Welcome to the second installment of the N00bism series. This time I will tackle probably one of the most highly debated aspect of digital photography. Note that I am very specific about “digital” here and you will see why in the next few blocks.
The topic I am about to discuss is the use of UV FILTERS.
Let me tell you right now that this is probably the biggest scam in the history of photography. Every sales person would sell an unsuspecting buyer a UV filter together with the entry level DSLR and kit lens. Sometimes they would even make them feel that they just made the greatest bargain by giving them a free UV filter after they sold the last remaining stock of last year’s entry level DSLR model.
Well actually, let me take that back. This is not the scam. The scam is when a buyer is forced to feel that they need the most expensive UV filter to pair with their very expensive lens. Let’s see: you already spent thousands of dollars on that lens so why ruin the image quality by screwing a cheap UV filter?! Doesn’t make any sense, no? So you buy each of your holy trinity of lenses the best UV filter you can find. Now THAT makes a lot of sense.
Or does it?
Back in those days when the word photographer actually meant something — back when people shot with film — a UV filter was part of the arsenal. Film is sensitive to UV light and that actually made the photos look cold and hazy without them. Photographers used UV filters because they do help make the photos look clearer. Not so with digital photography. Digtal cameras are corrected against UV light. Yes, your DSLR has a built-in UV filter. You do not need another UV filter.
But wait, UV filters are meant to protect your lenses!
Ok, so now you know that it’s useless as the accessory it was meant for so let’s discuss this positive side effect of doubling as a lens protector. Does it really protect your lens?
Let’s put this in proper context. What kind of protection do you expect from it? Protection against impact? Please consider the fact that a UV filter is just a very thin piece of glass bound by some metal screw mount attachment. Even a very light knock will scratch or break it because it is what it is: a very thin piece of glass. A serious knock will break the glass AND bend the metal mounting and ruin the thread of your lens’es screw mount. You’d be lucky if you can still unscrew the broken filter from your lens without further ruining your lens. It’s not really much of a protection, no? Use your lens cap and/or hood if you want real protection.
So how does the front element of your lens compare to a UV lens in terms of toughness? Firstly, it is so much thicker so it won’t break that easily. Glass is actually a very tough material. To cut through glass, you need the world’s toughest natural substance: a diamond! In the very unfortunate circumstance that you do break the front element, a UV filter would have not been able to save it either. If you do break the front element, expect that something in your lens’es internals would be broken as well due to the force of impact. The point is, don’t be stupid.
How about minor scratches? Front elements are quite tough buggers. You would think that lens manufacturers would consider fortifying this most exposed part of the lens, yes? And even if you do scratch it, you would have to scratch it very very badly before the effects would even start to show in your photos. I’m serious. If you don’t believe me, then check THIS
What about dust? Doh?! Just clean your lens with a cloth. If dust gets on your lens then surely a UV filter will get dusty too so what’s the deal? Even dust INSIDE your lens won’t affect your photos. I have a few old manual lenses with dusts in them but they still make very good shots.
Allow me to summarize those points: a UV filter does not provide enough protection. Your lens is way tougher than any UV filter. Minor lens blemishes do not affect image quality.
So enough with what a UV filter does NOT do. What does a UV filter do really? Unfortunately, nothing but negative 😦
Firstly, it causes flare. Some have lesser effects than others but when subjected to point light sources, UV filters will cause flare in images. This is especially true when shooting at night with light sources coming from different directions.
Secondly, with UV filters glued to your lens, you can’t attach other filters (that do matter) without causing image degradation. Stack a CPL and/or an ND filter in there and you will have bad vignette.
Thirdly, you are just supporting the scammers by buying expensive UV filters.
And that’s it folks! So now you have another method of detecting n00bs — they are the ones with UV filters on their lenses.