Which stacked filters for ultra WA lens?

I would like to use a ND filter + circular polarizer stacked on a Tamron 11-

18mm. What would work without vignetting?<div></div>

What's your camera?

You'll pretty much have to go to a holder setup like the Lee or Cokin P holders. Screw-in filters stacked are guaranteed to vignette (Since one has to be a full size filter). The other advantage to the holders is ND grads become viable.

 

Note Singh-Ray makes filters for Cokin P holders, so you aren't stuck with the generally low-quality Cokin Density filters (They aren't Neutral)

Check out the Colkin X-Pro series. The grad NDs are larger thus the vignetting is less eveident.

Polarizing an extreme WA gets you ugly, blotchy skies. And stacking guarantees heavy

vignetting.

 

Have fun!

If you are using digital and have Photoshop CS2, you can take several exposures and merge them using the HDR feature (high-dynamic range)

Another option is to get a filter size adapter and buy larger filters for the camera, the major drawback here is that you probably won't be able to use the hood with the lens.

Use a Lee filter holder and put the CR polarizer under the 4x6 GND on the Lee mount, thats what I use on my 17-40.

Just read W. Smith's reply - he is correct - I get one nice dark circular spot in the middle of the sky - not nice.

 

I should have kept my non-circular polarizer and adjusted the exposure with the histogram (circular polarizers apparently don't affect the metering, or so I've heard).

Don't do it. There's really little reason.

 

If you must, use a regular thin mount circular polarizer with an external 4" x 4" square filter in front of it (ND or grad ND).

 

Two screw in filters will vignette.

Possibly nothing at 11mm.

 

You can try an Hoya Pro 1 slim filter which has front threads and a 105mm wide filter in a wide angle holder.

 

Better yet, if the camera is tripod mounted, you can physically hold a square ND or rectangle GND against the front of an ultrathin polarizer.

 

As W. Smith notes using a polarizer can result in uneven polarization skies.

"If you are using digital and have Photoshop CS2, you can take several exposures and merge them using the HDR feature (high-dynamic range)"

 

You could but HDR tends to give unnatural results.

 

Often if it is just an issue of balancing the sky and land it is enough to just two bracketed exposures and layer mask them. In fact, shooting RAW you can often do two conversions of the same file to get good enough results.

 

If there are moving elements across both luminance zones however, ND grads are still needed.