Canon 300 F4 IS


Specs and Measurements

Focal length -  300mm,    Aperture – f/4,    Filter thread – 77mm,    IS – YES 2 stops,   USM – YES & FTM focus,    Focus limiter – 1.5 m - ∞ & 3 m - ∞,    Maximum magnification – 0.25x,    Weather sealed – Partially,    Weight (w/ tripod mount) – 1300 g,    Length (w caps) - 245 mm,    Width - 90 mm,  Lens hood included – YES integrated/sliding,   Case included - YES padded


The Canon 300mm f/4 L IS is one solid lens that has gotten me results time and again, rain or shine.  Like the black bear captured here in the drizzly interior rainforest of northern B.C..  It has seen some heavy field use, but still looks almost new and works as well as the day it was purchased.

Handling and Build Quality

The Canon EF 300mm F/4 IS L USM is a beautiful lens to handle and use.  A really nice combination of somewhat long focal length (300mm) and relatively wide aperture (f/4) make it very useful for wildlife and other telephoto needs while still being portable.  This is especially true when combined with a crop sensor body as the lens gives a similar field of view as a 500mm f4 lens.  It also has all the feature boxes checked:  image stabilization, silent/fast USM focusing, focus limiter, sliding lens hood, weather sealing and very close focusing.


I find the Canon 300mm f/4 L IS to be my most versatile wildlife lens.  When combined with a Canon crop sensor body you have a very formidable 480mm angle of view at f/4.  It is easily hand-holdable for long periods of time at just 1300 g and with the help of IS (albeit an older implementation).  Using a tripod was not an option while photographing these dear fawns as they approached in the Ottawa Valley.  I was constantly standing, squatting, kneeling, and even walking forward/backwards to keep them at the correct distance.

Having image stabilization (IS) in a telephoto lens such as this is indispensable. The IS works well and has 2 modes; one for static subjects and second for panning of moving objects.  There is only one problem with the IS on this lens IT’S OLD (engineered almost 20 years ago) and only gives 2 stops of increased handhold-ability (ex- instead of needing 1/320s to handhold you could get away with 1/80 s).  Despite this I try my best to not use such slow shutter speeds as subject movement plays such an important factor at these speeds.  I think that this was only Canon’s second IS lens produced. This puts the lens way behind newer implementations like the 70-200 f/4 IS  with it’s 4 stop IS and is my main criticism of its design.  The IS still does come in handy and I leave it in mode one 99% of the time it is handheld.  If you have the lens mounted to a tripod be sure to switch the IS off as it will make the images blurry (IS gets confused with to little motion), but you can leave IS activated if you are using a monopod.  When the lens is combined with the 1.4x converter I find the resulting 420mm lens decreases it’s efficiency to about a 1 stop IS advantage (ex- instead of needing 1/500 s to handhold you could get away with 1/250 s).

The lens is really well put together, with a metal alloy construction and partial weather sealing around the switches and seams, but not the lens mount.  It has a fair amount of heft to the lens weighing almost 1300 grams with the tripod ring installed but is very comfortable to handhold. I do like to use a body with a vertical grip attached to assist in holding and balancing the lens.  Without a doubt this is the most solidly built lens in my collection.  If there was one improvement I would like to see in an update of this optic it would be complete weather sealing, including the lens mount.  The sliding lens hood is an ingenious idea and I can’t believe its not implemented on more lenses.  You can never forget the hood and changing filters or replacing the lens cap is way easier than with conventionally designed bayonet hoods.


Having a 300mm lens that focuses down to 1.5 m (5 ft.) makes this lens work really well with macro subjects.  This along with the large aperture can produce wonderful blurred backgrounds (bokeh).  These dragonflies were trying to catch the last sun rays of the day from their flowers top perches, but were very skittish.  Having the ability to photograph them from 2-3 m away made these shoots possible, where as with a traditional 90-100mm macro you would have spooked the subject.

