Myth No. 5 - The Protection Filter

Established photo orthodoxy says that you should always fit a filter to every lens you own for protection. So what do I say? Piffle and poppycock, that's what.

There are perfectly good arguments both ways - and a few specious ones, too. In favour: Acts as an "invisible lens cap", prevents sticky fingers and wind-bourne debris from coming in contact with the lens. Can't (and don't) argue with that. Filters out UV (if UV or skylight filter) - helpful if there's a significant amount of UV, although generally not actually required with most lenses. Still, can't hurt. Provides impact/scratch protection. This is the one I really don't agree with - firstly, the filter is frequently some distance from the front element, and thus more prone to contact with the offending article than the lens element would be, and secondly, the ONLY incidence of lens element damage I've ever had came from a filter which shattered when I dropped the lens (on a tram at Crich Tramway Museum) and a shard of glass scratched the front element. That was over 20 years ago, and I've not had a scratched element since - and I wouldn't claim to be that careful with lenses. Easier and safer to clean a filter than a lens element. Well, it's safer, for sure, but I always found filters needed a lot more frequent cleaning and were more prone to smearing than lenses. Protects the filter ring from damage when the lens is dropped/bashed - sometimes it does, sometimes it causes more damage, but on balance it probably works, IMHO. Against: Damage - as above. I'm not claiming it's any more or less prevalent than without a filter, simply that the possibility needs to be considered. Flare. Extra glass/air surfaces increase internal reflections and thus veiling flare. In truth, with multicoated filters it's not a huge problem except when shooting contre-jour, but it's a consideration. Cost. Good filters cost quite a bit, especially if you have a few lenses. The insurance option may well be more cost-effective, and provides other benefits. Damage to filter ring - filters can damage, be cross-threaded etc. Not a huge concern, but an argument for filters in brass mounts, which tend to jam a lot less than some others. Danger of vignetting with wideangles when stacked with other filters. Reduction in resolution due to extra glass - frankly, I doubt if many, or any, users could spot any such reduction. Alternatives: - lens caps provide better protection when not shooting, less risk of damage than from a glass filter, and no optical loss when removed to take a picture. But they're more fiddly and easily lost, of course. Rigid lens hoods provide excellent protection against drop damage and make it hard (but not impossible) for anything to touch the front element. Conclusion So, am I saying you shouldn't use protection filters? No, certainly not. What I AM saying is that you should consider all the aspects and decide for yourself - not blindly follow the advice either of those who say they're essential or those who say they're more trouble than they're worth. It's not thinking through all the arguments that I think is dangerous - when you have, at least you've come to an informed decision. Personally, I rarely use them, but generally carry them - I do use them if there's salt spray, sand or dust storms etc. I use rigid hoods and lens caps all the time - and insurance.