Has it ever occurred to you that your images at Pond5 were rejected because they were too noisy? Noise is one of the most frequent reasons why photos are, according to our curators, technically insufficient. Here is an article that will help you understand what noise is and why it is undesirable, and most importantly, what to do to avoid noise and to have your photos accepted next time.
Noise in digital photography appears when individual pixels on the sensor create unwanted data. The photo looks grainy, sometimes you might notice that each pixel has a different colour. Grain is usually not considered a problem in art projects; in analogue photography, grain is perceived as one of its aesthetical elements, which makes the photos especially charming. However, such photos will be unusable for commercial purposes because noise is distracting. Additionally, customers often need to print photos in large format, which poses usage limitation to any photo that are not technically flawless.
The ISO value is the sensitivity of photographic material to light. The less light reaches the photographic material (or sensor in digital photography) the higher ISO value needs to be set in order for the photo to be taken. Usually, cameras can be set to ISO values from 100 to 3200, but a few models offer lower or higher values.
ISO noise appears most often in photos taken in poor light conditions. The most common example is night shots. Unlike the camera sensor, the human eye is a very flexible tool, so usually we would set lower exposition values than those which are needed indeed (for example in cloudy weather or dim light).
How noisy will the image be with different ISO values? It depends on the size of the sensor pixels of your camera. The smaller the pixels, the less light they can absorb, which leads to more noise. Generally speaking, when the ISO values are kept below 200, the noise is negligible when using most cameras. With higher values, the difference between simple compact cameras and professional DSLRs becomes obvious – DLSRs usually have built-in noise reduction software.
Colour noise in long exposures
Another type of noise is colour noise, which can appear when using low ISO values in combination with long exposure times, especially extremely long (in minutes). The sensor is warming up over time, which leads to single pixels of different colours in solid areas of another colour.
Just like ISO noise, the amount of colour noise varies for different cameras. If you are using a high-end DLSR camera, this is usually a negligible problem.
Because colour noise is caused by the sensor warming up, photos that are taken at the beginning of the photo session will be less noisy than the last ones. It is also good to turn on the Long Exposure Noise Reduction feature on your camera if you shoot long exposure shots.
How to avoid noise?
The key to avoiding noise is a properly set exposition. The easiest way is to use the lowest possible ISO value in combination with the fastest possible time (faster times prevent the photos from being blurry). It is recommended to use ISO 100 or 200, but it depends on the capabilities of your camera. Of course, it is necessary to keep an eye on the correct exposition, and to adjust the aperture and lighting accordingly to the set ISO value and exposure time. If the photo is too dark with low ISO, you can try using flash (but it depends on what you are shooting and you have to use it carefully).
It is also better to shoot in RAW format, which contains a lot more information and provides more options for further editing. It might be difficult to understand for basic users though.
Should you use software features of your camera, for example, sharpening or auto noise reduction settings? If you are a beginner and you are not that experienced with image editing software, you can try these features out and see if they are worth it in your specific case. Advanced photographers prefer to shoot a photo as it is and to apply filters like these in the postproduction, where they have more control over their settings.
How to get rid of noise?
Mild noise can be removed or at least moderated with various image editing software. You might apply special noise-removing filters to your photo or select specific areas of uniform colour (for example the sky) and blur them a bit. The most popular software is Adobe Photoshop, but there are also other alternatives (Zoner Photo Studio for instance). In Photoshop, you might use the Reduce Noise filter, which slightly blurs the image in order to smooth the noise. That might be a problem, so it is always better to apply it to selected areas only using a mask.
However, you have to keep in mind that the best choice is to use proper camera settings while shooting. The better quality the original photo, the better the result and less work for you. Photos with strong noise usually cannot be saved at all, because a strong post-production does not look natural, and we will most likely reject the image. It is necessary to be careful when fixing noisy photos. Adding contrast or saturation makes the noise more visible.
If you cannot or do not want to use image editing software to remove the noise, a quick fix can be downscaling the photo to 2MP size (which is the smallest size that Pond5 accepts). The smaller the photo, the less visible are technical imperfections. This trick can also help if your photo is not perfectly sharp. However, you are risking that for some customers might 2MP size be too small.
Pro tip: Always check the technical quality of your images in 100% magnification before you submit them to Pond5, and keep an eye on any possible noise, insufficient sharpness and chromatic aberration. The Pond5 curatorial crew will be looking at the same things, and based on them decide whether your images will be accepted or not.
Did you enjoy these tips? Next time we will focus on chromatic aberration. Subscribe to our blog and stay tuned for more on our Photohelp series!