I just bought a canon rebel x and extra lenses. A friend told me I have to have a filter to protect my lenses. Is this true and if so what kind do I need.

Thank you

-- Lori Kammerer (lori_kammerer@msn.com), September 05, 2001

Answers

Lori,

Congrats on your purchase! Yes, most people agree that you should keep a UV or Skylight filter (doesn't really matter which) on each of your lenses. The reasons are:

The front elements can be damaged/scratched by grit, salt spray, etc.

If you should drop your camera there's a good chance that it will land on the front of the lens -- if you have a filter it can absorb the damage. You'll have a broken filter, but hopefully an intact & functional lens. It sounds crazy, but it happens. I was once tackled on the sidelines of a football game -- my camera went flying...the flash exploded into a million pieces & I had to take the crushed UV filter off my Minolta 50mm f/1.4 lens with pliers...but the lens never developed any problems.

A flat surfaced filter is far easier to clean than the curved surface of your objective lens.

The filter diameter you need is usually marked around the front of the lens. It should be a two digit number (millimeters), and may be followed by a symbol that looks like an zero with a line through it.

-- Hung James Wasson (HJWasson@aol.com), September 05, 2001.

I never use a protective filter for my lenses. I understand the reasons for them, but with care, you really don't need them.

-- Jim Strutz (j.strutz@gci.net), September 05, 2001.

True, some people feel that any extra glass on the front of the camera reduces the quality of the light coming through but in my opinion it is negligible with a UV or skylight filter. Still, you'll eventually find out what's best for you.

In the meantime though, for a beginner it's probably a good idea to have a filter. My personal choice is a UV filter as a skylight filter has a very slight pinkish colour. The UV is colourless and will reduce haze caused by UV light. This is most noticeable in landscape type shots.

Nik

-- NikB (ndb_letters@yahoo.com), September 05, 2001.

The cost of UV filters for most consumer lenses (i.e. not the really big ones! :-) is quite small -- typically $12 (for a plain UV) to $20 (for a multi-coated UV). Multi-coated filters are treated to reduce flare & light reflections. If you decide you don't like it, you can always take it off. If you scratch your lens, you'll have to live with it.

If you plan to do much outdoor or landscape photography, you should also consider getting a circular polarizer. There are two kinds of polarizer, circular & linear. The former is a newer (& more expensive) design that will allow your camera to auto-focus, while the latter will still work -- it will hamper or disable the autofocus sensors. Some of the value of polarizers is in bringing out greater contrast between clouds and sky, intensifying the blue of the sky (your effect will vary dramatically -- depending on where the sun is in the sky), and reducing reflections in glass & other shiny surfaces (again, your effect will vary depending on conditions). The cost is greater, typically $35 for a non-MC circ & $60 with MC (Multi-Coated), but you generally only get one of these, and share among your lenses. If you have lenses with differing filter sizes, you buy a polarizer for the largest filter size, and a step-down ring to adapt the filter to the smaller size lens(es).

Final note: Some people will take off the UV filter when putting on a different filter, such as the polarizer. The desire is to reduce the amount of glass between the image & the film plane. Other people leave the UV on, and add or remove filters from there. It's a matter of personal preference & personal belief.

-- Hung James Wasson (HJWasson@aol.com), September 06, 2001.

One thing I just thought of, concerning linear polarizers. I've heard from some people that the linear filters can play havoc with the light metering systems of modern auto-focus cameras. I have no idea if this is true, or just a marketing ploy to get people to buy the more expensive filters.

-- Hung James Wasson (HJWasson@aol.com), September 06, 2001.

Lori,

If in doubt, carefully clean the front element of your lenses and then put a (clean) multi-coated UV filter on them. Jung James gives most of the reasons why.

you should keep a UV or Skylight filter (doesn't really matter which)

A Skylight filter has a very slight warm up effect, so it will make your pure whites slightly pink. Of course, if you are shooting Velvia you may not notice :-)

any extra glass on the front of the camera reduces the quality of the light coming through but in my opinion it is negligible with a UV or skylight filter.

