A lot has been written about the Nikkor Z 800mm f6.3 VR S as an ideal long reach, light, sharp lens for bird photography. Equally the Nikkor Z 400mm f4.5 VR S has been much lauded as extremely sharp and light. Is it an option to just add a 2x teleconverter to the 400 to create the equivalent of a 800mm f9 and achieve the same reach?
Teleconverters always result in some image degradation. To suggest they don’t is magical thinking, so the question is how much image degradation is tolerable while still achieving an acceptable image? In general, on a prime lens, a 1.4x teleconverter causes an insignificant loss of sharpness and is quite acceptable. When adding a 2x it can cause more degradation than many people will tolerate. As I have written before, I think that we now need to consider more than just hardware when making gear choices. Software allows us to manage noise in images far better than before and allows us to recover sharpness in ways that previously would have seemed impossible. The question now is – how much hardware lens degradation can we tolerate and then recover in processing and still achieve a satisfying image.
Looking back at digital images captured with 6-12 megapixel cameras from years past, I would have to say that even the degraded image from a zoom lens with a 2x teleconverter is providing far better detail and image quality than what we once had to accept. Reading online reviews of the Nikkor Z 400mm f4.5 often reporting that it is fine with the 1.4x but not so good with the 2x to the point that it is recommended not to use the 2x. Having had the chance to now test the combination personally I would like to share my results and opinion.
Firstly when using the 1.4x the degradation is minimal but with the 2x it is more noticeable. The 2 stop loss of aperture also requires boosting ISO so image quality takes a bit of a hit from this as well. Shooting my preferred flat profile means my image previews in camera are often disappointing but I have learned not to judge images until on my computer. Putting the RAW files through DxO PureRAW deals with noise issues and images that looked soft in camera end up with plenty of detail once processed.
It is always challenging to assess image quality in web res images so I have included crops from the full res processed images.
This hopefully show that this lens/teleconverter is quite capable of delivering sharp, detailed images.
This next series of images shows a full frame capture and cropped details again.
Those that follow my blog will know that I’m not a pixel peeper but more interested in the real world performance of gear. All I am interested in is “Can this this combination be used to achieve acceptably sharp images?” The gear is the starting point for my workflow choice and at times I am happy to trade a bit of image quality for convenience if the image quality is sufficient to achieve the result when put through my workflow.
There is no doubt that if I want an 800mm focal length my first choice is the Nikkor Z 800mm f6.3 VR S but there are times when I cannot justify taking the bigger lens and then the 400mm f4.5 with the 2x teleconverter is a perfectly capable option, trading a stop of aperture and a bit of image sharpness for weight. When I’m out for a walk with the off chance of photography I will be taking the 400mm f4.5 with the 1.4x and 2x teleconverters as a light and capable rig. When on a bird mission the 800mm will the lens to take and at times with the 1.4x teleconverter too.
My testing has highlighted an issue in very specific circumstances that I will discuss in next week’s post. If you’re contemplating this combo wait to read that post before investing. For me it is not a deal breaker but is definitely something to be aware of.
