I saw the 7345th post on a forum about whether the user should buy filters or not to protect their lenses from accidental damage.

There are advocates for filters and there are people who say its a waste of money. This is my take on the matter.

First off, there are four things to think about:

1. The real cost of filters
2. How often the damage occurs
3. How often a filter will save your camera
4. How much of a difference minor damage makes to your lens

The real cost of filters

The first thing to think about is the real cost of filters. This cost comes in two forms:

1. The image quality or
2. Your wallet

You don’t get to have both. Cheap filters impact your image quality. Expensive filters cost money.

Yes, you can get filters which are reasonable quality but most of those sit in the $50 camp. If you’re going to put a medium quality filter in front of a decent quality lens like a G Master or Canon L series lens, the question you have to ask is why you bothered getting them?

Conversely if you picked up a cheap lens, it’s probably not worth putting a filter on it at all.

If you multiply that by the number of lenses you have and the costs start to add up. I have about 10 lenses so my costs are somewhere between $500-$1000 depending on the filters I get.

Great, that’s cheaper than replacing a lens? Well, maybe not. Let’s move onto the next topic.

How often does damage occur?

I have only damaged one lens in the last 10 years. My Nikon D700 was on the table with my 2 year old daughter saw the strap hanging down and pulled it down. It was an expensive lens, the Nikon 24-70 f/2.8.

I would hazard a guess is about average for most photographers unless you’re really unlucky or clumsy.

So while a filter may be cheaper than replacing a lens, depending on how many lenses you have and how often it occurs, it’s starting to look a little sketchy from a return on investment perspective.

How much will a filter save your lens?

I would hazard a guess that the average filter protects your lens about as much as a hood.

What I am saying is the assumption a filter will save your lens is based on:

1. Low impact damage that only does light damage. A lens is still likely to be damaged if it hits filter downwards if the impact is high enough.
2. Damage where the camera/lens happens to land front down. If the lens lands on it’s side and the barrel is damaged, the filter won’t help.

Those are quite specific scenarios. The damage I’ve seen occur is often tripod drops, cameras/lenses dropped out of bags that weren’t closed properly, lenses rolling off tables, cameras/lenses getting water damaged.

Almost all of the above scenarios are unlikely to have been saved by a filter. Even the damage is light enough to only damage the filter, chances are it would be low enough be a sub $500 damage.

If it’s over $500 worth of damage, it’s not in the range that your filter would have saved.

So now, based on the above 3, we’re saying that a filter may only save your lens in about 1 in 5 falls, which reduces the ROI even further.

How much of a difference minor damage makes to your lens?

I’m not going to bother repeating what others have already done before. Petapixel created a nice article that covers this in details but the impact of the odd scratch is surprisingly low.

What this highlights is that even when a filter would have saved your lens from damage, if it’s only scratches (which would have been prevented by a hood), it doesn’t make that much of a difference.

How Much Does a Scratch Affect the Quality of a Lens?

Conclusion

So what is the relevance of the above topics?

I wouldn’t say that filters are redundant. I sometimes use them if I am photographing in sea spray because I can remove the filter from the body and wash it to prevent the salt built up. But I certainly haven’t bought filters for every one of my lenses and I don’t intend to.

The short answer is if you think filters are insurance, think again. Insurance is insurance, filters aren’t. They are not going to save your body or lens if the damage is substantial and they aren’t going to save your body or lens if it falls in water.