Skip to main content

Circular ND filters vs square ND filters

Good quality digital photography accessories can easily make a photograph look different. After tripods and flash units, one common accessory that can completely change the look of a DSLR photo is filters. Filters can be considered as a fairly good option if you are looking to improve your photography skills. Various types of photography filters include polarizers, infrared, neutral density and UV filters. To maintain the simplicity of this post, we will focus on neutral density filters only.

A neutral density filter is nothing but a piece of dark glass. The purpose of a neutral density filter is to reduce the amount of light entering the camera lens and thus hitting the sensor. ND filters with a constant density of darkness throughout are known as constant ND filters whereas ND filters with variable density of darkness are known as variable density ND filters. The density of darkness offered by a variable ND filter can either be smooth or hard. 

Square filter or circular ND filter

Let's focus on the shapes of ND filters. A neutral density filter can either be circular or square in size. Some ND filters come in a rectangular shaped glass too. Circular ND filters are also known as screw on filters as they can directly be screwed onto the lens thread. Square shaped filters do not have any thread, and therefore need a filter holding unit that gets attached to the lens. The filter glass along with light leak gasket can be pushed into the slot offered by lens holding unit. The image below shows my ND 3.0 filter from Haida. ND 3.0 means it is a 10 stop neutral density filter. If you want to know more about ND filter naming, here is my previous post about the naming nomenclature of neutral density filters.

Circular vs square nd filters

Most of the square-shaped neutral density filters come with a rubber gasket attached to them on the backside. The purpose of the rubber gasket is to prevent any light leakage when doing long exposures. The image below shows a generic holding unit for square shaped filters. The metallic part on the top is spring based and gets locked onto the ring attached to the camera lens.  This ring varies in diameter depending on the lens thread size. Example: 58 mm, 77 mm, etc. A 77 mm lens will need a different ring, but the same holder unit and ND filter can be used. So you see the advantage part now? No need to buy new filters again just because you upgraded to a new lens. All it needs is a threaded ring to hold the attachment for ND filter.

Circular ND filters vs square ND filters

Both screw-on and square ND filters perform the same role, but like any other photography discussion, which one is better? When it comes to circular ND filter vs square ND filter talk, here are a few advantages of a circular screw on ND filter:
- Easy to use and carry. Being smaller in size, circular ND filters are easy to carry around.
- Fewer chances of breaking.
- A variable density circular ND filter darkness level can be changed by rotating the filter. This doesn't apply to fixed density ND filters where the darkness is same throughout the filter.

Advantages of square ND filters:
- Cheaper longer term. It is easier to adapt to various lens sizes with a square-shaped filter.
- Less interference and vignetting.

Hope this post helped you to learn something new about filters. Based on the above discussion, which filter are you going to buy? Share in comments.


Popular posts from this blog

sRGB vs Adobe RGB colour space explained

Digital images are everywhere, both offline and online. Each digital image is made up of a large number of square sized individual pixels. Zoom into an image at 2000 % or more in any of the viewers, you will see these pixels. Here is an example:

In order to categorize pixel colours, RGB and CMYK are the two widely used colour models. According to the RGB colour model, each pixel colour can be considered as an addition of different shades of red/green/blue light. These light shades are calculated according to the bit depth of the image. Jpeg images are usually 8 bits per colour channel (red, blue or green), which means 2^8 ( 256) different shades of each red/blue/green colour are possible. Few examples to make it clear how different colours shades are represented:
Red: (255, 0, 0)
Green: (0,255,0)
Blue: (0,0,255)
White: (255, 255, 255)
Black:  (0,0,0)

What does CMYK do? It is a subtractive colour model for printing purposes and stands for Cyan, Magenta, Yellow and Black. According to …

Digital photography histogram explained for better photos

The ability to read histograms in digital photography is an excellent skill that every photographer should have. Getting a properly exposed shot is crucial when it comes to photography, and using the histogram is a solid way to achieve it. That 2 to 3 inch LCD screen located on digital cameras is only a quick way to look at the photo exposure and its details. In harsh lighting or vivid ambient lighting conditions, it can prove to be misleading to the human eye. Sometimes the LCD brightness level can also create issues with judging the exposure of a shot. So what does histogram explain about an image? How can histogram help you to take better images? In this beginner-friendly post, I will try to answer these questions. You can consider it as a tutorial or cheat sheet for digital photography histograms.
Photography histogram image examples: The histogram is basically a mathematical way of representing data, and it applies to digital image information too. In digital photography, histogr…

Darktable vs Lightroom Classic CC

I first heard about Darktable software in 2016 and actually was quite fascinated with the name itself.  Within a few hours of hearing about it, I went to the official Darktable website and downloaded it on my Linux machine. Have been using it for quite a while now alongside Adobe Lightroom Classic CC and hence decided to write this small review post. If you are looking for a free Adobe Lightroom alternative, this might be or might not be for you depending on what you need.  Darktable is a free open source post-processing software which can do non-destructive RAW photo editing and photo management. Non-destructive means it does not change the original RAW file, all the edits are written to a sidecar file. It has evolved through so many phases of bug fixing and operating system compatibility. The latest version is available for Linux, MacOS, and Windows. Being an open source software it doesn't surprise me that it is available in 21 language translations. That's the power of op…