Super Telephoto Lenses - A User Guide to Buying and Using
We've all seen them at major sporting events: banks of photographers with long white or black lenses delivering pictures that are the envy of many. Costing the price of a small car, they are the lenses of choice for wildlife and sports photographers as well as photo journalists around the world, offering incredible quality both in terms of design and the resulting images. Perhaps it’s just curiosity, but they also attract interest wherever they're seen or taken. At the annual Photography Show event in Birmingham, visitors gather around the manufacturers’ stands to try out their super-telephotos, picking off unsuspecting visitors like a sniper.
Buying one is a considerable investment and not to be taken lightly. The good news is that unlike camera bodies a well looked after Super Telephoto depreciates less than a camera body. Just consider any DSLR price at launch to its value 2 years later.
Using A Super Telephoto
Using one opens up new perspectives normally associated with binoculars or small telescopes with a narrow angle of view and compression of distance between objects. Over the past 20 years I've owned all of Canon's super-tele's at some point, and today have the 400mm f/2.8 LISUSM and 800mm f/5.6 LISUSM.
Optically, these lenses are almost as good wide open as they are stopped down both at the centre and edge of the frame. They incorporate high end, ultra low dispersion, optical glass and Fluorite that reduce optical aberrations so often present in other lenses. Their wide apertures, typically f/4, let in double the amount of light compared to a typical 400mm f/5.6 zoom. This makes auto focusing faster and more accurate given the prevailing sensitivity of AF points.
If you want the very best optics available with a long focal length then the super-tele's are the way to go. But owning one comes with its own unique practical & financial challenges.
Practical Considerations - Weight
Point of Reference - Canon 100-400 F/4.5-5.6 II LISUSM weighs 1640g or 3.62lbs.
Canon 400 f/2.8 LISUSM 11.8lbs
Canon 400 f/2.8II LISUSM 8.5lbs
Canon 400 f/2.8III LISUSM 6.3lbs
Sony 400mm f/2.8 G 6.4lbs
Canon 500mm f/4 LISUSM 7lbs
Canon 600mm f/4 LISUSM 11.8lbs
Canon 600mm f/4II LISUSM 8.6lbs
Canon 600mm f/4III LISUSM 6.7lbs
Canon 800mm f/5.6 LISUSM 9.9lbs
Assuming a photographer is comfortable in say hand-holding the Canon 100-400 II at 3.6 lbs Canon Super Telephoto's range from 2.7 to 8.2lbs heavier.
This is a key point to understand and one any potential buyer must be aware of.
My 400 f/2.8 held by the tripod collar seems quite manageable as a dead weight, but attach it to a camera body and hold it outstretched for 20 seconds and you’ll know about it. As a comparison, my 400mm weighs almost an extra 8.5 lbs more than my Canon 70-200mm f/2.8 II....... that's four bags of sugar!
Even the new 'lighter' versions, such as the Sony G Master 400, weigh over 6.4lbs, the new Canon 400 III 6.3lbs. Innovative design announced by Canon in Sept 18 saw their MKIII variants move the heavy lens elements to the centre of the optical configuration thereby reducing its size and weight. Nevertheless, hand-holding that mass outstretched for even a short period of time could prove a challenge for many.
With version III Canon super telephotos there has been a noticeable and well publicised reduction in weight but the changes in lens construction and their subsequent performance barely gets a passing comment. Let’s consider the changes with the Canon 400mm:
Version I Introduced 1999 - 17 Lens Elements in 13 Groups, 2 x UD Lenses & 1 x Fluorite
Version II Introduced 2011 - 16 Lens Elements in 12 Groups, 0 x UD Lenses & 2 x Fluorite
Version III Introduced 2018 - 17 Lens Elements in 13 Groups, 1 x Super UD elements & 2 x Fluorite
Incidentally the Sony 400 G Master has 3 fluorite elements!
We can see that the number of lenses and how they are grouped has remained almost identical. The difference comes in what those lens elements are made of and to understand that let’s see what Canon say - extracted from here and here.
