topic EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight? in Gear Guide

EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Tue, 22 Jul 2025 13:35:54 GMT

EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

Pairing with a R5 and R7, with all other factors aside, which is the better lens for sharpness for shooting "birds in flight" between these 3 lenses? I currently own the R5, R7 and EF100-400mm f/4.5-6.3 IS II USM.

Trying to decide if upgrading is necessary to achieve sharpness.

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

March411 — Mon, 21 Jul 2025 18:24:42 GMT

I have all three focal lengths you mention but my 100-400mm is the RF version. If you held my feet to the fire I would probably grab the RF500 f/4.5-7.1 L IS USM for birds in flight even though I give up 300mm in focal length. Personally the RF 200-800mm f/6.3-9 IS USM narrower view makes it more challenging for tracking and the zoom ring has a much longer throw making me re-grip to fully zoom to 800mm.

That being said the RF 200-800mm f/6.3-9 IS USM is a darn fine lens too and produces sharp images regardless of what body it's mounted.

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

Ceddy — Mon, 21 Jul 2025 21:26:42 GMT

I guess I should've pointed out "money being instrumental". Hahaha! I have the EF300 which I love with a 1.4tc, as my affordable prime. I was seeking out advice for a walk around bird photography option between the noted lenses. I really like the EF100-400mm but wondering if changing to an RF lens would produce better images or am I already sitting with a good lens. Thanks for the response!

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

FloridaDrafter — Mon, 21 Jul 2025 21:33:08 GMT

Hello, Ceddy!

@Ceddy wrote:

Pairing with a R5 and R7, with all other factors aside, which is the better lens for sharpness for shooting "birds in flight" between these 3 lenses? I currently own the R5, R7 and EF100-400mm f/4.5-6.3 IS II USM.

Trying to decide if upgrading is necessary to achieve sharpness.

The RF 100-500 f/5.6-7.1L IS USM is the sharpest of the bunch, then the EF 100-400mm f/4.5-5.6L IS USM II, then the RF 200-800 f/6.3-9 IS USM. The thing that sets the RF 100-500 above the EF 100-400 for sharpness is the flange distance, it's closer to the sensor so has better resolution. Add the extra 100mm's and the fact that RF is designed for the R series cameras with more contacts and faster AF response, then you get a stellar combo.

I have all three of those lenses and the R5 and R5 II. I used the EF 100-400 on my R5 and R6 when I first bought into the R system. With that first R5, I bought the RF 100mm f/2.8L IS USM Macro and quickly noticed how much better the RF lenses performed, so I bought the RF 100-500. I also have the RF 100-400 that Marc mentioned, but that is primarily on my wife's R6 II because it is so light. I've tested it on the R5 series, but that's it. She takes some really nice images of birds with that combo, but no BIF. I bought the RF 200-800 out of curiosity and although, IMO, its OK for the FL and price, it's not a lens I use that often and don't find to be a nice sharp lens. I typically use it on the R5 in well lit conditions and always have to do a bit more work in post to get the results I normally get with the 100-500.

I do own the RF 1.4X tele converter and when lighting permits, use it with the RF 100-500. This gives me 700mm and is sharper than the RF 200-800.

Newton

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

March411 — Mon, 21 Jul 2025 21:38:45 GMT

Exactly what Newton said.....😃

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

FloridaDrafter — Mon, 21 Jul 2025 22:42:10 GMT

@Ceddy wrote:

I guess I should've pointed out "money being instrumental". Hahaha! I have the EF300 which I love with a 1.4tc, as my affordable prime. I was seeking out advice for a walk around bird photography option between the noted lenses. I really like the EF100-400mm but wondering if changing to an RF lens would produce better images or am I already sitting with a good lens. Thanks for the response!

IQ is always a matter of what is acceptable to you. I am very demanding and my wife often says "You are your own worst critic". Be that as it may, I can see the advantage that RF glass brings to the table, both in post and performance. As I mentioned, there are technical reasons why RF is superior to adapted EF, given the lenses are similar to start with, say, you are comparing an RF 100L to an EF 100L or the EF 100-400L to the RF 100-500L, then the RF will be superior. Think of it this way, the RF equivalent of it's EF counterpart is the "mark XXX" of the EF version, at least that's the way I see it. For me, IQ was marginally better, but performance alone was worth the switch.

Newton

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

Ceddy — Mon, 21 Jul 2025 23:28:52 GMT

That's what I was wondering about. I have been leaning towards the RF100-500mm and this gives me a lot to go on. I appreciate the response and in-depth insight!

