Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Olympus Micro Four Thirds

Reply
 
Thread Tools Search this Thread
Old Jul 31, 2011, 1:43 PM   #1
Senior Member
 
Join Date: Sep 2010
Location: oakville, on
Posts: 491
Default Zooms -- a mechanical question

Just purchased the 40-150 M. Zuiko. Was playing with the lens prior to mounting it on my pl1. Noticed a "woosh" of air as it zoomed from long to wide. Coming from the mount end. Having only used primes in the past, never thought about this.

If the lens doubles the interior volume as it increases in length, then either air must be allowed to enter or they have to build it very strong to take into account interior pressure changes. And if air is designed to get in, then so will dust etc. Then gets released through the mount end -- guessing through the zoom barrel ring. I realize a small amount of dust in the interior should not drastically alter the image quality. But I can now understand the benefit of going to the "high grade" lenses.
KulaCube is offline   Reply With Quote
Sponsored Links
Old Jul 31, 2011, 4:29 PM   #2
Senior Member
 
Join Date: Jan 2011
Location: Australia, New South Wales central coast
Posts: 2,891
Default

G'day KC

Your observations are 100% spot on - and "not to worry, she'll be right mate"
Every mechanical item needs some {microscopic} slack space so that movement can take place (think of your tripod legs sliding inside one another), and a camera lens is no different

Some very expensive pro-quality lenses are 'enviro-sealed' and they are dust proof & water proof, and that brings its own issues. However, our consumer level 'day-to-day' lenses will, over time [5-10 years] allow some very tiny dust elements into the lens

Is it a worry & all that ??? .... Not in my opinion

I have used 2nd-hand lenses after 10yrs of someone else's use, inside the lens barrel, looking at the front-inside glass elements I can see 10-20 tiny dust spots, and photographically I cannot see any issues with image quality

"Maybe" if I was a pro-'tog and producing material of 1,5metre x 3metre sizes, it would be an issue, but for 4" x 6" to 12" x 18" .... not something to worry over

Hope this helps
Regards, Phil
__________________
Has Fuji & Lumix superzoom cameras and loves their amazing capabilities
Spends 8-9 months each year travelling Australia
Recent images at http://www.flickr.com/photos/ozzie_traveller/sets/
Ozzie_Traveller is offline   Reply With Quote
Old Aug 2, 2011, 5:16 PM   #3
Senior Member
 
Join Date: Sep 2010
Location: oakville, on
Posts: 491
Default

Thanks Phil
T'was more of an observation than a worry. It caught me by surprise when I first felt the whoosh. So I will keep the beasty sheltered from dusty environments (like our backyard with the construction going on behind our fence) and have fun exploring the abilities and options this lens offers
KulaCube is offline   Reply With Quote
Old Aug 2, 2011, 5:44 PM   #4
Senior Member
 
JeannieBug's Avatar
 
Join Date: Jul 2011
Location: Oregon, USA
Posts: 650
Default

If only I could keep mine out of dusty environments!
JeannieBug is offline   Reply With Quote
Old Aug 3, 2011, 4:36 PM   #5
Senior Member
 
Join Date: Jan 2011
Location: Australia, New South Wales central coast
Posts: 2,891
Default

G'day KC

Dunno what it's like up your way, but down here in the Oz outback we have a condition known as "bull-dust" ... a fine powdery dust just like talcum powder. As one travels thru the outback, it gets into everything - doors, windows, air vents in the vehicle etc etc. Run your hand over a table surface, you can feel it but it's too small to see till you look at your hand

It also gets into precision equipment [cameras & lenses in our case] and makes life difficult too, shortening the life of lots of things with moving parts

Regards, Phil
__________________
Has Fuji & Lumix superzoom cameras and loves their amazing capabilities
Spends 8-9 months each year travelling Australia
Recent images at http://www.flickr.com/photos/ozzie_traveller/sets/
Ozzie_Traveller is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 12:02 PM.