RF 24-70 f2.8 vs 24-105 f4

[bartonke]

Is there a difference in optical quality / sharpness between the Canon RF 24-70 f2.8 L IS USM lens and the RF 24-105 f4 L IS USM lens? Or is the difference between the two lenses only in the aperture range (i.e., f2.8 vs f4)?

[ebiggs1]

I don't have the R versions but I do have the EF models. The IQ is so close in those I would not see it as a maker or breaker. The 105mm end is sure and asset. But the one stop faster aperture is also an asset. Which will help you more? That is the question.

[shadowsports]

@bartonke,

Ernie has summed it up well.  I'll answer in a slightly different way.

Before upgrading to MILC, I owned a few DSLR body's.  I purchased many, many lenses.  Over time, I realized I had too much overlap in FL and aperture (way too much).  I sold a great deal of my lenses, kept my favorites and a few others for special purpose.  The second time around, I was very particular about what I bought.

I ended up with an EF trinity. Once again I added a few primes and special purpose lenses to compliment. When you look at all the factors, investment, performance and what you are able to use at any given time (one lens) unless you have more than one body, the amount of money you spend buying a bunch of lenses vs, a few really good lenses almost evens itself out in the end.     

The 24~105 f4 is a good lens.  The 24-70 f2.8 costs more.  In the end, its a higher performing lens with the ability to adapt itself to more shooting situations. Constant f2.8 through its entire range vs. variable on the RF24~105.  There are enough reviews of both out there with the consensus clearly in favor of the 24-70.  The shorter FL lens is slightly sharper, and it beats its rival by a small margin.  There is more to it though.  The key question is exactly what Ernie asked.  Example, if you walk inside a building with the f4, you might need a flash, you might not with the f2.8.  Conversely, if you can't get closer to a subject that margin of additional reach might be handy at the cost of background blur, ISO performance or separation.  

From my perspective, I'd ask how many other RF lenses do you plan to purchase or do you already own?  I only own 4 RF lenses now.  I plan for a 5th, and that will likely be it.  I'll have FL coverage from 15 ~ 200mm with constant aperture, a super light 100~400mm (non L), and something 200~(somewhere between 600-1000mm) hopefully if Canon Rumors is accurate.  My bag is lighter, less to pack and carry.  (Wallet is not however) but I know I have the best tools available for almost every situation, regardless of lighting, distance to subjects, etc.  This level of planning has greatly improved my love for photography and my hobby.  What I believe you want to avoid (as much as possible) is overlap.  Another lens, "So I can do such and such".  In some instances, it cannot be avoided.  In many cases, spending more upfront ends up being the wiser investment in the long run.  I also recognize and understand budget and cost as being deciding factors when making these decisions. I would buy the 24~70. This is my walk around lens. (Landscape and Architecture) I can shoot fountains outside or walk into a dark museum without a second thought. Art, no flash allowed is no problem. I can get the shot. Or, I can carry a prime with a better aperture, but I'll have to swap my lens on the go. Not always easy when shooting conditions are changing constantly. I hope this provides a slightly different perspective and helps with your decision.

[Danfaz]

I've owned both at the same time previously. Image quality is hard to distinguish unless you pixel peep. The RF 24-105 is significantly better than the EF version, which made choosing the 24-70 easier betweenthe EF versions. 

But as others have mentioned, which one you choose depends on your needs.