Filtering my (DSLR) results.

February 20, 2009 6:29 AM

Is it necessary to attach a filter to DSLR lenses to prevent scratching and damage to the lens?

I recently bought an 18-200 mm zoom lens for my Nikon D40 camera. Since I only purchased a bare-bones lens, it arrived on my doorstep without filters.

Now, I'm not interested in changing the light that enters the lens in any way. I simply want a filter to protect the lens against scratches and UV damage.

Is it necessary to buy such a filter, or is the glass in the lens scratch-resistant and strong enough to hold up to abuse?

Apparently, a 72 mm filter is required for this lens. If I need a filter, what's my cheapest option for one which will protect the camera without altering my photos in any observable way?

posted by Gordion Knott to media & arts (30 comments total)

Adding a filter as a lens-protection measure is extremely common; my father, a former photographer, reflexively buys a cheap UV filter for every one of his lenses at the time he buys the glass. I have filters, generally just UV, on all of my lenses except the 18-55 kit lens I bought for $40 and which I don't care much about.

This is a matter of some philosophical debate, mind you - many feel that since it's impossible to have a completely transparent filter, if you don't want to alter your light you shouldn't have one at all. Others, like me and my dad, figure that any infinitesimal effect is worth not having hundreds of dollars of lens damaged by a scratch.
posted by Tomorrowful at 6:35 AM on February 20

It also protects the lens when you clean it, i.e., you never clean the lens itself, just the filter. And if something does scratch it, your only cost is a filter. You can buy a used filter if you're worried about price.
posted by weapons-grade pandemonium at 6:36 AM on February 20

Allowing the light to pass through any piece of glass will change the light in some (small) way.
Having said that, if you don't want the UV-filtering effect, you can get a clear filter rather than a UV filter.
posted by le morte de bea arthur at 6:40 AM on February 20

Seconding its-a-common-practice. As you can learn at wikipedia, you can get clear filters for about $25, and you can also get UV filters for about $15.
posted by Mike1024 at 6:50 AM on February 20

Accidents happen. I have filters for all my lenses. It only took a second when I turned and bumped into some concrete to crack my UV filter. I would have just cried if it had damaged the actual lense.
posted by sanka at 6:55 AM on February 20

I would not go with the cheapest - with digital vs film, there's a lot more light reflecting off the sensor, and uncoated filters will keep those light rays bouncin'...

I would certainly have a filter though - my polarizer sacrificed itself when my $1000 70-200 fell on its noggin', driving the point home. The filter was a loss, but my lens was protected.
posted by notsnot at 7:03 AM on February 20

I'm going to have to disagree and say don't use UV or clear filters. I've got several thousand dollars worth of glass and I never use UV filters. I've abused my lenses (taken them out in typhoons, mountaintops, jungles, crazy temple ceremonies) to the point that there are all sort of visible marks on the barrels, but with the judicious use of lens hoods (i.e. always having them on), the actual glass is completely mark-free.

On the other hand, all but the most expensive UV filters will degrade your image. In particular, it exacerbates flare in early morning/late afternoon as well as night photography. Lens hoods on the other hand will prevent flare spots.

Get a lens hood and a polarizer filter.
posted by alidarbac at 7:07 AM on February 20 [1 favorite]

This is something that photo stores love to push. It's kind of like an extended warranty. It is decent protection, but if you are careful it will never be needed. The store's profit margin on cameras and lenses is quite low, but on filters it is more like 70%. If you buy one with the lens ask for at least half off of the filter. If it is an expensive lens, and yours is, you won't want to put a cheap filter on it as that will degrade the image. Your lens is also quite wide angle so you will need a low profile filter. A low profile filter of high quality glass in 72mm is going to cost probably $50, perhaps more. For such an expensive lens it might be worth it, especially if you shoot lots of photos in rugged environments. It's all about balancing the risk.
posted by caddis at 7:28 AM on February 20

I am working as a photography intern at a newspaper. I have a Nikkor 70-200mm f/2.8 on loan from the photo department. It has a rubber glare hood and UV filter on it. Yesterday I dropped this $1500.00 lens business end first from about 5 feet up onto concrete.

The only thing damaged that was the UV filter. I stopped crying and danced around my driveway is glee. Get a rubbery screw-on lens hood + UV filter (skip the cheap ones) for any glass you don't want to replace.
posted by YoBananaBoy at 7:55 AM on February 20

is in
posted by YoBananaBoy at 7:56 AM on February 20

No, it is not necessary. I personally think it's a bad idea, as you're putting an extra piece of (often low-quality) glass between you and what you are photographing.

The filter/no filter issue tends to be a religious one with photographers.

My advice: no filter, clean your lens (methyl alcohol and Pec-pads or cotton cloth), and put a lens cap on it whenever you're not using it.
posted by zippy at 7:59 AM on February 20

Is it necessary to attach a filter to DSLR lenses to prevent scratching and damage to the lens?

