Is 400mm Long Enough Focal Length For Bird Photography

Digital photography has been a game changer for birders and given rise to bird photography at a level never seen before. More and more birders accept added long lens cameras to their birding equipment arsenal and have begun identifying birds based on their photographic records rather than just what they see through their trusty binoculars.

Choosing the right size (aka focal length or magnification) camera lens for bird photography has therefore become a really important conclusion. A camera lens for bird photography needs to take sufficient magnification and then that yous are able to fill a large proportion of the frame with a bird without having to excessively crop the image. Having plenty magnification to avert cropping images will help provide enough particular so that your images not merely look good only are good enough to positively identify what you have photographed. Another important consideration is whether the magnification of the lens is variable, allowing yous to zoom in and out to frame your bailiwick to your choosing. With camera lenses, this magnification is described as either fixed focal length (prime number lenses) for lenses with no ability to vary the magnification, and variable focal length for lenses where y’all can rotate a ring on the lens to vary the magnification.

Variable focal length lenses with a maximum focal length of between 400mm and 600mm are by far the nearly popular lenses for bird photography as they provide 8X magnification at 400mm and 12X magnification at 600mm when shooting with a total frame sensor camera. If you consider that the nearly popular birdwatching binoculars are in the 8X to 10X range, it makes sense that the aforementioned would utilize to camera lens magnification. Some of the well-nigh popular long lenses are the Canon EF 100-400mm f/four.five-5.6L IS mk I & Ii and the Nikon 80-400mm VR Lens both of which fit neatly into the 8X magnification range for total frame cameras and 12X magnification range for crop sensor cameras.

What is the magnification value of a photographic camera lens?

Camera lens sizes are measured in mm focal length rather than an 8X or 10X magnification value as they are for binoculars and video cameras. At kickoff glance, focal length and magnification seem difficult to compare, however, there is a very like shooting fish in a barrel way to calculate an equivalent magnification value. A 50mm camera lens is the equivalent of 1X magnification and comparable to what is seen by the man centre.

Source: Nikon

To calculate the magnification value of a lens, the focal length value of the lens needs to be divided by 50mm, the 1X equivalent magnification. So, for example, a 400mm lens on a full frame sensor camera has a binocular-equivalent magnification of 8X (400mm divided by 50mm). See the focal length to magnification conversion table below.

The table beneath shows the 50mm equivalent range of full frame and crop sensor cameras taking a photo at a range of 30 yards. Remember that a 50mm lens on a full frame camera has a 1x magnification and is equivalent to the human eye. And then, for example, the table shows you that if y’all are photographing a bird at 30 yards with a Canon APS-C photographic camera and a 400mm lens, it would be the same every bit standing two.3 yards away from the aforementioned bird with a 50mm lens. This table helps give you a sense of how much magnification you can expect over a reasonable range of 30 yards.

Don’t be dislocated with the zoom range factor that some camera manufacturers use. This is typically the zoom range of a lens. For example, a Canon 100-400mm lens would take a 4X zoom range (400mm divided by 100mm) and a magnification of 2X at 100m and 8X at 400mm.

Do crop sensor cameras bear on lens magnification?

Yes, crop sensor cameras practice impact lens magnification. If yous are shooting with a full frame sensor camera, then the lens magnification will be proportional to the focal length value of the lens divided by 50mm as described above. If, notwithstanding, yous are using a crop sensor camera, then you will become further magnification over and higher up that produced by the lens. This is due to the magnification consequence of your photographic camera sensor beingness smaller than a 35mm full frame sensor. For Nikon APS-C crop sensors, this multiplier effect is ane.5X whereas for Canon’s APS-C crop sensor it is i.6X. Look at the crop gene diagram below for more information on this.

With this in mind, the Canon 100-400mm lens on a crop sensor camera such every bit the Canon 7D Mark Two would accept an equivalent focal length of a 160-640mm lens. Use a lens such as the Tamron SP 150-600mm F/5-half-dozen.3 Di VC USD G2 on the aforementioned ingather sensor photographic camera and you will get an equivalent focal length of a 240-960mm lens. This is a pretty significant difference and is a great manner to get some serious magnification for those long-distance shots or when you purposefully want to avoid agonizing a bird. The epitome quality volition probably suffer at those distances, however, in most cases the quality will still be sufficient for y’all identify birds in long distance photos. I have establish my Catechism 100-400mm on a Canon 7D mk II actually useful for identifying birds that are beyond the range of my 10X binoculars. So, carrying a long lens camera around, specially i with a ingather sensor, has some of the benefits of spotting scope.

