Lense hood trap door thing?

[dream rider]

Hello,

My Dad's girlfriend just got a new pentax K-10....and she got a lense hood (this one http://www.bhphotovideo.com/c/product/419170-REG/Pentax_38741_PH_RBA_Lens_Hood.html )

and theres a little tab you can slide off the bottom, like a trapdoor, does anyone know what it's purpose is? thanks a lot!

Jeff

 

[JIP]

One possibility might be to make it easier to adjust a filter like a CPL.

 

[shorty6049]

one other idea, could be that, if you're talking about the k10d, it could be for water drainage, because that body is weather sealed, so in the rain you wouldnt get pooling near the lens

 

[avcabob]

I have a K100D and in the manual to either the lens or the camera, I don't remember which, it says it's for rotating filters while having the hood on like JIP said.