No. My trick is to not rub random junk on the front element of my lenses. Also, I am pretty sure you can't damage a lens through UV radiation.

Keep in mind, if you are going to buy the cheapest filter you can, you're going to end up with way more flare in your pictures, since there is now another piece of glass for light to reflect off. Shooting at lights with a crappy filter will be very noticeable.

For every story of someone dropping their lens and having the filter save them, there is probably another story of someone dropping their lens, having the filter shatter and scratch the lens glass. Or having the filter deform to the point it can't be removed from the lens. Etc.
posted by chunking express at 8:14 AM on February 20 [2 favorites]

I started out not using them, but now I have them on every lens that I own.

The main issue, optically speaking, is glare. If you put an uncoated piece of glass on there, it will cause glare at certain angles and possibly ruin some pictures. Get a middle-priced UV filter with dual anti-reflective coatings and you'll minimize this to the extent possible.

The "UV" part is more or less nonsense. You don't need to protect your camera from UV, you need to protect the glass from dust, scratches, and impacts. And for this, as noted above, these filters work very well.

What I've discovered, and what made me put them on every lens I own, is that I feel very comfortable using the camera in poor conditions, like rain, snow, or on splashy streets, and I rarely ever put a lens cap on. Previously, I would put the lens cap on between shots or when out walking. Subconsciously, this would prevent me from taking some pictures. Now, since the lens is always ready to go, I take a lot more pictures, in more conditions, and that is easily worth the money.

In other words, go for it. You won't regret it and it may help you take more pictures and become a better photographer.
posted by fake at 8:36 AM on February 20 [1 favorite]

Funny, I just got the hard sell on this at my local camera store. While buying a lens, the guy behind the counter placed a filter on top without me even asking for it and started to ring it up. I told him to take it away, because I don't buy things I didn't ask for to increase some jerk's commission.

So glad to see my position vindicated here. I will probably go with keeping the lens hood on.
posted by drjimmy11 at 8:50 AM on February 20

I so disagree with using filters for so called lens protection it's not funny.

If there's anything you don't need in the optical path of a lens, particularly one like your zoom with many elements and groups, it's two more air/glass surfaces.

Using the correct shade is a good idea for a number of reasons; not the least of which is that it affords considerable protection to the front element and filter threads. It will also do a lot to keep rain, snow, or splashes off of your front element.

I haven't used "protective" filters on any of my many lenses for years, and have never scratched a front element. And, many of my lenses have huge front elements and all are sometimes used in "equipment hostile" environments.
posted by imjustsaying at 9:28 AM on February 20

It absolutely doesn't make sense to put a $15 filter on a $600+ lens. Get a decent or at least mid-range protective/UV filter, make sure it's multi-coated, and keep it on your lens at all times.

Keep your lens hood on at all times, indoors and outside (except when storing it), and forget about using your lens cap: you will miss a lot of good shots if you are busy taking it on and off.
posted by halogen at 10:02 AM on February 20

I'm a lot more worried about misalignment or internal damage from dropping a lens than damage to the front element. I don't use a filter. I had one (and it wasn't cheap) for a while and I got too many ugly flares. Here is an amazing article about how much punishment a front element can take.
posted by zsazsa at 10:18 AM on February 20

@halogen I'm not following your recommendation. You say a $15 filter is senseless, but a $40 filter is ok?
posted by teg4rvn at 10:37 AM on February 20

Back in the 1970's I worked in a camera shop, and remember a visit to our store by a Nikon tech rep for a free demo day.

During the course of this, he was asked by a customer about the need for a filter on the front of one's lenses for protection. He laughed out loud, and proceeded to aggressively stub his cigarette out on the front element of a Nikkor 13mm/f5.6 lens. This was an insanely exotic and expensive lens with a front element the size of a softball. He then spent thirty seconds cleaning it off again with his handkerchief and passed it around for inspection.

The only damage was confined to dents in the floor from all of our jaws dropping.
posted by imjustsaying at 10:58 AM on February 20 [5 favorites]

Exactly. Glass isn't soft. More so, damage to the front element isn't going to have nearly as big an impact as damage to the rear element. And even then, you seriously have to fuck the shit out of your lens for it to matter.
posted by chunking express at 11:13 AM on February 20

I think you should get a filter (probably UV). It's extremely easy to scratch your lens, and I'd much rather pay $15 than even $100 to replace it.
posted by majikstreet at 11:40 AM on February 20

Necessary? No, it's not at all necessary.

But UV filters are cheap, and if you were to scratch your lens on something, would your rather replace a cheap UV filter or replace the whole lens?

