Why do photographers need a UV Filter for their DSLR Cameras?
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The most basic filters are ultra-violet(UV) reducing filters (also referred to as Haze filters), Skylight filters, which depending on the manufacturer are either glass filters with basic anti-reflective coatings, or in some cases, merely plainclothes UV filters. To keep the front element of your lens clean and safe, any of the above will help you. And these will also help you to protect your lens & to improve the image quality of your stills and videos.
If you plan on photographing near large bodies of open water, at higher altitudes, in snow or other conditions that magnify the intensity of ambient ultra-violet light, you should definitely consider a stronger level of UV filtration (UV-410, UV-415, UV-420, UV-Haze 2A, UV-Haze 2B, UV-Haze 2C and UV-Haze 2E). Depending on the strength of the UV coatings, UV filters appear clear, or in the case of heavier UV coatings, have a warm, amber-like appearance and require anywhere from zero to about a half stop of exposure compensation.
An alternative to UV/Haze filters are Skylight filters, which are available in a choice of two strengths—Skylight 1A and Skylight 1B.
Circular Polarizer If you're interested in landscape photography, a polarizing filter is a must. Put simply, a polarizer reduces the amount of reflected light that goes to your camera's sensor. Blue skies appear a deeper blue, and reflections from water can be removed entirely. You can chose the amount of polarization that you add by twisting the outer ring of the filter, because this filter has two rings, one that attaches to the camera lens, and a free-form outer ring that twists for polarization. This adds polarization in degrees up to 180 degrees.
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The downside of polarizing filters is that they greatly reduce the amount of light reaching the camera's sensor, often by two or three f-stops.
One last important point to note: Don't be tempted to buy the cheaper option of a "linear polarizer." These won't work with cameras that have auto-focus or use TTL metering (Through The Lens) ... something that all DSLRs have.
Neutral Density Filter The only purpose of a Neutral Density (ND) filter is to reduce the amount of light that reaches the camera's sensor. This can be particularly useful when a sufficiently long exposure isn't possible within the aperture parameters. An ND filter is most commonly used when photographing running water, because it helps create a smooth and ethereal image.
The ND filter can also be used to convey motion by adding blur to moving subjects and to make moving objects, such as cars, less obvious in landscape shots.
The most popular ND filters reduce light by two (ND4x or 0.6), three (ND8x or 0.9), or four (ND16x or 1.2) f-stops. It's unlikely that you'll find much use for more reduction than this, although some manufacturers make ND filters that reduce light by as many as six f-stops.
Graduated Neutral Density Filter Graduated Neutral Density (GND), or Split, filters are an optional extra, but one that can prove useful if you don't like to do a lot of post-production work.
These filters reduce the light at the top of the image and then smoothly graduate through to allowing a normal amount of light to hit the camera sensor from the lower portion of the image. These filters allow for capturing landscapes with very dramatic lighting, allowing both the sky and foreground to be correctly exposed.
Left — Tire with Polarizer and-2-stop-hard-grad. Right — Tire with a Polarizing filter plus a 2-stop-hard-edge grad and-a 5-stop solid-ND filter. Note the movement of the foreground brush and the softness in the clouds. This was achieved by using the solid ND filter to get a slow shutter speed. Picture Credit: Darwin Wiggett.
How quickly the graduation and blend occurs depends on whether the filter is "soft" or "hard" edged, and this feature varies greatly from manufacturer to manufacturer. You need to do your research before buying these filters by looking at examples on manufacturers' websites. Like ND filters, GNDs are available in a variety of f-stop settings. You shouldn't need more than a one-to-three f-stop blend.
Should I consider warming and cooling filters?
While warming (adding yellow to the scene) and cooling (adding blue to the scene) can be applied to an image file post capture in Photoshop or other image-editing software, there are still those—including film shooters, who prefer to filter the lens at the time the exposure is made.
Most photographers warm or cool their images for aesthetic or mood reasons. A bit of warming is often desired for portraits, or when photographing at midday during the summer months when the sun's light can be bluer and harsh. Warming can also be effective when taking pictures on overcast or rainy days.
Conversely, cooling filters can be used to correct color in images in which the color temperature is too warm to suit your intentions. Warming filters include all 81 and 85-series filters, and cooling filters include all 80 and 82-series filters.
Newer lenses made after 2007 typically don't need a UV filter when mounted to digital cameras. After this year, the manufacturers started making filters with higher quality glass and metals/plastics. This is due to the advancements in lens coatings which help filter out and negate the effects of UV filters. This is also why, since around 2011, the entire industry of optics has advanced so much. Zeiss started making the biggest splash with their Otus lens lineup but then Sigma did as well with the Art lineup of lense, then Tokina, then Tamron, then all the primary camera manufacturers.
So when shooting with digital cameras you may not NEED a UV filter, but honestly they're still pretty good to have. I remember one night, one of my friend's camera was in his bag and bag fell off of a table. The lens attached to the camera took a hard, direct hit onto the floor. But the camera and lens kept working only because the UV filter had smashed and took the impact. Glass was shattered inside of the camera bag and yet he relieved to find hs camera kept working.
Best Filters for DSLR Camera Lenses Back in the days of film cameras, pro photographers carried a vast number of filters to deal with certain lighting conditions and to add effects. But, with the advent of DSLRs and their features such as white balance, many of these filters have now become obsolete. However, some filters remain very useful in digital photography, especially the best filters for DSLR camera lenses.
The most popular filters are screw-on filters, which fit on to the front of DSLR camera lenses.
These tend to be reasonably priced, but you will need to buy filters for each lens' thread size, which is listed in millimeters and can be found either on the front of the lens or on the back of the lens cap. Lens thread sizes range from about 48mm to 82mm on DSLRs.
The other thing to bear in mind is that any wide-angle lenses will require ultra-slim filters, which cuts down on the risk of vignetting at the edges of the photograph.
What filters do you use (if any)? What advice would you give DSLR owners looking at purchasing filters?