[6BQ5]

Is there something a filter (or similar lens accessory) can do that post processing cannot do? I understand colored filters can all be emulated in post processing so their relevance in digital photography has diminished. How about some of the others like haze, soft focus, etc?

Thanks!

[elliott]

Using a circular polarizer filter to kill reflections would be impossible to replicate in post.

[Barry Pearson]

Is there something a filter (or similar lens accessory) can do that post processing cannot do? I understand colored filters can all be emulated in post processing so their relevance in digital photography has diminished. How about some of the others like haze, soft focus, etc?

Thanks!

I carry the following around:

• Circular polarising filters (for reasons noted by elliot)
  
• Strong (9-stop) neutral density filters (to get vastly more motion blur, eg. on water, clouds, etc)
  
• Weak (2-stop) neutral density filter (for studio work, in case I can't reduce the light power enough to use the lens at about f/5.6 or f/8)
  
• Infra-red R72 (to block visible light; to experiment with)
  
• Singh-Ray Gold-Blue polariser (to experiment with; I have no idea whether this is a good idea yet!)
  
• Didymium "intensifier" (to experiment with; waiting for autumn colours)
  
• Protective filters for emergency, not default, use ("just in case")

[rbefly]

Hello Boris,
Except for a CPL and neutral density, I don't know of another filter that can't be duplicated in post; There's another factor, though. Suppose you try a soft-focus filter or a 'starburst' or a colored filter on-camera. Now, it's permanent, it's on the digital 'negative' for keeps. You might want to increase or decrease the effect, but you can't. With post-processing, not only can you try many different effects, but you can adjust the intensity or remove it completely.
One other exception might be a graduated color filter, the type that (for example) have a blue upper half, that fades to clear on the bottom half. These are used in scenics or landscapes to add color to a washed out sky, while leaving the detail below the horizon unchanged. I don't use these much myself, but I've heard other photographers say they like using it at the time of exposure, instead of adding the effect in post. YMMV.
Ron

[Nuff]

Hasselblad Softar filters are very hard to duplicate in post, they are not the usual soft focus filter. I love using my softar I for portraits, especially when direct sunlight is hiting the subject. You might be able to replicate it, but it's going to take a lot of time and it's just faster to use the filter.

[Not a Number]

In a single flash situation you can use graduated Neutral Density filters to even out the foreground and background and keep highlights from being blown-out. If highlight detail is lost there is no way to get it back in post-processing.

Maybe split-diopters which allow you to have close objects and distant objects in-focus at the same time. I suppose you could combine two images if you want to spend the time shooting to images and removing the background in one of them.

The thing is you can spend a few seconds to put a filter or two on you lens, take the photos and BAM! you are done. Or you can sit in front of your computer for many long minutes to achieve the same thing - time you could have spent taking pictures and enjoying the results.

[6BQ5]

Interesting replies! Using a filter upfront on the light coming in seemed like it could produce a more "pure" effect rather a digital filter in software trying to emulate it. But, like rbefly said, the effect is permanent. Has anyone tried doing a side by side comparison of a filter effect, physical vs. digital?

It sounds like circular polarizer filters, neutral density filters, and IR filters have very little to no imitation in post processing. I like the idea of soft focus and star burst filters.