Stacking Filters

[Paul]

What precautions must one take when stacking filters? As an example, a circ-polar and a grad ND. This using a Cokin style mount.
ATB

[William W]

I guess by precautions you are referring to any degradation of the image: in which case my answers are:

. Use the minimum number of filters possible.

. Problems are usually more noticeable with WA lenses (esp. vignetting) – so the thinner the stack the better or use an over-sized mount – i.e. use a mount and filters for a medium format camera on an APS-C or 135 Format Camera .

. If you are using a Grad ND, you will likely be in situation where Lens Flare and / or Veiling Flare is likely - a large black umbrella or couple of pieces of Black Cardboard to shade the lens might be your friend – but a shade cloth set with tent spikes is best, leaving your hands free – or take an assistant.

. Implied it would likely be a landscape shot or similar - use a tripod and cable release so both hands are free to play as described above.

. Look critically through the viewfinder – even then there will be times things are missed so if you are shooting digital have a detailed look after and take another if not sure - maybe use a viewfinder magnifier.

. Cleanliness and correct and straight insertion of the filters are a given.

WW

[perth45]

I have always used a polarizer, warm- up and grey grad......so at least 2 filters on virtually EVERY shot I've ever taken...image quality was never really an issue because I used a medium format camera.....but if I decide to shoot in RAW, do I not really need the warm up and the grey grad?...I have posted a new thread, Photoshop and RAW if anyone can offer any help understanding this.....MANY THANKS.................