Will f/1.4 produce better bokeh than f/1.8?

Will f/1.4 produce better bokeh than f/1.8?

That depends upon the lens design.

I suggest you visit a local camera shop and try out both lenses on your camera.

Copy the "test" shots to your computer and view the results on your computer monitor at 100%.

Only then will you know which is best for you.

My favorite lens for producing buttery out of focus backgrounds is a very old Nikkor 105 mm f/2.5 lens. This lens was built in about 1970, using a very old lens design. It used a Sonnar type design from the early 1950's

Since I typically set the aperture at about f/8, to assure good depth of field from the tip of my models nose to the back of their ear, being able to produce a nice soft out of focus back ground is essential when shooting head shots

For the same focal length, using that lens at full aperture, f1.4 will produce more extreme "bokeh" than f1.8. But some lenses make better looking bokeh, and that is alway a personal opinion.

As you noticed, "better" is subjective.
The f/1.4 lens will have a more shallow depth of field wide-open, that's all we know for certain.
Things that typically contribute to "better" bokeh are more aperture blades (so you don't get pentagonal out of focus highlights), more baffling in the lens (so you don't get as many internal reflections that make bokeh appear "noisy"), and the optical design of the lens itself. So it depends on *which* f/1.4 and f/1.8 lenses you're comparing. As someone already pointed out, the best way to determine if a lens is going to give you what you want is to go try the lens out, shoot some test shots, and compare the shots side by side.

Like fhotoface, I find older lenses often have much more pleasing bokeh. My favorite is a Vivitar 135mm f/2.8 I bought new in 1977, that I still have and use (it's a Pentax screw mount, and I use it on my Canons with an adapter). The out of focus backgrounds are silky, smooth, and creamy -- and the 8-bladed aperture makes nice round out of focus highlights.

It depends not only of f/1.4 or 1.8, but of focal length also. Choose 85mm+ lenses for your cropped or fullframe camera. Check if a lens has more than, say, 7 aperture blades. If yes then could be a perfect choice for portrait photography.

You could find out what lenses are suitable for different genres of photography with you camera with Photo Lens Finder: https://itunes.apple.com/...d828348957