Using lens bokeh as a design element
In previous articles we could see how a fast 85mm can be used for shallow depth-of-field to shoot nearly anywhere by melting away the background. There’s another aspect to this – the bokeh of the lens. The bokeh is a reference to how the quality of the background blur is rendered by a lens. It can be smooth, or have “jittery” patterns to the edges of objects, and the highlights.
Do note though that bokeh and shallow depth-of-field are not quite the same thing. While the DoF / choice of aperture does affect the appearance of the bokeh of a lens, the shallow depth-of-field look isn’t “bokeh”. Similarly, you can’t do something like “add more bokeh”. Bokeh is the quality of that background blur. It’s mostly an aspect of the lens design.
Now, very often, when a fast prime lens is used wide open, there’s a kind of swirly feel to the background blur – and if you’re aware of this, and find an appropriate background, it can really accentuate the portrait.
The image at the top of Jen & Corby, was shot at f/1.4 and you can see how the background behind them has a distinctive circular swirl to the out of focus high-lights.
Stopping down to f/2.8 you can see this characteristic has changed subtly. In other words, the bokeh has changed. The look to the background blur has changed. (Co-incidentally, the DoF also increased.) While with this second image I did change my position, and the two images can’t be directly compared for specific detail, you can see that the characteristic of the background blur has changed.
Camera settings for the image at the top: 1/320 @ f/1.4 @ 200 ISO
Of course, at such shallow DoF as f/1.4 and photographing a couple, extra care need to be taken to ensure they are both in focus.
Here is the 100% crop of the image at the top which was shot at f/1.4 and I knew that not every shot would work. The DoF is so shallow that it feels if you just breathe, your focus is out! So you have to get used to the idea that your success rate in terms of sharp images, will go down.
The way the background blur (the bokeh) appears, will differ from lens design to lens design. And a fast aperture is not necessarily an indication that the bokeh will be great. Many fast 50mm lens designs are notorious for having poor bokeh. Fast 85mm lenses tend to have wonderful bokeh, and this is something you can play with – using that specific look. Not all 85mm lenses have grey bokeh though. The Nikon 85mm f/1.8D had notoriously poor bokeh, but this was fixed with the f/1.8G update. Check review of the Nikon AF-S 85mm f/1.8G
- 85mm – the best lens to change your portrait photography
- 85mm f/1.4 portraits in the studio
- Shallow depth-of-field does not mean good bokeh
- Other articles on bokeh
Recommended 85mm lenses
The faster lenses are a bit more spendy than the f/1.8 optics, but the change in depth-of-field is incremental. You’d get a very similar effect at f/1.8 so if your budget is limited the f/1.8 optics are excellent choices too. In fact, I’d say the Canon EF 85mm f/1.8 USM (affiliate) is arguably their best lens for the best price. Similarly, the Nikon AF-S 85mm f/1.8G lens (affiliate) too is an optical gem at an affordable price.
The faster lenses are a bit more spendy than the f/1.8 optics, but the change in depth-of-field is incremental. You’d get a very similar shallow depth-of-field effect at f/1.8 so if your budget is limited these are excellent choices too.