Which Nikon Telephoto Zoom for the Nikon Z8 Camera?

 This is second part of a look at Nikon’s telephoto zooms. The first was for the Z50ii (DX sensor 23.5 x 15.7 mm; 20.9 megapixels) when a focal length of 400 mm is equivalent to a focal length of 600 mm. This part is for the Z8 with a full-frame sensor (FX 35.9 x 23.9 mm, 45.7 megapixels} when a 400 mm lens has a focal length of 400 mm

The reason for both these articles is because is endless debate as to which is the best Nikkor Z zoom lens at 400 mm focal length. I have all three of the lenses in question: 180-600 mm f/5.6-6.3 VR; 100-400 mm f/4.5-5.6 VR S; 28-400 mm f/4-f/8 VR. Last week in an idle moment I thought I would compare the three on a real scene at 400 mm looking only at sharpness (that mix of resolution or acuity and contrast) while completely ignoring attributes like weight, handling and price that are also important considerations.

I aimed my camera at the local school (50 m away) on a quiet Sunday morning. There was no sun and a slight breeze—ideal conditions for avoiding thermal gradients in the air between camera and target. I compared out-of-camera jpgs (which have of course been processed to that stage) at their maximum apertures (f/5.6 two and f/8 for the 28-400), and base ISO (64). The shutter speed (on aperture priority mode) remained  1/80 or 1/60 sec. VR was off and I chose a shutter delay of 2 sec to avoid vibration from any movement of the floor the tripod was standing on. I had to change the mounting for the lenses (28-400 has no collar) in use but made the changes as quickly as possible and each time I made sure the centre autofocus point (AF-S) was as near I could get it on the same object—a child’s cut-out drawing—on the inside of the school window.

With the images cropped to the same size in Lightroom and looking at the centre of the frame the 100-400 and 180-600 were sharper then the 28-400 but not by that much.. I then moved the crop to the bottom edge of the frame where the plane of focus was virtually identical. There was a  difference in sharpness in the order one would expect from the price of these lenses (100-400 mm f/4.5-5.6 VR S > 180-600 mm f/5.6-6.3 VR > 28-400 mm f/4-f/8 VR) with the last notably less sharp than the other two.

I also looked at the result of a simple adjustment in Lightroom of sharpening. The second series of photographs shows the result of increasing sharpening the RAW image (the camera saved both jpgs and raw images) but not to the point where over-sharpening is evident. On the Z8 I could not improve the sharpness of the 28-400 mm lens image to the point at which it approached the other two lenses.

Will I use the 28-400 with the Z8 where its performance—as expected—is lower than when used on the Z50ii? Probably not for still photographs since the both the other lenses are clearly superior and the Z8 is never part of a lightweight travel package. I will though see how it performs with video in FX and DX mode and where I routinely downscale in Final Cut Pro. The next test is looming.

The resiults are below but differences may be dofficulty to see because of the compression used on the site.