In this article, renowned photographer Darran Leal discusses the realities of long telephoto lenses and the incredible images they can produce.

It was not that long ago to have a 400mm lens or longer was too expensive for most people. Then came digital with its smaller sensor size and inherent magnification. That is, most of us enjoy a 1.5, 1.6 or even 2 times magnification factor when compared to 35mm film photography. For instance, Sony, Nikon and Pentax DSLR cameras have 1.5x magnification. Canon is 1.6x and Olympus is 2x.

So what is a telephoto lens? In simple terms, it is a lens that offers a magnification above that of our vision. Many of you may already have a medium telephoto 70-300mm lens. This is in fact an amazing step forward in photography as it becomes the 35mm equivalent of 105mm to 450mm lens in the more popular 1.5X sensor size. Overnight, what was traditionally a very expensive lens to buy became affordable for most people. As an example, this is the minimum telephoto lens that you need for the great wildlife photographs.

We can go a step further and look at even longer lenses. Sony has just released a 70- 400mm zoom. Canon and Nikon have similar versions and Sigma has a great new lens. These lenses with the smaller 1.5X sensor factor are fantastic for long telephoto work. The 70-400mm lens is actually the 35mm equivalent of a 105-600mm lens!

Perhaps the best way to understand all of this is to think in terms of magnification. With the average DSLR sensor, a standard lens would have a focal length of about 30mm. In other words, a lens of this range would not bring anything closer or push anything back. It would see at about the same magnification as the human eye. So, a 70-
300mm zoom means that you would have a lens that takes you from about 2x to 10x magnification all in one! A 400mm lens is about a 13X magnification and so on. However, when you get up to this kind of magnification we should also consider optical and image quality.

Quality

With computer designed lenses these days, no lens is bad. However, you get what you pay for. A long telephoto lens might do the job for you but will it always offer the quality that you desire as you improve your photography? I can guarantee that your interest in photography will change over time. Some lenses will out perform others. If your goal is to shoot the best, then you need the best tool for the job. Some great lenses are available from companies like Tamron, Tokina and Sigma.

I recently used the new Sigma 150-500mm f5-6.3 lens in Africa and it performed well. It was sharp, (my first key criteria) manageable to handle, but it has a little vignetting. This can easily be fixed in post processing. In fact I often add vignetting to draw the viewers attention to the key subject. Focusing was good but not perfect. But I am rather critical. In the hands of a new camera owner, it is an amazing lens and perfect for wildlife - and at a very good price.

Tamron offers another good alternative in a 200-500mm f5-6.3. It is a very good long lens that handles well.

What is best for me?

A little homework will help you. You can then go into your local photo retailer with the right information. Be prepared that you might need to wait for them to order the lens into the store. Don’t compromise as often this leads to disappointment! What lens is the best for me? That is very hard to tell as it depends on:

1. What do you want to use it for? (Future use needs to be seriously considered.)
2. Set yourself a budget but be prepared to go further if you can see the value. No use compromising
3. How does it handle and does it work well?
4. Take a camera body with memory card and shoot a few images to test you are happy. Make sure you are steady!

My suggestion is to look at the on line chats and website reviews for some comparisons. Simply type the lens into Google and you will see a list of pros and cons from users. Just remember they are often not the opinion of experts and some people are biased - for and against. So use this information only as a starting point

Using Your Telephoto

Any lens needs to be handled correctly with lenses of 100mm and longer requiring special attention. As a rule of thumb it is said that your shutter speed should never fall below the same as the focal length you are using. In other words if you are using a 400mm lens, then ideally you should use a 500th of a second or faster. Today we have another added piece of technology - Image Stabilization.

All camera systems now offer it. Most are built into the lenses with some like Sony and Olympus built into the body. Image stabilization is a fantastic technology for long telephoto lenses. Now you can hand hold a long lens down to much slower speeds. I was always happy to go down to a 60th of a second. But in theory, you can go lower.

However, you must be very steady. You can lean against a tree or kneel and use your other knee as support. Your subject also needs to be very still, otherwise you risk blur from movement. Motion blur is a common issue with a long telephoto lenses. Focusing is another issue faced by enthusiasts with long telephoto lenses. Due to the high magnification and limited depth of field focusing can be a bit of a hit or miss. So…

1. Be prepared. That is, have the right settings before you try to shoot. Check out the example images in this feature and the settings used
2. Know your subject. Whether it is a person, dog, car etc. If you know what it will or might do next, you can prepare yourself for whatever happens
3. Stabilise yourself. I do a lot of my work hand held. Some photographers feel they can not. Tripods are good but cumbersome. What ever technique you use, squeeze off the trigger and be stable for the sharpest results
4. Look at your subject and if it has eyes, try to focus on the eyes. If they are not sharp, you do not have the image. I love using long lenses. They are a great creative tool and add interest to images simply because of the way that they see. Compose tightly, watch your background and fire away! In time you will take some amazing images that will have viewers questioning - “how did you get that” and “ how close were you”. You will just smile knowingly…

Happy shooting!