Which produces sharper images Canon EOS R7 vs EOS R6 MKII with teleconverter?

[Ceddy]

I am boggled with choices. I would appreciate help in deciding on a 2nd combination for my photography collection. There is most likely an obvious answer to this question, however I am trying to achieve some equivalency of a $10k prime without spending $10K. I shoot mainly owls, raptors, and other wildlife.

I currently have the Canon R5 paired with Canon EF100-400mm 4.5-5.6/L usm ii (using an adapter, of course). I am debating between these options: Canon R7, Canon R6 mkii, Canon RF100-500mm 4.5-7.1/L, and Canon EF 400mm f2.8/L IS USM.

I would appreciate any recommendations! Totally irrelevant, however I am trading in my Canon EOS 6d mkii and a Tamron SP 150-600mm f/5-6.3 Di VC USD g2. 

Thank you in advance!

 

[johnrmoyer]

I use EOS R5 with EF100-400mm f/4.5-5.6L IS II USM +2x III

While a larger aperture would be nice, this combination is easy to carry. If you already have this lens, I see no reason to get a different one. What do you hope to gain? https://personal.canon.jp/product/camera/ef/ef100-400-f45-56l-ii-usm/spec has the MTF chart for the lens and https://personal.canon.jp/product/camera/ef/extender-ef2-iii/spec for the extender with various lenses. For the 100-500, https://personal.canon.jp/product/camera/rf/rf100-500-f45-71l/spec . Another lens comparison tool is at https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=972&Camera=979&Sample=0... .

This example was edited using DPP and I have listed all of the edits in a table below the photo. DPP "digital lens optimizer" does well at mitigating small aperture diffraction blur. Unsharp mask increases apparent contrast to make up for the loss of contrast when using the extender. Stopping down 1/3 stop from wide open seems to me to provide some improvement.

Northern Cardinal (Cardinalis cardinalis) in Norman, Oklahoma, United States on March 11, 2025

on my web server at https://www.rsok.com/~jrm/2025Mar23_birds_and_cats/2025mar11_cardinal_IMG_3005c.html

ISO	1250
FNumber	13.0
ShutterSpeed	1/400
FocalLength	800 mm
LensModel	EF100-400mm f/4.5-5.6L IS II USM +2x III
ExifToolVersion	13.25
FileName	IMG_3005.dr4
WhiteBalanceAdj	Daylight
WBAdjColorTemp	5200
UnsharpMaskStrength	2
UnsharpMaskFineness	2
UnsharpMaskThreshold	3
GammaShadow	1
GammaHighlight	0
GammaBlackPoint	+0.000
GammaWhitePoint	+2.000
GammaMidPoint	+0.000
GammaCurveOutputRange	0 16383
DPRAWMicroadjustBackFront	0
DPRAWMicroadjustStrength	8
CropRotatedOriginalWidth	8192
CropRotatedOriginalHeight	5464
CropX	114
CropY	229
CropWidth	7200
CropHeight	4800

100 per cent screen grab of the above photo:

[Ceddy]

Great information! Love the cardinal! I am very pleased with my current set up. I just want a back up.  After using the mirrorless, my DSLR seems so slow! hahaha! Therefore I am getting rid of the Canon EOS 6d mkii, and going with at least another mirrorless camera body but pair it with ??  I am searching for (clearly sharpness) but reach as well in my other set up. The tc option is very favorable! Bottom line: do I pair a EOS R7 with a 400mm prime lens or the R6 mkii with a 400mm  2.8/L prime lens and a tc? I understand the 400mm is a heavy lens however it seems like a 'dream' lens for the price for apeture. Thank you for your response, I appreciate it!

[shadowsports]

Greetings ,

I would choose the R6 mkII over the R7, even for wildlife.  Paired with good glass, I feel like you'd get better image quality from a full frame sensor with better light gathering capability and increased ISO performance.  

 Most owls are nocturnal, a smaller number of species are diurnal so you would probably be shooting more in the evening, and at dawn or dusk.  These would be my reasons for choosing the R6 Mark II, but where you live and the bird species you shoot most might influence your decision.

[Ceddy]

Rick, thank you for your response. I was leaning towards the R6 Mark II for the reason that you stated. I'm guessing you would suggest since I have a EF100-400mm usm ii lens, it probably would make sense to get the 400mm f/2.8 L, with a TC?