Canon 70-300mm f/4-5.6 L IS Lens Review

The Canon 70-300 f/4-5.6 L IS lens mounted on a 5D mark II body.

Figure 1. The Canon 70-300 f/4-5.6 L IS lens mounted on a 5D mark II body.

When I first heard that Canon was going to release a new 70-300mm zoom lens, I wasn’t very excited as Canon already had a number of zooms covering this range. When I heard that Canon was going to price it at $1600 for a variable aperture lens (f/4-5.6) I thought they were completely nuts.

Up until this point I had been using the 70-200 f/4 zoom and the 70-300 f/4-5.6 non-L lens to cover my telephoto needs. However, I was not happy with this combination:

  • The 70-300 f/4-5.6 IS non L lens did not have good enough image quality even when stopped down.
  • The 70-200 f/4 IS L lens, while producing very sharp images, simply did not have enough reach.
  • Carrying both lenses was not an acceptable solution either since it entailed extra weight and the 70-300 performance was worst at the long end.

I had thought about pairing my 70-200 f/4 with a teleconverter to get the extra reach but this also did not appeal to me as it was an extra piece of gear to carry around. Furthermore, I didn’t want the hassle of putting on and taking off a teleconverter while shooting.

As a result, I decided to try the 70-300L lens and I have been very pleasantly surprised by it’s performance. In short, if you need a travel or landscape zoom with edge to edge sharpness, the 70-300L is a very good choice.


When fully collapsed at 70mm the 70-300L is a short, squat lens. With a 3.5″ diameter it is wider than all my other lenses including my 24 TS/E II. It has a solid metal construction and weighs approximately 2.3 lbs. As you zoom from 70mm to 300mm the lens extends an extra two inches. With the lens-hood on, this make for quite an impressive looking lens (Figure 2).

Canon placed the zoom ring at the front of the lens which is the opposite of their other lenses where it is closest to the body. I find this awkward as I prefer to have my left hand under the zoom ring and thus need to move it forward.

The Canon 70-300L lens extends outward as one zooms to 300mm focal length.

Figure 2. The Canon 70-300L lens extends outward as one zooms to 300mm focal length.


This lens is sharp to the extreme corners of the image even when shot on a full-frame camera, wide-open. Read-on if you want to see the details.

To evaluate the sharpness of this lens, I selected an architectural column at Stanford University as a test subject and took photos at varying aperture and focal length. I used a Canon 5DII camera, tripod, mirror lockup, and remote release. Image stabilization was turned off and the camera was mounted with an L-bracket. The images were processed in Lightroom 3 with only white balance adjustments. Sharpening was left at the default levels (amount = 25, radius = 1, detail = 25, masking=0) and the crops were saved in photoshop with save for web (quality = 60).

Figure 3 shows an image of the full scene with the location of crops marked by the red squares. Figures 4-7 shows pixel level detail from these crops across as the focal length varies from 70mm to 300mm. In general I was impressed with the lens and I would summarize my findings as follows:

  • Corner sharpness is exceptional wide open and is the best I have ever seen on a zoom lens.
  • The lens is sharpest around 135mm but all focal lengths are good.
  • The quality at 300mm is very usable unlike the older non-L version of this lens.
  • Stopping down doesn’t help as much as you would think (since it very good already).
Scene for testing sharpness

Figure 3. Scene for testing sharpness. Red squares indicate location of 100% crops shown in other figures.

Figure 4. Performance at 70mm: pixel level detail from 100% crops.


Figure 5. Performance at 135mm: pixel level detail from 100% crops.


Figure 6. Performance at 200mm: pixel level detail from 100% crops.


Figure 7. Performance at 300mm: pixel level detail from 100% crops.

Color Fringing

The 70-300L lens exhibits some color fringing (chromatic aberration) in images taken at both the short and long ends of the focal range. For example, in Figure 8 you can see both cyan and magenta fringes around the edges of the square. This fringing is only present near the edges of the image and was not visible at other focal lengths (i.e., 135mm and 200mm).

70mm f/11300mm f/11
Figure 8. Color fringing occurs at the short and long ends of the zoom range for the 70-300L. Note that these image crops are magnified to 200%.


