topic Upgrading to R5 or buying EF 100-400mm in Gear Guide

Upgrading to R5 or buying EF 100-400mm

clevend — Mon, 24 Aug 2026 09:19:47 GMT

I am using a 6D which I absolutely love. I want to get a telephoto lens and I see two options. To get an R5 with a RF 100-400mm or to get an EF 100-400mm mkii at half the price.

I feel like it's just gear acquisition syndrome pulling me towards going mirrorless and my rational thoughts tell me that keeping my camera body and getting the EF100-400mm is the best option?

I will be using it for wildlife and landscapes

Re: Upgrading to R5 or buying EF 100-400mm

jrhoffman75 — Mon, 24 Aug 2026 10:01:13 GMT

@clevend wrote:

I am using a 6D which I absolutely love. I want to get a telephoto lens and I see two options. To get an R5 with a RF 100-400mm or to get an EF 100-400mm mkii at half the price.

I feel like it's just gear acquisition syndrome pulling me towards going mirrorless and my rational thoughts tell me that keeping my camera body and getting the EF100-400mm is the best option?

I will be using it for wildlife and landscapes

If the 6D is performing well and doing everything you want I suggest getting the EF zoom. When it becomes time to retire/replace the 6D you can move to mirrorless, use the RF-RF adapter and continue to use all your EF lenses.

Re: Upgrading to R5 or buying EF 100-400mm

March411 — Mon, 24 Aug 2026 12:11:11 GMT

I'm with John, if the camera you own today is providing you with good images and has the functions you need I would pick up the EF 100-400mm.

Re: Upgrading to R5 or buying EF 100-400mm

ebiggs1 — Mon, 24 Aug 2026 14:16:04 GMT

"I'm with John,..."

I'm with Marc.

Re: Upgrading to R5 or buying EF 100-400mm

pzphotomama — Fri, 28 Aug 2026 13:54:34 GMT

Im going to go another direction, I have the EF 100-400 and its a beauty lens, I use it with the lens adapter on my mirrorless camera's. Why are you jumping to the R5? You could get an R6MII and the RF 100-400 for the same price pretty much as the R5 alone. Even better if you can find used - in Canada where I am Henrys has some great options. OR you can still get the EF 100-400 and get the R6MII and still probably be around the same as an R5 alone. Then you can use the 100-400 on both cameras.

I have the R6MII and its a beauty, upgraded from my 5DMIII - which I still have and only upgraded as it was 12 years old and I felt the pull to mirrorless when I saw there was no "upgrade" to my camera as a DSLR beyond MIV.