Sometimes, there will be instances or occasions where dreamy looking effects such as soft focus help enhance the qualities of a great photo. This is specially the case in portrait photography or photography by documentary wedding photographer where such effects are being done to give a soothing effect to otherwise unpleasant fine details such as skin pores.
As such, this effect is not the same as blurring at least the elements of the image in question as the former still preserves the fine detail rather than blurring it away.
So how can a photo achieve such effects? There are a number of options available.
Soft Focus Filter
Probably the easiest and most obvious way to achieve this effect is to purchase a soft focus filter that you can place in front of your camera’s lens
Generally these filters are quite high quality, reducing the contrast of the image and adding a slight glow, while not having much effect on the resolution. On the other hand, they can be expensive, and if you want to adjust the amount of softness, you will have to purchase multiple filters in different strengths.
Clear filter plus Vaseline
If purchasing filters cost too much for your budget, there is an alternative available, using a clear glass filter and then putting some vaseline (petroleum jelly) on it.
For the glass filter, a cheap UV filter would do just fine, which is readily available online and in photography shops. The optical quality won’t be great, but as you’re going to be smearing vaseline all over the filter, that doesn’t really matter too much. Just be careful in putting too much vaseline on the filter (unless you want a really blurred effect). A tiny amount applied on the filter would do just fine.
With this technique, you can easily control the area of the frame will have the softening effect applied. You also get to control the amount of blur or glow by adding or removing vaseline from the filter.
Stockings over the lens
Another cheap DIY alternative is to stretch a piece of stockings or tights over the front of the lens. This thin material with its fine mesh acts as a diffusion filter, creating the softening effect. Just cut a piece of the stockings out large enough to stretch over the front of the lens and down the sides a bit. Then use an elastic band to hold it in place round the lens. The tighter the stretch, the less of an effect they will have.
Remember though that the color of the stockings can affect the color balance of the image. Black or gray stockings will be relatively neutral, while more flesh colored stockings may introduce a warmer color cast. (which is many cases can be a good thing)
You can also try using tulle netting, the material used for making bridal veils. This is available in a wide variety of mesh sizes and mesh shapes.
Adding the effect in post processing
A soft focus effect can also be achieved by taking an image shot normally, and then adding the effect using image editing software. One of the easiest ways to do this to use the clarity control feature present in Adobe Camera RAW or Lightroom or in some other software, though it may have a different name like tonal contrast.
Clarity control affects the microcontrast of an image. Using a negative clarity value reduces the microcontrast in a similar way to using a real soft focus filter.
The benefit of this technique is that you can specify in the image or part of it exactly how much soft focus you want, made possible by tools such as the adjustment brush in Adobe Camera RAW or Lightroom.
Using a soft focus lens
There are various soft focus lenses available that can give you soft images without the use of a soft focus filter. Many of these lenses allow you to control the degree of softness in an image through undercorrection or overcorrection for spherical aberration.