Knowledge Base

The single most important factor when purchasing an interchangeable lens camera is, as the terminology suggests, its ability to use different lenses. The versatility of such systems provides a photographer with the ability to capture everything from microbes to the stars, depending on where interests lie. Some manufacturers lens systems are vast, addressing most professional and amateur needs. From super wide-angle to long telephoto, there are variants that are weather sealed, fast, tiny, lightweight, stabilised, focus limited, manual…the list goes on. And then there are prime and zoom options.

So, you have purchased your camera and it arrived with a kit lens that has a focal length which runs from wide angle to short telephoto and decided that this does not fulfil your needs. Or it could be that you quickly outgrow its capabilities. You have a cursory look around the internet to be met with pages of offerings. But which do you choose? Focal length is relatively easy but there are several other attributes that need to be considered to ensure expensive mistakes are not made. And then there is the eternal question of Primes or Zooms, making the decision ever more complicated. It is impossible to recommend one type of lens above another as ultimately; the photographer needs to understand what they are trying to achieve with it. So, this and cost, coupled with less tangible aspects such as bokeh and tonality, combine to make it a very personal choice.

The purpose of this article is to discuss some of the properties requiring consideration when purchasing additional lenses. It is by no means exhaustive but hopefully, provides enough guidelines to assist with the decision-making process.

Some lens buying decisions are very easy; for example, a photographer may simply want a means to achieve super wide-angle effects or use a powerful telephoto to grab a sunset shot. I base this last sentence on my own requirements shortly after purchasing my first ‘real’ camera 35 years ago (which came with a ubiquitous 50mm lens). I was fascinated by the possibility of having a lens that allowed me to photograph architecture and get most or all the subject in the frame. It didn’t take me long to identify that a 28mm lens would suit my purposes and quickly purchased one. Similarly, cliched sunset pictures had not escaped my attention, causing me to purchase a 80-210mm zoom lens and use it at the ‘long’ end for this kind of material. Now I had a three-lens system that kept me happy for a little while.

Did I make the correct choice? I guess at the time my needs were fulfilled but if I was being honest, I relied on 1) recommendation and 2) popularity to make my decisions. Had I been a bit more educated or experienced, I think my purchases would have been very different.

NOTE Focal length values refer to those provided by 35mm (36x24mm) sensor sizes, therefore camera systems using APS-C or Four Thirds sensors will differ, although f-stops remain the same.

  • Wide Angle Lenses

    Take my choice of 28mm focal length. Available in abundance in the early 1980’s as prime’s and sometimes as part of a zoom’s range, I overlooked wider options like 24, 21, 18 and 16mm versions. 28mm seemed to offer the most ‘bang for buck’ at a reasonable price and was reasonably easy to compose with due to its 75° angle of view. Being a beginner, I was not concerned about its maximum aperture being a sedentary f2.8, and it has not gone unnoticed how much of a cost increase there was in f2 variants.

    What does 24mm offer over 28mm? In short, a heck of lot; 4mm does not sound much but it equates to an 84° viewing angle that not only fits more architecture in frames but helps create stunningly large skies. These attributes come at the expense of converging architectural verticals and diminished foreground interest with landscape work. Both require extra compositional skills to overcome. The problems are exasperated as the angle of view increases through increasingly wider (21, 18 16mm etc.) options, so much so that a photographer’s shadow can be problematic.

    Given the increased depth of field wide angle lenses provide, why is there a need for fast apertures? Apart from the obvious low light usage, I struggled with this question for a few years until I purchased a 21mm f2 Zuiko. It was a floating element design, resulting in close-up images being reproduced very well. I soon found that wide open close-ups taken with this lens allowed me some very original results and took to using it almost exclusively for this purpose. Adding a 7mm extension tube served to make things even more whacky. If distorted portraits are to your liking, then wider is better (or worse from your subject’s perspective).

    Of all lens groups available, wide angles provided me with the most fun and experimentation and always accompanied me on my travels. I found them extremely useful for environmental portraits. Although the 28mm variant fell out of favour with me many years ago, it was an inexpensive way into the wide-angle world of which I have very fond memories.

  • Standard Lenses

    The standard lens is an optic usually with a focal length of around 50mm. Its 47° angle of view offers a gentle and natural perspective often associated with the viewing angle of the human eye (not strictly true as we have two). Standard or ‘kit’ zooms will have this focal length covered albeit at a more sedentary aperture than prime equivalents.

