Tamron CEO lefthanded ?

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smythie wrote in post #18048181
yeah, push-pull is often a lot easier for zoom

Yes, I absolutely agree with you there.

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smythie wrote in post #18048181
yeah, push-pull is often a lot easier for zoom

And unbeatable as a dust-sucking design!

Alveric wrote in post #18048977
And unbeatable as a dust-sucking design!

No less so than any other design. It doesn't really matter what method you use, the same lens elements will have to move the same distances to achive the required focal length change. Yes I do prefer a push pull action, especially on a larger sized lens. I wish Sigma had made the 150-600 push-pull. Yes I know you can grab the front and move it that way, but it's not as easy as a propper design would be.

Alan

Well, some reviewers were saying (years ago) that the EF 100-400mm L had quite an issue with dust, and it was due to the push-pull design. That's the reason I didn't consider that lens any further.

Alveric wrote in post #18048999
Well, some reviewers were saying (years ago) that the EF 100-400mm L had quite an issue with dust, and it was due to the push-pull design. That's the reason I didn't consider that lens any further.

Abraham Lincoln said not to believe everything you read on the Internet.

Alveric wrote in post #18048999
Well, some reviewers were saying (years ago) that the EF 100-400mm L had quite an issue with dust, and it was due to the push-pull design. That's the reason I didn't consider that lens any further.

If you think about it, that makes no sense. Any lens that extends must pull air in to fill the expansion volume. Since the new 100-400 II extends about as much as the old 100-400L, it stands to reason that the two lenses will probably inhale about the same amount of dust.

About the only reason I can think of for specific lenses to get a reputation for dust is if they have a design where there is a black background behind the front element, or if the vents in the lens are in the front so that dust tends to accumulate behind the front element. The EF-S 17-55 comes to mind as a perfect example.

One ironic note is that a lot of people used to slap a UV filter on the 17-55 the instant they got it out of the box to keep dust out of the lens. Of course, this would not work, but it might shift the air pumping from the front of the lens to the back. That way the lens still ingests a lot of dust, but now it also blows dust all over inside the camera mirror box so that it can settle on the sensor or viewfinder. Also the dust can settle on the rear lens elements instead of the front elements. I'm not sure which is worse.

I think the 'the dust pump' moniker was earned not because it extends, but due to something inherent to the push-pull design that probably creates an inner vacuum that sucks dust in, versus non-extending lenses like the EF 70-200 f/2.8L, for example.

Never having possessed the EF 100-400mm L, I can't say yea or nay with any degree of authority. Here's one review where the issue was mentioned –curiously, not by the reviewer himself: http://www.photozone.d​e …ff/609-canon100400f4556ff

Regardless, my initial remark was a wee bit arch –not really looking to start a debate or a lens-bashing match.

Alveric wrote in post #18049089
I think the 'the dust pump' moniker was earned not because it extends, but due to something inherent to the push-pull design

This is precisely backwards. The lens is a dust-pump because it extends. It has absolutely nothing to do with being push-pull.

Right....lenses that do not extend (like the 70-200) would be much less likely to suck in air and dust. But a 70-200 is not a 100-400. And then back on point, it has nothing to do with the push-pull design, but just that the lens extends, which is true of any zoom competitor to the 100-400. (sorry....on edit I thought of the Sigma 120-300/2.8....a lens that does not extend when zooming and which can be seen as a faster competitor to the 100-400 especially when used with a 1.4X TC). I don't tend to think of the 70-200 lenses as 100-400 competitors because they are so different in range and speed.

Never having possessed the EF 100-400mm L, I can't say yea or nay with any degree of authority. Here's one review where the issue was mentioned –curiously, not by the reviewer himself: http://www.photozone.d​e …ff/609-canon100400f4556ff

Regardless, my initial remark was a wee bit arch –not really looking to start a debate or a lens-bashing match.

I don't see this as a strong debate or lens bashing match. It's just one of those things where the conventional wisdom is kind of wrong. It is true that the 100-400L will suck in air and dust over time. But that isn't because the lens is push-pull, it is because the lens extends upon zooming. And so the 'dust pump' moniker would equally apply to all such lenses even when they are twist-zoom. So the new 100-400 II, the 24-70, 24-105, 17-55, 70-300L etc. etc. are all 'dust pumps' too.

Well said Jeffrey

The one advantage of the slide zoom is that, especially with physically large lenses like the 100-400, or 28-300L, you can move from one end of the range to the other very quickly. I guess doing so could increase the pressure differentials over a slower moving twist zoom. Of course as well as potentially increasing the possiblity of sucking in dust, as you zoom in, you are more likely to blow it back out when you zoom out again. I guess the size, weight, and cost, of the 28-300L makes it less than a stellar selling lens for Canon, but you don't seem to hear the same complaints about that lens. Maybe thats because it's mostly used by working pros, and very few "consumers".

Alan

I think they should just create two different assemblies for Canon and Nikon users, since they are changing the flange distance and the mount anyway. Zeiss does this on Milvus and Otus lenses, where the focus rings rotates the correct way for both Nikon and Canon users

frankchn wrote in post #18049343
I think they should just create two different assemblies for Canon and Nikon users, since they are changing the flange distance and the mount anyway. Zeiss does this on Milvus and Otus lenses, where the focus rings rotates the correct way for both Nikon and Canon users

and unfortunately the added cost translates to higher price for the end user purchase compared especially to the other aftermarket lens companies

Archibald wrote in post #18049001
Abraham Lincoln said not to believe everything you read on the Internet.

But then Richard Nixon pointed out that the speed at which the zooming occurred absolutely does affect how much dust is sucked, and the push-pulls tend to get zoomed a lot faster.