I have been a Canon DSLR user for many years and I am thinking of upgrading to mirrorless, mainly to take advantage of the lighter lenses. The AF eye tracking is also very attractive to me. We live in Thailand where wildlife is utterly abundant and the focus of all my photography and, to a certain extent, my wife's gardening.

My main camera is a 7D II with which I have a Canon 300mm f2.8 IS USM L and a Sigma 70-200 f2.8 OS DG HSM plus 2x converter, which I use for birds and larger 'prey'. This is very heavy and, as have ageing issues with my spine, I am finding it increasingly hard to lug about let alone hold steady if I want to stalk handheld.

I also have a 7D setup for macro photography of insects, spiders, etc, with a Canon 100mm macro IS USM L and flash assembly. On upgrade the mark II would move here.

So my decision is whether to move to full frame and the R6 II or save some money for len(s) and stick with the crop sensor R7. I am thinking of starting with the RF 100-400mm F5.6-8 IS USM.

Has anyone else gone through this process or have advice for me please?

  • 1
    \$\begingroup\$ Are you aware that with a crop camera you're currently shooting at an effective focal length of 200 * 2 * 1.6 = 640mm (with the extender), but with full frame and the 100-400 you'd be getting the "true" focal length of 400mm? Are you happy with giving up that much reach? If not, this question solves itself. \$\endgroup\$
    – Philip Kendall
    Commented Sep 8, 2023 at 6:53
  • \$\begingroup\$ Thanks Phillip. Yes I am aware, but it seems that the quality of the R6 II is so much higher. The R7 is somewhere between the 90D and 7D II, while the R5 and R6 do seem a comparable upgrade to the D equivalents. Can you tell me about the quality trade off if cropping an image taken on the higher MP sensor? Looking around the Internet I seem to get conflicting views. \$\endgroup\$
    – mrwhit749
    Commented Sep 8, 2023 at 10:25
  • 2
    \$\begingroup\$ When talking about cropping, it's not just about sensor size, it's also about "pixel" pitch. That is, how many pixels are you getting on your subject? You're already limited to 24.2 MP with the R6 Mark II. By the time you crop that to APS-C (the full size of the 32 MP R7), you're only left with 9.45 MP, less than half what you have with the 7D Mark II. That won't leave much room for cropping unless you're only interested in web sized images. Even then, 9.45 MP leaves a lot less room for cropping than 32 MP does. \$\endgroup\$
    – Michael C
    Commented Sep 8, 2023 at 10:37
  • \$\begingroup\$ Thank you all for your input, it has been very useful in helping me to gel my ideas. For the record, and perhaps to help others in a similar dilemma, I shall probably go for the R7 and the RF 100-400mm. I may go for the 1.4 converter (f16 at 400mm?) or the RF 600mm f11. I may wait a year to see if an R7 II is likely to appear, but I don't know how many active years I have left and I don't really want to waste time. \$\endgroup\$
    – mrwhit749
    Commented Sep 12, 2023 at 6:50
  • \$\begingroup\$ If size/weight is a factor, consider micro-four-thirds. Smaller, lighter, cheaper. Allegedly, not that great in low light, tho getting better \$\endgroup\$ Commented Sep 13, 2023 at 4:24

1 Answer 1


I've been considering a similar switch, and I think maybe the R7 has the edge here for a wildlife shooter, but I do agree, it's difficult to decide between the two, and they're pretty evenly matched, since both cameras have:

  • Digic X processor
  • animal eye detection/tracking autofocus
  • in camera focus-stacking [handy for flower macros]
  • very high burst rates 30 fps/40 fps between R7 and R6 II
  • dual card slots
  • IBIS
  • a joystick
  • dual-wheel prosumer controls
  • they're close on size/weight
  • articulated LCD

Both, however, lack a pop-up flash. And neither has a top-deck LCD, things you may be used to having on your 7D II.

