have transformed long-lens photography.
Subject recognition, animal-eye autofocus and sophisticated tracking systems can make photographs possible that would have been extremely difficult when I first started.
But the photographer still needs to understand what the autofocus system is doing.
For a perched bird, a relatively precise autofocus area may be appropriate.
For a bird in flight, continuous autofocus and subject tracking may work much better.
For sailing, I might use tracking autofocus to keep the boat or crew sharp while panning.
The important point is to experiment with the camera before the important event.
The middle of a sailing race is not the ideal moment to start discovering what an unfamiliar autofocus mode actually does.
Exposure Becomes a Balancing Act
Long-lens wildlife and sports photography often requires a compromise between three things:
shutter speed;
aperture;
ISO.
Suppose I am photographing a bird in flight.
I might want:
1/2000 second
The lens might be at:
f/6.3
The camera then has to use whatever ISO is necessary to produce the correct exposure.
Years ago I would have worried considerably about raising ISO.
Modern cameras handle higher ISO settings remarkably well.
I would usually rather have:
a sharp photograph with some noise
than:
a beautifully noise-free photograph ruined by motion blur.
Noise can often be reduced afterwards.
Motion blur usually cannot.
Long Lenses Are Not Only for Wildlife
Wildlife is perhaps the obvious use, but long lenses have many applications.
Sailing photography
Long lenses allow me to photograph boats from the bank or another boat without needing to be immediately beside the action.
They are excellent for:
starts;
mark roundings;
crew expressions;
sail details;
close racing;
spray and water;
isolated action photographs.
Landscape photography
Telephotos can extract small compositions from huge landscapes.
Instead of photographing the entire scene, I might pick out:
a distant tree;
layers of hills;
a church tower;
sunlight hitting one field;
mist in a valley.
Garden photography
Long lenses can even be useful relatively close to home.
Photographing birds at a feeder from some distance away reduces disturbance.
A long focal length can also create beautifully soft backgrounds.
The Moon
The Moon is a wonderful long-lens subject.
Even 600mm will show a surprising amount of detail.
Using a crop-sensor camera can make the Moon fill even more of the frame.
Details We Normally Miss
Perhaps most interestingly, a long lens trains us to notice things.
A distant architectural feature.
An insect-eating bird on a television aerial.
A face in a crowd.
Rigging on a sailing boat.
Patterns on a distant hillside.
Photography becomes a form of observation.
The Temptation to Buy Ever Longer Lenses
There is always another lens.
If 600mm is useful, then surely 800mm must be better.
And if 800mm is useful, perhaps 1200mm would be even better.
Eventually the economics become rather uncomfortable.
Very long professional lenses can be extraordinarily expensive.
They can also be enormous and heavy.
Before purchasing specialist equipment, I think it is worth asking some very practical questions.
What will I photograph with it?
How often will I use it?
Could I hire one when necessary?
Would a teleconverter be sufficient?
Would a crop-sensor body give me the framing I need?
Could I simply move closer?
Would better fieldcraft produce a bigger improvement than another 200mm of focal length?
And, particularly for professional or company photography:
How will the equipment repay its investment?
Equipment Has to Earn Its Place
This becomes particularly important when photography forms part of a business.
It is very easy to admire an £8,000, £10,000 or even more expensive lens.
But an impressive specification does not automatically make it a sensible business purchase.
Suppose an expensive lens allows me to photograph a specialist event that produces commercial work.
Perhaps it contributes to:
commissioned photography;
stock photography;
educational material;
YouTube videos;
promotional images;
magazine work;
sailing coverage;
wildlife projects.
Then the investment may make sense.
But if it spends 360 days each year sitting in a cupboard, hiring it for the remaining five days might have been much more sensible.
Photography equipment should enable projects.
The project should not exist merely to justify buying the equipment.
Sometimes Better Technique Beats More Equipment
This is perhaps the most important lesson.
A photographer with a 600mm lens who understands light, movement, autofocus, composition and animal behaviour can produce extraordinary photographs.
Someone with an even more expensive 800mm lens who simply points it towards the subject may not.
Improving technique costs remarkably little.
Learn when the birds visit.
Learn where the sailing boats will round the mark.
Notice where the sunlight will come from.
Choose the background before the subject arrives.
Practise tracking.
Experiment with shutter speed.
Understand the autofocus system.
Find a stable shooting position.
Long-lens photography is partly about optics.
But it is equally about anticipation.
From Film Photography to Thousands of Digital Frames
When I think back to that Zenit E, the contrast with modern photography is extraordinary.
Every frame of film cost money.
There was no screen on the back of the camera.
I could not enlarge the photograph immediately to check the focus.
I could not simply increase the ISO for the next frame.
Autofocus did not find a bird's eye.
Image stabilisation did not compensate for camera shake.
Yet those limitations were also valuable.
They forced me to think carefully about each photograph.
Digital technology has made photography enormously more capable, but I still think there is something worth retaining from those early days:
Think before pressing the shutter.
What am I photographing?
Why am I photographing it?
Where is the light?
What is in the background?
What shutter speed do I need?
What will happen next?
Those questions matter more than whether the lens is 400mm, 600mm or 1200mm.
Conclusion: Reach Is Useful — Seeing Is More Important
Long lenses give photographers an extraordinary ability to explore parts of the world that would otherwise remain visually distant.
From borrowing my father's 300mm f/2.8 as a teenager with a Zenit E to using modern super-telephoto zoom lenses today, the technology has changed dramatically.
Modern cameras provide autofocus, stabilisation, huge usable ISO ranges, crop-sensor options and lenses such as the 150-600mm that offer a degree of flexibility I could scarcely have imagined when I started.
But the fundamental challenge remains remarkably similar.
The best long-lens photograph still depends upon being in the right place, understanding the subject, controlling movement, noticing the light and anticipating what is about to happen.
And perhaps that is why I still enjoy long-lens photography.
A telephoto lens does more than make distant subjects appear closer.
It encourages us to look more carefully at things that are normally too far away to notice.
