Canon Community

GJR1 · ‎07-22-2026

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.

SignifDigits · ‎07-23-2026

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...) (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..

>> Owns/Owned both Canon EOS mirrorless full-frame and APS-C cameras and associated RF, RF-S and EF adapted lenses - inventory tends to change on short notice. Same for flashes, tripods, bags, straps, etc.
Plus>> Canon imagePROGRAF PRO-1100 Printer. My photos are edited using no Adobe products.
>>The opinions and assistance are my own. Please don't blame Canon for any mistakes on my part.

View solution in original post

GJR1 · ‎07-24-2026

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.

View solution in original post

ebiggs1 · ‎07-22-2026

"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.

EB
EOS 1DX and many lenses.

GJR1 · ‎07-22-2026

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

March411 · ‎07-22-2026

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.

Marc
Windy City
To find common ground you must be willing to search for it.
Our interests intersect more than they diverge.

R5 Mk II ~ R6 Mk III ~ R7
Lenses: RF Trinity and others
Adobe and DxO PhotoLab Elite for post processing
Personal Gallery

ebiggs1 · ‎07-22-2026

‘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.

EB
EOS 1DX and many lenses.

GJR1 · ‎07-22-2026

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)?

March411 · ‎07-22-2026

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.

Marc
Windy City
To find common ground you must be willing to search for it.
Our interests intersect more than they diverge.

R5 Mk II ~ R6 Mk III ~ R7
Lenses: RF Trinity and others
Adobe and DxO PhotoLab Elite for post processing
Personal Gallery

March411 · ‎07-22-2026

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.

Marc
Windy City
To find common ground you must be willing to search for it.
Our interests intersect more than they diverge.

R5 Mk II ~ R6 Mk III ~ R7
Lenses: RF Trinity and others
Adobe and DxO PhotoLab Elite for post processing
Personal Gallery

deebatman316 · ‎07-22-2026

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.

-Demetrius
Bodies: EOS 5D Mark IV
Lenses: EF F/2.8 Holy Trinity
Speedlites: 420EX, 470EX-AI, 550EX & 600EX II-RT

SignifDigits · ‎07-22-2026

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.

>> Owns/Owned both Canon EOS mirrorless full-frame and APS-C cameras and associated RF, RF-S and EF adapted lenses - inventory tends to change on short notice. Same for flashes, tripods, bags, straps, etc.
Plus>> Canon imagePROGRAF PRO-1100 Printer. My photos are edited using no Adobe products.
>>The opinions and assistance are my own. Please don't blame Canon for any mistakes on my part.

Canon Community

Which 100-400 EF lens