erickter Loc: Dallas,TX

[quote=Kuzano]Sorry, but your point makes no sense. Dust does not enter the ends of a zoom lens. It enters at the joints sliding over each other in the tube of the lens. There is no entry point at the front and rear elements of the lens.

Lend me your favorite zoom, Canon, Nikon, or other and let me use it for one year at Crooked River Ranch in Central Oregon (WITHOUT REMOVING IT FROM THE CAMERA!!!).

I promise at the end of one year, I will send you a lens full of dust, courtesy one of the dustiest areas in Oregon.[/quote

The people who have push pull,s and like them are happy because dust and moisture are minimal or seldom an issue with their shooting style, care, and location. Not everyone needs or wants to shoot in Orgeon dust bowls, or rain forests. If so, plenty of options. Just get a twist zoom or prime lens, and use protective measures. One size does not need to fit all.

Push pulls - well made ones - still perform great for many photographers, including me, despite dust and fungus risk, which can be mitigated with proper care and usage in many cases. The many positive "push pull" posts here prove that point.

Twist zooms are much less prone to dust and fungus, but not completely immune. No lens is. Twist zooms minimize the sucking of air and moisture into the lens elements, and that,s good. But it is not a 100% remedy. Proper care, where you shoot, and common sense also factor in.

For those that don't want the higher dust and fungus risk, just get a twist zoom or prime, and stop winning about push pulls to those that have positive experiences with them. I,ve owned both types, on Nikons and Canons. I loved the IQ of the Canon 35-350 push pull. I hated the IQ and overall build of the early push pull Nikon 80-200, which was very old technology ( ai era).
Not long ago I bought ( and sold) a Used but much better made Nikon twist zoom 70-200, which had developed fungus prior to my buying it, unbeknown to me. I was lucky to even sell it. The Canon 35-350 L push pull zoom I bought used was much older, but had no fungus. A little dust, but marginal and no effect on final IQ. Stellar push pull lens. And, there are many stellar twist zooms from all the big Nippon camera players today.

Twist zooms are now the gold standard in zoom technology. More air tight, better AF, less dust and fungus. But a good push pull in excellent condition still works very well for many, many photographers under the right circumstances.

It,s not a black and white debate, like some here try to make it. There's a lot of gray ( and color) in between the rigid positions people feel compelled to defend for the sake of ego defense. People on this post, myself included, have had positive experiences with both push pull and twist zooms. And vise versa. That,s why there,s a thing called choice and freedom.

Mark7829 Loc: Calfornia

These are stories. Mine is personal experience. If this were as prevalent as you suggest all push pull zooms would have been scrapped long ago. My use of Canon is personal. I believe Nikon, Minolta, Pentax and others have survived. I have a 30 year old canon 80-200L that is push pull and perfectly fine.[/quote]

Okay, the way that I took your response was that, fungus and contaminates do not occur on push pull lenses because it has never happened to me. I understand the relevance of that personal comment. I don't have a problem with that unless you are implying that it is relevant for others as well for which I take issue. I am saying that due to the mechanical nature of push pulls they have a greater risk than those that zoom internally to become contaminated. If I was living and/or photographing in an area that has high humidity/moisture or dust the push pull function would have me reconsidering the use.

Imagine shooting in the mist or fog and you are zoomed out to 400 and then zoom back down to 100, anything and everything that came in contact with that lens's tube structure is now drawn into the lens itself. I know of no lens out there on a dslr that is waterproof. They are weather sealed only to be weather resistant.

RWR Loc: La Mesa, CA

Agreed. It doesn't always happen, but can happen.

davidk2020 Loc: San Diego

Perhaps I didn't think that through well enough and you are probably right. Nevertheless, I have a very nice dirt-free, fungus-free EF 100-400mm push zoom that's around ten-years old.

And no, you cannot borrow it. :-P

Mark7829 Loc: Calfornia

No one is saying that push pulls can not render a good image. That was not an issue. However the technology is prone to contaminates by its mechanical structure.