The argument is always: If the lens designer had wanted a piece of glass there, he would have put it there. Of course you loose quality but with a decent filter you'd have a tough time spotting it. That being said, I always remove the filter when shooting against the light, to reduce flare.

I've heard from some people that the linear filters can play havoc with the light metering systems of modern auto-focus cameras.

It can. But since you won't be able to (auto) focus it isn't much of a problem, is it? :-) Just buy the circular polarizers, though they are not as effective as the linear type.

-- Allan Engelhardt (allane@cybaea.com), September 06, 2001.

'Always' having a UV filter on your lens is about as much use as an 'ever ready' case. Such cases are never, in fact 'ready' in terms of the camera being ready for use, and such filters chiefly do nothing other than degrade resolution, increase flare, increase the chance of vignetting (especially with wide-angle lenses), and waste money.

I'm in no way a filter-phobic. I have lots of filters (including UV) and use them when I can see a good photographic reason so to do. But it is amazing, considering the amount of discussion there is- here and elsewhere- about optical resoloution- that there should be advocates of putting cheap galss in front of your expensive optics (and yes, even pricey filters are cheap glass compared with your lens!)

I had to laugh at the suggestion that a filter can protect your lens if it falls: if you are reckoning on dropping a lens don't count on a thin rim of base metal or plastic to save it! I, too, have had the remarkably uplifting experience of dropping a lens and it not breaking, but I put it down to luck, pure and simple!

What protects your camera and lenses best is a modicum of care in handling them. But, if they are to be things of use and not merely decorative adjuncts to your life-style, then get on and use them!

All the best, enjoy your photography! JIM

-- Jim Cross (iamacamera@hotmail.com), September 06, 2001.

I use filters on all my lenses, purely to protect them. I don't buy this "cheap in relation to your lens" thing. Let's have a look: A Canon 50mm F1.8 costs $90. A decent filter for it will cost $30. The lens contains carefully shaped, coated optics. The filter contains a single, thin piece of glass, which is again coated.

I use a Canon 77mm protect filter on my 300mm F4L IS. That lens has a protect element built into it, but even so, I believe the use of a filter to be sensible. It is noticeable that the filter has the same coatings (with the same greenish effect looked at from an angle) as the lens itself does. I use Hoya HMC UV and Skylight filters on my 70- 200 F4L and 24-85 USM respectively, and they are perfectly good. I believe that they do an important job of protecting the lens, and will continue to use them. I suspect I may well replace them both with Canon skylight or Protect filters (I think they only make a protect in the 67mm size), but this argument is nonsense. Filters are expensive for what you get, if you look at the larger sizes. The smaller ones for SLRs (eg 52mm, 58mm) are only cheaper due to economies of scale. If you buy things like the Hoya HMC series or Canon or Nikon filters, there is no compromise in optical quality.

-- Isaac Sibson (isibson@hotmail.com), September 06, 2001.

Lori,

As you can see, there's plenty of differences of opinion! :-)

Has this discussion given you enough points, pro & con, for you to come to your own decision?

-- Hung James Wasson (HJWasson@aol.com), September 06, 2001.

Allan,

Thank you for your input regarding my post! I agree with your conclusion about UV vs Skylight filters. The suggestion of removing the filter(s) when shooting against light is a good one (use of a lens hood may help as well, unless the light source itself is in the frame). Finally, thank you for confirming that linear polarizers can impair the light metering system as well auto-focus.

PS Thanks again for allowing me to post links to your informative website (Allan's Photo Pages)

-- Hung James Wasson (HJWasson@aol.com), September 06, 2001.

Sorry couldn't resist another bite at this cherry! Using an optical device (a filter) for physical protection is as daft as wearing spectacles all the time even when you have perfect sight, just in case some grit should ever come your way!

