Any diff bet UV guard and cir polariser filters?

[ah_fu]

hi guys

can any experts enlighten mi.....
it seems to mi the uv guard i have is useless if i have the cir polariser ......

[looteer]

cir polarizer will lower your exposure by about 2 stops.....

so there is definately a difference... so go buy a UV as well....quite cheap only so don't worry

[Barrios]

Quote: Originally posted by ah_fu hi guys can any experts enlighten mi..... it seems to mi the uv guard i have is useless if i have the cir polariser ......

UV filter, just like Skylight filter, can act as a lens protector and you can keep it on all the time but not the polarizer. You don't shoot using the polarizer at night. It's usage is limited.

[ah_fu]

so which should i use during the day time?
when i use the cir polariser... my pic is under expose....

when i use the UV guard,almost the same effect without filters.

[looteer]

Quote: so which should i use during the day time? when i use the cir polariser... my pic is under expose.... when i use the UV guard,almost the same effect without filters.

UV.....yes, for day time and night time 24/7....

underexpose..... not if you increase your exposure by 2 stops....

same effect...... yes, that's the whole idea, to protect your lens only......

A polarising filter is used to block out polarised light. This is useful for two main purposes: (a) to make the sky appear more "blue" by removing atmospheric scatter; and (b) to remove unwanted reflections by reducing specular reflections (which tend to be polarised). However, because polarising filters block out certain parts of light waves, they reduce the overall intensity of the light entering the lens, hence the 1-2 stop decrease.

Use the polariser only when you need it to achieve the above effects. As for the UV filter, you can pretty much leave it on your lens all the time as a protective element, since good UV filters will pretty much not change the light entering the lens at all.

[erwinx]

Quote: Originally posted by ah_fu so which should i use during the day time? when i use the cir polariser... my pic is under expose.... when i use the UV guard,almost the same effect without filters.

thats unusual. most cameras nowadays have ttl metering and you should need to compensate for a circular polariser

[ckiang]

Quote: Originally posted by erwinx thats unusual. most cameras nowadays have ttl metering and you should need to compensate for a circular polariser

Yeah, maybe this camera has an external, non-TTL sensor to measure the exposure. Uncommon for digital cameras. But he never said it was a digital.....

Regards
CK

[roti]

arrr........dont waste money on a polariser lens.....get a better uv or skylight filter form b+w or Rodenstock......

Quote: Originally posted by roti arrr........dont waste money on a polariser lens.....get a better uv or skylight filter form b+w or Rodenstock......

I have to disagree with that. A polarising filter is very useful for lots of outdoor photography situations, and its optical effects are virtually impossible to replicate in post-processing. At the same time, a UV filter is also useful for protective purposes (I would generally not recommend a skylight filter for this, but YMMV).

[Kit]

Quote: Originally posted by roti arrr........dont waste money on a polariser lens.....get a better uv or skylight filter form b+w or Rodenstock......

You obviously haven't used a polariser before have you?

[roti]

Quote: Originally posted by Kit You obviously haven't used a polariser before have you?

i had one which is collecting dust in my studio......hehe not very useful for my work...........

[shay]

ah!! potential disposal of polarizer...

would you care to sell it to new owner instead of gathering dust...

pray tell its 52mm... dun wanna get a stepup/down

[roti]

Quote: Originally posted by shay ah!! potential disposal of polarizer... would you care to sell it to new owner instead of gathering dust... pray tell its 52mm... dun wanna get a stepup/down

sorry to say its 72 or 67mm.......and i cant sell as well.......it belongs to my co......