Before the Sony 600mm f/4 GM lens became available, I did use the Canon EF 600mm Mark II version with some success. I felt the Sony 400mm f/2.8 GM was too short focal-lengthwise to fill the shoes as a birding lens. It worked great for stationary targets and for largish birds with predictable flight patterns. You can read my experience here: https://www.fredmiranda.com/forum/topic/1569131/0 and here: https://www.fredmiranda.com/forum/topic/1585940. I used Sigma MC-11 on that 600mm Mark II lens and it is labeled as "DT 600mm f/4 SAM" in the exif. I also used a Sigma 1.4X TC for some of the images posted there.
The setup did less so for smallish birds and especially those with unpredictable flight pattern. In the summer of last year, I went ahead and purchased the Sony GM lens and I have not looked back since.
The Canon Mark III lens has a similar weight distribution design as that of the Sony. For all intense and purposes, their optical performance is similar to each other. On the native Canon body, the lens is reported to do really well. You can read quite a few threads on the Nature and Wildlife forum of folks that use the setup and actually based on their images, you can see how well the AF and optical performance of the combo. Although I have not done so, nor did I come across any report about how well the AF of the Mark III lens performs on the Sony A9 or A9 II, I assume that it is similar to that of the Mark II version.
Judging by the current price and current availability, I would select a native long lens on my body, be it a Canon or Sony. However, based on your question, it sounds that you already have the Canon Mark III lens already. In that case, I would rent a Sony A9 or A9 II and try it out yourself whether the combo can meet your purpose. As long as you do only occasional BIF of larger birds with predictable flight patterns, you should be fine, I would say. I am referring to cranes, pelicans, geese, etc. here.
It works pretty well for anything other than challenging BIF. Ducks might be possible but I'd stick to eagles and herons with it if you do BIF. For perched and floating birds it can easily substitute for the Sony version. But for sure if you are going all Sony, I'd buy the Sony even if you have to sell the Canon (if you already own it).
Joshua's suggestion is a good one if you already have the Canon lens...buy or rent an A9 and see how it works. I had great adapting results with my MC-11 and never tried the Metabones. I was adapting my 400DOII up until 4 months ago and using it for all types of perched/floating birds even with the 2xTCIII on it.
Other option is patience and waiting for the Canon R5 which could turn out to be a winner.
AGeoJO wrote:
Before the Sony 600mm f/4 GM lens became available, I did use the Canon EF 600mm Mark II version with some success. I felt the Sony 400mm f/2.8 GM was too short focal-lengthwise to fill the shoes as a birding lens. It worked great for stationary targets and for largish birds with predictable flight patterns. You can read my experience here: https://www.fredmiranda.com/forum/topic/1569131/0 and here: https://www.fredmiranda.com/forum/topic/1585940. I used Sigma MC-11 on that 600mm Mark II lens and it is labeled as "DT 600mm f/4 SAM" in the exif. I also used a Sigma 1.4X TC for some of the images posted there.
The setup did less so for smallish birds and especially those with unpredictable flight pattern. In the summer of last year, I went ahead and purchased the Sony GM lens and I have not looked back since.
The Canon Mark III lens has a similar weight distribution design as that of the Sony. For all intense and purposes, their optical performance is similar to each other. On the native Canon body, the lens is reported to do really well. You can read quite a few threads on the Nature and Wildlife forum of folks that use the setup and actually based on their images, you can see how well the AF and optical performance of the combo. Although I have not done so, nor did I come across any report about how well the AF of the Mark III lens performs on the Sony A9 or A9 II, I assume that it is similar to that of the Mark II version.
Judging by the current price and current availability, I would select a native long lens on my body, be it a Canon or Sony. However, based on your question, it sounds that you already have the Canon Mark III lens already. In that case, I would rent a Sony A9 or A9 II and try it out yourself whether the combo can meet your purpose. As long as you do only occasional BIF of larger birds with predictable flight patterns, you should be fine, I would say. I am referring to cranes, pelicans, geese, etc. here.
Minor point - possibly timewasting, sorry - if you switched across to the Sony lens last Summer and never looked back, did you see what the Canon's performance was like with the major a9 firmware updates (and corresponding MC-11 updates) released at around that time? I'm sure it wasn't a gigantic improvement even at best, but I wondered whether you'd factored in any possible recent improvements from those updates in your summary.
GHarris wrote:
Minor point - possibly timewasting, sorry - if you switched across to the Sony lens last Summer and never looked back, did you see what the Canon's performance was like with the major a9 firmware updates (and corresponding MC-11 updates) released at around that time? I'm sure it wasn't a gigantic improvement even at best, but I wondered whether you'd factored in any possible recent improvements from those updates in your summary.
The improvement was minor and it had more to do with the spread of the AF points. Since the situations are not repeatable, the shooting conditions changed continuously, I wasn’t sure how much, if any, of an improvement the new FW brought.
For sure, the biggest improvement came about with the new Sony GM 600mm. I was floored how well this lens could track. It happened on the second day of my evaluation of the GM lens in August although I posted the images in October of last year here: https://www.fredmiranda.com/forum/topic/1617547.
The point I am making here is, for the best AF performance for fast action BIF is to stick with a native body for the lens that you already have. I am sure the new Canon 1Dx Mark III is a great performer, too. And bird photography is not always about small and fast flyers. I took my Canon 400mm f/2.8 Mark II to Costa Rica a few years back and came back with plenty of keepers and I even used it on a slowish Sony A7r II; the A9 wasn’t available then.
johnvanr wrote:
A related question would be how well the Canon lens performs with the adapter on a Canon mirrorless body.
If the R5 is the same as the EOS R then no issues at all. Every lens I own works seamless on the R being adapted, that includes the the 600mm MK III. Canon did a great job with the adapters. I have the control ring and the standard adapter.
RobAmy wrote:
If the R5 is the same as the EOS R then no issues at all. Every lens I own works seamless on the R being adapted, that includes the the 600mm MK III. Canon did a great job with the adapters. I have the control ring and the standard adapter.
I would if I was you. All my larger glass works great and even better with extenders. I think it gives new life to them. You may want to make a post in the Canon board as this is for Sony related vs Canon
An EF MKIII Great White is a very expensive lens. I suggest that you rent both an A9 and 1Dx MII to see which system is best for you. Then decide what camera/tele combo you want to pay for.