The USM focusing on the 300mm is fast and very accurate.  Again the lens does show its age here, as its just not quite as fast a similar lenses like the 70-200 f/4 IS.  If you employ the focus limiter the AF gains a nice improvement in speed.  The largest difference between the 300mm and newer models is only apparent when focusing in very poor light as it will occasionally hesitate.  This is not such a big deal as we are talking about near darkness when taking pictures is not usually likely to occur.  The 300mm actually focuses much more quietly than some newer supposedly silent USM lenses that I own or have used.  Despite all the goodness I have mentioned so far my favorite feature has to be the 1.5 m minimum focus distance.  This allows the lens to produce about 1:4 (0.25x) magnification and makes a fabulous semi-macro lens.  Subjects that I often find myself photographing at this distance, range from dragonflies and butterflies to wild flowers to song birds.  Because of the relatively long focal length and fast aperture it can provide nice shallow depth of field to really isolate your subject.  In fact I am usually stopping down quite a bit near the minimum focus distance to gain some depth of field.

Score: 8.5/10

Optical Quality

All of my observations are based on the results obtained using a 1.6x crop body like a Canon 50D or 7D.  I have not tested this personally, but the results on a full frame body are similar in the middle of the frame and are a little poorer in the corners.

Sharpness is one of the best attributes of this Canon lens.  At f/4 the lens is really sharp and I use this setting any time I need to freeze movement or action.  Stopping down to f/5.6 increases the sharpness a little to exception levels.  Continuing to stop down shows little to no improvement and it actually starts to decrease at f/11 and beyond due to diffraction (as does every lens). I really choose the aperture for purposes of shutter speed and depth of field rather than sharpness as it is so good at any setting.

When the lens is combined with a 1.4x converter to produce a 420mm lens the sharpness does drop a little, as expected.  This combination is still very usable and I get really nice results most of the time.  The now 420mm lens does benefit more from stopping down than the bare optic.  Usually I try to use f6.3 or more to gain some sharpness when possible.  I still do not hesitate to use this combination wide open and it can yield excellent results as those seen below.  I also can not crop the files as much when using the 1.4x converter and still get the tack sharp results I am used to.


When combined with a 1.4x converter the Canon 300mm f/4 L IS still does produces very nice images. It does not focus as fast and you need to watch your shutter speeds but I usually get pleasing results as shown by the great blue heron and reflection above (420mm & f/5.6).

Despite all the gushing I am doing over the lens there is one area I do find it lacking.  It is just a little soft when it is focused at distant objects starting around 75 m and getting worse as you progress farther. I have tested this extensively and I know that other factors like air temperatures, humidity and air particulates can cause problems at very long focal distances.  The problem is not terrible but it is noticeable.  Luckily this is rarely an issue as most subjects are way too far away for a 300mm lens at 75- 100m to give decent results anyway.

The lens has so little distortion that it is hardly worth writing about and creates nice smooth blurred backgrounds (bokeh) when used near wide open(f/4).  Contrast is another area where the lens does very well and images produced almost never need much boost in contrast during post production.  I have never been able to make the lens show any flare from bright light sources but I do not go looking for this either.  The lens does produce a noticeable amount of chromatic aberration and also some annoying purple fringing on extreme contrast zones like dark branches and bright sky.  These both can be mitigated some what during post processing but it would be nice if they were not there in the first place.


 On its own Canon 300mm f/4 L IS produces about the best results of any lens I have ever used. The family of feeding grizzlies in the Khutzeymateen Bear Sanctuary was shot with all of the conditions against me (a heavily rocking zodiac, harsh light and moving animals) but still the lens delivered pleasing results.

The lens also makes a decent macro lens and gives really nice working distance for small animals that scare easily.  I use this feature all the time and it gives amazingly sharp results.  You can get shots that are not possible with a 100mm or even a 180mm macro lens as these lenses would require you to be too close and scare off your subject.  The macro capabilities can be extended even further with the use of extension tubes and I have used them before with success.

