reverseosmosis中文

Reverse osmosis (RO) is a process where water and contaminants are separated by passage through a thin semipermeable membrane. The membrane creates a barrier between water molecules and chemical or microbial contaminants as high-pressure forces water through the membrane, leaving contaminants behind. RO systems can remove most organics, metals and nitrate but are often used in succession with activated carbon and UV light for increased efficiency and for removal of inorganic compounds. This multibarrier approach eliminates a wide variety of contaminants that no single system can fully address.

reverse osmosiswater中文

John got this one.  I have seen numerous mis-matched held help meters and cameras.  It is always better to meter light at the subject instead of at the camera.  Are you holding each at the same place?  A hand held light meter does not go through the lens for one reason.

However, I did come across this Canon Learning Center video that pointed out some interesting features of the 7D Mk II's built in metering. The dual spot metering feature was especially interesting to me.

Does the camera expose correctly in reflected mode i.e. the in-camera meter? Does the hand held give appropriate results with a different camera?