Its so annoying.
I have a 24-70mm F2.8 MKI and one of the elements has moved ever so slightly so at 70mm it has a distortion bottom right.
Nobody will touch it because Canon have discontinued support meaning no parts. So if they open it and a component breaks they won't take it on because at that point its a paper weight.
The annoying thing is mine is a DEC 2012 build date so coincided with the MKII being released. Cast your mind back that lens was delayed until September 2013 so I bought the MKI.
This means its had a 12 year life span which is low for an L series lens. Obviously they were released in 2002 so its an "old lens" but not all are 22 years old. Just annoying in my case as for the R6 R6 MKII R8 the lower MP bodies its still a great lens.
The EF-S 17-55mm was released in 2006 and has support until 2030. 24 years
Mine is essentially now a paper weight when it's a perfectly good useable bit of glass.
To replace it for RF its £2500 here in the UK!
From these charts the RF doesnt perform much better than the MKI
View the image quality delivered by the Canon EF 24-70mm f/2.8L USM Lens using ISO 12233 Resolution Chart lab test results. Compare the image quality of this lens with other lenses.
www.the-digital-picture.com
Ridiculous.
I bought my EF 24-70mm f2.8 L mk I back in early 2008 and it was one of my "darling" lenses. It was so versatile and I like the (often misunderstood) reverse zoom function. The hood worked spectacularly well in the wet and harsh sun, keeping the element clear at 70mm and 24mm really well. My copy was nice and sharp, even at 70mm f2.8. It's a lens I know well and used a lot. It's ability to shoot wedding rings shot on the fly was amazing. I used it on my 5D/ mk II & mkIII.
I've been very blessed with my copy, it had a hard life and the riggors of wedding photography and landscape workshops could be hard on this well documented lens. It could suffer from optical alignment issues if it was dropped or bumped. I was fortunate that my copy never suffered from this. I've also heard that calibrating this lens was a literal night mare.
However, with my migration to mirrorless last year I found the R8 / R6ii's sensor was exposing my copy of this lens' optical deficiencies in sharpness at 70mm @f2.8. it was fine stopped down to f4.
So I figured that maybe it was time to migrate to either the RF version or the EF mkII. Trust me, the mkII lens is a lot sharper at 70mm @ f2.8.
I chose the Ef mkII lens over the RF version for a number of reasons.
Firstly, because I can use a EF to R drop in adaptor. This allows me to use rear mount drop in polarisers & ND filters with this lens and all my other EF lenses and I don't need to take an arry of filter duplicates or troublesome step down rings with me. I've also found that the canon lens coatings are far superior then any 3rd party filter I have used. having the filter behind then les has yielded better IQ and lower ghosting and flare issues too.
Secondly, the optics. Optically, the EF mkII lens is pretty much the same sharpness as the RF lens, it's a similar size (when adapted) and about the same weight. The Mk II is vastly sharper than the mkII and this is easily seen in photos from my R6 & R6ii. I'm guessing it would be even more obvious on a R5.
Thirdly, it's a LOT cheaper. 2.5x cheaper new (£1K vs £2.5K) and far more available S/H in immaculate condition.
The RF lens has two main benefits over the EF mkII. It's MFD is slightly better than the EF mk1 and a lot better than the EF mkII. I use a small extension tube with my EF mkII to off set this. The other feature of the RF lens is the inclusion of an optical Image Stabiliser. My R6ii has IBIS so it's a but mute, however the IBIS is inferior. 3-4 stops - better at the wide end than at the long end vs the 8.5 stops of the combined snf coordinated lens IS and IBIS that the Rf lesn offers.
If I was really interested in the RF version, I would probaby step sideways and get the RF 24-105mm f4 LIS instead, because the never cameras have better ISo noice ability and the fact that it's only £1.5K compared to the over priced £2.5K of the RF 24-70mm f2.8 LIS. I like good / great...but I also like cheap.