In this article I take a look at the performance of the older Canon 100-400mm lens when fitted with the latest Canon 1.4x III extender (aka teleconverter). The addition of the extender gives a very useful 560mm, but at a cost, as you'll end up with F8 at wide open aperture setting. As a result, low light performance suffers with the extender. Some would argue that even F5.6 creates a challenge for low light photography!
That said, the Canon 7D Mk II, which I use as my main camera body, works well right up to ISO6400 for birding, thanks to a brand new 20.2MP CMOS sensor and the improved DIGIC 6 processor. The Canon 7D Mk II is at least one stop better than the old 7D at high ISO and images are cleaner and noise (when it appears) is more manageable. So, when it comes to high ISO noise, a photograph taken at ISO6400 on the new 7D Mk II has the edge on a picture taken at ISO3200 with the old 7D. I own both bodies, so have done direct comparisons. Interestingly, the Canon 7D Mk II is much improved at low ISO too, there are cleaner edges and borders on subjects, with less noise on background textures.
One of the first issues to consider if you're planning on using the Canon 100-400mm lens with a 1.4x extender is one of Auto-Focus. Many Canon camera bodies (including the original Canon 7D Mk I) will not auto-focus with this combination, which means the added inconvenience of using manual focus - which is not really practical for birding, when the subject is constantly moving.
Of course, using a 1.4x extender will always reduce image quality (IQ) to a degree and although the Canon EF 1.4x III extender is excellent, there is inevitably going to be IQ degradation. This results in soft images, which aren't tack sharp, particularly at wide-open F8 aperture settings.
To assess image quality for the tests, I took some pictures of Greenham Water Tower, which is about half a mile away from this location. To be kind, I chose a day with good natural light and took several images using each lens combination, in order to choose the sharpest of each.
With the converter in place, I took pictures at F8 and at F11 and without the converter at F5.6 and F8. The Canon 100-400mm L IS has a reputation for not being tack sharp wide open and these test images demonstrate that. Unfortunately, with the extender fitted, that means using F11 or narrower apertures to get anything like decent image quality. Very restricting in the UK, with all our dull days!
For those of you who have always wondered what kind of image quality difference you'd get from a good quality prime lens, I also include some comparison pictures taken with the Canon 300mm F2.8 IS II lens, fitted with the same extender - which gives 420mm at F4. As you would expect this combination provides best-in-class image quality, especially when used stopped down to F5.6 or F8. I love this lens! It is so versatile and easily hand-holdable. The Canon 300mm F2.8 IS II will be the subject of my next lens review. Stay tuned!
Test Images
All images below were taken with a canon 7D Mk II body. All the lens combinations were micro-focus adjusted, as I have found this can make a significant difference to the image quality.
The micro-focus adjustments for my particular lenses, with the Canon 7D Mk II body were:
- Canon 100-400 no extender +3
- Canon 100-400 with 1.4x extender (telephoto) +12
- Canon 300mm F2.8 with 1.4x extender +8
All images are 100% crops and not adjusted in any way, each being saved at 100% quality in Adobe Photoshop. Click to enlarge each image. The camera was spot focused in the centre of each frame.
Figures 1 and 2 are of the Canon 100-400mm L IS lens with no extender fitted:
Figure 1 - Canon 100-400mm L IS USM. F5.6, 1/800sec, ISO100, 400mm
Figures 3 and 4 are of the Canon 100-400mm L IS lens with Canon 1.4x III extender:
Figure 3 - Canon 100-400mm L IS USM, 1.4x III extender. F8, 1/1000sec, ISO320, 560mm
Figure 4 - Canon 100-400mm L IS USM with 1.4x III extender. F11, 1/800sec, ISO500, 560mm
Figures 5 and 6 are taken with the Canon 300mm F2.8 IS II lens with 1.4x extender:
Figure 5 - Canon 300mm L IS II USM with 1.4x III extender. F4, 1/2000sec, ISO100, 420mm
Figure 6 - Canon 300mm L IS II USM with 1.4x III extender. F8, 1/640sec, ISO160, 420mm
This shows that even the best lenses are sharper stopped down!! This lens is amazing at F8. Remember that the subject is half a mile away and the brown pipe is probably only 4 feet tall.
Conclusion
The overall results of this test show that there is little benefit in using the 1.4x III extender on the Canon 100-400mm f4.5-5.6 L IS USM, as cropping down the images obtained with the lens minus the extender, actually gives better results - at least with the Canon 7D Mk II, which has dual DIGIC 6 processors, 20.2MP and a decent CMOS sensor.
Canon 100-400 L IS II Release
The Canon 100-400mm L IS lens has recently been superceded by the Mk II version, which, at £1900, comes at quite a price premium over the Mk I version. The Mk II has better image quality and four stop image stabilisation, so it would be interesting to see if the 1.4x extender fares better with that lens. I have already read reports that the results with an 1.4 x converter are a lot better.In reality, you need a lens that is sharp wide-open to work well with a converter and this is the failure of the Canon 100-400mm L IS USM. It loses that bit of sharpness at F5.6, resulting in mediocre performance when the extender is fitted, especially at F8. Even at F11, although better, it is hard to recommend owners of the Mk I to invest in a 1.4x converter.