    The term ‘standard’ seems to have been applied many years ago, back in the days of film. A 50mm lens was what used to be bundled with a camera body, usually with a maximum aperture of 1.7 to 2.0. Neither wide or telephoto, its versatility lay in its ability to capture scenes naturally while allowing creativity to be applied by careful use of aperture. It was the first lens I owned and went misunderstood by me for many years while I enjoyed exploring a wide-angle world.

    As my photographic knowledge expanded, I returned to the subtle world of the 50mm, finding it far more useful than I remembered. It saw increased use in the landscape as well as when generally on a walkaround and has become one of my favourites. The standard lens’ lineage and popularity means its design has probably had more R&D that most other focal lengths; considering even a modest design has a large aperture it is not hard to see why the envelope was pushed and they are available at speeds of up to 0.95 (albeit at a massive cost).

    If you find yourself using the 50mm setting of your standard zoom a lot, I would encourage the purchase of a prime equivalent, as this will free you of restrictive maximum apertures and demonstrate the full potential on offer. The chances are it will also be much smaller and lighter, so what is there not to like?

  • Telephoto Lenses

    Telephoto lenses are, as their name suggests, designed to bring the subject closer and offer a very narrow angle of view. Broadly speaking, they range from ‘short’, i.e. focal lengths of around 90mm (ideal for portraiture) to ‘long’ i.e. 200mm and above (ideal for intimate landscape shots or wildlife/sports). Some short telephotos feature close-up or true macro capabilities so if interests lie within a world of close-ups, it is worth checking this option out. Longer focal lengths, particularly 400mm and above are more specialist. Combining power with fast speeds becomes expensive, so the buyer should think carefully about the intended use.

    If you are a fan of shallow depth of field, a telephoto of around 100mm combined with an aperture of f2 allows for superb subject separation, lending itself well to candid and portraiture work. Out in the field, their use when isolating landscape features should not be underestimated – indeed I often use just a 90mm when shooting outdoors.

    My own use of longer focal lengths has seen much experimentation, but my shooting style does not really call for them, other than for experimental purposes. Not being a sport or nature/bird photographer has meant that my efforts have been limited to landscape and sunrise/sunset work. Lenses that are 500mm or more are generally large and heavy (perhaps with the exception of Micro Four Thirds offerings). I quickly found that toting such behemoths around meant strong shoulders and a significant amount of dedication, which for me, became onerous due to my optical passion lying elsewhere.

  • Macro Lenses

    Macro lenses come in many variations. There are those that are dedicated to the close-up realm and those, as discussed above, that double up as telephotos. A true macro lens is one that offers 1:1 reproduction, that is to say reproduces life size images. Having explored this world thoroughly back in my 35mm film days, I have owned many including those that offer up to 9 x magnification. Such lenses are for the true enthusiast, requiring painstaking attention to lighting, composition and depth of field.

    More general macro lenses offer image reproduction at around half or life size. Focal lengths are varied, depending on their intended use. Insect and small creatures benefit from those with a longer working distance (so as not to scare them off), therefore something in the region of 90 – 150mm is more suited. If it is simply inanimate objects that are being photographed, a focal length of around 50mm will suffice. The subject will be closer to the front lens element and, while being lower in power, they can often be matched with an extension tube to increase magnification if required.

    Most modern macro lenses double up as either standard or telephoto lenses meaning they will focus from their closest point all the way out to infinity, making the lens a more versatile proposition. A lens is usually optimised to deliver its best results at infinity. However, a macro lens’ optimal performance is at its closest focussing setting. This is apparent when looking at MTF (Modulation Transfer Function – a measure of a lenses performance) charts but I have not found it to be of detrimental effect in the real world.

  • Specialist Lenses

    Specialist lenses are those that have a specific function therefore may not be used often. These include:

    • very long telephoto, i.e. 1000mm and above; ideal for close-up wildlife studies, unusual landscape images.
    • architectural (tilt/shift); offer correction for converging verticals.
    • circular fisheye; produce 360° circular images – not everyone’s cup of tea but can be useful capturing images of the hemispheres.
    • high power macro/micro; such lenses do not focus at infinity and require some form of extension (i.e. bellows/extension tube/microscope) to form an image.
  • Environmental Sealing

    Environmental sealing is an important consideration if your camera gear is exposed to harsh elements. Additional gaskets are included in their construction to prevent ingress of moisture and sand that can have catastrophic effect on equipment. It goes without saying that sealing will have an impact on cost, but if your shooting style means you are spending long periods of time in inclement conditions, it is a small surcharge to pay. After all, what use is gear if you have to store it just when it is needed? Additionally, if you have a weather sealed camera body, it makes little sense for the lens not to be.

