# Slow AF, RF50 and RF85 or R to blame?



## Viggo (Mar 4, 2020)

Hi!

I find AF to be waaay to slow for fast action like someone starting to run etc.

I have the RF50 and RF85 and they aren’t exactly the fastest AF.

My question is, is it mostly the R or would be WAY better with a RF70-200 or RF24-70?


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## Bennymiata (Mar 5, 2020)

That surprises me.
My R focusses lightning fast with the RF24-105 and all my other EF lenses and other brands too.

Either there is something up with your settings or something is wrong with the body.


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## Viggo (Mar 5, 2020)

Bennymiata said:


> That surprises me.
> My R focusses lightning fast with the RF24-105 and all my other EF lenses and other brands too.
> 
> Either there is something up with your settings or something is wrong with the body.


The 24-105 and others have completely different motors, and the focusing groups are WAY heavier in the RF85 for instance, a good reason they use the same USM as the 400 f2.8. Heavy glass move slow if it’s accurate so it’s no surprise. I just haven’t used any fast AF glass with the R, so can’t tell where the issue is... thanks for chiming in


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## Del Paso (Mar 5, 2020)

What I don't understand is that, according to reviews, the 400 f.2,8 seems to be a fast focusing lens.
So, why should the RF 50 and 85 be slow, since the are said to be fitted with the same AF motors?
The 24-105 is indeed extremely fast!
PS: according to TDP, the RF 85's AF is very fast...


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## Viggo (Mar 5, 2020)

Del Paso said:


> What I don't understand is that, according to reviews, the 400 f.2,8 seems to be a fast focusing lens.
> So, why should the RF 50 and 85 be slow, since the are said to be fitted with the same AF motors?
> The 24-105 is indeed extremely fast!
> PS: according to TDP, the RF 85's AF is very fast...


I guess because the focusing group of the 400 is much smaller and lighter?

if the RF85 is fast, is it fast for an 85 f1.2 or is it fast? I don’t think it’s fast when comparing to the L f2.8 zooms etc. and tracking a cat running is nowhere near what I got with the 1dx2 and 24-70. So if there’s someone out there with the RF85 and 24-70 please share your experience with tracking with each of them.


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## privatebydesign (Mar 5, 2020)

Viggo said:


> I guess because the focusing group of the 400 is much smaller and lighter?


And less accurate. It is a lot easier to get accuracy at f2.8 at a longer distance than f1.2 at a closer distance.

But I fear we have entered the 'Viggo Spiral'©, you love your new toys and proclaim them better than anything previous, you then find faults, you then find numerous faults and send stuff back for service and swap stuff out and generally hyper analyze. You then get down on a piece of equipment by which time Canon EF toR or Profoto to Broncolor give you another option and you chase that path. meanwhile most people who view even your rejects of shooting your kids are blown away at how good the actual images are. Your content vastly outstrips the perceived flaws or limitations of the highest end gear you use and I say all that with the very greatest of respect.


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## Random Orbits (Mar 5, 2020)

Servo AF is definitely slower and less capable on the R than it was on the 5D4. The target: a LEGO version of a pinewood derby. Lenses used: 28-70 and 70-200 f/2.8 IS II. Used the 5D4 with EF 24-70 and 70-200 last year and had better tracking results. At this point, it's probably the biggest reason why I haven't switched over to mirrorless entirely...


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## Frodo (Mar 5, 2020)

Do you have the camera set to AF tracking? I don't have the two lenses you mention. Last night I shot an event, mainly EF 85/1.8 and EF200/2.8, mostly using eye tracking. Brlliant!. Focus on eye, recompose, expose. Really quick and accuate for relatively static subjects. Previous time out shooting running event. Tracking seems to slow AF aquisition, and so got lot of OOF images. Turn tracking off, but keep servo AF - much better.


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## Viggo (Mar 6, 2020)

privatebydesign said:


> And less accurate. It is a lot easier to get accuracy at f2.8 at a longer distance than f1.2 at a closer distance.
> 
> But I fear we have entered the 'Viggo Spiral'©, you love your new toys and proclaim them better than anything previous, you then find faults, you then find numerous faults and send stuff back for service and swap stuff out and generally hyper analyze. You then get down on a piece of equipment by which time Canon EF toR or Profoto to Broncolor give you another option and you chase that path. meanwhile most people who view even your rejects of shooting your kids are blown away at how good the actual images are. Your content vastly outstrips the perceived flaws or limitations of the highest end gear you use and I say all that with the very greatest of respect.


I appreciate that, and normally I would totally agree with you. It all changed after going to Broncolor and the R plus RF, I’m actually very, very happy with the gear and how it performs.
The issue in this thread isn’t a fault, it’s a limitation of the R, I think, comparing to the 1dx2 I had. I do realize it’s never meant to compete with the 1dx2, and for 90% I blown away by the fact it’s just better at everything.

My question was really if it would help with the fastest action with a lens with faster AF, or if it’s the R that is the limitation? Nothing more, nothing less.

In other words, will an R5 with the RF85 be faster and better at tracking than the R with the RF85, or would they both be much better with the RF70-200. The reason why I ask if the lens is the limiting factor I’m not going to consider the R5. Going by experience the 85 L II performed much faster on the 1d than the 5d. However it wasn’t enough to justify that as the only reason for upgrading.


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## Viggo (Mar 6, 2020)

Frodo said:


> Do you have the camera set to AF tracking? I don't have the two lenses you mention. Last night I shot an event, mainly EF 85/1.8 and EF200/2.8, mostly using eye tracking. Brlliant!. Focus on eye, recompose, expose. Really quick and accuate for relatively static subjects. Previous time out shooting running event. Tracking seems to slow AF aquisition, and so got lot of OOF images. Turn tracking off, but keep servo AF - much better.


I use release priority if that’s what you mean, getting 5 instead of 3 fps. More chance of oof images, but frankly it doesn’t miss for anything but the fastest action.

Guess the only way to find out is try out the R5 for the things the R misses on.


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