Zoom lenses extend issues (Page 2): Is your premise on the fact that the cylinder you reference does not change size (length)? My lens changes overall length... If you are saying that...

Longshadow Loc: Audubon, PA, United States

Grahame wrote:

Let's make it really simple for you. br br Imagin... (show quote)

Is your premise on the fact that the cylinder you reference does not change size (length)? My lens changes overall length...
If you are saying that the lens length is constant, and the elements are moving iside (like a piston), then yes, air can move from in front of the lenses to behind the lenses that move.
If the overall length of the lens "cylinder" changes, so does the volume of air inside the lens.....
Sucks air in when extended, expels the air when contracted.

Grahame Loc: Fiji

Longshadow wrote:

Is your premise on the fact that the cylinder you reference does not change size (length)? My lens changes overall length...

If you took some time to read and understand why a comment has been made in reference to someone else's comment you would not need to ask so many questions.

Within this thread larrypage made the following comment'

larryepage wrote:

The fact is that internal zooms also draw in and exhaust air when zoomed,

Note the word "internal", and to this specific comment I made the following response.

Grahame wrote:

They can also be designed so that there is a balance between the areas so that nothing is drawn in or exhausted out, simply exchanged.

You then responded to my comment,

Longshadow wrote:

That would be interesting.
Where is the air stored?

I am not discussing your lens, any lens that extends externally on zooming but solely internal zooming lenses.

Longshadow Loc: Audubon, PA, United States

Grahame wrote:

I am not discussing your lens, any lens that extends externally on zooming but solely internal zooming lenses.

I was discussing lenses that extend........

Architect1776 Loc: In my mind

imagemeister wrote:

Lenses bigger than 70-200 suck MORE air and therefore, more contaminates ....

So fewer contaminants is ok?

Grahame Loc: Fiji

Longshadow wrote:

I was discussing lenses that extend........

In response to a comment that was very clearly to do with a lens that does not extend, really.
Seems there are those that just want to respond to someone's comment for the sake of it, taking absolutely no notice of what that person has said.

Longshadow Loc: Audubon, PA, United States

Grahame wrote:

In response to a comment that was very clearly to do with a lens that does not extend, really.
Seems there are those that just want to respond to someone's comment for the sake of it, taking absolutely no notice of what that person has said.

Shoot me................

Bill_de Loc: US

Longshadow wrote:

Shoot me................

I thought we don't "SHOOT" anymore.

Longshadow Loc: Audubon, PA, United States

Bill_de wrote:

I thought we don't "SHOOT" anymore.

Yea, bad word, bad word.
CLICK me then.

Oh, wait, I still shoot pictures.

I guess I got stuck on discussing the OP's statement.....

TonyP Loc: New Zealand

larryepage wrote:

I have both internal zoom and traditional zooms am... (show quote)

You are so right.
And as to Mr Northrup, you've been watching the same YouTube videos as I have

SuperflyTNT Loc: Manassas VA

Architect1776 wrote:

Then why all the panic over some lenses yet silence on others even though they all do the same thing as far as balance and sucking crud in?

I’ve never seen “panic”. And yes, it’s pretty common for 24-70 and 70-200 lenses to extend. It’s with longer lenses that the advantages of non-extending lenses really make a difference.

SuperflyTNT Loc: Manassas VA

imagemeister wrote:

Lenses bigger than 70-200 suck MORE air and therefore, more contaminates ....

Also are more prone to throwing the balance off.

SuperflyTNT Loc: Manassas VA

Longshadow wrote:

Is your premise on the fact that the cylinder you reference does not change size (length)? My lens changes overall length...
If you are saying that the lens length is constant, and the elements are moving iside (like a piston), then yes, air can move from in front of the lenses to behind the lenses that move.
If the overall length of the lens "cylinder" changes, so does the volume of air inside the lens.....
Sucks air in when extended, expels the air when contracted.

My Olympus 40-150 Pro and my Nikon 180-600 do not extend. Only the elements within the lens move.

User ID

Grahame wrote:

Is there no end to you drama? Peoples valid sensible concerns and awareness now become "panic" in you mind.

(Download)

User ID

SuperflyTNT wrote:

I’ve never seen “panic”. And yes, it’s pretty common for 24-70 and 70-200 lenses to extend. It’s with longer lenses that the advantages of non-extending lenses really make a difference.

Lower mass is its own reward.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Architect1776 wrote:

Why do UHH people and reviewers panc over some zoom lenses that extend when zoomed out talking about dust and moisture as a fault.
Yet the Z 24-70mm f2.8 and Sony 24-70mm f2.8 trombone in and out when zoomed with no concerns expressed here Or in reviews. Would this not change balance and allow dirt and moisture in as the lens is zoomed?

A lot depends on the design and sealing of the lens. There is more of a tendency for dust to enter on a lens that externally changes as it zooms. Think suction. The faster you do it, (move it in and out) for men not on the toilet, but out in the field, the greater the suction effect. If the lens is sealed properly, then you might be OK. But generally speaking, lenses that externally zoom, may get dust over time.
My main grip out externally zoomed lenses is the fact they cannot be used on a Gimbal type head because as you zoom you change the balance of the lens rendering the Gimbal ineffective.