Is RF 28-70 F2.0 suitable for fast moving objects? (AF speed)

I am tempted to buy this humongous glass, but I read in a thread @Canon EOS R an opinion expressed by an advanced amateur, that 28-70 tends to have some AF speed issues with fast moving objects. As I am not able to test it before purchase I would like to hear from the the real users of RF 28-70 if you have any observations in this regard.

I can guess that moving such a big piece of glass might require some sort of brutal force and the whole system might be slower than RF/EF 24-70.

bernie r wrote:

Tommy S wrote:

I am tempted to buy this humongous glass, but I read in a thread @Canon EOS R an opinion expressed by an advanced amateur, that 28-70 tends to have some AF speed issues with fast moving objects. As I am not able to test it before purchase I would like to hear from the the real users of RF 28-70 if you have any observations in this regard.

I can guess that moving such a big piece of glass might require some sort of brutal force and the whole system might be slower than RF/EF 24-70.

Yes, it's suitable... But the RF 70-200 2.8 is faster.

+1 here. You nailed both, and this is where I might grab a 70-200 over the 28-70; speed usually equates to reach. But the 28-70 is capable; no issues here with it not keeping up on my lowly R, except maybe the swing test. Most cameras and lenses fail that test though with the only passer being the M6 II + 70-300 IS USM. That’s a HARD benchmark to pass. The 28-70 faired well still though.

If I had the R5 the 28-70 probably would pass that test though. The scan rate of the original R is a bit slow for demanding AF needs.

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Camera:
Canon EOS R5
Canon RF 15-35 2.8
Canon RF 28-70 2
Canon EF 70-200 2.8
Canon RF 85 1.2
Canon EF 500 f/4 L IS II USM + 1.4X III
Other:
Gitzo Fluid Gimbal Head
Gitzo GT4543LS Systematic Series 4 Carbon eXact Long Tripod
Benro Mach3 TMA38CL Carbon Fibre Tripod
Benro G3 Ball Head
Canon Speedlite EL-1 Flash
Canon Speedlite 470EX-AI Flashgun
Gitzo Adventury 45L

bernie r wrote:

Tommy S wrote:

I am tempted to buy this humongous glass, but I read in a thread @Canon EOS R an opinion expressed by an advanced amateur, that 28-70 tends to have some AF speed issues with fast moving objects. As I am not able to test it before purchase I would like to hear from the the real users of RF 28-70 if you have any observations in this regard.

I can guess that moving such a big piece of glass might require some sort of brutal force and the whole system might be slower than RF/EF 24-70.

Yes, it's suitable... But the RF 70-200 2.8 is faster.

I ditched the idea of having RF 70-200 due to its long and cumbersome focus ring. This video convinced me to buy EF 70-200 USM II

For shots like this below I need a shorter zoom, and RF 28-70 F2 is on my wish list, but I do not want to kick myself for slower AF-C, even if great bokah, and low light are main advantages of this humongous glass.

I guess it's about preferences....

Tommy S wrote:

I ditched the idea of having RF 70-200 due to its long and cumbersome focus ring.

Curious what this means?  Had me take out my 70-200 and try to understand (admittedly haven't MF'd it much to date).  The focus ring appears to be of average cumber.  I'd call it narrow rather than long.  If you mean focus range, it takes around 3/4 of a turn to go from close to infinity focus when set to linear.  One advantage it has over the EF is you can set it up for variable sensitivity based on how quickly turn and that has it go from close to infinity in less than half a turn, easily.

Depends on how you define fast moving objects but I would say yes.

aut0maticdan wrote:

Tommy S wrote:

I ditched the idea of having RF 70-200 due to its long and cumbersome focus ring.

Curious what this means? Had me take out my 70-200 and try to understand (admittedly haven't MF'd it much to date). The focus ring appears to be of average cumber. I'd call it narrow rather than long. If you mean focus range, it takes around 3/4 of a turn to go from close to infinity focus when set to linear. One advantage it has over the EF is you can set it up for variable sensitivity based on how quickly turn and that has it go from close to infinity in less than half a turn, easily.