Score: 8/10


At its current price of $1500 CAD it’s expensive but very useful and delivers great results.  If this lens were updated with improved optics, complete weather sealing and newer IS in a version II the price would likely increase by 50-100%.  There are several other alternatives that you may consider in this focal and price range:

Canon 100-400mm f/4.5-5.6 L IS USM – I have owned this lens previously and was very satisfied with its results.  Obviously this lens is a zoom and extends out to 400mm and down to 100mm which can be a distinct advantage.  This lens is of a similar vintage and technology but costs couple hundred dollars more.  At 300mm both lenses are very sharp with a slight advantage going to the prime lens.  When combined with a 1.4x converter the 300mm has a slightly longer reach (420mm), but is also a little less sharp and contrasty compared to the zoom at 400mm.  The biggest difference in favour of the Canon 300mm is it’s a whole stop faster (f/4 vs. f/5.6) at 300mm.  If you can only carry or afford one telephoto lens, the 100-400mm might be a great option as it offers more flexibility.

Canon 400mm f/5.6 L USM – I have not used this lens personally but it is worth some consideration as it is apparently just as sharp as the 300mm and better than the 300mm + 1.4x combo.  You do give up IS but 400mm does beg for tripod use anyway.  You need to decide how much you will be using 400mm and how important IS will be as both lens are about the same price.

Canon 70-300mm f/4.5-5.6 L IS USM – I have not used this lens either but it may be an option as it’s apparently very sharp also (much more so than the non-L version) and has the versatility of zooming out to 70mm.  It’s also much more compact than the 300mm prime but surprisingly not a lot lighter.  This newer lens gives up a lot of light with its slower aperture but has much more effective IS.  Both lenses also have a similar price so you need to consider compactness and versatility against faster glass.

Tamron 150-600mm f5-6.3 VC USD – I currently own this lens and it could be a decent telephoto option as it includes the 300mm focal length.  The Tamron zoom lens would be more versatility, but also has some drawbacks.  This would only be a good choice if you do not need the extra stop of light (f/4 vs. f/5.6) and the faster focusing the Canon lens provides.  The Tamron is also a lot heavier (1300 g vs. 2100 g), larger to store and more difficult to handle.  Since buying the Tamron, I use the Canon less and almost never with the 1.4x converter.  At 300mm both lenses are optically similar wide open but the Canon takes the lead when stopped down to match the Tamron at f/5.6.  When set to 400mm the Tamron is better compared to the 300mm + 1.4x both optically and mechanically (focus speed and IS).  Obviously the zoom also goes out to 500 and 600mm where the Canon can’t compare.  If focal length is your main concern over portability and speed then the Tamron is an easy choice.


The Canon 300mm f/4 L IS focuses very fast and is excellent for tracking and capturing fast moving subjects such as this juvenile green heron in flight.

Score: 8.5/10


Since purchasing the lens in 2010, it has been my most used lens.  The reason why; it just does so many things well.  It makes an excellent telephoto for larger wildlife especially on a cropped sensor body and is decent for birds and distant wildlife when combined with a 1.4x converter.  The lens is exceptionally sharp on its own and very nice when combined with a 1.4x converter.  As a cherry on top it’s also an excellent near macro lens for skittish little critters like butterflies and chipmunks.  There is some slight chromatic aberration but the largest weaknesses is that is it is just not pin sharp as very long focal distances (75 m or more) and the older IS.  This lens works really well for me but may not be great for someone who only wants to own one telephoto lens (one of the zooms above may be a better option).  I will be keeping this lens for a long time even though I have a longer lens and faster lenses because it gives an unmatched combination of focal length, speed and weight.


There have been few cases where the Canon 300mm f/4 L IS has let me down (not even with an erratically charging reddish egret).  It’s very sharp, with low aberrations, relatively light weight, is solidly built, focuses reliably and close.  Bottom line it gets the job done, so it’s my most used lens!

Overall Score: 8.5/10

Other Reviews

photozone - I find this review matches my findings very closely as they tested the lens on a crop sensor body.  This page gives excellent technical data that can be compared to the many other lenses reviewed on the site.

the-digital-picture – This is another review that I feel mirrors my experiences as well.  The author does some really nice comparisons at the end to other options.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>