It takes four times longer to grind a fluorite element than a glass element − one of the reasons for the increased cost of an L-series lens. The results, though, are lenses that all but eliminate chromatic aberration, resulting in sharper images since the light is recorded as a point rather than a blur of colours…….The emergence of UD glass and Super-UD glass came after Canon had successfully incorporated fluorite into some of its lenses. Using optical glass, rather than fluorite, to correct chromatic aberrations, is more cost-effective………….Two UD lenses are equivalent to one fluorite lens - Canon dramatically improved upon the optical performance of UD lenses and developed Super UD lenses that are nearly as effective as fluorite lenses.
From this we can see that the change in optics from version I to version II was effectively none given 2 x UD lenses are equivalent to one fluorite. The change from version II to III see one extra Super UD element added. Version I to version III sees an extra fluorite element and a Super UD element added. But what does all this mean in terms of the final image? For that we need to look at MTF charts for the 3 lenses.
These charts might look confusing but in essence they’re quite straightforward. The horizontal axis (0 to 21.6) is the distance from the centre to a corner on a full frame sensor. The vertical axis (0 to 1) represents the fidelity and optical quality - the higher the better.
Black lines reflect lens performance at widest aperture i.e f/2.8, while Blue lines show the performance at f/8. Thick lines indicate lens contrast, thin lines indicate lens resolution. Dashed lines: Lens performance with meridional lines. Solid lines: Lens performance with sagittal lines - Closer sagittal and meridional chart lines indicate more 'natural' out of focus areas. For a reason unbeknown to me Canon reduced the amount of analysis with the version III lenses - only Contrast is shown (thick solid or dashed lines).
Please keep in mind that we are considering super telephoto lenses and that the key subject of focus is likely to be either in, or very close to, the centre. Unlike lenses we might use for Landscapes, corner performance isn’t as critical - well certainly not for me.
You can draw your own conclusions from these charts but here is my take from them. The version I performs better than the version III at f/8 and almost as good at f/2.8 until it reaches the corners. The version II lens shows the strongest performance of the all 3 lenses. According to Canon’s engineers, a lens with contrast readings (thick lines on the MTF chart) of 0.6 or higher will deliver entirely satisfactory image results while a lens with contrast ratings of 0.8 or higher is considered “a superior lens.” If you wanted to pick hairs, the best performing lens is the version II - remember these are Canon’s own graphs, not mine! In short………How superb do you need superb to be?
For some circumstances though hand-holding is unavoidable; my own military aviation work in the low flying areas is one example. Trying to rotate a super-telephoto through 180 degrees around a tripod/monopod on the side of a hill with a jet approaching at 450mph just doesn't work – I know, I've tried it. Thankfully (in this case), the jets are gone within a few seconds.
So what are the alternatives? The more popular would include: tripod, monopod and beanbags, with the decision really based on the subject matter and budget! A beanbag is by far the cheapest option but also the most limiting in that it generally can't be used for anything other than a stationary subject, or one slow moving at a distance. The monopod is ideal and certainly the preferred choice of the sports photographer/photo journalist: it not only offers good support, but can also be used to carry the lens over short distances. Alternatively, a tripod with appropriate long lens head (such as the Wimberley) is perfect if the photographer is going to be in one place. Trying to carry a tripod, Wimberley head and camera lens/body is both uncomfortable and difficult over anything more than a short distance.
Of course, there will be times when support isn't practical or when prevailing circumstances require a relatively slow shutter speed. In these cases, using a super-telephoto can run the risk of inducing camera shake since small arm/hand movements are magnified by the longer focal length, which can be a contributing factor in blurred images.
One solution is to engage the Image Stabilisation/Vibration Reduction function found in the Super tele's nowadays. Introduced in the mid 90s, stabilisation sensors can detect camera shake and adjust the optical system to stabilise the image with a proclaimed benefit of around 4 stops. I've met many photographers who never use it, claiming they don't want any moving parts within the optical elements. Others swear by it and always leave it On. Modern mirrorless cameras have stabilisation within the body (In Body Image Stabilisation - IBIS) with custom functions allowing it to be assigned to a convenient button.
