SteveR Loc: Michigan

That does answer my question....at least for this lens.

CanonTom Loc: Birmingham

imagemeister Loc: mid east Florida

Then I guess I cannot help you ....

SteveR Loc: Michigan

If other lenses didn't have these problems, though, would it matter how many shots they had taken as long as the mechanical aspects of the lens were still working? When purchasing used prime lenses, for instance, we seem to be more interested in the exterior condition and appearance and that the lenses are not scratched.

Architect1776 Loc: In my mind

Many lenses suck debris. Just the nature of many unsealed lenses like the Canon 100-400 MI.The MII is sealed and dust is not such a problem at all, in my years of using mine around the country including dusty desert locations.
See conclusion remarks on this pair of lenses.
https://www.kruger-2-kalahari.com/nikon-80-400mm-review.html

the f/stops here Loc: New Mexico

Marycar, it depends on what you like to photograph and your budget. I have found the version I push pull is no more susceptible to dust that the mark II. The original is an excellent lens but the mark II has one advantage that makes it my "go to" lens. It focuses very close even at 400mm. I can photograph butterflies or dragonflies and get so close that I'm beyond getting the entire subject in the image ... all without extension tubes or dioter lenses. That means I haven't used my 100mm Macro lens since I started using the 100-400mm mark II.
When not photographing insects or flowers, I capture images of birds. I use the mark II with and without the 1.4X extender mark III with good success and therefore have a smile on my face. The first version was excellent but I never used used it with an extender as I had a 500 f/4.
The Tamron 100-400 is excellent but like the Canon version I will not get you in close without extension tubes or diopter lenses.
Hope this helps you have fun.

imagemeister Loc: mid east Florida

It is all about moving parts wearing out. Zoom lenses have many more moving parts than a prime lens ! Prime lenses still have the diaphram and the focusing parts that are most likely to wear out.

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amfoto1 Loc: San Jose, Calif. USA

I appreciate that. I think there was some reluctance to make the switch early on... but it sounds as if the II has won a lot of converts.

It's also pretty fast zooming... I'd guess it's around 1/4 to 1/3 turn of the ring to go from 100 to 400mm.

Incidentally, I've personally never been a fan of push/pull zooms. But a lot of other people are. Seems like folks either love em or hate.

marycar53 Loc: Tuscumbia Al

I'm using the 100-400 L IS v1 with the 1.4X vII extender. I use it on both my 7D MII and 5DMIV camera.
Until recently, I was getting good shots. I thought I had a lens issue due to the age of it, but was a slowly developing focusing issue at the 400mm end with out of focus and in focus in the same shot on the 5D. I'm attaching a shot I took Saturday with the 7DMII and convertor. I wasn't using a tripod.

marycar53 Loc: Tuscumbia Al

I do mostly birding with it. It's been serviced and ring replaced about a year & half ago. I have problems with turning it and accidentally locking it to a setting and then have to unlock it trying to get a closer shot, and by that time, the bird is past the best spot for shooting. I find that irritating with the lens.

rob s Loc: La Mesa, CA

Most definitely not an 'old wives tale'. I turned down a trade with an owner of one of the Mk 1 s who told me while we were discussing the lens of his need to have this professionally cleaned every year. I live in San Diego County which is hot dry and dusty in the summer and had no reason to doubt him since he was trying to get rid of it and giving full disclosure. I now own the EF 100 - 400 L Mkii, (which I'm planning to sell if anyone is interested), and all comments as to it's excellence and very good performance with an extender are spot on. One of Canon's best lenses to date.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

First, I was not knocking the Sigma lens at all. I own a few Sigma lenses, both Sport and Contemporary series and the Sport series have slightly better optics and are built much tougher than the Contemporary series. I have both Sport and Contemporary versions of the Sigma 150-600, one with Canon mount and the Contemporary is Nikon mount. I often carry my D500 with the Sigma lens in the trunk of my motorcycle and it has held up just fine.

Since I already own a Canon EF 100-400L II, I doubt I will ever own the Sigma 100-400. That doesn't mean I don't believe the Sigma is a good lens, it is a good lens, it's simply not in the same class as the Canon. There's a whole lot more to a lens than just optics and there is nothing bad at all about the Sigma's optics. But, take into consideration the overall build quality, both external and internal, environmental sealing and durability and the Canon is simply a better lens. It doesn't cost what it costs simply because it displays the Canon name. It costs more because of how it is made.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

The EF 28-300L is a great lens but they do have an internal design flaw than may rear its ugly little head depending on age and amount of usage. There is a ribbon cable that wears out with age and usage that will totally cripple the lens.
A little background; I bought my EF 28-300L used, from an art school in Canada. I paid $1500 USD for it several years ago and it was both clean and worked fine. As this is my favorite utility lens, it gets used quite often. The first symptom I noticed that something was not right was when the lens would no longer zoom all the way in to 28mm. A while later, soon after I began using it on my new 5D mk IV, I began getting error codes. Resetting the camera cleared the error and the lens worked ok until the next time it errored. I actually wondered if there was a compatibility issue with the new body and older lens, which of course is not the case. The errors were very intermittent, some times several times a day and sometimes nothing for several days or weeks. One day I was shooting one of my daughters college graduation and the lens suffered terminal failure. Bummer... I took it to my lens repair guy who disassembled the lens. He told me he could fix it but it would be less expensive if I sent it to Canon repair in New Jersey. The lens was reassembled and I sent it to Canon. Before they would diagnose the problem I paid them around $330 USD. The next day I received an email from Canon repair explaining what all was wrong and what it will cost to repair. That was on a Thursday. I paid the additional amount, around another $325 USD. I received another email from Canon repair the next day, the repairs were completed and the lens was being shipped back via UPS, Should receive it the following Monday.
The lens looked and worked like new. The main problem was the ribbon cable failure which caused other internal parts to fail. All worn out parts were replaced, the lens was cleaned inside and out and it was back to like new and works perfectly.
It again resumed the role of my favorite lens.
Being a push pull zoom is irrelevant to me. I have both twist and push pulls and I have no problem using either. A lot of people call them dust pumpers but I've never had that problem with any of my Canon push pull zoom lenses. Maybe those that do need to learn how to better treat and operate these lenses.
Anyway, that's my EF 28-300L lens story. I like that focal range so much I bought the Nikkor 28-300 for my Nikon bodies. It's not in the same league as the Canon but it's a nice lens none the less.

anotherview Loc: California

You have to go with your experience and your technical understanding. I do the same. In the process, I've found the Sigma 100-400mm lens to produce superb images. Being a fair-weather photographer, I do not miss weather seals in this lens. I look for capability and performance. That's about the size of it.

Fotoserj Loc: St calixte Qc Ca

Why don’t you simply rent the new version, take the same picture with each lens and do your own evaluation, lot cheaper than buying an deciding that the original suit you better.