Re: EF100-400mm f/4.5-6.3 IS II USM vs RF 200-800mm f/6.3-9 IS USM vs Rf-500500 f/4.5-7.1 L IS USM

Ceddy — Mon, 21 Jul 2025 23:30:22 GMT

Fantastic analogy! I am going to take your advice and upgrade. I appreciate your response!!!

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

ebiggs1 — Tue, 22 Jul 2025 14:32:44 GMT

This is even a contest the Canon RF 200-800mm f/6.3-9 IS USM Lens is the choice by far.

"the RF 200-800mm f/6.3-9 IS USM narrower view makes it more challenging for tracking..."

The Canon RF 200-800mm f/6.3-9 IS USM Lens has 500mm Included in its FL so a "narrower view makes it more challenging for tracking." is a moot point.

"...a much longer throw making me re-grip ..."

Look all lenses have their pluses and minuses so each lens has to be evaluated on the total package and not a single spec or perhaps just a couple. The Canon RF 200-800mm f/6.3-9 IS USM Lens as a package is the real deal and by far the better birder lens.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

March411 — Tue, 22 Jul 2025 15:26:12 GMT

For static subjects I would very much agree, birds in flight the narrow view and having to re-grip to zoom does not make it a good choice. So it may depend on scenarios a person intends to use to each of the lenses mentioned. And I strongly agree that one size doesn't fit all, darn near every lens has some type of compromise.

Shooting all three frequently I would have to agree that FloridaDrafter nailed it, the RF100-500mm is in a class by itself when it comes to sharpness. I would add that tracking and adjusting the zoom range is far superior, at least for me with the RF100-500mm especially for fast moving subjects.

All of these shots are from the same location using the R5 with the RF 100-500mm .The second shot of the Killdeer, it would have been extremely challenging with the RF200-800mm. Because of the fast movement I was racking the zoom to fill the frame and keep the bird in the EVF. I've tried similar shoots with the long lens and my hit rate drops. For larger slow moving soaring birds it is outstanding.

I added the Black Wasp because of the sharpness, one would assume this may have been shot with a Macro.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

ebiggs1 — Wed, 23 Jul 2025 14:47:41 GMT

"...the narrow view and having to re-grip to zoom does not make it a good choice."

The "narrow view" has nothing to do with it, a moot point, since the 200-800mm has all the FL available. If a certain FL is "better" I.E. 400mm and 500mm and is what you want and need select them. However, if 600mm or 700mm or 800mm FL is what you want and/or need those lesser lenses don't have that option.

In two of the samples you offered I doubt seriously you had any trouble "re-grip to zoom". Even the BIF looks pretty simple to obtain. A good photographer will know with a good guess what FL is close for the shot also limiting the amount of "regripping" necessary.

I use the Sigma 150-600mm f/5-6.3 DG OS HSM Sports Lens which is a big heavy lens and have little difficulty using it for BIF. You can never have too much FL and there is no substitution for native FL. But if you think you can do all you want with 400mm or 500mm Canon is there ready and willing to sell you those lenses.

As to IQ all of these lenses has great IQ and the debate of how great or how much is needed will never end. Fair to say all are beyond adequate in the IQ spec.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

March411 — Wed, 23 Jul 2025 15:11:34 GMT

Appreciate your thoughts ebiggs. Having all three and using them regularly I was simply giving the OP my opinion on the each as he/she requested.

I would add that the RF 100-500 is also shorter fully extended then the RF 200-800 is fully collapsed and the RF 200-800 is a little over a pound heavier. When loading a bag the RF 100-500 an easier carry and just as nice in the field.

Also, owning the Sigma monster EF 60-600mm I understand what you are saying, I've grabbed some excellent image of BIF. It's a bit more work panning the beast but your assessment is correct. We simply have different opinions from a hands on user perspective of the three pieces of glass the OP inquired.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Thu, 24 Jul 2025 13:50:10 GMT

Fantastic shots! I appreciate the more in depth response!

