# Canon RF 24-70 f/2.8 Axial Chromatic Aberration



## MartynV (Dec 15, 2019)

Hi,

I have an EOS R, RF 24-105 f/4L kit lens, 35mm f/1.4L II and EF 100mm f/2.8L Macro. 

I'm thinking of getting an RF 24-70 f/2.8L possibly for photographing weddings, but I saw the disco axial CA/spherical aberration on The Digital Picture's review (https://media.the-digital-picture.c...8-L-IS-USM-Lens/Spherical-Aberration/70mm.jpg). Perhaps I'm expecting too much as the RF 24-70 f/2.8L doesn't have a BR element like the 35mm f/1.4II so shows lateral and axial CA. To what extent is this disco CA a real-life problem? 

Alternatively, is the 15-35 f/2.8L a better option for this application? I like the RF 70-200 f/2.8L, but it's a dust-puffer and the front focussing issue is a deal-breaker. Some online shops seem to have temporarily discontinued sales.

Any advice gratefully received.

Kind regards,

Martyn


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## Viggo (Dec 15, 2019)

They test in an absolutely worst case scenario, I’ve owned many lenses which looked very poor in these kind of tests, but simply forgot about it when shooting.

btw, calling the 70-200 a dustpuffer is plain wrong. Quoting Roger Ciala “the worst offenders when it comes to dust are all primes, not a single zoom lens”. And reading the teardown of the 70-200clearly shows they have some extra protection against dust when zooming.


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## MartynV (Dec 15, 2019)

Viggo said:


> They test in an absolutely worst case scenario, I’ve owned many lenses which looked very poor in these kind of tests, but simply forgot about it when shooting.
> 
> btw, calling the 70-200 a dustpuffer is plain wrong. Quoting Roger Ciala “the worst offenders when it comes to dust are all primes, not a single zoom lens”. And reading the teardown of the 70-200clearly shows they have some extra protection against dust when zooming.


Thanks, I'm glad the 70-200 is not a dust-puffer. Which lens would you suggest of the trinity? I'm sceptical of the 70-200 until the front focussing issue has been resolved by Canon, either by a firmware update or a recall.


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## Viggo (Dec 15, 2019)

MartynV said:


> Thanks, I'm glad the 70-200 is not a dust-puffer. Which lens would you suggest of the trinity? I'm sceptical of the 70-200 until the front focussing issue has been resolved by Canon, either by a firmware update or a recall.


That entirely depends on what focal length you want/need. But I wouldn’t either buy the 70-200 before the issue is resolved.
Personally I could make use of all three of them, but if I had to choose just one it would be a very difficult choice indeed.


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## Sporgon (Dec 15, 2019)

Viggo said:


> They test in an absolutely worst case scenario, I’ve owned many lenses which looked very poor in these kind of tests, but simply forgot about it when shooting.
> 
> btw, calling the 70-200 a dustpuffer is plain wrong. Quoting Roger Ciala “the worst offenders when it comes to dust are all primes, not a single zoom lens”. And reading the teardown of the 70-200clearly shows they have some extra protection against dust when zooming.


I read that review too and was quite surprised at Roger’s comment because I’ve never come across anyone before who didn’t associate the “dust pump” tag with getting dust onto the sensor by pumping air in and out of the camera, not dust in the lens.

On my 5DSs I never had a zoom on them and the sensors have remained spotless yet I change lenses all the time.


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## Viggo (Dec 15, 2019)

I’ve never heard of anyone getting dust on the sensor due to an extending zoom lens, is that a thing? I assumed it was getting inside the lens. Well, I shoot large apertures so not bothered by dust anyhow


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## analoggrotto (Dec 17, 2019)

Want dust all over your beautiful full frame sensor? Shoot primes, all of that lens changing is really messy. But I'm a prime fiend so thats how I roll, and the dust on the sensor isnt a problem anyway.


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## Sporgon (Dec 17, 2019)

analoggrotto said:


> Want dust all over your beautiful full frame sensor? Shoot primes, all of that lens changing is really messy. But I'm a prime fiend so thats how I roll, and the dust on the sensor isnt a problem anyway.


I have found that changing lenses a lot, in all sorts of conditions, doesn't influence dust on the sensor. Maybe it would on cameras that don't have a closed shutter.


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## Optics Patent (Dec 17, 2019)

I'm an amateur, but have been married three times, so feel qualified to advise a wedding shooter. 

The RF 70-200 is a game-changer having little in common with all the 70-200 "horse's legs" you have used before. At 70 it's a great portrait lens in a compact form that may be your favorite wedding lens to go with the 35mm 1.4. It's my favorite for toddler and baby shots. As they grow I might need to go wider.

There is no evidence that this has a dust problem, nor that any real world shooter will be affected by a temporary focus issue that requires deliberate care even to replicate. I suspect that some people need to talk themselves into being happy not making a particular purchase.

My best advice is to try the RF70-200 and if you aren't in love with the handling, send it back (what I like about Adorama).


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## analoggrotto (Dec 18, 2019)

Sporgon said:


> I have found that changing lenses a lot, in all sorts of conditions, doesn't influence dust on the sensor. Maybe it would on cameras that don't have a closed shutter.


A little bug got into my prism box and died. My sensor is pretty dusty really, but its not awful.


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