Canon EF 100-400mm L Series USM Lens Plus 1.4x Extender Review

Rabbit, Centerparcs, Longleat Fores

Handheld at 400mm, f8, 320th sec.

I’ve owned this lens for almost a year now and so thought I’d put down a few thoughts I had on the lens in the hope it may be helpful to anyone thinking of purchasing it. First off, I know that being a zoom the quality won’t be up to that of a prime, but having said that my initial reaction when first using it was WOW! I’ve used Canon’s 500mm f4 L Series and yes, it is an amazing lens, but the 100-400mm isn’t that far off! The image stabilisation is incredible and has enabled me to get pin sharp images handheld at 400mm with little problem.

Prior to owning this lens I’d been using no more than a Sigma 72-300mm zoom with a Sony Alpha 200, but I realised that in order to continue my progress and make the step up I would have to get a far more capable lens. To be fair, I had managed to get the odd decent image, but successes were far less frequent than I would’ve liked. The Canon 100-400mm gives you a far greater chance of success.


Robin, shot at f9, 1000th sec with 1.4 Extender, camera resting on window ledge.


Shot with 1.4x Extender fitted, resting camera on a window ledge. This shows perfectly sharp images are possible with the extender, just so long as the bird keeps still!

One thing I don’t think is an issue with the Extender is the loss of a full stop. I’ve found that at f5.6 the depth of field is just too shallow. For instance, focusing on a birds eye at f5.6 will render the feet out of focus, so I always find myself using f8 with or without the extender. More recently I’ve been experimenting with f9, and I seem to be getting more reliable, and sharper, results. In summer you can get away with an ISO of anywhere between 200 to 800, but come the winter 1600 or even 3200 ISO is more likely, and then you have the problem of noise. Add a little sharpening in post and it only makes it worse. I’m currently looking at Noise Reduction Solutions, and NIK Software’s Dfine looks pretty useful.

Coal Tit

Shot at f9, 1/400th sec., ISO800 with extender fitted. f9 seems to give just that little bit more depth of field that ensures better front to back sharpness on the bird.

On the plus side, the flexibility of having a zoom comes in very useful at times. I do still dream of owning a 500mm, but there would be times when the weight and inflexibility would have meant losing shots. The ideal solution of course would be to own both! Unless I win the lottery however it’ll remain just a dream.

One thing that seems to have been made a large fuss of is the push/pull mechanism. I have to say it really is much ado about nothing, it very soon becomes second nature. For the majority of the time you’re using it at full extension anyway, its not too often your subject gets TOO close as we all know.


Tripod mounted, with 1.4x Extender fitted, cable release.

To extend or not to extend?
The downside is of course the maximum focal length. 400mm is still often just not long enough, hence why I bought the 1.4x Extender. When I first purchased the kit I did a fair amount of practising in the back garden with the birds. With extender fitted, tripod mounted and a cable release, prefocusing on the perch I was able to get some sharp shots. Over time, and with a little practice I’m now able to dispense with the tripod and instead rest the camera on the ledge and still manage to get very sharp images. However, when photographing the Grebes for instance, when prefocusing is out of the question, the success rate rapidly diminishes. Because I’m using a 500D body I lose the autofocus and image stabilisation with the extender on, and so in these instances I would say go without extender and crop in post if needs be. With autofocus enabled, and set to AI Servo you’ll have a much greater chance of capturing the moment. Its also important when using AI Servo to use centre weighted metering rather than spot otherwise you’ll get some wildy differing exposures when firing off several frames in quick succession. I almost without exception set the camera to Aperture Priority and then under expose by around 2/3rds of a stop.

In summary I would most definitely recommend this lens. At just over a grand it is far more affordable than the 9 grand or so for a 500mm. If you’re wondering how it compares with the L Series 400mm Prime you may also be interested to read my article on the subject here.

Blue Tit

f9, 1/400th sec, ISO800. Check out the detail on the lichen!

Squirrel, Centerparcs, Longleat Forest

Handheld at 400mm, f8, 250th sec.

Anyway, hope my two pennies worth helps anyone who may be undecided.

7 thoughts on “Canon EF 100-400mm L Series USM Lens Plus 1.4x Extender Review

  1. Hut down very nice photos. I do own Canon 100-400mm and considering to buy extender so your article was useful. Can I ask you which extender did you use 1.4 II or 1.4 III?
    Keep up good work 😉

    • giantsquid on said:

      Thanks Peter, glad to hear it was useful to you. It’s the 1.4II I’ve got rather than the 1.4III, I see there’s quite a price hike for the newer version. Might be worth looking on ebay for the II, £450 seems an awful lot of money for an extender.

  2. Hi Craig, I’m not fussed by price as it is not imminent buy.
    However not sure where you been looking on price as even Amazon has 1.4III for only £380, or if you will trust my recommendation you can get it from HK through for £360 including delivery ( I got Canon EF 100-400mm from them 🙂 )

    • giantsquid on said:

      Hi Peter

      I was looking on Warehouse Express where its £450, so quite a difference. On a different note I’m a little concerned that my Extender has started causing an ‘Err01’ (communication error between camera and lens). Despite cleaning the contacts it’s still occurring, so hoping it’s still in warranty.

  3. As you say the 100-400 is sharpest around f/8 but I also restrict it to around 350mm – goes increasingly soft beyond that. I wouldn’t let the 1.4x anywhere near it I have to say – very soft unless you’re downsizing and sharpening for low-res web use. You can get it to autofocus in Live View but only useful if tripod-mounted. It’s a good flexible lens but at the long end the 400 prime is superior I believe. Try Lightroom 3 luminance noise reduction btw – bit of a revelation and you might find yourself re-processing your entire collection…

    • giantsquid on said:

      Hi Dom, thanks for your comments. I’d have to disagree about going soft with the 1.4x on, I’ve got some very sharp results at full extension with the 1.4x fitted, and that’s without any need to downsize. It may require a little more diligence but it certainly is possible. Thanks for the Lightroom tip, will have to give it a try. The thought of reprocessing all my shots fills me with dread, but if its as good as you say I know I would have to do it!

    • Some came with very very stiff zoom ring (one of my friends renertud his because that), which will loosen itself over time. Mine is ok, but it creeps after walking for a few minutes at times. I sent the lens back to Canon to tighten the zoom ring after almost a year because I started feeling a small gap when I turn the zoom ring. Now it doesn’t creep anymore.