Should I use a teleconverter for bird photography?

Netra’s shot of a Wedge-tailed Eagle in flight, near Broken Hill NSW. Olympus OM-1, M.Zuiko 300mm f/4 PRO lens with TC-20. Focal length 600mm, f/8. Effective field of view is that of a 1,200mm lens on a full frame camera. We will use the 2.0x teleconverter for big, slow flying birds too, not just for static images.

Wildlife photographers, but especially bird photographers, often resort to using teleconverters with their main lenses to gain more magnification. Why is that? Well, in some 20 years of bird photography, I can honestly say, that I needed a longer focal length far more often than not. This is very much the case with most wild birds. When I first started out in the early 2000s, I figured a 300mm lens will be enough. Little did I know! And even then, not all 300mm lenses are made the same quality! With optics the more you pay, the better the performance of your lens is. It is really that simple. Back in the old days, let’s say more than 20 years ago and the times before that, teleconverters were not necessarily the most amazing bits of kit. You’d often hear mixed reports from users of the performance of these. Especially the “dreaded” 2x teleconverters. So what do these magical bits of equipment do? By placing a teleconverter between the camera and the main lens, you effectively increase the magnification by the multiplying factor of the teleconverter. The most common teleconverters are the 1.4x and 2.0x teleconverters, increasing the lens’ focal length by 1.4x and 2x effectively. These increases in magnification, however, don’t come without a cost. They come with a cost of losing light. In case of a 1.4x teleconverter, you lose one stop of light. With the 2.0x teleconverter you lose two stops of light. A 300mm f/2.8 lens will become a 420mm f/5.6 lens with the 1.4x teleconverter and a 600mm f/5.6 lens with the 2.0x teleconverter. This means that you must adjust ISO or shutter speed according to what you want to achieve with your planned shot.

See sample images below, all taken from the exact same spot but without and with teleconverters. The captions will have the details you need to know.

Canon EOS 1DMkIIn, EF500mm f/4L IS USM without a teleconverter. Total focal length = 500mm with a maximum aperture of f/4.
Canon EOS 1DMkIIn, EF500mm f/4L IS USM with an EF1.4x teleconverter. Total focal length = 700mm with a maximum aperture of f/5.6.
Canon EOS 1DMkIIn, EF500mm f/4L IS USM with an EF2.0x teleconverter. Total focal length = 1,000mm with a maximum aperture of f/8.

You can immediately see the big increases in the image magnification when adding the teleconverters to your main lens. But other than the loss of one or two stops of light, depending on whether you are using the 1.4x or 2.0x teleconverter, you will quickly realise, that these glass magnifiers work best with only a small range of lenses, usually the professional – or most expensive – lenses of your chosen brands’ available lens selections. It was only in the last 20 or so years when glass manufacturing really improved to the highes standards that I have seen little image degradation of the final images when using teleconverters. In fact, in many instances now, we find it hard to notice whether we used a 1.4x or 2.0x teleconverter. Naturally, the main lens on its own will always work the best. Once you add the teleconverters, your image quality may reduce a little, and more noticeable with a 2.0x teleconverter, depending on the lighting and other factors surrounding your shooting. Most of the time the use of a teleconverter is not really noticeable. The important thing to remember is, that it’s a good idea to always be as close to the subject as possible. There’s no point trying to take a photo of a small bird from 30 meters away using a 2.0x teleconverter, then cropping the image tight to show the bird. You will simply not get really good quality images shooting in that manner.

Crested Shrike-tit – Canon EOS 1DMkIIn, EF500mm f/4L IS USM lens and EF1.4x teleconverter. Total focal length 700mm at f/5.6.

I tend to shoot full body images first. Then I work out in time whether the bird will allow me to get closer and try some tighter framed images to show the small detail. When you have extremely cooperative subjects, then you’ll be able to get some unusual images even of common birds and capture detail not possible from a distance if you had cropped the image to the same size.

Teleconverters are not always everyone’s favourite tools, but for us they are very useful accessories to be able to photograph our beloved subjects.

We love using them, and I have even had moderate success stacking them when I was shooting with the Canon professional system to get even more magnification than achievable with a single teleconverter. I’ll throw in a couple of nice example images below.

Bar-tailed Godwit sleeping. Canon EOS 1DMkIII, EF500mm f/4L IS USM, stacked 2.0x and 1.4x teleconverters. Total focal length = 1,400mm, maximum aperture of f/11. I was barely 6m from this snoozing bird on a rock platform. It never moved, even when I slowly inched my way back out on my knees (I was wearing knee pads).
Black-shouldered Kite with a high level of tolerance for humans allowed me to get close to get this tight portrait. Canon EOS 1DMkIIn, EF500mm f/4L IS USM, stacked 2.0x and 1.4x teleconverters. Total focal length = 1,400mm, maximum aperture of f/11.

Current teleconvers from the main camera manufacturers:

Canon: https://www.canon.com.au/lens-extenders

Nikon: https://www.nikon.com.au/mirrorless-lenses

OM System: https://asia.olympus-imaging.com/product/dslr/mlens/index.html#anc04

Sony: https://www.sony.com.au/electronics/camera-lenses/sel20tc

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