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Thu, 24 Jul 2025 13:52:19 GMT

Thank you for your response. I agree, if money were no object there are VERY clear choices.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Thu, 24 Jul 2025 14:21:29 GMT

Thank you to all who replied and gave their advice off of their own experiences. I used to own the 6d mkii and paired it with the Tamron 150-600mm g2 and the EF100-400mm usm ii and got some fabulous captures. Debating about upgrading to the RF100-500mm, the Canon's reps have sworn the EF100-400mm usm ii is very comparable to the since I already own it. I am waiting for the EF100-400 to come back from Canon and will try it again to see if I notice any differences in both the response for BIF and even static shots. I will be the first to admit that I am not a fantastic photographer nor do I post process so I would go with 90% user error however apples to apples to what I have shot in the past with my Tamron 150-600mm g2 and EF100-400mm usm ii paired with the Canon 6d mkii, I notice that even my static shots are soft. Maybe my expectations are much greater using a mirrorless or maybe my camera settings could be off as well? ugh, that poses a whole new debate! Ugh....I appreciate the responses, thank you!!!

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

March411 — Thu, 24 Jul 2025 14:29:06 GMT

Ceddy,

The Tamron 150-600mm G2 is reported to be a pretty sharp lens. I don't remember, are you using the Canon EF/RF adapter?

Also have you used/tried Canons Digital Photo Professional to look at your focus points? Its a nice piece of software for reviewing images, checking focus points and culling bad images.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

ebiggs1 — Thu, 24 Jul 2025 14:38:27 GMT

My main point was the issue that the 800mm would be more difficult to track BIF because it is 800mm. The reason being that 400mm and 500mm are available so it is not a consideration. And the fact that more FL is almost always if not always a good thing made even more positive you don't have to use it if you don't want or need it. Better to have it and not need it than to need it and not have it. And again the regripping is mostly a moot point because zoom, or FL, is better judged before you try to do BIF. Not a good procedure to have it set to 200mm when you know you want or need 600mm or more FL. This should be helped by experience.

"...the RF 100-500 an easier carry and just as nice in the field."

I know I am a little short sighted on size and weight because I am a bit over 6'2" and 220 lbs so weight never concerns me. I sometimes carry the big Siggy Sport on a 1 Series and a 24-70mm on another 1 Series at the same time. However, since I am nearing 80 I don't do it as often as I used to. But I know weight is a factor to some and if weight is a major factor that person should perhaps consider a different subject for their photography or even a different hobby. Photography is what photography is and certain facts and physical attributes are what they are. Accessories like the fantastic Black Rapid shoulder strap for instance can be a big helper. I have three of them.

Look makes no difference me what lens people use if it does what they want I merely pointed out the better choice for a wildlife, BIF, lens VS lens. Any lens can be used for wildlife photography but there is always a best option and right now, today, it is the Canon RF 200-800mm f/6.3-9 IS USM Lens. A couple years ago it was one of the 150-600mm super zooms with the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 being the best of that bunch.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Thu, 24 Jul 2025 14:42:39 GMT

I have Canon adapters on both the R5 and R7. Thinking I will be dumping the EF100-400mm as I also have the EF300mm f2.8L IS II, and have tried it on both bodies. Although it's not apples to apples for lenses (telephoto vs prime) static shots should be crisp from both lenses. I was very happy with the EF100-400 with the 6d, so I'm thinking it's just not performing well with the mirrorless bodies.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

ebiggs1 — Thu, 24 Jul 2025 14:49:08 GMT

"... owning the Sigma monster EF 60-600mm ..."

I tried to like that lens but just never did and did not buy one. I just never got the whole idea behind it and think Canon was much wiser to make the short side of their super zoom 200mm. The fact is nobody buys a big heavy super zoom to use a slow 60mm not even 150mm. Super zooms are at the long side way, way more often than they are at the short side.

I suspect that would not be such a factor if the FL you are considering is one of the 100-400mm zooms. But a 100-400mm isn't a good wildlife or BIF choice either as much better options out there.

Re: EF 100-400mm vs RF200-800mm vs RF100-500mm: Best for birds in flight?

Ceddy — Thu, 24 Jul 2025 15:06:02 GMT

Canon R7 with Canon EF100-400mm f/4.5-5.6L IS II USMCanon 6d markii with Canon EF100-400mm f/4.5-5.6L IS II USM Here's a couple of "not so great" photos but for the purpose of a comparison using the same lens (Canon EF100-400mm f/4.5-5.6L IS II USM with the different bodies. The Great Grey owl was shot with the Canon R7 and the Loon with the Canon 6d mark ii. I feel the GGO should've been tack sharp as it wasn't moving at the time of the photo. I've also taken of the Great Blue Heron that was sitting less than a foot from a boardwalk that should've been tack sharp as well with the R5 and it wasn't.