Bokeh – quality of lens blur
The way that a specific lens renders the out-of-focus areas in the background (ie, the bokeh of the lens), is always an interesting aspect of any lens’ behavior. If the out of focus areas show hard edges, or highlights with a kind of double edge, then the bokeh can appear intrusive. Then it is called harsh bokeh. If the out of focus areas are smooth without the edges being defined, then the bokeh is described as being pleasant. And then on occasion, you get bokeh that is … well, let’s just call it ‘interesting’.
I noticed that the Nikon 105mm f/2.8 VR macro (affiliate) can at times show a weird circular swirl in the background. It is especially noticeable if there are bright out of focus highlights. The photo at the top shows this clearly, even with a background that should appear smooth. In comparison, we can see how the famed Zeiss Makro-Planar T* 100mm f/2 ZF (affiliate), renders the highlights. Smooth. Just as you’d expect from a lens with such a reputation. (Both images were shot at f/2.8 although the Zeiss is capable of f2 which is exceptional for a 100mm macro lens!)
Just for interest here, I thought of showing how a few other lenses compare in how they render the background. The simple portraits here of Jessica, my assistant, aren’t as controlled as they need to be for specific comparison, but will still give an idea of how these lenses perform in terms of their bokeh. Jessica stood still, and I tried to maintain more or less the same distance and point of view. Next time, a tripod for sure. To make the comparison here, all the lenses were used at f/4 in the following examples. With the zooms, I tried for an 85mm focal length.
Just a quick note – keep in mind that shallow depth of field is NOT the same thing as bokeh.
The Canon 85mm f/1.8 (affiliate), is a gem of a lens. Affordable, and with speedy auto-focusing and great optical quality … including stellar lens with a very good reputation for speed of auto-focusing. On top of that, this lens has superb bokeh. Just look at how smooth the out of focus areas are!
The Canon 24-105mm f/4L zoom (affiliate), has superb image sharpness for such a wide-range zoom, but typically of the wide-to-tele zooms, the bokeh can be intrusive. You can see the background is more noticeable here when compared to the Canon 85mm f/1.8
The Nikon 24-120 f/4G VR II (affiliate), exhibits similar bokeh – little too busy, and not as smooth as some of the prime lenses. You can see it in how the circular highlight appear. Neat little lens though as a general purpose lens.
Here is the new Nikon 85mm f/1.4G (affiliate) … and as expected from the update to a lens renowned for superb bokeh, the background appears smooth. The circular highlights are smoother than shown in the two photos by the wide-to-tele zooms.
Out of interest, I wanted to see how the Nikon 70-200mm f2.8 VR II zoom (affiliate), performed compared to the 85mm (used at f4), but something odd happened. With the new zoom’s known ‘focus breathing’ issue, the focal length at such a short distance had changed and the angle of view was wider than the 85mm focal length I was trying to maintain for this series of images. So I had to zoom to around 130mm to get approximately the same portrait size … but now in comparison, this lens has a much softer background. From this, the bokeh looks incredible, but I wonder how one would be able to make a fair comparison if the focal length changes.
This wasn’t a scientific or controlled test by any means, but hopefully the examples shown here will give some idea of how good and poor bokeh compares .. and of course the “interesting” bokeh of the Nikon macro.
- How to get a blurred background in photos
- review: Canon 50mm lenses – bokeh
- Using lens bokeh as a design element
- Bokeh vs shallow depth-of-field (DoF)
- Review: Canon 135mm f/2L vs. Canon 70-200mm f/2.8L IS II