While there are other uses for these lenses, these are by far the most commonly photographed subjects with these focal lengths. While no one will consider these lenses inexpensive, no one will consider the image quality they deliver to be anything short of stellar and image quality is not a differentiator here. Those who know what they want, want these lenses. While having both of these big whites in the kit would be perfect, most of us cannot afford or justify the purchase of both. Thus, the question of "Which one?" arises.
The obvious (and only) difference in the names of these lenses is the focal length number. These lenses were announced at the same time, arrived on my doorstep on the same delivery, appear very similar and indeed share the same overall design concepts and construction materials. Those wanting as much reach as possible will of course want the 600mm option.
But, sometimes a selected focal length can be too long. A too-narrow angle of view may make it too hard to quickly find a subject in the viewfinder, hard to keep a subject in the frame (especially if it is in-motion) and, if framed too tightly, important parts of a scene may be cropped from the frame. Because APS-C-format cameras have smaller imaging sensors and therefore use a smaller portion of the image circle provided by these lenses, they "see" an angle of view equivalent to a 1.6x longer lens on a full frame body. Thus, on an APS-C body, these lenses frame a scene similar to a 800mm and 960mm lens on a full frame body and at these angles of view, "too long" comes more frequently.
Similarly, a focal length can be too short. Too short is usually the result of not being able to get close enough to a subject. Reasons for this situation include physical barriers (a fence, a body of water), subjects that are not more closely approachable (wildlife tends to be uncomfortable with us nearby) and safety (dangerous wildlife, unsafe proximity to race cars). Too short usually results in an image being cropped with a lower resolution image remaining.
Another focal length related tip to consider is that, the longer the focal length, the longer the time span a moving subject is likely to remain in near-ideal framing. Without a zoom range available to quickly fine tune framing, prime lens-captured images often require cropping in post processing. However, the longer focal length lens has a narrower angle of view, which requires you to be farther from the subject for optimal framing and at that longer distance, an approaching or departing subject changes size in the frame at a slower rate. That means more images can be captured within the period of time with optimal framing. For the same reason, a larger physical area can be ideally-covered by the longer focal length – such as a larger portion of a soccer or football field. While the difference between 500mm and 600mm is not dramatic in this regard, the 600mm lens has an advantage.
Another benefit provided by a longer focal length is greater-enlarged background details, meaning that a longer focal length can create a stronger background blur. The 600mm lens can create a stronger separation of a subject from its background than the 500mm lens can. Most of us love an extremely blurred background and the longer focal length makes it easier to produce (though both of these lenses rank very highly for this purpose).
A longer focal length means a longer camera-to-subject distance and with more atmosphere placed between a lens and its subject, there is an increased likelihood that heat waves will cause image distortion. The longer working distance required by the longer focal length also provides more opportunity for obstructions, such as tree branches to get between the lens and, for example, a wildlife subject. The longer subject distance also delivers a slightly more-compressed perspective, creating a slightly different look to the subject (not necessary a benefit to either lens specifically).
Although focal length is typically my first priority for choosing a lens, it is not always the most important. In this lens comparison, there is a substantial size, weight and price differential that can sometimes be more important than the differences already discussed.
The site's lens specifications comparison tool has a detailed comparison between these lenses, but here is a quick look:
|Model||Size w/o Hood||Weight|
|Canon EF 500mm f/4L IS II USM Lens||5.75 x 15.08" (146 x 383mm)||112.6 oz (3190g)|
|Canon EF 600mm f/4L IS II USM Lens||6.61 x 17.64" (168 x 448mm)||138.4 oz (3920g)|
How old are you? How old do you want to become? How do you want to feel when you get that old? Safe to say is that all of us are getting older and also safe to say is that most of us reach a maximum strength point somewhere far prior to reaching the age we hope to survive until. And, how we feel at the end goal date is partially conditional on how we treat our bodies during the younger years. Just because you can handhold a 600mm f/4 lens for long periods of time now does not mean that you should do this and the strain placed on our bodies now may be long-lasting. If you are not able to use a lens support most of the time, the 500mm option is going to be the better option for most.
Size also matters, but when lenses get this big, the size differences don't seem to matter so much. Smaller is better, but neither is close to what I would consider small. You will likely find the biggest size difference to be in the volume of comments generated on the sidelines and the case size required by the lens. That said, I frequently carry the 600 with me on airplanes (in the USA), typically using the MindShift Gear FirstLight 40L and always as carry-on. With the 500, a modestly smaller case can be used or slightly more can be included in the same case.
The size difference between these lenses is apparent in the product comparison image accompanying this post. See the same comparison with the lens hoods on here (and also compare these lenses to other models).
The 500mm focal length is 83% as long as 600mm and the similarity factor for a majority of the above-discussed differences is about the same. One exception is the price factor, with that one dropping to just below the 80% mark. While neither lens is inexpensive, the 500 costs considerably less than the 600 and that factor alone will be the basis for this decision for some. That quality lenses typically hold their value well means that overall cost of ownership is not as bad as it first appears.
Most often, I recommend the 600mm lens for full frame bodies and the 500mm lens for APS-C bodies, though there are some exceptions.
If photographing big field sports such as soccer, the 600mm lens is my choice for a full frame camera and I would rather have the 500mm lens on an APS-C body.
Those photographing small birds will likely find the 600 preferable in front of any camera.
Those needing to handhold the lens with any frequency probably should select the 500mm option.
The Canon EF 600mm f/4L IS II USM Lens is one of the most important and most used lenses in my kit (primarily composed of full frame cameras). Many of my favorite images can be attributed to this lens, from irreplaceable memories of the kids playing soccer to captures of incredible wildlife in the mountains. The weight of this lens is a definite downside and I have more-than-once become worn out from carrying it, but ... the results are worth every bit of the effort.
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What are you doing this weekend? Spend some time getting to know and having fun with these big white lenses without the large price tag. Try renting! Lensrentals.com has the Canon EF 500mm f/4L IS II USM Lens and Canon EF 600mm f/4L IS II USM Lens ready to ship to your doorstep.