I use UV filters on all of my lenses (that cost a lot more than your lens!). My photos are sharp as ever, and if I do ever notice undesirable effects (like unwanted reflections or vingetting when stacked with other filters) the filter is easy to remove.
posted by geeky at 11:40 AM on February 20

I like imjustsayings account of the sales rep, and I will take that story to some old timer photographer friends of mine, but I really put my equipment through the ringer. I also know when it is just fine to take the filter off: see studio work. I'd rather break a filter then drop the cash on a replacement lens. I also dont see the need to use a lens cap, since I have the filter in place. Come to think of it, where is my lens cap?
posted by captainsohler at 12:01 PM on February 20

Put the filter on. Will it degrade the image in some way? Sure. Will it be detectable? I would assert not, but it's debatable.

What it will do is provide some minor protection. Chunking might be right and it could introduce just as many risks as it resolves, but I doubt it. There's a good probability you'll never need protection either way though; I was a glass snob for a lot of years during which I carried my gear daily and never had a filter on the four lenses I traveled with - never had an issue.

What I think it does most, though, is provide a very nice and simple flat surface to swab clean quickly, and that's why I now have one on my 18-200. I've come to the conclusion that the most important thing for me is "get the shot" and I am certain that the picture I take is better than the one I don't. Cleaning the 18-200's native face is harder since it's not flat and the material around the outer rim attracts dust.

Then again, I keep my D80 in a tuque that I have put a grommet in to run the strap through. So consider the source.
posted by phearlez at 1:35 PM on February 20

imjustsaying: That's a really interesting story.

I take great care of my lenses, but I always use filters ever since noticing two random scratches right on the middle of my f/1.4 50mm's glass which I couldn't remove. I have no idea how they got there in the first place, but since I was doing absolutely nothing crazy and it still happened, I figure the clear filter should be on there for safety.

As for the quality argument: I literally do not comprehend this. Can someone give me some actual data on why you feel like the extra layer of glass is a problem? I've taken thousands of photos in nearly as many lighting conditions with the above-mentioned lens and never noticed anything wrong with the results that could be attributed to the clear filter.
posted by odinsdream at 1:40 PM on February 20

Here is one example, and an argument for not using them.

An example on Flickr.

And another.

And you can probably keep looking for more.
posted by chunking express at 1:49 PM on February 20

Another.
posted by chunking express at 1:52 PM on February 20

You're playing with pretty low percentages of fail in either case; it's really just a question of what you feel more comfortable with.

If you nick your lens on a metal/stone corner, drop it in sand, or clean it with a foreign-substance attacked microfiber cloth, there's a decent chance you're going to damage your lens--or in the very least cause a mess that won't be easy to clean up. (You can still shoot without issue even with a beat up front element, but that's another debate.) The chance of any of that actually happening: relatively low (although, i've gotten plenty of nasty gunk on my lenses). I've seen Canon L front elements beat to shit. So if anyone is suggesting they're indestructible, they've just not destroyed one yet.

As far as filter flare... only going to happen in predictable or extreme cases (and even that's somewhat dependent on the quality of your filter), and in a good chunk, you'll see it while chimping your LCD and could be able to remove the filter and reshoot. Shooting straight into a bright light source? Take your filter off. It's removable, and it's not rocket science.

Make smart choices with whatever option you choose, and you'll likely be fine. Maybe not, but that's the breaks. That's all there is to it.

My polarizer is my best friend, so I either have that on or the lens is bare... My primary lens' front element is definitely not in EXCELLENT shape, but it's not a lens with a ton of resell value, so that's okay. I definitely feel a bit more comfortable when there's something on it, but the hassle of handling/swapping multiple filters in the field makes a bare lens worth it for me.
posted by pokermonk at 3:11 PM on February 20

But UV filters are cheap,

One that won't turn a $600 lens into the equivalent of a $150 lens is not cheap.

The best part of all this debate is how black and white the issues are. Good filters cost real money (I did a little cost checking and you can at least double my above estimate) and that makes the insurance policy pretty pricey. Now if you frequently take the kind of shots that a UV filter is designed for then you will want one anyway and the protection cost drops to zero. If you shoot mostly indoors or shaded close shots the need for this expensive filter as a necessary tool for visual effect is limited. Then it becomes a very expensive insurance policy, perhaps, even probably, more expensive than is warranted. I love how contentious is the debate and how difficult it is for the individual lens owner to judge the risks and rewards. Photographers are such geeks. I have no filter on my most expensive lens, twice the price of the camera body, and do have one on a cheaper lens that is used more often, but then I shoot a lot of outdoor scenes with this lens where this filter (now almost $100) produces noticeable results.
posted by caddis at 7:27 PM on February 20 [1 favorite]

It looks like I've overestimated the consequences of scratches to the front glass. Per the advice given here I'm going to stop using a filter and see how it goes. I will however get a lens hood.
posted by odinsdream at 6:40 AM on February 24