Sidenote: most folks are trying to decide between an R8 and an R7, given that they're both the same price in the US ($1500, body only). And in that case, it's more R7 for the features (IBIS, joystick, dual card slots, in-camera focus stacking etc.) vs. R8 for the full frame.

Why the R7 might better:

  • Higher resolution (33MP vs. 24MP). While this will lower dynamic range and high ISO noise performance, for a wildlife/bird shooter, being able to crop with less detriment is always a bonus.
  • Crop factor can help you achieve more apparent "reach" with shorter/smaller/cheaper lenses than crop. On full frame, all your lenses look 1.6x shorter. So, say, the RF 800mm f/11 DO IS STM on an R7 will have 1280mm equivalence; and the RF 100-400 f/5.6-8 IS USM has 160-600mm equivalence.
  • Lower pricetag new (US$1500 vs. $2500) so you'll have $1k more to spend on lenses.
  • Easier to find on the used market and refurbished (at least here in the US at this moment; a refurb R6 II is back ordered, while the R7 is in stock).

Why the R6 II might be better:

  • Full frame (though this can also be more of a PITA for wildlife/birding (needing 1.6x longer lenses to frame equivalently) and macro (thinner DoF, because longer lenses or shooting from closer)
  • Of the 30 or so R-mount lenses Canon has released at this time [Sep 2023], only three of them are RF-S (crop-specific). The array of native lenses is far more complete for full frame. While a crop shooter can use full-frame lenses; right now there are lenses you can get for R full frame you cannot get for R crop: an ultrawide zoom, a pancake lens, and an f/2.8 walkaround zoom. Yet.*
  • The AF performance will be stickier/faster, because the R6 II has faster sensor readout, and with mirrorless, there's only one sensor doing all the work of image capture, metering, and autofocus.

*This is likely a temporary situation; remember Canon has EF-M crop mirrorless optical designs to leverage. If you look at the three RF-S lenses, they appear to be tweaked versions of EF-M designs. The RF 18-45 from the EF-M 15-45, the RF 18-150 from the EF-M 18-150, and by extension, the RF 55-210 from the EF-M 55-200. Which is probably how Canon could release all three lenses in one year. If Canon "ports" the EF-M 11-22 and EF-M 22/2 pancake designs to RF-S, then two of the three missing types are ticked off the list. However, Canon never made an EOS M f/2.8 walkaround zoom, so it's likely starting from the EF-S 17-55/2.8 design would take more time due to the greater mount depth difference. But if you need one of these types of lenses right now for an R crop body, your only option is to adapt EF-S lenses like the 10-18, 24/2.8, and the 17-55/2.8.

  • \$\begingroup\$ DiG!C X is an architecture, not a specific chip, unlike the previous DiG!C numbers which were specific chips. DiG!C X is kind of like Intel's Rocket Lake or Alder Lake CPUs. There are various different chips within each family. \$\endgroup\$
    – Michael C
    Commented Sep 13, 2023 at 0:37
  • \$\begingroup\$ @MichaelC Is there a way to tell which specific chip is in which model? Everything I've read has referred to as a processor not an architecture, even in Canon literature. \$\endgroup\$
    – inkista
    Commented Sep 13, 2023 at 19:09
  • \$\begingroup\$ In this podcast Canon Europe Product Specialist Mike Burnhill mentions it in response to a question at 12:10. The question asks if AF improvements in the latest EOS R cameras such as the R3 and R8 will be added to previous models, such as the R5, via firmware updates. He says this is not possible because they have different processors. He goes on to plainly say that DiG!C X is a "family of processors" and then lists various models that have different DiG!C X processors in them. \$\endgroup\$
    – Michael C
    Commented Sep 14, 2023 at 8:20
  • \$\begingroup\$ I do not know of anywhere that lists specific SKUs or part numbers for various DiG!C X processors. \$\endgroup\$
    – Michael C
    Commented Sep 14, 2023 at 8:26

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