topic Re: Which 100-400 EF lens in Gear Guide

Which 100-400 EF lens

GJR1 — Wed, 22 Jul 2026 13:25:52 GMT

I have an EOS Rebel SL1 and would like to get a Canon 100-400 lens. I'm confused as to which version to purchase as I believe there have been some changes in the lens over the years. What lens should I be looking for to ensure that all features work as they should? Thank you very much for help.

Re: Which 100-400 EF lens

ebiggs1 — Wed, 22 Jul 2026 14:56:18 GMT

"What lens should I be looking for to ensure that all features work as they should?"

Any of the EF 100-400mm zooms will function and "all features work as they should."

The problem is with IQ. The original suffered with IQ compared to the latest EF version.

Re: Which 100-400 EF lens

GJR1 — Wed, 22 Jul 2026 15:16:15 GMT

Could you please explain this in greater detail (IQ?) How much of a difference would it make and if I was to look for the latest version, what is the "model number"? Thanks

Re: Which 100-400 EF lens

March411 — Wed, 22 Jul 2026 15:45:29 GMT

The original was a decent lens but many including myself believe that the EF 100-400mm f/4.5-5.6L IS II USM was superior. It uses a better motor for it's AF (USM vs Nano on the original) with an improved zoom design. While subjective the IQ was said to be far superior to the original release.

That being said the original can be picked up used and excellent condition for around $1000 while II USM goes for twice the price. If the funds are available, buy once and be happy and go with the II.

Re: Which 100-400 EF lens

ebiggs1 — Wed, 22 Jul 2026 16:46:14 GMT

‘If the funds are available, buy once and be happy and go with the II.”

My recommendation too. IMHO, I had both and didn’t like either. If I wanted a 400mm I muchly prefer the ef 400mm f5.6 prime. 400mm is what I consider minimum for wildlife which is what I wanted it for. So the 100-400mm zoom didn’t offer me much.

BTW, the 400mm f5.6 prime is a fantastic lens. It is very light and great IQ.

Re: Which 100-400 EF lens

GJR1 — Wed, 22 Jul 2026 17:12:37 GMT

You have given me something to think about that I had not considered. I have the 300 zoom and want to go bigger for my wildlife photos. Has the EF 400mm prime changed over the years and, if so, is there a particular version that works best (with my SL1)?

Re: Which 100-400 EF lens

March411 — Wed, 22 Jul 2026 17:35:00 GMT

And if you really want to think out of the box, save some money and extend your reach don't hesitate to look at something like the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 for Canon EF. You will give up a stop but it is always a decent lens as well as the sigma in the same range.

Re: Which 100-400 EF lens

March411 — Wed, 22 Jul 2026 18:16:44 GMT

I'm going to make a correction here based on a friend and associate deebatman316 helping me in my confusion.

Both EF versions used Ring Type USM. My apologies for posting incorrect information.

Thanks Demetrius for catching this and giving me a heads up.

Re: Which 100-400 EF lens

deebatman316 — Wed, 22 Jul 2026 18:33:30 GMT

Thanks @March411 for mentioning me. To the @GJR1 your camera is only COMPATIBLE with EF lenses. So ensure the lens you do purchase has an EF Mount. NOT RF Mount or any other lens Mount on the market. Those lenses are NOT COMPATIBLE with your camera. If 3rd Party make sure it’s for the EF Mount.

Re: Which 100-400 EF lens

SignifDigits — Wed, 22 Jul 2026 18:48:46 GMT

I think "none of the above" is the correct answer. The SL1 is a 13 year old APS-C camera that had a 2024 end of life that we're talking about putting a $1,000-$2,000 lens on it.

I'd recommend taking your money and getting an RF 100-400 f/5.6-8 IS USM and an R100 - new for about $1,100. Less for refurbished and/or used and less what you can get for selling the SL1. With that money you can buy an RF to EF adapter and use any old EF lenses that you might have.

The R100 has similar controls to the SL1. If you can afford it, upgrade to the R50 body.

Re: Which 100-400 EF lens

shadowsports — Wed, 22 Jul 2026 20:44:46 GMT

@GJR1

I like @SignifDigits recommendation best.

R50 + RF100-400

Also grab an EOS R to EF if the other lenses you own are not ancient. Forget the R100. No articulating LCD, No touch screen and limited ISO in comparison to the R50 which the R50 has + better low light performance. The features are worth the $250 price difference. If you buy these items refurb you'll save a bundle and get a lot more (modern) and higher performing bang for your buck.

Re: Which 100-400 EF lens

ebiggs1 — Thu, 23 Jul 2026 14:12:31 GMT

"I have an EOS Rebel SL1 ..."

I am never a person that says don't buy a new camera but if the SL1 is working as it should and you have no desire to get a new body get the lens instead. Lenses are where it's at not the camera. Good lenses always, always, trumps a good camera. Actually in order of preference a good post editor is first, a good lens is second and a good camera is third.

Re: Which 100-400 EF lens

ebiggs1 — Thu, 23 Jul 2026 14:16:37 GMT

"...look at something like the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 for Canon EF."

