Well there’s a query for the modern era. The final answer may surprise you. For serious photographers be it professional or advanced amateur, film camera kits had several ‘must have’ filters. For B/W film the classic Orange, Yellow, and Red contrast enhancing filters were standard fare. For color and B/W a polarizer was a must along with many other specialty filters such as soft focus for portraits or artistic still lifes, UV/Haze as a general correction, graduated filters were pretty critical for landscape work, and there were many more. At one point in the 1980s when I was a factory rep for Hoya filters we had a catalog with nearly a hundred different filters. Back in the film days you needed a filter to correct for tungsten light, or a warming filter for cool outdoor color temperature in winter. The list went on and on.
In this modern digital age, many of those color correction and color balance filters have been rendered obsolete. Does that mean filters are obsolete? Well, not really. If filters were obsolete, then lens manufacturers would not worry about filter thread size, nor would reviewers comment on it either, yet they do. I use filters far less often with my digital cameras than I did with film, but there are a few that are hard to replace. The venerable polarizing filter is one such case.
The polarizing filter, and to be clear most cameras film or otherwise made in the autofocus era, require a ‘circular polarizer’ not a ‘linear polarizer’. This refers to the optical method in which the polarizing effect is generated not the shape or the way it is used. A polarizer is a staple among landscape photographers particularly in images that will feature a large portion of sky. The filter is designed to polarize the light thus reducing or eliminating reflections off of blight surfaces such as the sky, surface of water, windows, etc. When using it on landscapes, the sky becomes a rich darker blue and any clouds in the sky tend to pop much better. In this application software can duplicate this function pretty well. But other polarizing effects are not easily duplicated in post. The polarzing filter can remove the surface glare off off water allowing the image to reveal details beneath the surface, like a coral reef, or divers under water. It can also remove the glare from windows on a building allowing the details behind the glass to be revealed. Sometimes the photographer may want the reflection in the glass or water as part of the image, but other times, perhaps not. The polarizing filter becomes a necessary tool even in this modern age. One user tip, when using a polarizing filter on an autofocus camera be sure to focus first and then rotate the polarizer into the position that delivers the effect you want. Many AF lenses rotate the front of the lens when focusing. A polarizer works only at certain angles and that is why they have a rotational ring to allow you to get the effect you want. A polarizer will typically knock about 2 stops off your exposure.
Neutral density filters are every bit as relevant today as they were in the film era. Some video cameras have them built in. The ND filter allows the photographer to use wide apertures in bright conditions thus allowing for artistic motion shots of things like waterfalls in full sun. They more commonly allow for excellent background separation and creamy bokeh in brightly lit areas. They are also used for creative effects in daylight like photographing a busy freeway in the middle of the day with an exposure time long enough to blur moving cars to the point they are invisible. This grants an eerie effect of emptiness, it can be quite effective. With film cameras that had a fixed ISO for the whole roll of film, 1 stop and 2 stop ND filters were useful. These days in the digital era they are essentially obsolete. But 8 stop and 10 stop ND filters are absolutely viable in this day and age, and allow photographers to achieve images they otherwise could not get. There are even modern versions that have variable ND that work by rotating the filter ring to darken the image.
Graduated Neutral Density filters fade from zero correction to any where from 2 to 6 stops. These are ideal for bright skies against a dark foreground such as a sunset. I routinely use graduated ND filters in post but for fine art landscapes a filter can yield superior quality to a heavy post edit.
The bottom line is that filters are alive and well and many remain an essential part of the complete camera kit. Below is a list of analog filters that are still viable in today’s digital world. It just so happens you can find a HUGE selection of filters at PhotoFair and other camera show. Tim Rice with Filterfind will have thousands of filters available at the next show in Newark, CA on Saturday the 12th of November (2022).
- Circular Polarizer: An essential piece of kit as described above
- Neutral Density 4x to 12x: An essential piece of kit as described above. These come either fixed or in some case a variable ND controlled with a rotating ring.
- Graduated Neutral Density: These are not essential but they are not obsolete either. This is ideal for landscape scenes with a level; horizon and a sky that is much brighter than the foreground, scenes such as sunsets. This effect can easily be duplicated in post if the camera has high dynamic range, but comes at a cost of increased noise. The filter will minimize the level of correction with software allowing for a cleaner image. the best versions are those used in a filter holder that allows for adjustment, screw in filters of this type have the graduation line in the middle.
- UV-Haze: Not obsolete but not essential either. Modern digital cameras are not as sensitive to UV type hazing so the filter is not necessary from an image quality standpoint. However the idea of a filter offing some surface protection for the lens is still viable even today. Just make sure you are using a quality filter.
- Infrared: If you have an IR converted camera, these are still essential kit pieces.
- Astronomy: There are many different filters designed for astro-photography and they are just as relevant and necessary today as they were in the film era.
- Cross Screen / Star Effect: These filters are still viable today. The filters are designed to make bright points of light into specific star points typically of 4, 6, or 8 points. This can be created without a filter but typically requires stopping down to dim apertures and is dependent on the design of the lens aperture diaphragm. The filter allows the effect to be specific and at any aperture.
- Soft Focus: There are many variants on this theme and they are almost obsolete now. The latest AI tech in image processing software allows photographers to do an excellent job creating brilliant soft focus and isolating the effect to specific parts of the image. For photographers that don’t do heavy post work these are still viable filters, but for others software has eliminated their usefulness.
- Color Correction: These are more or less obsolete with modern digital cameras.
- Special Effects: Most special effects filters like motion blur, and other swirly blurs and such can be easily done in post. These are for the most part obsolete in digital imaging.
Screw in filters are the most common and tend to be made from high quality glass and even offer multicasting in some cases. Brands like B+W, Hoya, and Tiffen are top choices. But for many photographers buying these types of filters can be troublesome when various lenses in the kit have different sizes. In general one should buy the larger size and then seek out a step down ring to allow the filter to be used on smaller diameter lenses. bear in mind that this may interfere with the use of a lens hood on the smaller lens. Stepping rings are much cheaper than filters however.
Another possibly is use of square polymer filters that mount in a filter holder and utilize adapter rings to fit a variety of lens sizes. These are usually 3×3 inches or 3.5 inches square. They are ideal for any graduated filter as the photographer has the ability to mount the filter with the graduation line anywhere in the frame rather than limited to the middle.
Even further, many filters are now available as a clip in for popular DSLRs and mirrorless bodies. These filters literally clip into place in front of the sensor and allow the use of any lens in front of it. Photographers must be careful when installing and removing them as they are only a few millimeters in front of the sensor. Scratching or damaging the sensor or the shutter curtain in front of it is very expensive to repair. I use clip in filters for my astronomy and my IR cameras, but tend to use tradition filters with my standard cameras.
I hope that helps, be sure to visit Tim Rice on Saturday, he has thousands of filters.
'Couv' Camera 