It is all about ergo, when I need to hold it for the whole day to track moving objects. I spent 2 days with 100-400 USM II and the focus ring at the end and a pretty long throw is not what I liked. YMMV though.

bernie r wrote:

Tommy S wrote:

aut0maticdan wrote:

Tommy S wrote:

I ditched the idea of having RF 70-200 due to its long and cumbersome focus ring.

Curious what this means? Had me take out my 70-200 and try to understand (admittedly haven't MF'd it much to date). The focus ring appears to be of average cumber. I'd call it narrow rather than long. If you mean focus range, it takes around 3/4 of a turn to go from close to infinity focus when set to linear. One advantage it has over the EF is you can set it up for variable sensitivity based on how quickly turn and that has it go from close to infinity in less than half a turn, easily.

It is all about ergo, when I need to hold it for the whole day to track moving objects. I spent 2 days with 100-400 USM II and the focus ring at the end and a pretty long throw is not what I liked. YMMV though.

Shooting with it all day... Purposefully used the heavier EF 70-200 than RF 70-200...

Oh gosh - I am pretty fit, so the weight is not an issue - otherwise I would not be considering such a humongous glass.

Interesting!  Sorry, I can't be of help on the 28-70.

1Dx4me wrote:

i am gonna hold on to all of my :EF" "L" lenses when i move to R3 or R! when the time comes. RF lenses are expensive and offer no benefit compared to EF lenses. so i am ready for R#/R1 cameras in your case, i would definitely consider a canon 24-70 f2.8 II, it is a wonderful lens, check it out.

This 24-70F2.8 USM II I already have it, nut am tempted to exchange it for 28-70 for the benefits of being fitter, having better low light control, better bokah, and more artistic look of action/sports photos.

bernie r wrote:

1Dx4me wrote:

i am gonna hold on to all of my :EF" "L" lenses when i move to R3 or R! when the time comes. RF lenses are expensive and offer no benefit compared to EF lenses. so i am ready for R#/R1 cameras in your case, i would definitely consider a canon 24-70 f2.8 II, it is a wonderful lens, check it out.

'No benefit' is a stretch.

Although true, I find the benefits for the price difference pretty bad value for money in some cases.

Comparing the RF 24-70mm f/2.8 to the EF 24-70mm f/2.8 mkII  i've found the following differences:

1. The RF lens has smoother bokeh

2. The RF lens has a bit better stabilization, as it isn't leaning on IBIS only. Yeah, there are two bodies without IBIS, but the R is more of a landscape camera being better served with the RF 24-105 f/4.0 L, and the RP and the RF 24-70 f/2.8 IS USM - although fully compatible - aren't really in the same price segment.

3. The RF lens could have a little bit better contrast and/or center sharpness, but it doesn't have benefit's only. The EF lens is a bit better at the wide end for instance.

I've tested my EF lens on the R5 for AF tracking speed, and my use cases aren't enough of a stress test to find any flaws, even when trying to stress the lens enough. Although the RF lens could be better, I'm wondering what improvements where needed.

1. is a biggie

2. is only a marginal difference in my opinion

3. is only a marginal difference in my opinion

My used but mint EF mkII was 1000 euro. A new RF lens is 2500 euro. In my opinion it's better value for money to get the EF lens and use the other 1500 euro to add one or two good primes. 1500 euro is what I've payed for the 40mm f/1.4 Art plus RF 85mm f/2.0 IS stm.  Because of these lenses my 24-70mm is primarily my best 24mm.....  It's also - secondary - my standard zoom, but hey, zooms will always be just just zooms, no matter how expensive they are.

Here's the 28-70 wide open tracking a running dog. Yes, it's not as fast as the RF 70-200, but it's still pretty darn quick. 
If it matters: I sold my RF 24-70 for the 28-70, and also own the 70-200 2.8 and 100-500.

There is an astonishing amount of conjecture and uniformed opinion in this thread.