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Very Basic Filter Advice for New DSLR Shooters

(This article has been slightly updated since it was originally posted.)

Earlier this morning I replied to a question about filters from a new DSLR owner who wondered which filters he “had to get” to use his new camera. I realized that this sort of question comes up from time to time, and I thought that the answer might be useful to others. So here it is!

With DSLRs there are typically four types of filters that most people might consider. You do not necessarily need filters – it is a question of shooting preference and some stylistic issues.

“Protective” filters

Some believe or have been told that they need so-called “protective UV filters” on their lenses. The thought is that these filters will protect the front element of your lens from possible damage, and there is an old school notion that reducing UV (ultraviolet) light will improve certain types of photographs. DSLRs are not sensitive to UV light  in the way that film was, and there are some compelling arguments against using filters for protection in normal shooting. My thoughts on this are posted elsewhere on this blog.

I must acknowledge that opinions vary on this issue, and that this discussion (oddly, but like those about certain other photography equipment issues) can become rather heated. I don’t use protective filters. Others do. You’ll have to weigh the arguments yourself on this one.

Circular Polarizing (“CP” or “CPL”) Filters

Contrary to what you may think, CPL filters are generally not simply placed on the lens and left there, but they may be added occasionally for certain shots and in certain conditions. You do not necessarily need them, but in some situations they are useful. There are several things that they can do:

  1. In some photographs they can increase the contrast between things like clouds and sky, possibly producing a more dramatic photograph. This does not always work – it depends on things like the angle of the sun and the nature of the sky. It also does not work well on very ultra-wide-angle lenses. You almost certainly would want to use this effect sparingly, since it easily become a cliche.
  2. The CPL can control or reduce reflections from things like the surface of water or windows. It can also be useful in some situations for reducing the reflections from shiny foliage. Some find the CPL useful for photographing waterfalls and cascades.
  3. The CPL can also function as a stand-in neutral density filter when you want to use a slightly longer exposure time or a larger aperture.

In the first two cases, you rotate the filter to control the effect. There is usually a small dot on the edge of the filter and you can maximize the filtering effect by rotating in 90 degrees away from direction of the sun.

Neutral Density (“ND”) filters

These filters simply darken the image by some number of stops, ranging from one stop to as much as 10 stops. ND filters allow you to use a longer exposure and/or a larger aperture in conditions that might otherwise not allow this. You might do the former to allow motion blur, for example with photographs of water or clouds. You might to the latter to limit depth of field in very bright conditions. (As noted above, a CPL can stand in for a mild ND filter in some cases.) Contrary to some claims you will read, they do not really alter the overall brightness or color balance of photographs at all. (The very dark 9- and 10-stop filters can produce an unwanted color shift.) Most photographers starting out will not need neutral density filters.

Graduated Neutral Density (GND) filters

These filters are darker on one half than the other, with the clear and darker sections separated by an area of relatively smooth gradation whose width may vary. The dark section may reduce the light by two or three exposures. An example of their use might be a scene with very bright sky and darker foreground – the filter is lined up so that the graduated section is on the horizon and the darkened section covering the sky. Although screw-in versions of these filters are available, their usefulness is very limited. More common are large rectangular versions that are attached by means of a holder in front of the lens and then positioned manually. This is a fussy bit of business, and if you are new to this it is quite unlikely that you want to “go there” at this point. (I have heard some argue that they should be called “gradated” rather than “graduated” neutral density filters. I may be dense, but I’m, uh, neutral on this question. ;-)

Filter Alternatives

Today we can emulate the effects of most filters in software. In most cases this gives us more options and greater control than attaching filters to the lens at the time of exposure, and it also means less gear to carry. The circular polarizing filters is an exception, in that you cannot really emulate its ability to control reflections using photography post-production software.

Bottom Line

In my opinion, if you just got your first DSLR and suddenly find yourself in the mood to start buying lots of accessories… hold off on getting filters for a while. Not everyone needs them, and at first you can probably do everything you need to do without adding this additional complication. Eventually, once you become more comfortable with your camera, the filter that is most likely to occasionally be useful to you is perhaps the circular polarizer since it is useful in several different ways and because its effect is generally not one you can duplicate in post-processing.

