The Canon RF 24-105 F2.8L IS USM Z jumped into the limelight with the latest announcement. This lens may not be for you. It’s big, it’s heavy, and pricey and Canon really wants this lens primarily for the cinema cameras. From all reports it’s not fully parfocal (which means the focus will change as you zoom), but it’s also not the insane price that fully cinema lenses cost either. But with the price and complexity of the addon power zoom accessories, it’s safe to assume that Canon is gearing this lens for its RF C line and hoping to find that balance between performance, price and usability for the cinema line. Canon has certainly flexed its engineering and optical talent and created a lens that has never been done before. We can all be excited to see Canon push the boundaries, regardless of this being a lens in which we’d actually purchase.
Now there are MTFs to look at, and we have a few 24-105s in Canon’s RF arsenal to compare against, but the one that it should be compared against is the Canon RF 24-105 F4.0L IS USM. It should be fairly noted that Canon spared no expense and no size / weight limitations on RF 24-105 F2.8L it seems, so without even comparing the charts, I would honestly expect the lens to perform nearly as well as its slower brother.
We have to bear in mind that with these MTFs we are comparing the lens wide open, but we can see that the new RF 24-105 F2.8L IS USM Z holds its own showing better contrast (black lines) throughout the zoom range, resolves more (blue lines) in the corners at 24mm and also at 105mm. While the lens is expensive, big and heavy, it matches expectations of being better than the proceeding Canon RF 24-105 F4.0L. To achieve that performance required a much more complicated lens as shown below. The left lens is the F4.0L and lens to the right is the F2.8L.
For some reason the english speaking Canon websites are lacking on details, so we had to pull that from the Japan website. The elements are as follows;
- Light green are aspherical elements
- Dark green are UD elements
- Red Square surrounds the IS elements that shift with movement
- Dashed red line is ASC or Air Sphere Coatings
Some in the forums have said they would be comparing this against the 24-70 for their own use, so I’ll add the comparisons here as well. Comparing a 24-70 or a 28-70 to a 24-105 isn’t really that fair because as the optical zoom factor increases, optical design becomes more complex. the 24-70 or around 3x zoom factor has been the designer’s sweet spot for a while, which is why you atypically have seen the standard professional grade lenses from all manufacturers as 24-70 and 70-200. Attempting to break that mold and coming out with a 24-105 in the same grade is bound to have some compromises. But the exercise is good, as we get to see just how close Canon managed to make this “compromise free”.
First up we have the 24-70 F2.8L against the shiny newcomer, the 24-105 F2.8L. For the wide end, the 24-70 F2.8L shows a higher amount of contrast and resolution in the corners, but the 24-105 has a slightly higher resolution in the center. You would be hard-pressed to see the difference between the two on the wide end (24mm) in practical terms. If we compare 70mmn and 105mm we see that Canon has a slightly better contrast and resolution over that of the 24-70 F2.8L. Of course, this doesn’t tell us if there are any soft spots in the zoom range, but at the two extremes, Canon is looking like it’s done an excellent job of managing the difficult task of making a 4x zoom as good as a 3x zoom.
In case you are one of those people who have the 28-70mm F2.0L and are looking at the 24-105L as a smaller edition, what do you gain and lose? The 28-70 F2.0L is a magical lens and it’s certainly harder to compare that against the 24-105L, as the 27-80 has an even smaller zoom range so they can optimize the optical quality.
The 28-70 certainly more a smoother resolution falloff as it goes into the corners, it also has better bokeh at 28mm F2.0 than the 24-105 has at F2.8. The 24-105 has a slightly higher resolution at the center though. At the telephoto end, the 28-70 has better resolution, slightly better contrast, and better bokeh as well. Overall the 24-105L has slightly better resolution in the center at the two extremes, but not as good in the corners. Bokeh should be far better on the 28-70 overall.
All in all, we can see that the 28-70 certainly is the dream lens for Canon and it doesn’t disappoint. It’s a bridge too far for a 24-105 to compete head-to-head against it. Canon designed the 28-70 to have zero compromises and it shows. However, to be fair to the 24-105L it holds its own, and outside of bokeh, you would be hard-pressed to see any difference in real life.
In summary, this is a landmark lens from Canon. One user commented somewhere that for the longest of times, people said they wanted this lens, and others said it would be big, heavy, and expensive. Guess what? It is. But innovation comes at a premium, and if this is a lens you have been waiting for, then Canon made your dreams come true. You can also use how you feel the Canon RF 24-105 F4.0L’s performance as a basis of comparison as the new lens should be better. So if you are satisfied with the performance of that lens, you should be pleased with the new RF 24-105 F2.8L.
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