Bokeh originated in the Japanese word [boke], which means blur. Today many photographers are going out and buying the ƒ/1.4 lenses to get that silky smooth background for when you shoot the lens wide open.
If the reason I am reaching for a lens based on getting a silky smooth out of focus background I might be wasting my time. You see so much of what I shoot is with the AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR and to take the lens off to put on my AF NIKKOR 85mm f/1.4D IF I could be just creating an unnecessary step.
If you compare the lenses at the same aperture and focal length then it would make more sense to grab the 85mm ƒ/1.4. As you can see in the photo below shot on the 85mm @ ƒ/5.6 the background isn’t all that silky Bokeh.
Shooting however at ƒ/2 you are seeing a major difference on the 85mm as compared to itself. But now compare it to the first photo on this blog shot with the 28-300mm when the lens is zoomed in to 300mm and shot wide open at ƒ/5.6. I am having a really hard time seeing any difference in the Bokeh.
When shooting at ƒ/1.4 with the 85mm the depth-of-field is tad bit more shallow than the 300mm @ ƒ/5.6.
This is where you might just be scratching your head as I was after doing this little test.
The trick to getting that really silky smooth background has as much to do with how close you are to the subject as the ƒ-stop.
I would argue that if you are wanting that shallow depth of field with a creamy Bokeh you can do it with the 28-300mm ƒ/5.6 and not have to buy another lens to carry around.
There are other reasons you might want an 85mm ƒ/1.4 in your bag–stay tuned in for that post later.