I’m currently shooting birds with a Canon R7 + EF 100–400mm Mk II using the RF/EF adapter. The combo gives me great results, but I’m looking for more reach and struggling to choose between a few upgrade paths:
Add the EF 1.4x III teleconverter to my 100–400
Replace the 100–400 with the RF 100–500 (though I’m not sure the extra 100mm justifies the price)
Add the Canon RF 200–800 alongside the 100–400
Budget is a factor - I can’t go much above ~$2,000 for options 2 or 3. Another thought is investing a bit more in option 2 by pairing the RF 100–500 with the RF 1.4x extender.
I don't think the TC or to 100-500 will give a meaningful upgrade in reach. I have the 100-400 II and a 1.4x TC but usually just use the lens bare. I'd go for the 200-800 or maybe the 800/11. I rented one once and it's a fun lens for birds. It's pretty cheap and feels very light in the hand. Just gotta be done by sunset, but that's pretty much true of your other options too.
I'd second this. The 200 - 800 is probably the best bet. You are already pushing the boundaries of affordable combinations so the only real way to step up after that is a big white lens.
The 100-500 works reasonably well on the R7, but with a TC it is worse. I don't use the 200-800 due to the MTF. I normally use the 100-500 on R5/R5 II and then go to a 500/4 or 600/4 when more reach is needed. R7 + [500/4+1.4x or 600/4+1.4x] are my go to for extra reach with smaller species. Always try to reduce the subject distance. If the air is bad you are just magnifying the disturbance with a longer lenses and smaller pixels.
Whatever you do it's best to rent first to determine where the IQ lands compared to the bar you set.
Flyer73 wrote:
Thanks.
How do you find the 100-400 with the extender? Are the phots sharp enough?
They're OK on my R6. The AF does take a hit though and I notice less keepers. It seems to need hard light to look good more than the bare lens. I'm kinda on the fence about using the TC. If you're printing large and want every megapixel, it probably makes more sense to use the TC. But I'm mostly displaying stuff online. It probably won't hold up as well on the R7's high pixel density.
Mike_5D wrote:
They're OK on my R6. The AF does take a hit though and I notice less keepers. It seems to need hard light to look good more than the bare lens. I'm kinda on the fence about using the TC. If you're printing large and want every megapixel, it probably makes more sense to use the TC. But I'm mostly displaying stuff online. It probably won't hold up as well on the R7's high pixel density.
The R6 has large pixels (5.96µm). Even with the 1.4x TC it has less reach than the R7 (3.19µm) has without a 1.4x.
Technically the R7 is like a 1.86x TC on the R6 based on pixel pitch.
For me, the EF 100-400L always did very well with the EF 1.4 lll TC, nearing the IQ of the bare lens providing it was "good" light, both with my EF7D2, and for the short time I used it with my R5, prior to obtaining an RF 100-500L.
My choice was to go with the RF100-500L.
Are most of your shots with the 100-400 at 400mm? If so, I'd consider selling it and buying a used 500 or 600 f4. If you use the in between focal lengths often you might consider picking up a used RF 800 f11. They can be had pretty cheap.
Mmeece wrote:
Are most of your shots with the 100-400 at 400mm? If so, I'd consider selling it and buying a used 500 or 600 f4. If you use the in between focal lengths often you might consider picking up a used RF 800 f11. They can be had pretty cheap.
This isn't a bad option. I use one from my kayak for wildlife on my morning paddles and it does really work quite nicely and is quite sharp given the price -- yes, I also have a 600 f4 and there's no comparison, but I strongly suspect it won't be all that different than the 200-800 zoomer.
I went through the same exercise in the Spring of 2024. What I was getting with my R7+EF 100-400 II [+ EF 1.4x III TC] was just getting me barely into the ball park of the bird images I see posted here on FM daily. I started looking for a solution.
My decision was to get the RF 100-500. In contrast to previous posters, I did see noticeable image improvement using the RF 100-500 over the EF 100-400 II. Eventually, I also added the RF 1.4x TC which I use almost anytime I don't expect the subject to fill more than abut 50% of the R7 frame.
I was choosing between the RF 100-500 and the RF 200-800. I decided on the RF 100-500 for the following reasons.
1) the RF 100-500 had the better specs
2) the RF 100-500 would fit in my existing camera bag with the body mounted. The Rf 200-800 was too long.
3) the RF 100-500+1.4x TC had a weight advantage over the RF 200-800.
I did, later, also buy the RF 800/11 from MPB. The cost was just too trivial [for me, YMMV] to pass up. It has become my most used lens for bird photography. Most of my bird photography occurs when I'm out to get walking exercise [often 1-2 hours in duration] or just get out of the house [I'm retired and I need excuses to get out]. Like cocodrillo above, it is just too easy to carry and use. So, the circumstances under which you are wanting to use the lens is an important consideration.
I won't argue that the RF 800/11 is a "better" lens than the RF 100-500 configuration....which I use when I think my shooting goal is critical.
I have been using the R7 with the 200 - 800 lens since February 2025, mostly for bird photography. Still learning, but have had good success. I am especially impressed with the stabilization. I accidently shot photos of a desired bird at 1/20 and was able to get some decent images. I am a beginning photographer at best and excuse my potential misuse of photo terminology.
I have the RF 100-400, RF 600 f/11 & the RF 800 f/11 for when I want to go long on my R100. This guy was around 400' away, and the 800 did it's job. I've seen this lens sell on the B/S Forum between $450 & $500.
Jim
I still use my EF 100-400 with my R7 & R5 with both EF extenders. The 1.4x is a no brainer, it just works with very little loss of anything. The 2X works OK (still sharp) on the mirrorless bodies with the obvious slower autofocus. Certainly better than it did on my 1DX when it was manual focus. My main lens is the Sigma EF 500 f4 DG OS. It will be burnt with me when I am cremated.
I know that both the 100-500 and 200-800 are sharp lens but to me they have too many compromises. Canon needs to stop releasing these stupid lens and copy Nikon and Sony with good mid range telephoto zooms and 5.6 primes so they are affordable.
tkbslc wrote:
Sigma 150-600mm lenses work with the RF adapter. MUCH cheaper than the Canon version, especially used.
Would get you up to near 1000mm equivalent.
The AF-performance of the adapted Sigma 150-600mm lens is very poor compared to the Canon lenses, regardless of whether they are native RF (100-400, 100-500, 200-800) or adapted EF lenses (100-400 II).
The Sigma 150-600 „works“ but I would NOT recommend it.
