Comparing the 50mm f/1.8G with the 50mm f/1.8S on the Nikon Z7
Almost every photographer has at one point owned a 50mm prime lens. That’s because the “nifty fifty” lenses are inexpensive, fast, and well-corrected. You can use a 50mm prime in a variety of situations, especially for portrait work where you want nice out of focus backgrounds.
I recently purchased the Nikon 50mm f/1.8S Nikkor for Z-mount, and I wanted to compare it to my trusty 50mm f/1.8G for F-mount. I tested both lenses wide-open on my Nikon Z7 by using the Nikon FTZ adapter with the 50mm f/1.8G lens. My experience with the 50mm f/1.8G was that it was a decent performer, but it was sharpest when stopped down to around f/2.8 or more.
Center Sharpness
At the center of the frame, sharpness was noticeably better with the 50mm f/1.8S. This didn’t surprise me, because I’d seen the MTF charts, but the difference was pretty astounding.
Corner/Edge Sharpness
With respect to edge sharpness, here is where I fully expected the 50/1.8S to shine. The new Nikon Z mount is much larger than the old F-mount, which allows Nikon’s lens designs to have better performance at the edges of the frame. Of course, this may not matter for portrait work where the edges of the frame will be rendered out of focus anyway. Indeed, the S lens outperforms its F-mount predecessor here pretty handily.
Chromatic Aberration (CA)
One reason I chose the 50mm f/1.8G over the 50mm f/1.4G was because I thought it handled chromatic aberration better. Looking at the 50/1.8S I find that the native Z lens is also superior. The S lens has much less green & purple fringing wide-open when compared to the G lens.
Autofocus Speed
I tested AF speed by capturing slow-motion video and counting the number of frames required for each lens to achieve focus. Focus was set to AF-S single-point mode. The 50/1.8S focused on my target in 0.13s while the 50/1.8G required 0.35s. Moreover, autofocus was nearly silent with the S lens; a huge plus for videographers.
Conclusions
Given its price tag of nearly $600 USD, I was originally hesitant to purchase the 50mm f/1.8S. Instead, I figured I’d be happy to just use my 50mm f/1.8G on my Nikon Z bodies via the Nikon FTZ adapter. However, after looking at my test images, I can conclusively say that the native Z lens is absolutely stellar. It’s sharpness wide-open is outstanding; images captured with my 50mm G lens look hazy in comparison. While the 50mm f/1.8S is much more expensive than the G version, it’s only slightly more expensive than the Nikon 50mm f/1.4G. Based on my previous experience with the two F-mount Nikkors, I feel like this Z-mount lens outperforms them both in terms of optical quality and autofocus speed. Being able to shoot wide-open at f/1.8 is a huge plus with this lens, and makes it a worthy addition to my kit. I’m planning to upgrade my collection of Nikon primes to the native Z-mount versions very soon!