Personally, if I can achieve a shutter speed of the reciprocal of the focal length then I'll turn it Off as the stabilisation has reached its effective limit. However if I'm panning at, say, 1/200 sec with a 400mm f/2.8, it will be turned On. Equally, and even with the lens tripod/monopod mounted, if a shutter speed of less than 1/focal length is selected then my preference is to normally have it selected.
Portability vs Mobility
Okay, so you've taken the plunge and bought or rented one; how are you going to carry it? These lenses come with a very strong, robust carry case that is ideal for storage or if the lens has to be carried a short distance. For anything else, a good quality rucksack is required.
Carrying a super-telephoto, one or two camera bodies, perhaps a mid-range zoom and associated accessories – not forgetting food/drink – is going to weigh quite a lot. A good rucksack that securely holds everything in place is a necessity.
Choosing one that incorporates a high quality waist belt to move the weight to the hips can make a difference in spreading the load and ease the burden on aching shoulders. As ever there's plenty of choice, but my preference is for those made by ThinkTank, especially when travelling, Tenba and or MindShift 40L are my choices when I want to carry loads of kit. I personally dislike the harnesses found on LowePro bags having tried them on 2 rucksacks.
While the Canon super-tele's carry an UltraSonic/Silent Wave Motor to help drive the auto focus in an almost silent manner, perhaps one of the key benefits of these lenses is their aperture size for the focal length. At f/4, twice the volume of light is entering the lens than at f/5.6, which not only means a brighter viewfinder, but also more light hitting the AF sensors on the camera body, resulting in both faster and more accurate auto focus.
From my own experience, I know that my 800mm f/5.6 'needs' a lot of light for the AF to work quickly. If it's a very dull overcast day then the AF will be comparatively slow and can, on occasion, 'hunt'. This can often be overcome by engaging useful functions built into the lens such as Focus Preset, which allows a preset focus point to be memorised and quickly returned; and by setting the Focus Range Limiter Switch to an appropriate distance.
In comparison, my 400mm f/2.8 lets in four times the volume of light as the f/5.6, making AF lightning fast and accurate. One can understand why that lens is so popular amongst sports photographers around the world and why it was the first super tele Sony introduced.
Using a Super Telephoto
Given their focal length, super-telephotos open a new range of possibilities that other lenses can't. Beyond the most obvious of bringing a subject closer, I've categorised them into three areas: Image Compression, Depth of Field and Resolution.
A super-telephoto allows the scale/size of a subject to be communicated. The compression delivered by the image below of a US Airways Airbus 330 crossing in front of the Moon is a case in point. With a 600mm lens plus extender, the sheer scale of the moon is portrayed in contrast to the jet. The Moon is over 230K miles away, the airliner 7 miles, but the lens has compressed the distance between the two dramatically!
Over 7,000ft up in the Swiss Alps and an F5 Tiger from the Patrouille Suisse.
Depth of Field
For a given distance to subject, a super-telephoto captures shallower depth of field than other lenses. At relatively short distances this can lead to wonderful, buttery smooth background blur and superb isolation of the subject. Yet equally it brings its own challenges, as wafer thin depth of field could lead to misinterpretation of camera/lens focusing issues. I took this image in my garden at home, with a super-telephoto and a relatively short distance to subject of around 20ft; my lawn is completely out of focus and allows the subject to be isolated.
This image illustrates the creative effect of throwing both the foreground and background (differential focus) out of focus to isolate a subject. Taken with a 400mm lens and a 1.4 extender at f/4, the low point of view allows the foreground grass to soften while retaining sharp focus on the eyes. The long focal length and wide aperture deliver results just not possible with medium telephoto lenses at the same distance. Minimum focus distances can be an issue at short range, but the ubiquitous extension tube can quickly help resolve that.
In summer of 2011 I was invited to the Orleans Forest in France to photograph ospreys as part of the ongoing conservation work. One of the challenges was to identify (photographically) the metal ring on one of the birds from around 200m away. Such rings, supplied by the National History Museum in Paris (M.N.H.N), measure under one centimetre in width, and the engraved numerals only a few millimetres. The image below shows the view from my hide, taken at 100mm on a full frame camera. The osprey can be seen perched to the right of the nest.
