I doubt the designs need much correction. I haven't seen ANY patent applications on their high end primes needing significant image circle correction.
distortion was / is always corrected even with EF, same with vignetting - and that wouldn't necessarily show up on the MTF.
Also; MTF is usually just the lens itself. correction happens after sensor readout. You aren't seeing the entire systemic MTF because that would be impossible, it would change for every camera. a different microlens design can easily affect your overall contrast and resolution performance.
Yes, I agree for the primes but the for the ef 70-200 f2.8 II LIS vs rf 70-200 f2.8 LIS Z it's a bit more critical because there is less optically between these two lenses.
Canon have stated previously that their newer MFT charts includes a level of software optimisation that matches the code used in their cameras bodies. This explains why the recent EF MFT's are superior to the slightly older MFT charts (and way better than the older pre 2018 system). A good example of this is the EF 135mm f2.0 MFT charts. Another example is the new RF 10-20mm, its MFT's are clearly adjusted / optimised for corner distortion etc.
In terms of optical design, any Canon L lens from 2009 seems to have employed a higher reolution target as part of it's design mandate. At that time, Canon knew that higher resolution sensors were coming and started to prepare for them. Lens sharpness is not a function of a growing technology but simply a design mandate / goal. Previously, Canon lens design was matching the "already established" film resolution. The early digital sensors were happy with these. But as the MP race was poiting towards 50mp sensors, higher resolutions targets were needed to satisfy the resolution requirements of those higher MP cameras. These higher targets could have been done before, it's just that Canon had no reason to.
It's also why canon will be sticking to a 45mp max resolution sensor for some time to come. Any more than this will need a whole revision of the RF line up with 80-90mp resolutions in thier design mandate. Regardless what the competition are doing or if we like it or not the 24/45mp sensors are what Canon will offer their customers for a long time to come.
Essentially, any EF L lens pre 2009 is easy game for Canon to upgrade from a sharpness perspective. Anything after that point has ony maginal or incremental resolution gains and Canon have to chase the "Complete package of uprgades" to woo customers from their beloved late model EF lenses.
Canon's marketing game has been very clever in hiding this fact from new or slightly ignorant customers.
Many photographers (there I go again...sorry...an unqualified
many) think that "all the EF lenses were rubbish" and all of the RF lenses are "way superior". It's an incorrect mantra I hear spewed at lot on various FB groups.
This might be true for lenses pre 2009 but it's simply not true for any later lenses releases from Canon. For example a comparison between the EF 35mm f1.4 II L and the newer RF 35mm f1.4 VC L shows little improvement over the EF lens. The EF lens was a 2015 model and was tracking the 5Dr's reolution capability. It's a similar story for the EF 70-200mm f2.8 LIS II and even the EF 24-70mm f2.8 II L. Both fare very similar to their RF counterparts. The RF lenes generally gain in weight reduction, superior AF capabilities, better MM and MFD numbers and often include optical image Stabilisers or at least superior versions.
I've noticed that a lot of the early RF lens reviews were compared to the older mk I EF lenses and often ignored the later mkII EF variants. Or ignored the EF lens variants entirely form their reviews. TDP is a good example of this, there is a curious lack of MFT charts on their site for many RF lenses that weren't much better optically that the precious EF versions. Only the lenses where there is a clear advantage optically, such as the RF 85mm f1.2 L vs the EF 85mm f1.2 II L, again low hanging fruit for Canon to upgrade optically.
I'm very excited for these new lenses.
For my use case scenario, I have a clear upgrade path for my vererable EF 70-200mm f2.8 LIS II and the new RF 50mm VC L is a very interesting lens fro me too. However, I have to compare it to the price point & features of the current RF 50mm f1.2 L. it's ironic that it's nearest competition is from it's own RF sibling and not from the previous camera mount.
