Now we see through a glass, darkly...
- Apr 5, 2016
Only Canon knows the size of the 7Dii user base. It is an assumption that all current 7Dii users will buy a R7. It is also an assumption that all 7Dii users were birders etc requiring the extra reach compared to other systems. It is not clear how many current 7Dii users have moved to 5D or other systems in the last 7 years or even moved to the R6/7. I moved from 7D to 5Diii to 5Div to R5 for instance.
The R5 has the best AF/fps/weather sealing that you want on a R7. Saying that 17mp equivalent reach on the R5 is not sufficient as the D90 etc has 30mp doesn't make sense as the 7Dii only has 20mp. 17mp vs 20mp is not a large difference in linear resolution. If pixels on subject is mandatory then use D90/M5ii.
I contend that the 7D/7Dii were marketing unicorns ie best AF/weather sealing/fps in a relatively inexpensive body doesn't make sense in Canon's market segmentation today and unlikely to continue in the future. 5 year refresh from 7D to 7Dii and now 7 years with no refresh supports my argument.
I don't think anyone is saying ALL 7D Mark II users will buy an R7. But the type of shooters who found a use for the 7D Mark II are the same type of shooters who would be interested in an R7.
No one is saying all 7D Mark II users are birders, either, particularly not me since I rarely shoot birds/wildlife.
What I am saying is that, in my experience, almost every 7D Mark II user I know also uses FF cameras already. I already owned a 5D Mark II before I bought my first 7D. I didn't stop using the 5D Mark II. I started using both of them.
I regularly use a 5D Mark IV, a 7D Mark II, and a 5D Mark III. I rarely shoot three bodies at once. Which one or two I use for a given shooting scenario all depends on the circumstances of that assignment. For most scenarios other than field sports I use only FF cameras. Most days I don't use the 7D Mark II. But when I do use it, it is for a specific purpose when it best meets my needs: More reach with a 70-200/2.8 shooting things that require high frame rates and very large numbers of images over the course of the shooting session. Even though I only use the APS-C camera on about 25% of the sessions I shoot per year, 75% of the frames I shoot each year are on that body. It saves my more expensive FF bodies for where they are most useful.
It's not an either/or decision between APS-C or FF. For most of us who use higher end APS-C bodies it is a decision between another extra FF body or one less FF body and a lower cost, faster APS-C body that also tends to last longer on which to do our "high mileage" telephoto work, be that birds, night sports, or whatever.
"Saying that 17mp equivalent reach on the R5 is not sufficient as the D90 etc has 30mp doesn't make sense as the 7Dii only has 20mp."
Dude, if Canon had offered a 32MP 7D Mark III in the last three years or so, many 7D Mark II users would already be using that camera instead. The only reason most of us passed on the 90D was because of the less durable shutter rating and the downgraded AF system compared to the 7D Mark II. Those of us still using our 7D Mark II bodies would be more than happy with the 90D/M6 Mark II sensor in an R5/R6 body.