filter or not

[bobfoster]

Hi all,
This is probably a stupid question but is there any reason you could not use a fixed polarising fliter and during proc essing add a graduated filter instaed of using a cricular polarising filter. The reason I ask this is becaused when my camera a canon 550d focuses the outer edge of the lens turns and I often forget to turn the filter.

regarsd bob

 

[vizzair]

A polarising filter doesn't work like a grad Im afraid. It blocks reflected light off shiny bits or the sky ( which is reflected blue light off dust" )
So you need to turn it to get the effect you like, good for taking pictures of fish in water for example.

grads you use to block out excessive light in some of the view to allow the camera to capture more range that would have overwise been "blown" out.
Like bright clouds over dark sea, if you expose for the clouds you lose range in the sea and visa versa, using a grad can even the light so you can capture more details overall.

 

[weybourne]

If by fixed polarising filter you mean a linear polarising filter (as distinct from a circular one) then you might find that your camera struggles to meter and focus correctly.

 

[bobfoster]

Thanks for that guys it was just a thought

regards bob

 

[DorsetDude]

As you are using a polariser I assume you are taking landscapes? If so, you can take your time so you just need to try and develop a routine, a part of which will be, focus on relevant area, turn focussing to manual (if not already), rotate polariser to best angle, etc etc.
Having said that its easier said than done I know. I always forget either mirror lockup or to set the ISO to 100 or to turn off multiple exposures or to put the viewfinder blind over the VF or something...

 

[bobfoster]

hey, I`m with you there always seems to be something

 

[vizzair]

especially when the light is going and you've just abandoned the car in the middle of the road to get that perfect sunset

 

[gnirtS]

A polariser effect can't be created in software - its not simply darkening an area. It reduces glare and removes light coming from certain directions so there is no substitute for using one.

A ND Grad can be replicated in post processing though so maybe that's what you're getting confused with.

Its your lens not the camera causing the front to rotate so the basic solution is to upgrade the lens (or just remember to turn the thing!).

..then again ive just taken a batch of photos at ISO3200 and a ridiculous shutter speed by forgetting to check ISO.. whoops.