R7 vs R6 vs R5 vs R3

Archibald wrote in post #19442804
So what does sealing protect you against?

I have always taken to mean superior sealing against dust and humidity compared to more entry-level equipment but not waterproof. I know this from personal experience. I have usually used Optech rain sleeves in Oregon to protect against the mild drizzle that tends to be present many months of the year. However, every once in a while, I would forget, and I have never had an instance of water entering the camera or lens in the 10-15 years that I shot in Oregon. However, I have no doubts that if the rain was heavier, water will get in. So, I would view the "sealing" claim as hindering but not preventing water and dust penetration.

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Scrumhalf wrote in post #19444444
I have always taken to mean superior sealing against dust and humidity compared to more entry-level equipment but not waterproof. I know this from personal experience. I have usually used Optech rain sleeves in Oregon to protect against the mild drizzle that tends to be present many months of the year. However, every once in a while, I would forget, and I have never had an instance of water entering the camera or lens in the 10-15 years that I shot in Oregon. However, I have no doubts that if the rain was heavier, water will get in. So, I would view the "sealing" claim as hindering but not preventing water and dust penetration.

Yes, that is how I was thinking. Based on that, I try to handle my gear with care whenever possible, regardless of build quality and claims.

Tom Reichner wrote in post #19442839
It all depends on exactly what type of weather sealing it is. In the case of the Canon 100-400mm IS v1, the weather sealing didn't protect it from much of anything in my experience.

Well, the EF 100-400 mm f/4.5-5.6L IS USM doesn't have any excessive sealing. The easiest way to see if an EF lens has a more elaborate weather sealing is to check that the rubber lip seal is present around the bayonet mount. It isn't on the EF 100-400 mm f/4.5-5.6L IS USM. Neither is it on the EF 28 mm f/2.8 IS USM, which happens to be within arm's length when I write this, but it is present on the EF 85 mm f/1.4L IS USM, standing beside it.

The EF 100-400 mm f/4.5-5.6L IS USM doesn't have it because it's from before the era when Canon upgraded their sealing ambitions, and the EF 28 mm f/2.8 IS USM doesn't have it because it's in a class of lenses that aren't comprised by said ambitions.

apersson850 wrote in post #19444725

Tom Reichner wrote in post #19442839
It all depends on exactly what type of weather sealing it is. In the case of the Canon 100-400mm IS v1, the weather sealing didn't protect it from much of anything in my experience.

Well, the EF 100-400 mm f/4.5-5.6L IS USM doesn't have any excessive sealing. The easiest way to see if an EF lens has a more elaborate weather sealing is to check that the rubber lip seal is present around the bayonet mount. It isn't on the EF 100-400 mm f/4.5-5.6L IS USM. Neither is it on the EF 28 mm f/2.8 IS USM, which happens to be within arm's length when I write this, but it is present on the EF 85 mm f/1.4L IS USM, standing beside it.

The EF 100-400 mm f/4.5-5.6L IS USM doesn't have it because it's from before the era when Canon upgraded their sealing ambitions, and the EF 28 mm f/2.8 IS USM doesn't have it because it's in a class of lenses that aren't comprised by said ambitions.

Don’t lenses need a filter also, to protect it from the elements at the front end?

I would think it difficult back in the day for canon to weather seal the 100-400 due to its push/pull functionality. It is almost like there is just some sort of felt or paper that exists for prevention of undue amounts of dust but nothing more.

I have had whatever that is inside degrade and start to fall out even.

Levina de Ruijter wrote in post #19444736
Don’t lenses need a filter also, to protect it from the elements at the front end?

In my experiences, a filter at the front is more about trying to prevent dust from getting inside the lens more than prevention of water. As the lens contracts/expands due to focusing or focal length changes, having that filter will help prevent path of least resistance from outside particles from going into the innards.

However it certainly makes sense too that if you are caught in the rain, having anything in the front of the lens (ie. a filter) that restricts air movement from that area could also help reduce water ingress. Unfortunately water has a way of finding every nook and cranny to run into, like switches, zoom ring gaps, etc, and is more destructive to lenses than just dust.

I think the first gen 100-400 is probably one of the least protected lenses based on what I saw when I started the tear down of it.

I don't get why people feel that a lens that you extend by pulling directly on it would fare worse than a lens which extends because you rotate something to extend it?

For some lenses, Canon specifically states a filter is a part of the sealing. But not for all.
Renember that a hood is a good thing against water too. What doesn't hit the front lens will not get in behind it either.

apersson850 wrote in post #19444825
I don't get why people feel that a lens that you extend by pulling directly on it would fare worse than a lens which extends because you rotate something to extend it?

For some lenses, Canon specifically states a filter is a part of the sealing. But not for all.

I've never understood how a filter with a screw thread could seal anything -- unless the filter has a seal. Do they make those? I've never seen a filter with a seal.

Also, a filter or seal can't change the amount of air passing in or out of a lens. If it did, the air pressure inside the lens would be different than outside the lens, and the differential pressure would immediately force-zoom the lens to equalize the pressure. I'm guessing the purpose of seals is to prevent ventilation when the lens is static, and to direct the air flow where particulates can be filtered out when zooming.

Archibald wrote in post #19444847
I've never understood how a filter with a screw thread could seal anything -- unless the filter has a seal. Do they make those? I've never seen a filter with a seal.

Also, a filter or seal can't change the amount of air passing in or out of a lens. If it did, the air pressure inside the lens would be different than outside the lens, and the differential pressure would immediately force-zoom the lens to equalize the pressure. I'm guessing the purpose of seals is to prevent ventilation when the lens is static, and to direct the air flow where particulates can be filtered out when zooming.

Take apart the 17-55 to clear the dust inside and you can see why. That cosmetic cover that says 17-55 f2.8 barely covers a gaping hole around the front element. So the dust has no resistance at all and would be deposited under the front element. Put a filter on and the air flow is obviously different and seems to keep dust away from the front element. Might be something similar for other lenses… seal off the front element with a filter and air flows from other points in the lens more designed to help keep things out of the interior off the lens?

I have only taken apart four or five lenses, so I don't know, just an educated guess.

apersson850 wrote in post #19444825
I don't get why people feel that a lens that you extend by pulling directly on it would fare worse than a lens which extends because you rotate something to extend it?

For some lenses, Canon specifically states a filter is a part of the sealing. But not for all.
Renember that a hood is a good thing against water too. What doesn't hit the front lens will not get in behind it either.

I feel that way because i took the 100-400 apart and it basically has a “skirt” sliding on the barrel of the lens barely protecting it from anything especially consider that baffling material deteriorates over time.

I don’t see that on geared lenses that you turn to expand or contact the lens, but hey who knows maybe it’s the same ?

If you take a lens that's geared, but still protrude when zooming, like the EF 70-300 mm f/4-5.6L IS USM, how do you expect the protruding part to be sealed there? It's a similar design task as for the push-pull zoom lenses.

Of course a screw in filter will seal better than no filter at all. It doesn't need a rubber sealing to do some good.

My 100-400 II had some dust in it which I professionally cleaned before I sold it. I could feel the air on my chin when I zoomed it in.