For both physical protection of the front element AND for the improvement of performance a good proportion of the time, the advice should be to always use a lens-hood! An appropriate lens hood cannot impair resolution, but will often cut down on the image degradation caused by flare.

Cheers JIM

-- Jim Cross (iamacamera@hotmail.com), September 07, 2001.

Basic Principle: Use a filter because of its desired effect on the light captured in the image.

A "protective" filter can actually be a hazard. When you take the filter off to switch it out for the filter you need you're typically juggling a couple filters, increasing the chance that one or both will tumble.

Time: it takes time to remove the "protective" filter and install the filter you actually need.

Protection: use a haze or skylight filter only when you need the extra protection, perhaps when shooting crashing waves, in rain, splashing children, etc.

If you do wimp out and decide to use a protective filter at all times at least make sure it's multicoated. It will significantly aid contrast and color saturation. The HMC filters mentioned earlier are a good quality, affordable option.

A note on Canon filters. When I bought my Elan 7E I figured, cool: I'll get a Canon UV-haze filter, too. Upon inspection, the Canon uv-haze filter proved NOT to be multicoated, and was made in, as I recall, the Phillipines. I returned it and got a HMC uv-haze filter (which I never use anyway!) (I'm not sure how Canon brand circular polarizers stack up -- I got a B+W mc cp and am not sorry I spent the extra money.) The Canon close-up lenses (250D and 500D) are different beasts entirely: they are splendid pieces of glass.

***

-- Rod Nygaard (rod.nygaard@boeing.com), September 07, 2001.

Just to be clear (pun?): a multicoated uv-haze will significantly improve contrast and color saturation versus a non-multi-coated filter . Better yet is no filter at all.

One more note on protection: the point made earlier about the hood is excellent. Also, never underestimate the amazing protective power of the humble lens cap.

-- Rod (rod.nygaard@boeing.com), September 07, 2001.

Lori: In addition to the spirited responses you've recieved thus far, try entering "protective filter" into Photo.net's search engine, and you will find a wealth of discussions on this issue. In fact, it may take you days to read all of them!

As you can see, this is an age-old debate in which there is no dearth of opinions. I happen to be in the camp that generally advocates for the use of protective front filters, and accordingly, I offer the following thoughts:

1) 1st, there's really only one caveat to be remembered with regard to lens HOODS-- Buy the correct hood for a given lens, and then use it, religiously! Regardless of whether one uses protective front element filters, rigid lens hoods will not only help to shield the lens from stray light and glare, but they are also a good mechanical buffer if the lens is dropped and lands front-first. In this case, the inexpensive lens hood may be damaged, but there's a good chance it might save the front of the lens. In addition, because the front of a lens is recessed behind the lens hood, such hoods may help to... A) deflect stray twigs or other objects which might otherwise poke the front of the lens while walking about in the woods, etc.; B) they help to shield the front of the lens from rain, snow, etc.;

2) For beginners, I feel that the use of protective front filters is often wise, especially for... A) Those who had to stretch their discretionary spending funds to purchase their initial lens(es) in the first place, and can't easily afford the often substantial cost to have a front lens element replaced; B) Those who may be lending their camera/lenses to their kids, teen-agers, friends, etc.; C) Those who are not sure they will maintain an interest in photography, and may want to sell their gear down the road, at the best possible price; D) those who may simply be prone to clutziness and carelessness when entrusted with more "delicate" objects;

3) Those photographers who eschew protective front filters may advise that one should not use filters to PROTECT the front of a lens, because this is the job of the lens CAP. However, lens caps are usually in place only when the lens is not being actively used, and a front lens element will often be most vulnerable to potential hazards when it is uncapped and in use!

