11-09-2024 01:33 AM - edited 11-09-2024 12:06 PM
I'm looking to buy a used EF 100-400mm lens. The one I found at a local camera store is in like new condition with one exception. It has quite a few dust spots behind the front lens and on the second lens from the front. I've been told this won't effect the images, but before I invest $1600 I'd love to know what others might think. The dust spots are very small, but there are quite a few. Maybe 20 or more.
Also, any particular methods to test if they will affect the images?
Solved! Go to Solution.
11-09-2024 02:29 PM - edited 11-09-2024 02:30 PM
Dust and other artifacts (fingerprints, smudges, water spots, even scratches) on the front, rear or inside of a lens do not show up in images. They are so far from being focused-on that they are invisible. An EXTREME amount can cause loss of contrast, but it'd take a lot. You don't see them in the viewfinder, do you?
You test a lens for problems in this regard by taking picture and looking at them.
11-09-2024 09:12 PM
I bought mine (EF 100-400mm f/4.5-5.6L IS USM II) new shortly after its release in 2014. It was heavily used until about 2.5 years ago when I started using the R system and switched to RF glass. I never thought about it [dust] so I just took mine out of its case and looked at both ends and only saw a couple of small specks inside, and I had to look hard to find that.
IIRC, this was one of several L series lenses that Canon recommended using a "protector" filter on to enhance its weather/dust sealing. If the lens never had the filter, it could be why it's so dusty inside. Another possibility is that the seals inside the lens are worn.
Judging from the way mine looks inside after years of heavy use, in some pretty dusty conditions at times, I would be cautious. Without seeing it myself, it's hard to say if the amount of dust in it will effect image quality, but if indeed there is a lot of dust, it may indicate an underlying condition that is permitting dust to get by the seals.
Newton
11-09-2024 08:41 AM
KEH and MPB have a real good rating system. The gear meets or exceeds the rating displayed for items I have purchased from them and the bonus is the return/exchange policy.
And like John mentioned, that price does seem a bit excessive.
R3 ~ R5 ~ R6 Mk II ~ R50
Lenses: RF Trinity and others
Adobe and Topaz Suite for post processing
Personal Gallery
11-09-2024 08:44 AM
To be clear, this is a version II and other than the dust is in near mint condition. From my research the price isn't my concern, I'm wondering if dust in the objective end of the lens will present issues with the image.
11-09-2024 11:08 AM
Just take some test photos. It is rare not to find some dust in a lens. While the general consensus will be that it is unlikely to see an effect only you are actually seeing the lens.
11-09-2024 05:09 PM - edited 11-09-2024 05:15 PM
That many dust specs cant affect the optical performance much,if at all.If compared to a perfect lens i'd be surprised if it can be measured (see below).
However it will affect resale value so make sure the price is good! (i'm unfamiliar with prices for that model)
DPreview did a video where they tested for dust and also damage to the front element.It's shocking how much damage can be done without it showing in the images! Contrast is first thing to be affected,then resolution.
DPREVIEW damage testing
11-09-2024 09:03 AM - edited 11-09-2024 09:05 AM
Hey Husker,
Historically this lens has had challenges with dust and those who discuss it state that has not cause problems with there images. It's very widely talked about and the conclusion seems no be no impact. If you do a search on EF 100-400mm II you will see what I mean, discussions as far back as 2016.
R3 ~ R5 ~ R6 Mk II ~ R50
Lenses: RF Trinity and others
Adobe and Topaz Suite for post processing
Personal Gallery
11-09-2024 09:15 AM
Over priced. You could pay half that amount for a dusty Mark II on eBay.
11-09-2024 11:42 AM
"Over priced. You could pay half that amount for a dusty Mark II on eBay."
Absolutely, way too much money for that lens probably by double.
"Historically this lens has had challenges with dust and those who discuss it state that has not cause problems with there images."
While this is true but I doubt it is fact. I've owned two of them if we are speaking the old push-pull zoom(?) All zoom lenses, well they zoom. They move in and out it really doesn't matter if it is a rotating dial or a push-pull the movement is still there. The exception might be the internal zooms.
Excuse me if we are not talking the push-pull model. But the reports and discussions about it are simply not true, IMHO..Unless you know the history and how the lens, any lens, was used and treated, no factual bottom line can be made. It's possible to get dust inside any lens zoom or prime.
But to the OP, pass on this one unless the store comes down by a lot, a whole lot.
11-09-2024 01:08 PM - edited 11-09-2024 01:09 PM
At it again I see Ernie.
"Historically this lens has had challenges with dust and those who discuss it state that has not cause problems with there images."
"While this is true but I doubt it is fact."
Interesting, I never saw that I used the word fact in the post you quoted, seems like a bit of a misrepresentation.
R3 ~ R5 ~ R6 Mk II ~ R50
Lenses: RF Trinity and others
Adobe and Topaz Suite for post processing
Personal Gallery
11-09-2024 02:50 PM - edited 11-09-2024 02:53 PM
I believe the OP said it is a Mark II. Reports and complaints about this model being prone to collecting dust are few. It uses internal focusing and not the pump action for zooming.
So a copy that exhibits such issues is a major red flag in my book.
09/26/2024: New firmware updates are available.
EOS R5 Mark II - Version 1.0.1
EOS R6 Mark II - Version 1.5.0
07/01/2024: New firmware updates are available.
04/16/2024: New firmware updates are available.
RF100-300mm F2.8 L IS USM - Version 1.0.6
RF400mm F2.8 L IS USM - Version 1.0.6
RF600mm F4 L IS USM - Version 1.0.6
RF800mm F5.6 L IS USM - Version 1.0.4
RF1200mm F8 L IS USM - Version 1.0.4
Canon U.S.A Inc. All Rights Reserved. Reproduction in whole or part without permission is prohibited.