Do you use the Canon 100-400mm IS II USM? What's that perform like with the 1.4x III converter? Drop me a line to let me know and I'll add your comments here...
About the Author
Written by Steve Larkins.
Purchased the new 100-400mm IS II USM and a 1.4x converter together and was told by the dealer it would work with my Canon 70D. Well, as I discovered, it wouldn't auto focus and as I photograph birds that was a no go. I got a refund of the converter and have continued using the 100-400mm on its own. It's still not enough zoom and I find the photos are not very sharp at full zoom. I am disappointed as I paid £1799 for it. My friend uses a 300mm prime and a 1.4x converter and gets very clear photos. Should have gone down that route I suppose.
ReplyDeleteHi Steph,
DeleteThanks for your comment on my blog. Sorry to hear that you aren't happy with your purchases. The shop should have known that the 70D wouldn't auto focus with the 100-400 and a 1.4x extender. I think the 7D MK II is one of the only Canon bodies that would AF with that combination.
I own the older 100-400 IS I USM push-pull zoom lens and a 300 F2.8 IS II Lens and both are capable of taking decent images. The Mark II 100-400 is much better than the older one that I have. To see the results this Mark II 100-400 lens should be capable of taking see http://instagram.com/bass23. This person uses a 7D MK II and your 100-400 IS II, with superb results. The 70D should give pretty comparable results. If it doesn't then something is wrong.
I think your problem may be one of two things:
1. Some slight camera movement may be causing the images to lose sharpness at full zoom. Try using shutter priority (TV) with the lens and set the shutter speed to be 1/1000s to 1/1250s or higher in good light. 1/2000s can be used in very good light. This will help reduce any softening of the images caused by tiny amounts of camera shake.
2. Both of my lenses gave soft images when I bought them (even the 300 prime lens!). Both needed adjusting to the camera body to get the best results. Your 70D has an adjustment called 'micro focus' which corrects for the tolerances in the lens and the body to ensure that the camera always focuses exactly on the object and not on a point slightly closer or further away.
I was delighted with the image sharpness difference micro focus made on my own equipment, when I set it correctly. I used it both in my 7D and my 7D MK II. The difference (and any micro focus error) will be more noticeable where depth of field is at its lowest (I.E. at F5.6 on your lens at 400mm). Interestingly, this is precisely when you see images which are not 100% sharp.
There are a few good tutorials on You Tube which tell you how to set up micro focus, so I would recommend that you familiarise yourself with these and then consider checking how far out your lens is when attached to the 70D. Micro focus makes a big difference to the ultimate sharpness of a lens. The default setting of micro focus is '0', but the adjustment ones for -15 to +15 in single digit increments. Since the default setting for micro focus is 'off' or zero, you can always turn it off if it makes no difference.
Some of my lenses needed very little micro focus adjustment (+1 was the lowest), whereas others like my 300 +1.4 converter needed +9, which amounts to significant adjustment. The 100-400 needed +3 at 400mm. Typically Canon lenses seem to need positive micro focus adjustment, to some degree.
If you don't fancy adjusting micro focus yourself, then a Canon approved dealer should be able to set it up for you. The whole process takes 30 minutes or so. If you plan on trying it yourself, make sure you use good light and take quite a few pictures to compare them, in order to get the best setting. Then take some test shots of distant options at zero setting micro focus and then at your chosen setting. You will see the difference it makes. This can be significant!
Hope this helps. Write back to let me know how you get on.
Hi I came here via a link I read in the EOS Magazine forums. I am concidering weather or not to buy the 1.4x iii Extender and using it in conjunction with my 100-400 mk1. Your artical is very interesting, especially the comparison photos with and without the extender. Am I correct in thinking there isn’t much difference in reach. Would you say spending £360 is worth it for that extra 160mm.
ReplyDeleteHi. I have the 100-400 lens and bought a 1.4 converter, but I have a Canon t7. I lost all auto focus capabilities, which is inhibiting my biriding photography. I considered buying the lastest version of the extender, hoping that the auto focus was just because of the older lens, but I don't know if I will actually get the auto focus with it. Is it my camera? Or is it the lens? Is it worth investing in another extender? Honestly, with everything on back order due to the past year, I've had time to research it. I still don't know if it is worth the money with my camera and lens. Impute would be appreciated!
ReplyDeleteHi, thanks for your comment. You should be able to find the answer to your question on https://shuttermuse.com/canon-cameras-autofocus-extenders-f8-aperture/ this contains a table that clarifies which Canon camera bodies (T7i included) will support auto focus with 100-400 lens and a 1.4x converter. You don't say which particular 100-400 lens you have. The push-pull Mark 1 (IS I); or the later 'rotate to zoom' mark IS II type. Reading the article it seems to say that the Canon T7i requires a Canon 100-400 IS II lens (the later version) and a third generation 1.4x extender (1.4x III) to provide up to 24 point autofocus.
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