4) Protective lens filters should not be viewed as an omnipotent shield against most any accident. For example, if you drop or somehow "crash" an unhooded lens that has a protective filter in place, the results may be catastrophic--period! With a severe impact, the filter's glass may shatter, and the filter's mounting ring may be so bent that it can't be removed from the front of the lens, and the lens may be a total loss;

5) Let's talk about the advantages of protective filters--> The majority of modern lenses often feature various types of anti-reflective optical "coatings" or "multicoatings" that have been applied to their various lens elements. At the risk of oversimplification, you can think of these coatings as being a type of metal oxide or other chemical vapor that has been deposited onto the various lens elements as a fine layer or coating, intended to reduce or minimize the internal reflections or "bouncing back-and-forth" of light rays as they pass through the many glass elements of a lens. When such anti-reflective materials have been applied in several layers or applications, the term "multicoated" is often used, and this is usually a more expensive process. In general, these chemically deposited lens coatings are often rather delicate, and they are vulnerable to degradation by a variety of insults, including improper or overzealous cleaning, chemical attack, scratching, pitting, and so on. Protective front filters thus serve as an outermost "sacrificial" barrier to help to protect an otherwise pristine front lens element from such things as acidic skin oils (e.g., finger prints); insect repellents such as DEET; ocean salt spray; blowing sand and dirt; tobacco smoke; scratches; repeated cleanings, etc. Obviously, the strategy here is to subject the protective filter to such day-to-day hazards and abuses, while protecting the delicate underlying front lens element. If a protective filter becomes damaged, the cost of replacing it will often be trivial when compared with the cost and down-time of replacing a lens' front element;

6) If you decide to use protective filters, the price of those filters should generally be commensurate with the price of the lens you wish to protect, as well as your expectations. For example, if the lens in question is rather inexpensive, and you're only interested in creating small prints, it may not make much sense to spend a premium on the finest filters. In this case, an inexpensive UV or skylight filter (such as those offered by Tiffen) may be most appropriate. On the other hand, if you've become more advanced, and are using more elaborate and expensive lenses, then you should consider buying the best quality filters you can reasonably afford, such as those made by B+W Schneider, or Heliopan;

7) Keep in mind that no matter how good a coated or multicoated filter may be, it is still an additional layer of glass that can occasionally create unwanted internal reflections and "ghosting". When faced with conditions where flare and "ghosting" is likely to occur with a filter in place, one can always temporarily remove protective filters, if the environment is not too hostile. Would you remove a protective filter while shooting at the beach, with blowing sand and salt spray? Well, what would you do in this situation? Answer: If you start out with inexpensive filters, or happen to mildly or moderately damage more expensive filters, be sure to keep those filters for later use as "knock-around" filters which you might use and further sacrifice under such harsh conditions. If they become totally trashed in the process, simply throw them away, and buy some more cheap filters to use when faced with major hazards, such as blowing salt spray and sand. Save your fine filters for more benign conditions;

8) BIG telephoto lenses, and ultra wide angle lenses, don't generally accept protective filters, so don't think that protective filters are available for every lens that exists.

I've not had time to proof-read my post, so I apologize for any typo's, etc.

-- kurt heintzelman (heintzelman.1@osu.edu), September 07, 2001.

A couple of points that I have to add, in the light of subsequent comments to my previous post:

1. Lens hoods. I religiously use lens hoods. The hood on my 24-85 remains mounted in the shooting position permanently. The hood on my 300 F4L IS is built in. I always use the hood on my 70-200 F4L. Even so, I still prefer to use a protective filter in addition to this.

2. "Creative Filters". I don't use these. I don't use filters, other than my protective filters. Thus, the swapping argument is null for me.

I agree with Kurt's second point. I have kept lenses in mint condition to then sell on when I have upgraded by the use of protective filters. I now have L series lenses which I could not afford to have repaired. I am also a teenager. :-). However, no one else (except my parents, and close friends under supervision) ever handles my lenses.

I suspect also that views on this will vary a lot, according to what kind of photography people do. If my gear always lived in a studio, then I might not have protective filters. As it is, trapsing through a bird sanctuary, or walking on a beach with sand blowing around, I think I'll stick to my filters!

-- Isaac Sibson (Isibson@hotmail.com), September 10, 2001.