Air coming out from viewfinder - Normal or not?


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tyts77

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Jul 27, 2007
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#1
I have a 70-300 zoom lens and whenever i zoom in/out, i feel a gush of air coming out from the viewfinder...is this normal or something wrong with my lens or cam? :dunno:

Thanks!
 

Lolrence

New Member
Oct 15, 2006
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#2
It's the first time I hear of air coming out from the viewfinder.. something doesn't sound right :nono: Are you sure it's not from 'around the viewfinder' instead?
 

#4
This is normal. Some lenses when zooming, suck in and push out quite alot of air. This is especially evident for lenses that extend its length by alot when zoomed. When you zoom out, the air goes in. When you zoom back in, the air has got to go somewhere and it does go through the viewfinder especially for some cameras where the penta prism is not completely sealed.

Ken Rockwell calls it eye blow. An example is here: http://www.kenrockwell.com/canon/lenses/70-300mm-is.htm#perf . Click on eyeblow.

The only problem with this is that it can be irritating if you've sensititive eyes, and it also means dust will get sucked in and blown into the VF more frequently.
 

ykia

Senior Member
Apr 23, 2005
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PunggolJetty.Com
#5
It's normal, especially with long zooms and a wider VF. The air in the lens has to go somewhere :)
 

tyts77

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Jul 27, 2007
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#6
Thanks to all for the comments! :D
 

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