General
Variable vs fixed ND filter: Which is better to choose?
ND filters are a must-have accessory for any photographer or videographer dealing with bright light. The question is: should you go for a fixed or variable ND filter? In this blog, we'll explore the differences, advantages of each filter type to help you make an informed decision.
How fixed and variable ND filters work
All neutral density (ND) filters serve one purpose to reduce the amount of light entering the camera lens. They do not change the image colour but allow for the use of wider apertures or slower shutter speeds in bright light. The amount of light ND filters cut is measured in stops; the higher the stop is, the less light enters the lens.
Classic fixed ND filters have a single, unchanging level of light reduction, e.g. 2-stop ND, 6-stop ND, etc. One filter – one certain stop. These ND filters are made of a piece of glass or resin with a uniform ND coating and can be in circular or square/rectangular shapes.
Variable ND filters offer a range of stops, e.g. ND filter with 1.5-5 stops. They allow you to regulate how many stops of light you want to cut. Variable ND filters are built differently: they consist of two polarising layers. By rotating the outer layer, you can adjust the light reduction level.
Pros and cons of fixed ND filters
Fixed ND filters are usually a go-to choice of professional landscape photographers. After taking a look at the advantages and disadvantages, you’ll understand why.
3 main advantages of fixed ND filters
- High quality consistent across all images: Because of how they are built, fixed ND filters do not introduce polarisation artifacts as variable filters do. They have better colour accuracy and do not degrade the image quality. And since fixed ND filters have a single density, this quality is consistent.
- Maximum performance: Fixed ND filters often perform better at extreme levels compared to variable ND filters. Even with a high stop of light reduction, you get an image of good quality.
- Less vignetting or no vignetting at all: Circular fixed ND filters typically produce less vignetting. With a rectangular ND filter of fixed stop, you can forget about this problem (just be sure to pick the right size for your lens).
Disadvantages of fixed ND filters
- Less flexible: You can’t easily jump from one stop to another. If you want some flexibility to be able to shoot in different lighting conditions, you'll need to buy and carry with you multiple ND filters.
- Slower to change: Changing ND filters, especially if they are screw-in, can be cumbersome and time-consuming during a shoot. It can be quicker to do this with magnetic ND filters though.
Kase top fixed ND filters for quality lovers
Pros and cons of variable ND filters
Some photographers tend to demonise variable ND filters, saying they are much worse than fixed ones. It depends on the situation which filter to use, but variable ND filters definitely have their pros and cons.
Advantages of variable ND filters
- Flexibility: That’s probably why you are looking into these filters, right? They do not offer just one stop of light reduction, the range is usually around 4 stops of light. Variable ND filter is especially convenient when shooting in quickly changing lighting conditions.
- Quick to use: You do not need to stack or swap filters while shooting, by turning a filter it takes a second to adjust the light reduction level. That allows you to capture more material without spending extra time.
- Easy to transport: Only one variable ND filter is needed to cover the range of stops. That means you need to carry less with you!
Disadvantages of variable ND filters
- Cross-polarisation (X-pattern): The crosshatch effect (when you see the dark X on the photo) can appear with a variable ND filter when used at the maximum density. This is due to the uneven polarisation at extreme settings. To avoid this, do not go over the maximum value suggested by the manufacturer.
- Possible vignetting: Variable ND filters are generally thicker than fixed ND filters, which might cause vignetting, especially with wide-angle lenses.
- Colour variations: Some variable ND filters may cause a colour shift, affecting the overall colour balance of your photos or videos. This usually requires post-processing correction.
- Cost: A variable ND filter has a complex construction, that is why they usually cost more than fixed ND filters. However, if you choose between several fixed ND filters or one variable, it will most likely be cheaper to buy one variable ND filter.
It’s worth noticing that the issues with image quality caused by variable ND filters are minimised when the filter is of high quality. For example, colour accuracy will be much higher if the filter has an optical glass with nano-coating. If you want to enjoy the convenience of variable ND filters, pay attention to the quality of the filter and don’t buy super cheap ones – they may ruin your images.
Discover high-quality variable ND filters from Kase
Variable vs fixed ND filter: what is better for photography?
Choosing between variable and fixed ND filters depends on your specific needs and shooting style.
For photographers who prioritise image quality and shoot in stable environments, fixed ND filters are the way to go. For example, if you shoot landscapes and you’ve got time to compose the shot, fixed ND filters will work for you better.
On the other hand, if you need versatility and ease of use, especially when moving between different lighting conditions, variable ND filters may be a good choice.
Variable ND filter vs fixed for video
Videographers use both variable and fixed ND filters, but the choice usually depends on the workflow.
Variable ND filters for shooting videos
In video production, maintaining a consistent shutter speed and aperture is crucial for achieving a cinematic look. Variable ND filters let you control exposure without changing these critical settings and interrupting the process, ensuring a smooth, professional-looking video.
Variable ND filters are more versatile and perfect for documentaries, travel videos and other scenarios where lighting changes rapidly.
Fixed ND filters in videography
While less flexible than variable ND filters, fixed ND filters still have their place in videography. They are used to achieve high image quality in controlled lighting conditions, like in the studio. Also, fixed ND filters can be used for a planned shooting outdoors: for example, if you shoot only one scene and the light is consistent.
Conclusion: is it better to buy a variable or fixed ND filter?
For photographers focused on high-quality results, fixed ND filters may work better. On the other hand, for shooting scenarios requiring quick adjustments, such as run-and-gun video shoots or outdoor portraits, variable ND filters work best.
If you are still in doubt about which filter fits you best, don’t hesitate to contact us!