And I'd mostly agree with them. Except for two particular filters.
UVs and Polarisers.
A UV filter does something Photoshop would struggle to do – it physically protects the front of your lens from damage, whether it's being clonked against the corner of a brick wall, or adding an extra layer of protection if the camera gets dropped. It's much cheaper to unscrew a broken filter and replace it with a new one than it would be to have the front element of a lens replaced. It also cuts through any UV haze, making your pictures look clearer on bright sunny days, especially up mountains or near the sea where there is more UV light around. But in terms of affecting the photo results you get, there is minimal effect under most conditions.
Polarising filters also do something that Photoshop can't do. They reduce reflections on any non-metallic surfaces, thereby adding a vibrancy and an extra level of saturation to the end result as, almost magically, you get to see the true colour of an item rather than the washed out effect created by the glare of light bouncing off it.
The best known application for polarising filters is for making blue skies bluer. Think travel brochure Caribbean blue, with startling white clouds dotted around. This is achieved by removing the glare of the sun off the atmosphere. So your sky looks darker and bluer, but your clouds are unaffected, by contrast giving the impression that they're whiter than they were before. Water too can benefit massively from having the reflections on the surface reduced – suddenly you can see the bottom, and rather than a washed out grey, the water looks enticingly blue/green! And taking photos through windows – you can completely remove any reflections as long as you're standing at the correct angle to the glass.
But really, anything with a remotely shiny surface will benefit from a polariser being used. Leaves on trees, hard wood floors, paper, bowls of fruit, still lives, city scenes – they all look richer and more vibrant when a polarising filter is used.
Photoshop is amazing in many, many ways, but it would be difficult to totally impossible to replicate the effects of a polarising filter. So one of these is, in my view, an essential bit of kit to carry in your camera bag and something no self-respecting photographer should leave home without!
If you’ve got a question about UV or Polarising filters, why not post a comment in the box below and we’ll do our best to answer them for you.