What most using teleconverters to increment magnification?

An piece of cake manner to increase a lenses focal length is to use a teleconverter. A teleconverter is a small device that is mounted between the lens and the photographic camera to increment the focal length of the lens by between ane.4X and 2X in most cases. Use a 2X teleconverter and a lens with a maximum focal length of 400mm and it will be boosted all the way out to 800mm on a full frame camera and a whopping i,280mm equivalent on a Canon crop sensor camera. This magnification boost makes teleconverters a handy accessory to go along in your camera pocketbook. Accept a wait at the lens magnification table below for the magnification achieved by a full frame and crop sensor cameras using one.4X and 2X teleconverters.

The table below is the focal length equivalent subsequently factoring in the additional magnification from teleconverters and crop sensors. Then, a 600mm lens and 2X teleconverter on a Canon crop sensor photographic camera would requite 38.4X magnification and a focal length equivalent of 1,920mm.

There are, even so, three drawbacks of using teleconverters:

Firstly, adding a teleconverter reduces the maximum aperture by ane terminate for 1.4X teleconverters and by 2 stops for 2X teleconverters. If you have paid a small fortune for something similar a Canon EF 400mm f/2.8L, you volition probably be somewhat loathed to lose the benefits of your f/2.viii aperture.

Secondly, adding a teleconverter to your setup introduces more glass between the incoming lite and the photographic camera sensor. Calculation more drinking glass, even something as sparse as a UV filter, will reduce image quality.

Thirdly, depending on the photographic camera and lens y’all are using, yous may lose autofocus functionality or have reduced autofocus performance. This is because DSLR’s have a minimum aperture that they can autofocus at. Almost Catechism DSLRs can only focus at an aperture of at to the lowest degree f/5.six or wider. When the teleconverter is added it reduces a lenses maximum aperture by i stop for a i.4X teleconverter and 2 stops for a 2X teleconverter. And then, if you are using a f2.8 lens with a 2X teleconverter, you volition all the same be able to autofocus equally your maximum discontinuity is reduced from f2.viii to f5.6. However, if you were to use the same 2X teleconverter on a f4 lens, your maximum aperture is reduced to f8 and autofocus will stop working.

Then, as a rule of thumb, teleconverters are nifty for occasional utilise but you should consider getting a longer lens if you lot rely on it for all your photography.

Fixed vs variable focal length lenses

Fixed focal length (prime number) lenses are lenses with a stock-still magnification (focal length) whereas variable focal length lenses allow you lot to accommodate the focal length or magnification. There are a few pros and cons of fixed vs variable focal length lenses that need to be considered.

Probably the first and most important thing to consider is cost. High magnification (long) fixed focal length lenses are generally pretty expensive. In contrast, variable focal length lenses with high focal lengths are available in a wider variety of qualities and prices. For example, y’all tin become a lower quality variable focal length lens such as the Catechism EF 75-300mm f/iv-5.6 III for around $200 or a loftier-quality lens such every bit the Canon EF lxx-300mm f/4-5.6L IS USM Cost. On the other hand, the best value for coin 300mm fixed focal length lens would probably be the Canon EF 300mm f/4L IS USM at around $one,350.

The 2nd most of import consideration would probably exist versatility. A variable focal length lens gives y’all a lot more options in the field. With something like the Canon EF 100-400mm, you could be snapping away at a bird at your feet 1 minute and then zoom into a bird at altitude the next infinitesimal. Variable lenses also permit yous to keep a single lens on your photographic camera which means you carry less gear and spend less time changing lenses when you could exist taking photos. This is probably what makes lenses such equally the Canon EF 100-400mm best sellers.

The third consideration is prototype quality. Because fixed focal length lenses have fewer moving parts, they tend to deliver higher quality results when compared to variable focal length lenses. This difference in quality is specially noticeable when it comes to cheaper lower finish variable focal length lenses.

Finally, weight is some other factor in a decision between fixed vs variable focal length lenses. For shorter focal length lenses below 500mm, fixed lenses tend to be lighter than variable lenses. Eastward.one thousand. the Canon EF 400mm f/5.6L USM Super Telephoto lens weighs about two.8lb compared to about 3.46 lbs for the Canon EF 100-400mm f/4.v-5.6L IS Ii. For longer focal length lenses in a higher place 500mm, stock-still lenses tend to be heavier than variable lenses. E.g. The Canon EF 500mm f/4L IS USM Super Telephoto lens weighs about 5.5lb compared to virtually 6.31 lbs for the Sigma 150-600mm 5-6.3 Sports DG Bone HSM Lens.

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