topic EF 100-400 L I or save longer for the mark II for wildlife? in Gear Guide

EF 100-400 L I or save longer for the mark II for wildlife?

weqinoran — Thu, 23 Apr 2026 09:01:24 GMT

I shoot on a Canon R7 and mostly do birds and larger mammals. My budget is tight but I found a used EF 100-400 L IS version one for around $800. The mark II is about double that. I know the mark II is sharper and faster to focus, but is the original still usable on a high megapixel body like the R7? I don't need perfection, just something that won't frustrate me. I also shoot handheld most of the time, so weight matters. Should I grab the version one or just wait and save for the newer lens?

Re: EF 100-400 L I or save longer for the mark II for wildlife?

kvbarkley — Thu, 23 Apr 2026 12:22:43 GMT

I would suggest a different direction, go for the Sigma or Tamron 150-600's, you get that little extra bit of reach at about the same price. They seem to take well to being adapted to RF, too.

But if it was me, and you want Canon, I would save my pennies for the RF 200-800.

Re: EF 100-400 L I or save longer for the mark II for wildlife?

jrhoffman75 — Thu, 23 Apr 2026 12:54:00 GMT

The Canon RF100-400 gets very good write-ups. lighter, less expensive.

Re: EF 100-400 L I or save longer for the mark II for wildlife?

SignifDigits — Thu, 23 Apr 2026 14:18:19 GMT

I see one in good condition for $759 on MPB right now. I've had good luck with MPB. 200-800 is over twice that used (I have it and really enjoy it), but on an R7 getting 160-640 effective range seems pretty good. Shooting birds we always want more range, though, I know. I would go with MPB or others that offer a warranty and 30-day return.

Personally, I would only buy it when I knew I would be using it heavily so that I could return it in the 14-day policy if using it with the slower AF, etc. was just too frustrating.

The Tamron Gen 1 is about $150 more, and longer range. Gen 2 is considerably more - same as with the Canon

Can't tell you how to manage your own budget but the Canon EF 100-500mm f/4.5-4.6L IS USM seems like a nice pairing for an R7 for the money. Buying used you'll only be out $200 or so when/if you decide to upgrade (you can always check your "risk" by getting a quote from MPB via mail - there are a lot of that model on the site so you might be risking as much as 50% of your price)

Re: EF 100-400 L I or save longer for the mark II for wildlife?

March411 — Thu, 23 Apr 2026 14:21:10 GMT

With you owning the R7 and saying you are looking at possibly spending $800 for the EF 100-400 L IS or double that for the Mark II. It sounds like a working budget of $800 to $1600.

Personally I would purchase RF glass and use all the benefits like burst rate that the EF may not offer. Additionally, no need for an adapter, weighs less and the IQ is comparable to the EF lenses you mention. The RF100-400mm F5.6-8 IS USM sells for $700 New. On the R7 you would acheive an effective focal range of 160 - 640mm.

A little over budget ($400) is the RF200-800mm F6.3-9 IS USM coming in at $2000 and an effective focal range of 320 - 1280mm.

Yes the EF will offer the same effective range but is bulkier, weighs more, is moving to end of life and all features may not work on the R7.

Since you are spending the money now would be a great time to transition to RF and enjoy the lighter, equally as impressive IQ an a mount that is made for your body.

Re: EF 100-400 L I or save longer for the mark II for wildlife?

SignifDigits — Thu, 23 Apr 2026 14:40:57 GMT

Good point Marc. I hadn't thought of the RF 100-400, but should have. The burst rate is a big deal IMO - I have a number of bursts where there is just the one great shot in the pile which might have been missed at a slower rate. I owned that lens at one time and a 2x converter as well. It was a bit dark for most wildlife shooting with the converter but I got some nice shots of the 2024 solar eclipse with it, and at long as it's in bright sunlight it was suprisingly good. Not as good as the 200-800 I have now, but a lot of folks have significant success with that lens.

Re: EF 100-400 L I or save longer for the mark II for wildlife?

zakslm — Thu, 23 Apr 2026 15:21:24 GMT

I use a Canon 90D that has a 32.5mp sensor similar to the R7's sensor. I don't know if this information will extrapolate to the R7, but I suspect it will.

There is a Facebook Group for the 90D that is was established by Michael the Maven. You may wish to go over this list Michael published: https://www.michaelthemaven.com/canon-90d-m6ii-lenses-which-have-enough-resolving-power-which-do-not/ listing lenses that have sufficient resolving power to completment the 32.5mp high density sensor of a 90D. The discussions I've read indicate that the 100-400L I has some resolving power issues. It's a film era design and not necessarily optimized for use with a high density digital sensor. The 100-400L II seems to be a favorite among 90D users and is highly regarded in general.

Annecdotally, I rented a 100-400 L I about a month after I got my 90D and to be honest, I was quite pleased with the results. It seemed to work well on my camera.

Here's a few of examples of shots with the 100-400 L I:

EF 100-400L I, 400mm, f6.3EF 100-400L I, 320mm, f6.3EF 100-400L I, 310mm f9

The push/pull zoom was a bit annoying but I got used to it.

Personally, the 100-400 II would be my choice because of the internal zoom, stellar reputation and overall wide acceptance and praise of the version II by 90D users.

If practical, you may wish to rent one or both of the lenses for a day or 2 to have some hands on experience before making your decision.

Hope this helps!

Re: EF 100-400 L I or save longer for the mark II for wildlife?

March411 — Thu, 23 Apr 2026 18:37:28 GMT

Great frames LZ, I had a pet Prairie Dog that fat. You cough she barked.

Re: EF 100-400 L I or save longer for the mark II for wildlife?

TomRamsey — Sat, 25 Apr 2026 00:06:41 GMT

Personally, I would go for the RF over the E and adapter. But go for the best solution that you can afford. If you are going to save up for a lens, save for the RF200-800 or 100-500. I love my RF200-800 and R6ii combo, didn't save for it but got free credit and paid for it in 1 year, well worth it.