Canon EF 100-400mm f/4.5-5.6 L IS versus IS II lens

65% crop, Canon 100-400 IS II - click image to enlarge

65% crop, Canon 100-400 IS - click image to enlarge

30% crop, Canon 100-400 IS II - click image to enlarge

30% crop, Canon 100-400 IS - click image to enlarge

15% crop, Canon 100-400 IS II - click image to enlarge

15% crop, Canon 100-400 IS - click image to enlarge

I recently got the chance to try out a Canon 100-400 IS II telephoto lens. Hence, I was very keen to compare the image quality between the new lens, versus my Canon 100-400 push-pull zoom, which has been my travel lens of choice for many years.

To compare the two lenses, I took photographs of our rather grubby Neighbourhood Watch sign, which has spots and marks aplenty, to compare detail and image sharpness. The spot focus target was the head of the child (the small person icon), which is directly above the "T" in "WATCH".

More details of how these comparison images were taken and prepared, can be found in the "Image Quality" section below.

Given that the MK I version of the lens was originally introduced back in September 1998, I was expecting considerable improvements and there is some improvement, but it's not massive.

The 100-400 IS Mk I still gives great image quality, but the 4 stop image stabiliser on the Mk II lens is one notable improvment over the Mk I 100-400mm.

The other main gripe with the original Canon 100-400 IS lens was its sharpness wide-open at F5.6. Some reports also claim variability between Mk I 100-400 lenses, with "sharp" and "soft" ones supposedly in circulation.

I must have been fortunate in this respect, as my lens was always sharp, even at its widest aperture. Although, as expected, sharpness does improve as the lens is stopped down to F6.3, F7.1 or F8.

Further image quality improvements were gained by micro-focus adjustments to match the lens to my particular Canon 7D Mk II body. Micro-focus adjustment (when done properly!) prevents a lens from front or back focusing.

I remain somewhat sceptical about the so-called "soft lenses". Personally, I believe they may have just needed micro-focus adjustment to suit a particular camera body, as Canon's quality control would have picked up an 'out of spec' lens, before it left the factory.

Primarily, buyers of the new Canon 100-400 IS II will be looking for improvements in image quality, as a result of twenty years of technical progress, since the last lens was designed.

The new Canon 100-400 IS II does offer some improvement in resolution, but it is questionable whether the cost makes it a worthwhile purchase for image quality alone. It is a little sharper wide-open at F5.6 than the Mk I and the comparison images show this.

The corner of the frame sharpness is improved a little more on the Mk II, but as many people will use the lens for wildlife photography, sports and for air shows, the corner sharpness is, for the large part, an irrelevance.

Canon 100-400 IS II Improvements

I provide a list of the main improvements of the Canon 100-400 IS II, versus the 100-400 IS below. These are based on my use of the lens, having become familiar with the old lens over many years. The list provides compelling reasons why you should upgrade to the 100-400 IS II:

• Image Quality - There are noticeable improvements in all-important centre frame sharpness, when compared to the old lens. The images above show this. Maybe not dramatic, but resolution is certainly improved.
  
  The comparison pictures were taken with a carefully setup tripod, both at widest aperture (F5.6), with around 20 frames from each lens being taken, spot focused on the head of the lowest person in the Neighbourhood Watch sign, about 20 metres distant. The sharpest images from each lens were then taken and crops were prepared and saved at 100% quality in Photoshop (no processing or sharpening applied). Both lenses were micro-focus adjusted to the 7D Mk II body, to get the best IQ.
  
  Unfortunately, the image attributes were slightly different, due to slight changes in light levels between me changing the lenses (although this shouldn't make too much difference). The Mk I 100-400 IS picture was taken at F5.6, ISO320, 1/500s, at 400mm. The 100-400 IS II picture was taken at F5.6, ISO400, 1/640s, at 400mm.
  
  The original pictures can be downloaded from my website, for better comparison. All images were taken on a Canon 7D Mk II body, so taking the 1.6x crop factor into account, the focal length equivalent is 640mm.

• Image Stabiliser Performance - The improved four stop image stabiliser, over the two stop stabiliser in the old MK I lens. The new four stop image stabiliser on the Canon 100-400 IS II produces rock steady images, even on crop sensor cameras, like the Canon 7D and Canon 7D MK II.
  
  On these camera bodies the equivalent focal length is actually 640mm (400 x 1.6), due to the 1.6x crop sensor fitted to the camera.
  
  There's no doubt that the 'keeper rate' for the new lens will be higher due to the significant IS improvements alone.
• Auto-Focus Speed - The IS II lens has a noticeably quicker auto-focus speed, with almost instantaneous focus being achieved on all subjects when paired with my Canon 7D Mk II. The Canon 400mm F5.6 prime lens always bettered the 100-400 in terms of fast auto-focus, now the 100-400 IS II has redressed this imbalance.

• 1.4X converter compatibility - This is where the Canon 100-400 IS II really excels, compared to the old lens. I was staggered by the image quality obtained when using the 100-400 IS II with a Canon 1.4x Mk III Extender. Whilst this combo seemed to need quite a bit of micro-focus adjustment to optimise focus (+10 on my setup), the results achieved are very impressive.
  
  I never really considered the Mk I lens as being really usable with a 1.4x converter, but the IS II works incredibly well. That said, you get a 560mm lens at F8, so it does have its limitations, especially in a country like the UK which has challenging light conditions for 6 months of the year!
  
  Overall though, the better image stabiliser combined with faster focusing make the 100-400 IS II and 1.4x extender a viable combination. There were no discernible chromatic aberrations on any of my test pictures either. All in all, very impressive. But, you would need to restrict using this combination to cameras that will auto-focus at F8, like the Canon 7D MK II. The older Canon 7D will not auto-focus with this lens, paired with the 1.4x extender.
  
  I will endeavour to upload some pictures with the 1.4x converter in the next few weeks, to demonstrate the highly credible performance of the Canon 100-400 IS II, when paired with Canon's 1.4x III converter.
• Closer focusing - The minimum focal distance is now down to 98cm. This will prove a real benefit in day to day photography, adding to the lens's versatility.
• Improvements in optical design -  21 elements in 16 groups (versus 17 elements in 14 groups for Mk I). This does add to the weight of the IS II lens though, it weighs in at 190g heavier at 1.57kg, versus 1.38kg for the older lens.
• Improved weather resistance seals - An improvement over the 'partly sealed' original design. However, several reports mention that the newer lens is still susceptible to dust ingress. Something to keep an eye on.

Author: Steve Larkins (09/2017)