Basil Loc: New Mexico

If I were to get the RF200-800, I would not need to sell the Sigma.

MountainDave

I am cured with an eye for detail and use a R5 + 100-500. The AF, tracking and eye detect are insanely good. I suggest you check pro reviews on line. Throw in the Tamron G2 while you're at it. See which one fits your needs/budget.

Basil Loc: New Mexico

When you say if you were to make the choice today, do you mean you'd get the RF200-800 instead of the RF100-500? My biggest hesitation with the RF200-800 is the small aperture. If I sold the Sigma for the RF100-500, I'd only be giving up a 1/3 stop but also be giving up 100mm of reach. If f/7.1 is a handicap, I can only imagine f/9 is a much bigger handicap. I like to shoot birds at the Bosque Del Apache and some of the best shots occur in sunrise or sunset conditions. I'm wondering how high I'd have to crank the ISO to compensate.

Basil Loc: New Mexico

Thanks for the links. I actually had already watched the Jan Wegener comparison of the 100-500 vs 200-800.

MountainDave

People worry too much about high ISOs. There are a number of noise elimination tools available, including PS, that do a great job. I saw a video with Wegener using 12,800, 25,600 and higher. After using the tools, you'd never guess the ISO was so high.

Jimmy T Loc: Virginia

MtManMD Loc: Beaverton, Oregon

If depends on what you like to shoot. The RF 100-500mm on my R5 is my most used combination for wildlife. It is an excellent lens. It is excellent at close focusing distances, and I also use it for close-up shots for things like flowers, insects, etc. A 1.4x extender works well on it if you want to extend it out to 700mm.

If you are primarily a bird photographer, maybe the 200-800mm would be the better choice. People that have one seem to be very satisfied. I have one on order, as an additional tool rather than as a replacement for the 100-500mm. There are many thousands of us waiting impatiently on back-order status for this lens. Demand far exceeds Canon's ability to produce, so you will be waiting for a long time if you go this route. Many who ordered at time of release in November are still waiting.

As for the R7 body, some really like it and some of us don't. For me, not only have I experienced all of the common well documented issues, but image quality in most photos is poor or worse. I think I got a lemon. I can't wait for the R5 II release so I can pre-order one and sell the R7.

What is the current shortcomings of your 150-600mm? It is a really good focal range. If it's not broke, don't fix it!

clint f. Loc: Priest Lake Idaho, Spokane Wa

How do they do that exactly?

Basil Loc: New Mexico

Well, probably the main thing is, while it does take sharp pictures, I find that the keeper rate isn’t what you would call super high. I have heard that the RF lenses are much better at auto focus and tracking. So I don’t know if I would call that a shortfall, but it would be nice to have a better keeper rate when I’m shooting for example, birds in flight.

Weight is another factor, though less important. The sigma lens is not super heavy but it’s also not super light. I can handhold it but it does get tiring after a while. Of course, the 200–800 would be even worse in this regard.

MtManMD Loc: Beaverton, Oregon

That keeper rate percentage plagues all of us. I read that top pros throw out 98% or more of images. However, I can confirm that the R5 and RF 100-500mm combo will give you the tools to consistently create good images. The rest depends on the photographer.

Some wisdom's I've ingrained in my head recently:
(1) Shoot short high-speed bursts of shots to enhance chances of sharpness and action is captured in at least one of the sequence of shots.
(2) Poor light generally creates poor photos. See Jared Lloyd's articles on how to use high ISOs.

Canisdirus

I really don't know, but since the camera recognizes what is on it via contacts.
It's probably a software code that places a 'governor' on the third party lens' AF.

clint f. Loc: Priest Lake Idaho, Spokane Wa

That seems very unlikely to me but I’ve been wrong before. Wouldn’t it be counter productive to make images that are degraded on their cameras for any reason because people have a 50-50 chance of believing it is the camera. Not a great business plan. The better plan would be to have the engineers make their respective brand lenses even better.

robertjerl Loc: Corona, California

Well, I already own the R7 & RF 100-500L. They work great together but my R7 with my EF to RF mount adapter on my 150-600 also takes great images when mounted on a tripod and I do my part.

If money is a problem for you, I would be tempted to say get the R7 and an adapter for your Sigma. I am going on the assumption you want to do birds, wildlife, planes, sports etc. that call for a "Long Reach". Then start saving your pennies for the RF 100-800L.

Oh, do you own an RF body now? You mentioned R5 and R6 so I don't know if you own one of them or are just thinking about it.

What gear are you usig now?

Basil Loc: New Mexico

Money isn’t a problem per se, but I just set a limit for myself not to spend over $2,000 (additional out of pocket). Your assumption is correct that this will be mainly for birds and to a lesser extent general wild life. As I mentioned in another reply, the Sigma is good but I’m sure the keeper rate would be better with one of the RF mounts.
My current gear (for birds) is the R5 with the Sigma 150-600.

MountainDave

You already have a great camera. Why not invest in better glass? The R7 has mixed reviews regarding AF performance. It probably won't work well with your Sigma. If you watched Wegener's videos, you already know the 100-500 is a better lens overall. However, I was very impressed with the performance of the 200-800, especially for the money. I shoot a lot of small birds and rarely need more than 500mm on my R5. Long shots result in atmospheric distortion and haze, so I find them unappealing anyway. I have a 1.4X but seldom use it. The R5/100-500 combo weighs 5 lbs and I can carry it for miles comfortably. The R5/200-800 is probably around 7 lbs. I also use the 100-200 range quite a bit. The eye detect and tracking is like cheating. Almost every shot is precisely focused. It also has a short minimum focus distance and good magnification which I find very useful. The choice, it seems to me, comes down to whether you really want the extra 500-800mm with its attendant compromises. Either one is a great choice. I plan to pay attention this summer to assess how often I could use more reach and decide whether or not to add the 200-800.