From the start we've said photography is very subjective, and if there's something that highlights that condition, it's the use of filters. Some apply them exclusively through digital means, while others feel more comfortable using physical filters installed in front of the lens. The correct use of a filter can transform an ordinary photo into an extraordinary shot, but to achieve that we need to know its benefits thoroughly and know the right moment.
Filters have the ability to give a photograph that small extra push it needs, or ruin it completely. Just go through Instagram to see what its users do with filters. It's very hard to call photography what that service offers, with its stamp-sized images, the plague of selfies, and the constant contradiction between images of food and gym addicts… but I'm getting off track. Both enthusiasts and professionals of photography play with filters, and although the digital route is convenient, real filters carry a more natural profile, or at least that's what you hear. Truth be told, certain photography competitions prohibit the use of digital filters in their rules, because of the things achievable with the assistance of advanced tools. Of course, investing in filters is a complex process, since the photographer must know in advance which ones they'll need, and not fall into the trap of cutting their budget too much. A bad filter is equivalent to a bad image, and no matter how many times a capture can be repeated, what's lost in the end is time and money. That said, let's look at some filters:
UV and Skylight
For years we've known these filters as barriers to protect the lens, which is definitely what you want to do. Bad luck isn't limited to a lost capture or dead batteries at the last instant. A hit or scratch on the lens can have dire consequences, and in the face of that possibility it's always preferable for the filter to serve as the sacrifice. Still, filtering ultraviolet light (UV) and exercising greater control over the blue color (Skylight) isn't a bad idea for certain photos.
Infrared
No, this filter has nothing to do with the thermal vision of Predator. Its general role is desaturation (the RAE will excuse), that is, blocking colors to play with paleness and grays that appear in certain scenarios, especially those with lots of vegetation, vast forests, and water. Now, don't take that as a rule by any means. Photography demands that we explore, and if you think an infrared filter will provide solid results on a shot, go ahead.
Polarizer
A workhorse if you'll allow the expression, the polarizing filter is widely used to optimize contrast in a photograph. At the same time, it also removes unwanted reflections on surfaces like water and glass, and many photographers swear by its excellent effect on transparencies. If the scene already carries a lot of contrast, the polarizing filter would be redundant, and experts suggest that the light source be positioned to the sides.
Enhancer
The concept of temperature is very important in any photograph, and that's when the enhancer filter, also known as the intensifier, comes into play. What it does is completely ignore most colors, but saturates those considered warm. If for some reason an area looks too pale when it should have a more desert-like profile, or the rust seems too dull, the enhancer filter could help. Obviously, moderation is recommended so as not to place too much heat into the image.
Neutral Density
Just like with the polarizing filter, the neutral density filter has enormous relevance for any photographer because it reduces the amount of light received by the sensor. The neutral density filter has no influence on color, but if the plan is a long exposure with a low shutter speed, it presents itself as a good ally. Now, a smaller amount of light on the sensor has consequences, and if you notice that the camera struggles to focus, you'll most likely need to give it a hand. What would be a good starting point? All arrows point to three or four f-stops to begin.
Graduated
For some photographers, the graduated filter should be placed in the category of effect filters, but others prefer to mention it separately. Something like a not-so-distant cousin of the neutral density filter, the graduated filter stands out when balancing contrasts, which again implies a reduction of light. Depending on the situation, we'll find neutral or colored variants, which to some extent will tint the scene. For greater flexibility, the recommended approach is to use the square style, with a compatible filter holder.
Color
Finally we come to the color filter, although at this point opinions diverge a bit. Some photographers believe that with the use of white balance, color filters are easily replaced, while others stick to the traditional method of saturating one color above the rest. They're quite inexpensive, and very popular in black-and-white photography.
At the end of the day, it's you who decides whether to use filters or not, or if you prefer digital solutions to individual filters. There's also a budget question that must be carefully evaluated, but that's very common in the world of photography. As a closing note, I'll just say this: Take your camera and go look for something to photograph. Every tutorial has its limits, and you won't become a better photographer staring at a monitor, but by taking photos. Good luck!
