Recently, I was asked about whether or not I put a clear protective filter on our lenses. The answer is, it depends.
When I was working in a camera shop, the answer was always yes. They protect the lens, they don’t harm the optics that much and if you scratch your filter, then it’s fairly cheap to replace, if you scratch your lens, it’s not! Plus filters have a high markup and a good commission. It’s an easy sell for a salesperson, and most of the time the correct one. My advice to 99% of you is to buy a filter for your lenses. (And I don’t get commission for that comment). That leaves two questions. Which filter, and who is the 1 percent?
If you’ve invested in a lens that has superior optics (think over $1000), then purchase a middle of the road B+W UV filter. They should run about $50 – $100. It’s worth the investment. If you’re really worried about the loss of quality, B+W sell a clear filter for about twice the price.
If you’ve invested in a less expensive lens, then by all means get a Hoya or Tiffen UV filter. They cost from $20 to $50. They will protect your lens, and you don’t need to worry about keeping perfect optics.
So, what do Katrina and I believe… Well, we use a filter on our main lens. We do this because the lens we use most of the time isn’t made anymore, and the optics in the new lens aren’t as good as ours. We might loose a little quality in our images, but it’s better than having to use an inferior lens. Overall, our main lens with the filter is better than the new one without. On our other lenses, we don’t use filters. To us, image quality is paramount. We don’t want to loose any quality through an optical system.
Having said that, there are times when I will put on a filter. If we are photographing somewhere where the lens might get damaged, I will put on the filters. Here’s an example of one of those shots.
In this image we had Brad breaking ice and the shards were coming straight at the camera. I had a filter on the lens.
When we travel, I put on the filters. Travel images are unlikely to get sold, so lens protection is more important than optical quality.
In short… If optical quality is the number one priority, don’t use a filter. If protection is the priority, then do. If you’re not sure, make a test image with a filter and one without, and see if you can spot the differences.
As a side note, most photographers, professional and amateur alike, cause more image degradation due to dirty equipment than having an extra layer of glass on their lens. If you really want ultimate quality, clean your lens and take off the filter.