I’m as big a fan of Canon lenses as anyone; I’ve resisted the temptation to switch brands for years simply because they offer certain lenses that I couldn’t imagine not having. However, when it comes to the new RF 800mm f/5.6 L IS USM and RF 1200mm f/8 L IS USM lenses, you really should think twice before you buy them.
Canon’s latest lenses, the RF 800mm f/5.6 L IS USM and RF 1200mm f/8 L IS USM, continue to perfect their RF line and evolve into new extremes. However, at $17,000 and $20,000 respectively, they are among the most expensive consumer lenses ever made, and even professionals, for whom such lenses are in demand. Daily requirements should also be rethought. However, there is more to the price point at which you should pause. Before you begin, however, let’s determine all relevant prices.
Prices of Canon lenses, teleconverters and their combinations
- 2x RF Extender: $599
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Canon RF 400mm f/2.8 L IS USM: $11,999
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Canon RF 600mm f/4 L IS USM: $12,999
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Canon RF 800mm f/5.6 L IS USM: $16,999
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Canon RF 1200mm f/8 L IS USM: $19,999
Similarities with existing lenses
Adding a 2x teleconverter to the lens doubles its focal length at the cost of reducing its maximum aperture by two stops. For example, a 100mm f/2.8 lens becomes a 200mm f/5.6 lens with the included 2x teleconverter. As a result, you may find that the new RF 800mm f/5.6L IS USM and RF 1200mm f/8L IS USM are, at least in numbers, equivalent to 400mm f/2.8 and 600mm f/4 lenses with 2x remote adapter. . The RF 400mm f/2.8 L IS USM and RF 600mm f/4 L IS USM existed, as well as 2x . RF Extender.
Of course, just because the numbers line up, that doesn’t mean Canon simply put a 2x teleconverter inside existing lenses and called it a date. Manufacturers optimize the design of different focal lengths specifically to deal with their own unique challenges and problems; otherwise we would all become far more teleconverters and far fewer unique lenses. However, the following should be noted:
Weight of Canon lenses, teleconverters and their combinations
2x RF Extender: 12 oz / 340 g
Without a doubt, the combination of the teleconverter and the corresponding shorter focal length is quite close to the longer focal length, although not quite the same.
Designs
There have been rumors that these lenses are nothing more than 400mm f/2.8 and 600mm f/4 with 2x teleconverters dropped in. Let’s see.
RF 400mm f/2.8L IS USM Plus Extender RF 2x vs RF 800mm f/5.6L IS USM
As you can see, the difference is near the stand. The 800mm f/5.6 has an extra group of normal elements capable of serving as additional magnification. However, there is an additional extra-low dispersion element in front of the aforementioned group, which can potentially be used to correct for chromatic aberrations that often increase with teleconverters. So to be fair to Canon, the 800mm is more than just 400mm with the teleconverter fitted inside. However, is it worth the steep price increase for the extra element(s)?
RF 600mm f/4L IS USM Plus Extender RF 2x vs RF 1200mm f/8L IS USM
Same story here. The front design is identical. Closer to the mount, we see a magnifying group along with an extra-low dispersion element likely designed to correct for chromatic aberrations from the additional magnification. So again, isn’t this just a 600mm f/4 with the teleconverter inside, but is it worth the extra $6,000 compared to just using the 600mm with the teleconverter? Let’s take a look below.
MTF chart
This is what you should be most concerned about. All the design and weight arguments are interesting, but in the end, how good will the images from each lens and combination be? Let’s take a look.
RF 400mm f/2.8L IS USM Plus Extender RF 2x vs RF 800mm f/5.6L IS USM
We can see that the 400mm and 2x extenders offer almost identical contrast performance compared to the 800mm f/5.6. There is a slight decrease of about 0.05 in the Meridional measurement towards the corners of the frame, but the difference is so small I would hardly believe it would be noticeable to all but the observant. and can be easily corrected in the article.
As for resolution measurements, the Sagittal orientation is functionally identical, save for a very slight drop near the poles of the frame. There is a noticeable drop in the Meridional measurement, with a gap that starts at the center of the frame and reaches a maximum difference of about 0.15 about 17 cm from the center. Still, it’s still pretty strong in performance and is pretty close to the 800mm f/5.6 closer to the center.
Is the difference worth $4,401? That’s your call, but if it were me, based on the MTF chart alone, the answer would be no.
RF 600mm f/4L IS USM Plus Extender RF 2x vs RF 1200mm f/8L IS USM
We can see that the 600mm and 2x extenders provide almost identical contrast performance to the 1200mm f/8. There is a slight difference in the Meridional line near the corners, but the gap is never greater. 0.03 and is unlikely to have any noticeable real-world impact.
When it comes to resolution, there is a constant gap of about 0.02 in the Sagittal line up to about 17 cm, where it widens about 0.05 at the extremes. The Meridional line shows a wider gap of about 0.7 at 10 cm, extending to a maximum of about 0.12 at the extremes. However, both have shown impressive performance.
So I’ll ask again: is the difference worth $6,401? I do not think so.
Think differently
Weather protection
It should be noted that all else being equal, a single lens is more weather resistant than a lens plus a teleconverter, simply the front lens has fewer buttons and intrusive spots. enter more to protect. That being said, all the optics in this comparison are some of Canon’s best, and I suspect weather resistance will be a big deal in all but the most extreme cases, whatever setting you choose.
Auto focus
Traditionally, the teleconverter has affected autofocus performance, especially with the 2x extender. That being said, the teleconverter has come a long way, and the RF Extender 2x’s autofocus performance is often commendable.
Increased flexibility
A 1200mm lens is a 1200mm lens. A 600mm lens has two teleconverters, the 600mm, 840mm and 1200mm lenses. Yes, of course, you can add a teleconverter to the 1200mm lens to extend it and it will probably work better than stacking multiple equivalent teleconverters onto the 600mm to push through the 1200mm. , but when was the last time you needed a 1680mm or 2400mm lens? Sure, they sound neat on paper, but their real-world applications are few and far between. The same argument also applies to the 800mm case.
What should you spend your money on instead?
If it were me, I’d save thousands of dollars and get the shorter focal length and teleconverter without hesitation. The increased flexibility and substantial savings outweigh the relatively small gains in contrast and resolution. You can get a EOS R3 with a change to fallback if you go with the 600mm combination instead of the 1200mm!
In fact, I won’t even get an RF lens. I adjusted the EF 400mm f/2.8L IS Mark I USM to suit EOS R5 for years without complaint. The autofocus is perfect (even better than it was on my 1D X Mark II) and the image quality is breathtaking. Canon has completely improved the image quality on versions of these lenses, but they start out so high that even my picky geek is perfectly happy with the Mark I. The real advantage you get gain when moving to newer versions is to save weight. There’s absolutely something to be said about that (carrying that stuff always makes me think twice), but I always think about the few thousand dollars I’ve saved, and then, I’m totally happy. Happy to deal with large numbers.
Your thoughts
What is your opinion? Is the resulting image quality worth the extra thousands of dollars for 800mm and 1200mm lenses, or is it better to save your money and use a teleconverter?
