Nikon 85mm f1.4 vs Nikon 85mm f1.8

A Simple Comparison

Don’t ask me why, but I decided to “upgrade” my Nikon 85mm f1.8 lens. It is a great lens, but I read in various reviews and news groups that the 85mm f1.4 was sharper than the f1.8 at f2 and f2.8, so I thought it would be great to have a sharp lens for low light situation where I had to shoot with a wide aperture. So I got the f1.4 (new) as my Christmas gift.

When I started taking portraits of my son, I noticed that the results with the f1.4 were not as good as what I remembered with my old f1.8. So I decided to run the tests described below, and indeed my old f1.8 was sharper at f2 and f2.8 than the new f1.4! At f4 and f5.6 they were roughly the same. These results were for a distance of about 15ft, which is in the ball park that I use most often with an 85mm.

I repeated the tests at a closer distance (6ft), and here the f1.4 was a bit sharper. But since I do not usually shoot that close up, these results were not as important to me.

The results are of course only valid for the two lens samples I used. I do not know if my f1.4 lens was below average, or if my f1.8 lens is way above average. But in my case it did not make sense to own this particular f1.4 lens just to be able to shoot at f1.4 where it is clearly not very sharp. So I returned the f1.4.

Setup

I used the target found at photo.net at http://www.photo.net/learn/optics/. Camera was a Nikon D1x with mirror lockup and using the timer to avoid camera shake. Tripod was Gitzo 1320 with Arca B-1 ballhead. Raw images were processed with Bibble and then sharpened in Photoshop (setting 180-1-3). (Conclusions are the same if you look at unsharpened images; see last set of images below.) Note that D1x has higher horizontal resolution, so vertical bars always look sharper. The images at 15 ft cannot be directly compared to those at 6 ft since they show different parts of the test target. All images below show small crop where differences can be seen, at full resolution. First two sets of images taken with flash; second two sets without.

Results at 15ft (Flash & Sharpening)

f1.4 @ 1.4 ................................................................................... ..... f1.8 @ 1.8

f1.4 @ 2 ................................................................................... ..... f1.8 @ 2

f1.4 @ 2.8 ................................................................................... ..... f1.8 @ 2.8

f1.4 @ 4 ................................................................................... ..... f1.8 @ 4

f1.4 @ 5.6 ................................................................................... ..... f1.8 @ 5.6

Results at 6ft (Flash & sharpening

f1.4 @ 1.4 ................................................................................... ..... f1.8 @ 1.8

f1.4 @ 2 ................................................................................... ..... f1.8 @ 2

f1.4 @ 2.8 ................................................................................... ..... f1.8 @ 2.8

f1.4 @ 4 ................................................................................... ..... f1.8 @ 4

f1.4 @ 5.6 ................................................................................... ..... f1.8 @ 5.6

Results at 15ft; No Flash; with sharpening

f1.4 @ 2.8 ................................................................................... ..... f1.8 @ 2.8

f1.4 @ 4 ................................................................................... ..... f1.8 @ 4

f1.4 @ 5.6 ................................................................................... ..... f1.8 @ 5.6

Results at 15ft; No Flash; No Processing

f1.4 @ 2.8 ................................................................................... ..... f1.8 @ 2.8

f1.4 @ 4 ................................................................................... ..... f1.8 @ 4

f1.4 @ 5.6 ................................................................................... ..... f1.8 @ 5.6