Excellent idea and avice. You say you have a 300mm lens so going to a 400mm isn't going to be a huge gain. Going to 600mm is a huge gain. It is going to be a bigger and heavier lens but a big tele is going to be ... well... big.

Re: Which 100-400 EF lens

ebiggs1 — Thu, 23 Jul 2026 14:21:26 GMT

"I'd recommend taking your money and getting an RF 100-400 f/5.6-8 IS USM and an R100"

Here's the deal, any and all your EF lenses will go right along with you if you decide you want that new R100 or R50 later on. So, buying EF lenses and using them now on the SL1 is a no brainer especially if money is an issue. That's another reason why lenses are where it at, not the camera.

Re: Which 100-400 EF lens

SignifDigits — Thu, 23 Jul 2026 20:33:28 GMT

I agree it is a no-brainer to choose the newer RF setup. Certainly lenses are where it's at. But consider :

Lens tech of 2014 (EF) vs 2021 (RF) gives the nod to RF.
IQ is at best a toss-up, and probably goes to the RF lens as APS-C only uses the center of full-frame lenses (and RF lens actually looks better to my eyes at https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=1572&Camera=1508&Sample=0&FLI=0&API=0&LensComp=972&CameraComp=0&FLIComp=0&APIComp=0) (and as you have pointed out before out any IQ concerns can likely be solved in SW in post)
EF lens support period will undoubtedly end before RF
L lens is weather - sealed, but for years nobody cared and only a few people really do today, but that nod goes to the EF
Build quality goes slightly to the EF L lens, but doubt the OP is a full-time pro tossing lenses around in a case shooting an SL1. Canon makes extremely good lightweight lenses
5.5 stops of IS (RF) vs 4 (EF)

So the RF lens is better, at least for APS-C and anyone on any sort of budget when ROI is a concern.

So unless one is working to satisfy some white lens status or envy, and really wants to just take great pictures (samples of this for the RF 100-400 abound on this site), going RF and spend the $$ on a new camera is a no-brainer, because doing so you get:

New camera warranty and support - SLI is beyond EOL with no support by Canon
At least 650 AF points instead of 31 and 9 zones on the SL1, and an AF system developed (All of the lens IQ in the world won't fix bad focus)
4 FPS on the SL1 vs 6.5 on the R100 and 15 on the R50

I'm not saying the EF 100-400 isn't great glass, but plunking done one's hard-earned cash on good glass to use on a camera that is more likely to croak due to age and is out of support seems like a bad ROI decision.

So I agree, for the same $$ the spent on a new RF system the decision is a no-brainer.

We've at least let the OP know they have different choices to think about and factors to consider..

Re: Which 100-400 EF lens

GJR1 — Fri, 24 Jul 2026 14:51:40 GMT

I want to thank the Canon community for their range of responses. Since funds are tight and my, so far, relatively light usage of the SL! (which works fine for me) I'm going to pursue a 100-400 lens. Although a camera upgrade may occur in the future, I think at this time it's best to put some money into a bigger lens to enhance my interest in wildlife/bird photos and then maybe a newer camera body later on.

Re: Which 100-400 EF lens

ebiggs1 — Fri, 24 Jul 2026 14:57:39 GMT

"EF lens support period will undoubtedly end before RF"

It seems so many people seem to think EF or EF-s lenses will self destruct when Canon support ends. That's not true. They will continue to work as they have for years, decades to come. And, if budget is an issue it is the least expensive to get great lenses. Plus those lenses will still operate admirably on a new R series camera if that is the next chapter in the OP's life.

Look I am not saying never go R series I am only saying buy the lens use it, learn it, gain experience and then decide if a new camera is the solution. The OP does not know what he/sh needs that is why the query which is a good way to start. Suggesting you need to start from scratch because what you have is going to "croak" soon is nonsense.

Re: Which 100-400 EF lens

ebiggs1 — Fri, 24 Jul 2026 15:11:45 GMT

" I'm going to pursue a 100-400 lens."

Although I wouldn't buy that lens you made the right decision. Going slowly not just because of budget is almost always the best course. Jumping in the deep end before you can swim type thing is always going to be the wrong path. That new camera will always be there and your new lens will be right there too.

Now make some great photos.

Re: Which 100-400 EF lens

SignifDigits — Fri, 24 Jul 2026 15:26:50 GMT

I agree @ebiggs1 - the OP was right in going slowly. I didn't want to suggest old gear is going to "croak" or "self-destruct" today or tomorrow, but new is more likely to outlast old (unless it's Stanley tools made in the US). I love old gear (often too much), but if they were going to drop up to $2k I just didn't see wisdom in putting that into the EF line. The EF line and gear will, I have not doubt, outlast me. I drove my cars over 200,000 miles long before it was more common to do so and only buy used cars, so used and old stuff is right up my alley.

But the EF line support will dry up before the RF line. That's just a fact. But I do NOT mean to say anything negative for those that live the rest of their photographic lives in the EF line. If you love it, don't leave it! It's a bargain hunters dream!