G Dan Mitchell is a California photographer and visual opportunist whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
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Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

The Economics of DSLR “Protective” Filters

The subject of whether or not to get so-called “protective” UV filters for DSLR lenses comes up a lot. I used to respond to the question frequently – so frequently that I eventually gave up and just wrote a post on the subject that I could refer people to when they ask.

However, during a recent weak moment I wrote a new response to the notion that ‘protective’ filters provide good value for all photographers. As I do from time to time, I’m sharing it here:

Someone wrote: … would you rather pay $150 on a filter that *might* compromise your shot or spend $150 on replacing the front element and have *no* possible risk of image degradation from the extra piece of glass?

I replied: This is essentially an insurance question. Obviously, if we knew that our lens would certainly be destroyed in a way that was 100% preventable by using a filter we would almost certainly get a filter. But that is an imaginary scenario that is far from reality.

Most lenses will never be damaged in any serious way. My hunch is that this is actually the fate of a very small percentage of lenses – probably far less than 10%, and I would bet closer to 1%.

Of those that are damaged, only some will suffer a blow to the front element. There are many other modes of failure – a dropped lens that breaks the mechanism, something crashing into the side of the lens, water damage, etc.

Of those that suffer a blow to the front of the lens structure, only some will result in contact with the front element. Of those in which contact with the front element occurs, some would not cause any damage or any significant damage. Some would damage the front element, but would be violent enough that the filter would not have prevented the damage. A few that might not have damaged the front element will send glass shards from the broken filter into the front element and damage it. In some subset of cases, all of the variables might line up just right and prevent damage.

At this point the user would have to replace the broken high quality filter at a cost that varies depending on a number of factors. Let’s use a figure if $100 for an expensive L zoom. The owner has now invested something on the order of $200… which is not much different from the cost of replacing a front element, as I understand it.

In terms of the probability of damage, the cost of the filter, the likelihood that the filter would save the day… the filter is probably one of the worst insurance investments you could make.

Am I unalterably and completely opposed to the use of ‘protective’ filters? Almost, but not quite. While I do not think that it makes sense to automatically stick such a filter on every lens for general use – see the link above for more on this topic – I can think of one sort of situation in which I might use one. I would consider a filter if I were shooting a sealed-body camera (such as a Canon 1-series) and was working in conditions that were truly dangerous to my equipment (and not just a bit of mist or ocean spray) and I was using of the small number of L lenses that become sealed (and not all do) with the addition of a filter.

Other than that? No.

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Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

Lens Protection: Ultraviolet (UV) Filter or Lens Cap and Hood?

(This has become one of the most-read articles at this site. For some reason, the question of whether or not it makes sense to add these little filters to your lenses generates a lot of interest… and sometimes a lot of lively debate. Portions are now a bit dated — the article comes from 2007 — but the general concepts discussed here still hold. From time to time I make small updates based on new information or questions that have come up. Note that there are links to a couple of related posts listed near the end of the article.)

Sellers sell, and some buyers buy, ultraviolet (UV) filters for their cameras. The main advantages are said to be twofold: some reduction of haze that is invisible to the human eye but which the camera purportedly might register, and some protection for the front element of your lens.

On the other hand many photographers wouldn’t think of putting an extra layer of unnecessary glass in front of their lenses. They would rather accept the (rather small) possibility of a scratch on the front element of a lens than possibly reduce the quality of their images, and/or they prefer to protect the lens by using a lens cap and lens hood.

I’m in the latter camp. I no longer use any UV filters* and I can think of darned few situations in which I’d want to use one. (One possible exception being the use of fully-sealed lenses on which the seal is completed by adding a front filter – and here only if I were to use the lens in an extremely hostile environment and with a fully environmentally sealed camera body.) My preference is to handle my camera and equipment relatively carefully, keep the gear protected when not actually using it, use a lens cap, and to almost always use a rigid lens hood.

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