Kuzano

Well... that's OK, because next I wanted to borrow the camera? No go, I guess???

:thumbdown:

GENorkus Loc: Washington Twp, Michigan

Got the Tamron SP 70-120mm f:3.5 push pull and loved it! Had to go f:2.8 and found they didn't make a modern push/pull. Still have it and miss using it. Modern glass technology wins out.

The only hassel, if you want to call it that, is after I lost my lens cap. When trying to replace it, nothing worked.

Everything hit the built-in lens shade when I pushed it outward. So I stopped using it. Many filters would hit also.

One thing I found. Unless I was jumping around etc. I never experienced and sizeable lens creep.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

My walkabout lens is a Canon EF 28-300L zoom lens. I've had this lens for a few years and have taken thousands of photo's with it. It is a push pull zoom and it has a tension ring that eliminates creep. The AF is fast and accurate and the IS works really well. This is probably the closest there is to a one size fits all lens.

GENorkus Loc: Washington Twp, Michigan

Sorry, just re-read my post. It's a Tamron SP 70-210mm f:3.5. (Smart phone error. LoL)

amfoto1 Loc: San Jose, Calif. USA

Push/pull zooms are similar to "protection" filters...

People either love em and swear by em... or they hate em and swear at em.

Push/pull are fast-operating. A lot of airshow and birds-in-flight shooters love the original Canon EF 100-400L. (The EF100-400L Mark II is now the more typical 2-ring design, so the EF 28-300L is now the only push/pull zooms in the Canon lens line-up... Not sure how many push/pulls are currently being made by other manufacturers, but it's probably not a lot.)

Most of my experience was with the vintage, manual focus push/pull. I found those very frustrating and seemed to have a lot more focus issues with them. Haven't used modern AF push/pulls enough to really judge how I feel about them, they might be different.

I've also often heard of the concerns about dust with push/pulls. In fact, the Canon 100-400L is sometimes referred to as "The Dust Pump". Someone told me if you remove the lens from your camera, then operate the zoom rather swiftly, you can feel air being pushed out of the rear or the lens... which would be pumping it into the camera when the lens is mounted on one. Can't say if it's true or not, you'd think manufacturers could design something that didn't have such issues, a means of equalizing air pressure as the zoom/focus is operated. Not to mention that 2-ring zooms also have moving internal parts. Further, Canon prides themselves on the sealing and dust/moisture resistance of their L-series lenses (and both the push/pulls they've made in recent decades have been L-series). That sealing isn't 100%, by any means... they aren't claiming that.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

I wouldn't make the same comparison. A "protection" filter is something you install as kind of insurance and remove it when you are actually using the camera. I usually always have a "protection" filter on my lenses, especially the Canon L glass, when not in use and I take the filter off with the lens cap. I do this because I'm smart and I learned from a past experience, it's cheaper to replace a 10 to 20 dollar filter than it is to have a 1500 to 2500 dollar lens repaired. Don't see love hate here, just good old common sense. For those who chose not to use them, that's their choice.

As for the push pull zoom, as I previously stated, I have the Canon EF 28-300L push pull zoom and I use it pretty much all the time, it's a great lens for what it is, in fact I'd say it's the best lens there is for what it is. It's fairly heavy, 'cause its built like a tank, not to mention its got some serious glass in it. Its has dual mode IS that works great and the AF has a limiter to speed it up a bit. Creep is not a problem because it has a slide tension/lock ring. In fact that's my only problem with the lens, the tension ring is right up against the focus ring; you get use to it...

As far as dust, yes, there is some minor dust in the lens; it's to be expected for a lens that has been used as much as this one has, but the dust has absolutely no ill effect on lens performance or image quality.

As far as sucking and blowing air, come on, get serious, who slides the lens that far that fast that often, that it really makes a difference?! Maybe someone who's really trying to break it. It's not like you're working a bellows. It's an expensive precision device that should never be placed in the hands of someone who's interested in seeing how much air it can move.

I know nothing about the Canon EF 100-400L, I've got the 100-400L II version...