Vignetting is very noticeable on the lens when shot wide open. Figure 9 shows an example of how much the edges/corners are darkened when using the largest aperture.

Vignetting of the 70-300L lens at 300mm.

Figure 9. Vignetting of the 70-300L lens at 300mm. The left image is taken at f/5.6 and has considerable light falloff towards the edges of image. The right image is taken at f/11 and has much more even illumination. Both images were taken with equivalent exposure.

Compared to the 70-200 f/4 L IS lens

  • Both lenses have very good center sharpness but the 70-200 f/4 may have a slight edge in quality.
  • On a full-frame camera the 70-300L has much better corner sharpness than the 70-200 f/4.
  • The 70-300L is significantly heavier at 2.3 lbs (compared to 1.6 lbs) but is more compact with the lens is collapsed at 70mm (about an inch shorter).

Figure 10 shows a comparison of the 70-300L with the 70-200 f/4 and 70-300 non-L lenses when collapsed and extended.

For more information, you can also see my review of the 70-200 f/4 L lens. I used the same test subject so you can directly compare their sharpness.

Compared to the 70-300 f/4-5.6 IS lens

The Canon 70-300 f/4-5.6 IS USM is an older consumer grade lens that covers the same focal length range as the 70-300L. However, the only advantage of this older lens is its price ($550) and weight (1.4 lbs). In all other aspects including image quality, autofocus speed, and construction, the 70-300L blows the older lens out of the water.

Three telephoto zoom lenses: 70-200 f/4 L, 70-300 f/4-5.6 L, and 70-300 f/4-5.6.

Figure 10. Three telephoto zoom lenses: 70-200 f/4 L, 70-300 f/4-5.6 L, and 70-300 f/4-5.6.

Tripod Collar

Canon sells a lens collar for the 70-300L for approximately $200. Given the extremely high price for the lens, I feel that Canon should have included this with the lens instead of requiring an additional purchase. Currently the collar is out-of-stock, but in all likelihood, I will purchase it when it becomes available (or get a third party substitute) to improve stability.

Other Comments

  • The lens comes with a rubber gasket to keep water and dust from entering in the gap where the lens is mounted to the camera body.
  • The 70-300L cannot be used with Canon teleconverters.


For a travel photographer, the 70-300L is an exceptional telephoto zoom lens that achieves very good image quality in a compact package. The lens is sharp across the entire frame even when shot wide open on a full-frame camera.

The main drawbacks of the lens are its cost, weight, and variable aperture. At $1600 it’s nearly three times the price of it’s non-L sibling and $400 more than the 70-200 f/4 L lens. The lens weighs in at 2.3 lbs making it considerably heavier than other tele zooms in the same focal range. Finally, with a maximum aperture of f/5.6 at the long end, this lens won’t be my first choice for action, indoor, or handheld low light photography.


  1. Joseph says

    You’d think Canon would have gotten this right with the teleconverter and and tripod collar – its the reason I won’t be purchasing this lens. Keep up the good work Canon. :o(

  2. Michaël says

    Thank you for your article concerning zoom lenses 70-200 and 70-300. Very interesting. I did not know to buy which, I think that I am going to take 70-300 more polyvalent. I still have to test the grip on my 550 D before making the final choice.
    I am writing from France, sorry if there are some mistakes.

  3. says

    Interesting article and lens for sure. I am still a bit shocked to see this lens images sharper then the famed f4. amazing since this lens is on sale now for 1,400 at B&H. I will probably be one of the rare few who have decided to sell thier beloved 70-200 f2.8L ii for this lens and use flash(s) instead of high ISO. I didn’t use my f2.8 much and it’s heavy plus limited reach and this lens looks sharper. I guess its a mater of needs rather then features. I need more range and always apreciate sharper images, plus will love the compact size and weight savings. Just lose low light capabilities. If I was a wedding Photographer maybe, but I only shoot a few weddings now and use flashes any way. Even on my 5Dmk3 and the f2.8 I still got better images with flashes and exposure compensation either way.

    Thanks for the interesting article and images, well done vik.

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