Using an 800mm lens on a Canon 1D Mk IV mounted on a Wimberley head on top of a Gitzo tripod, a series of images were captured that showed the full code inscribed on the metal ring. The image shown below, cropped to 100 per cent, illustrates the capability of the lens in rendering such detail at distance. Timing of the shot was of course crucial: we chose an hour before sunset to let the temperature cool, as trying to shoot this image at 2pm would have been akin to shooting through a swimming pool. These lenses will capture atmospherics our eyes might not see. “They don’t tell you that on the marketing literature!”
Buying a Super Telephoto
Making the decision to purchase a super-telephoto requires a lot of time, research and thought; they're not cheap. Unless you know for absolutely certain one is for you, I'd encourage trying one first. Renting is fairly easy these days or, better still, ask someone who owns one if you can join them for a day and try it out. If you have a special holiday such as a safari planned then do consider renting. The 500mm f/4 or 200-400mm f/4 offer an excellent balance between weight and focal length. The quality of images you'll make will be far superior to nearly all zooms and will last a lifetime.
Speed vs Weight
Be aware of the crucial balance between focal length, auto focus speed and weight. For those not wanting to spend thousands of pounds, both Canon and Nikon offer zooms up to 400mm focal length that are relatively light and portable. Used on a camera with a smaller than full frame sensor is going to provide an extended 'effective focal length' due to the crop factor. So a 400mm could become effectively 600mm on a 1.5 Nikon sensor. Of course, the apertures aren't large and are typically f/5.6 at the full focal length. But being aware of the limitations of each lens and adjusting accordingly will make a huge difference. Back off the zoom and close the aperture by a stop and the image quality will improve, after all the noise performance on digital cameras is improving all the time so a one stop increase in ISO shouldn't really hurt.
Adding an Extender
Another cost-effective option is to add an extender to the lens. These lightweight, versatile add-ons multiply the focal length by anything from 1.4 to 2 times the original length, at the expense of 1 or 2 stops of light. While they'll attach to all lenses, care should be taken that the camera itself will be able to auto focus with one attached (refer to your manual). Extenders can be a great addition to your kit when weight and space are a concern.
For example, if used on a 300mm f/4 prime the photographer has not only a 300mm f/4 lens, but also a 420mm f/5.6 with a 1.4 extender and a 600mm f/8 with a 2x extender. This is one of the reasons I think the 400mm f/2.8 is such a versatile lens; not only is it exceptional as a 400mm, but it is superb with a 1.4 extender attached, giving a 560mm f/4 and useable with a 2x at 800 f/5.6.
Throw in a combination of using say 2 camera bodies, one a full frame and the other a cropped body, and the range of 'effective' focal lengths increases again. Considering such permutations is prudent, eye-opening – and confusing!
The fun really starts when one adds an extender to an 800mm. The image above was taken at a focal length of 1,120mm (800mm + 1.4x) on a full frame body at 1/100 sec with the lens/camera mounted on a Wimberley head attached to a Gitzo tripod.
I have the image printed 30 inches wide on display at home - try doing that with a 100% crop from a shorter focal length - you might get away with it displayed (as many do) on some social media platform or mobile phone but then if that's "your thing" don’t bother buying a Super Telephoto lens!
Try Before You Buy - Renting one is a great way to get a feel for them.
With Canon in-particular you could save a huge amount of money by buying a well looked after 2nd hand super telephoto. While the older lenses are heavier the optics perform just as well, if not better, than the latest versions (400mm and MTF charts above refer).
There is a huge premium attached to the newer lighter lenses.
Consider how you will transport it - check rucksack size and ensure it has a good waist belt
Consider alternatives to hand-holding - good tripod head, a tripod that can comfortably support the weight
Expect a period of getting used to one - an 800mm is akin to looking through a straw!
For full disclosure I have no affiliation with any camera manufacturer at all - I've used Canon equipment for over 30 years which is why it is referenced throughout the article. Other equipment references are just my preference or opinion.