Loïc Magnien Street Photography About Lens Filters 26

About Lens Filters

Post Process it

With recent softwares you can absolutely apply filters to your photos in post processing however some filters can’t be reproduced digitally yet, hopefully machine learning will help with it in the future. The filters you can reproduce depend on the software you are using but most of the colour filters are totally fine to reproduce, other filters in comparison, as the CPL (Circular Polarising) can produce results that are difficult to impossible in post processing: cutting aerial haze, intensifying a blue sky and controlling colour saturation in foliage. Here are some I think are still worth buying.

Ultra Violet

An ultra violet (UV) filter reduces light above a certain frequency. As the sensor doesn’t record this frequency range separately, it can’t be recreated in post-processing. Note that this is not a big problem for digital cameras as most of the recent sensors embed a UV filter and are generally not so sensible to UV. The main purpose of UV filters is the protection of the front element of you lens, particularly if you have a fixed lens camera.

Polarising

A polarising filter removes light beams with a specific angle. As the sensor doesn’t record the angle of the light beams, it can’t be recreated in post-processing. You can always bump up the colours with the vibrance to achieve the blue skies often shown as typical examples of polarising filter use but you won’t be able to remove the reflections. The preferred version is the CPL (Circular Polarising) so you can polarise the light in the direction you want regardless of your frame.

 

 


 

Neutral Density

Neutral Density (ND) filters are pretty useful when it comes to using wide apertures in good light conditions, i.e. trying to achieve background blur in daylight. That’s situations in which you camera will increase the shutter speed to the limit. thus, another usage of ND filter is to decrease the shutter speed and introduce any kind of blur. ND filters are pretty useful to maintain a 50 FPS shooting in daylight, that’s part of the reason why videographer often have different densities of ND filters. In my case the Fujifilm X100F as a 3 stops ND filter built into the lens.

 

 


 

Star

Star filters are dramatic multi-point light flares or rays of light also know as a “star effect” to bright or strong point light sources in a scene. It also gives a slight soft focus effect. They are great for Street lamps at night or for photographs of jewellery or other objects with strong specular highlights or reflections. They come in different arrays, 4, 6 or 8 spoke stars. Result is so kitch !

 


 

Soft

Soft focus filters are used for reducing the local contrast in an image, and sometimes also for adding a kind of dreamy glow. The main use for this is in portrait photography – the filter reduces the appearance of fine detail such as skin pores, giving a smoothing effect. The effect is not the same as just blurring an image. A good quality soft focus filter reduces the contrast of fine detail rather than blurring it away. You can totally post process it.

 


 

Close-up

All lenses have a minimum focusing distance, which is as close as you can get to an object and still have it be in focus. A +2 filter will make it possible for a lens with a minimum focusing distance of 1 meter to now focus on something .3 meters away. A +10 filter would decrease the minimum focusing distance to .09 meters. To know your new focal lengh, the formula is : 1/newfl = 1/fm + 1/fc, where fm and fc are respectively the main lens’ and closeup filter’s focal length. Close-up filters are also very inexpensive and you can often find a set with three or four filters that will work with your lens.

 


 

What size should you buy ?

The size of your bigger lens diameter. this way you only buy one of each type. Good quality filters are expensive and you are better to buy good quality than cheap filters. So if you have 5 lenses and want to get a UV, CPL, Star, Soft, Close up for each of them, you are going to end up spending too much money. The trick is to use step up rings to adapt the bigger diameter filters onto your smaller diameter lenses. Step-up adapters rings are very cheap, just make sure you you go through all the steps of your lenses.

How to store them ?

You want to avoid dust getting onto your filters. Usually you’ll be sold a filter case or pouch, they are fine if you plan on carrying your filters in a backpack as they tend to get bulky because they are usually designed generically for bigger diameters filters. I opt, as always, for a rather unconventional way, I use a notebook that comes with a zip pocket to store business cards or other flat items… like filters.

 

If you buy step-up rings you can also thread them all together and store them instead of a lens in your kit.