    Having used environmentally sealed gear in the past, it offers a good level of reassurance that it will continue to function and can be used with confidence in deteriorating conditions. My own experiences have seen my equipment covered in snow and soaked by heavy downpours, but it has never caused me to miss a shot. Since moving to Leica however, the system I use has no weather sealing so I have to adopt a more cautious approach when out in rain, snow or sand. Consequently, I have abandoned a couple of shoots due to driving rain… something that was never an issue with my previous system. Ethan uses Pentax K3’s and 5’s which are superb performers in bad weather, although some of the lenses used have no sealing.

  • Zoom or Prime?

    The eternal question that has been debated for decades. Many years ago, there was an argument that zoom lenses underperformed their prime counterparts. This was in part down to the number of elements a zoom lens needs to meet its specification; more elements, more glass surfaces for potential aberrations to become apparent. Given the mechanical complexity of zoom design, tolerances were not quite as tight as they were in primes. Zooms are inevitably larger, heavier and often slower than primes too. But in their defence, they provide convenience when it comes to image framing and are also much more convenient due to not having to change lenses as often. Given their ability to replace two or three primes, they are often seen as a less expensive alternative.

    Many years ago, I was put off zooms due to their mediocre image and build quality, and only revisited them in 2005 when I got into the Four Thirds system. How things had changed; the Olympus 11-22mm became one of my all-time favourite lenses and I used it exclusively for a couple of years. Since then I have always had one zoom in my kit, the latest being Leica’s 11-23 offering. I find them most useful for travel photography, when I need portability but lack time.

    A zooms flexible framing perfectly suits specific styles of photography such as sport, action and wildlife. It would be fair to say that modern designs have liberated the photographer, freeing them from onerous lens changes and the potential for missing the perfect shot.

    I still tend to shy away from zooms that span massive focal lengths, convinced that a ‘one stop shop’ will never be as good as two or three zooms that cover specific focal ranges. For a lens to deliver results from wide angle to medium telephoto requires certain optical compromises, from increases in weight and size, to image degradation when used wide open. If choosing an all zoom kit, my preference would be to have separate wide angle, standard and telephoto zooms, thus overcoming some of the optical challenges.

    For the first time in my photographic career, I am on the brink of owning two zoom lenses and will be adding a 55-135mm to my kit, giving me a bit more reach than my primes allow. But this is for a specific purpose and I will continue to use primes as my go to lenses due to their speed.

  • Aperture

    Speed is a very important consideration in lens choice, particularly if you like low light shooting or are a fan of producing glorious out of focus transition effects (bokeh). Personally, I love fast lenses and always have at least one in my kit, the latest being a 35mm f1.4 for my Leica T. The creativity offered appeals to my style of photography, but it comes at a much higher price than I am comfortable with – hence not all of my primes are fast. They have a very clear purpose that should be understood before purchasing. Fast telephotos are particularly useful in the worlds of nature and sport, allowing the preservation of moments that would otherwise go almost unnoticed.

    It is important that a fast lens performs well wide open, as this is the reason it is purchased. The spectre of chromatic aberration increases significantly as f stops get lower, therefore check the lens delivers results in line with expectations before committing to it. They will always perform better when stopped down a little but how much of this is acceptable can only be answered by the user. I once owned a Zuiko 50mm 1.2 that produced very soft images wide open. However, the dreaminess and other less tangible qualities produced were very likeable. Stopped down to f4 gave stunningly sharp results. Similarly, I owned a 21mm f2 with the ability to focus very closely. Again, the wide open results were not the best, but in conjunction with its closest focus point some really whacky images were possible due to the enormous angle of view and out of focus background.

    Fast lenses are always more expensive than their slower counterparts. Larger and more complex optical formula’s are required in the their production. Therefor if speed is not important to you, there is no point reaching deep into your pocket.

  • Filters

    Filters may need to be taken into consideration when purchasing any additional lenses. I tend to keep their use to a minimum, using only a polarising filter to remove reflections occasionally. Many years ago I used UV and Skylight filters to protect the exposed front element but no longer do this, which is ironic as I now use Leica glass! Screw-in and slide in square versions are readily available, the latter needing a mount. Regarding the screw-in variety; if you are considering building a lens collection, it is worth researching if the same size filter mount can be shared as this will reduce the cost. Like lenses, buy the best you can afford as cheap ones can cause significant image degradation.

To sum up, interchangeable lenses offer the opportunity to focus (no pun intended) on those areas of photography you are most passionate about. I recommend researching fully any intended purchase to ensure it meets requirements. A good lens is expensive, therefore research will go a long way to preventing buyers’ remorse. A good lens could also be a partner for life, which is what a handful of mine have become. Try before you buy, ask lots of questions and enjoy the journey.