TIP: Fader ND Filter = Polarising Filter (for £8.95)

[Jacek]

Just want to show you my solution to use faderND filter as polarising filter at the same time (cost: £8.95).

It is very simple, but surprisingly hard to find such informations in the net.

 

If you have faderND filter, it is (always?) made from 2 polarising filters. Like mine:

When you use it, the problem is, that you rotate front polarizer and stop it on random angle, so you have no control over which polarization you accept (most importantly - which polarisation you completely cut off). So it is not only useless as Polariser, but sometimes it can cut off the reflections which shouldn't be cut.

 

The solution is simple - buy a rotating spacer ring like mine (here put on a 43-52 step up ring for 52mm FaderND):

I bought mine here (they have really cheap Europe shipping) - http://srb-photographic.co.uk/rotating-spacer-rings-1126-c.asp

If you use step-up ring - put the spacer ring after step-up ring (if you put it before, you can introduce a lot of vignetting).

 

How to use it?:

Screw Rotating spacer ring and than your FaderND. When you set up all parameters, first rotate FaderND to proper ND level (you have to hold spacer ring not to rotate, because it is rotating much lighter (in my case)), and then rotate whole filter with your new spacer ring to adjust first polarizer angle (spacer ring rotates really light, so it is impossible [in my case] to change ND level by accident).

To make it even simpler, I made a test (LCD monitor is polarised so it is very helpfull) and marked a vertical and horizontal position of front polarizer with lacquer dot (if it's on top, I know that it's close to vertical/horizontal polarization):

It is really very fast and simple to use. Don't throw your money on additional polarizer (and don't add additional glass in front of your expensive lens) you have it already, but you wasn't using it.

 

NOTE: Spacer ring adds some space before filter, so can make some vignetting if the filter is not big enough for your focal length.

[Cinegain]

But cool share nontheless! We should fill a whole thread/section with tips like that.

[tellure]

Awesome idea!  I'd never heard of it before, thanks for posting.

A couple probably stupid questions (I'm pretty inexperienced with polarizers): what kind of test pattern do you use on your monitor to create the vertical / horizontal position, and what situations do you want to use the vertical or horizontal setting?

[Jacek]

13 hours ago, tellure said:

what kind of test pattern do you use on your monitor to create the vertical / horizontal position

Point the camera on white lcd screen (like Eoshd forum :)) and rotate polarizer to see black screen on camera (deepest black in the middle of the screen). It's good to confirm polarization on some reflective surface, couse I'm not sure if all lcd screens are polarized vertically/horizontally. So you have first red dot. Second will be just 90° from first one (or you can rotate screen or camera 90° and again find black screen).

13 hours ago, tellure said:

 and what situations do you want to use the vertical or horizontal setting?

vertical or horizontal (not sure which is which) are your starting points to clean water reflections (see through), hide wet/polished horizontal surfaces reflections or the same for vertical surfaces - like hide/show somebodys reflection in windows..

Any reflective horizontal/vertical surface (walls, floors, water, buildings..) will generate in most situations vertically or horizontally polarized light, so these are most used filter polarizer positions to hide or let through these reflections.