Air coming out from viewfinder - Normal or not?

[tyts77]

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]

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?

 

[blazer_workz]

:bigeyes::think::sweat:
It's certainly not right..IMO..:sweat:

 

[JoshSiao]

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]

It's normal, especially with long zooms and a wider VF. The air in the lens has to go somewhere

 

[tyts77]

Thanks to all for the comments!

 

[Redsun]

cool!I never realise theres something like this:embrass:
muz go try

 

[advrider]

learn something new.

 

[gryphon]

wow... later eyelashes kenna suck in and stuck to sensor :sweat:

 

[Redsun]

wow... later eyelashes kenna suck in and stuck to sensor :sweat:

then you'll have a digital single lens reflex eye!!