Canon 300mm f4 L IS USM or Canon 400mm f5.6 L lens?

[Sabyasachi Patra]

I have been asked this question a number of times. Shall I buy the Canon 300mm f4 L IS USM or the 400mm f5.6L?

Before I start comparing, let me tell you that I had pondered over the same question in 2002 before choosing the Canon 300mm F4 L IS USM. With my increased understanding in the last seven years, will I make the same decision that I did earlier?

Well a disclaimer to start with. Both are very capable lenses. You will get good results with either of the two. :-)

Image Stabilisation:
The first difference between the two is that the 300mm lens has image stabillisation. The image stabilization is good for upto two stops. That means, if you can normally get sharp shots at 1/500 th of a sec, using the IS you can get sharp shots at even 1/125th of a second. Ofcourse the rule of thumb for handholding says you can get sharp shots if you are shooting at 1/focal length. So for the 300mm F4L IS USM lens, it should be 1/300th sec. And if IS gives 2 stops of benefit, that means you can get sharp shots at 1/60th sec. You will appreciate the need of image stabilisation, if you have ever climbed on top of an elephant to track tiger in the jungle.

The 400mm f5.6 L lens doesn’t have image stabilization. So according to the rule of thumb, you need to shoot at 1/400th sec to get sharp shots when you are handholding.

However, both these lenses are good for handholding and work well on monopod.
Check the following image. It was made with a flimsy manfrotto tripod, raised to its full extent and the shutter speed was 1/20th of second. Only image stabilisation can give you a sharp shot like this.
Wild boar scavenging on deer carcass - Indiawilds: Land of the Tiger. Conservation, Wildlife Photography, Communities

Two lenses & Focal length advantage:

The 300mm F4 L IS Lens comes in handy in low light situations in early morning and late evenings. Lot of times, I have sacrificed focal length for the extra stop that I have got from the f4 aperture. At times, it becomes the difference between a perfectly usable shot and a blurred image.

The 300mm lens also works well with a 1.4x converter. The combination becomes a 420mm f5.6 L IS USM lens. So you get advantage of 20mm over the 400mm f5.6 lens.

Is it only 20mm advantage?

We normally think that increase in 20 mm over a 400mm lens means an increase of (20/400)*100 = 5%

However, the image size is a function of square of the focal length used.

So the difference between 420 mm and 400 mm is {(Square of 420 – Square of 400)/Sq. of 400} * 100
= {[(420 *420) – (400*400)]/(400*400)}*100 = 10.25 %

Speed of AF

Any lens will slow down when used with a converter. However, I haven’t found the focusing speed with 1.4x II TC to be a problem in action shots. This combination is not significantly slower in autofocussing speed than the 400mm f5.6 L lens.

Quality of the 300mm F4L IS plus 1.4x TC combination:
The quality obtained is excellent with this Combo. Some of my photos have clicked with this combination has been printed at 20 inch by 30 inch size and sold to demanding art buyers.

Quality of the 300mm F4L IS lens plus 2x II converter:
The quality drops and I would not consider using such a combination. However, I had used this combination when I was focal length challenged.

400mm f5.6 L lens with 1.4xII TC:
I would not use this combination as the quality goes down. Ofcourse, in internet forums, there are people who will argue for countless hours in support of it. Though technically it is possible to fit a 1.4XII TC the combination becomes 560 f8 lens. With a 1 series camera you can autofocus using the central AF point.

Minimum Focussing Distance:
The minimum focussing distance of the 300mm F4 L IS USM lens is 5 feet. So you can use it for close subjects as well as isolate nature patterns etc for some macro work. The 400mm f5.6 L lens focusses at 11.5 feet. So if a tiger comes close to you, then it is a tough to get it in focus. Hence, the 300mm F4 L IS lens wins here as well.

Price:
The Canon 300mm F4 L IS USM lens price is 1210 USD as per B&H in USA. The 400mm f5.6 L is 1140 USD. These prices are excluding shipping. This price can be seen as an indication, as the grey market price in India is likely to be cheaper. 400m f5.6 L lens has a slight advantage in terms of price. However, it is insignificant to tilt the purchase decision.

To conclude, if I were to decide between the two lenses, then I will definitely choose the 300mm F4 L IS USM lens over the 400mm f5.6 L lens again.

The enclosed image of the tiger was taken from an elephant back. Canon EOS 10D, Canon EF 300mm f4 L IS USM, ISO 200, f4 at 1/90 sec