Re: Deciding between Nikon 600mm z 6.3 vs 400mm z 4.5 with TC1.4
Cliff L. wrote: ilkka_nissila wrote: Cliff L. wrote:
I sold my 600mm f6.3 PF after using it for a few weeks - the 4m MFD was the deal-breaker for me, since I photograph a lot of really small birds.
That lens has the lowest magnification ratio (0.15x) in its class; even Nikon's own marketing suggests using the lens in DX crop mode to get "closer" to your subject.
0.15x is a typical magnification for a fixed focal length 600 mm lens.
Canon RF 600/11: 0.14x
Canon RF 600/4: 0.15x
Nikon Z 600/4: without TC 0.14x, with TC 0.2x
Sony FE 600/4: 0.14x
I am not sure which 600mm lenses you are comparing to. Zooms that go to 600mm do feature greater maximum magnification factors but they do it by sacrificing focal length dramatically, so they can actually be more like 200mm or 300mm when achieving that max magnification factor. I think for most wildlife subjects the lack of working distance to not spook the subject then can become an issue. I've tried to photograph frogs with the 100-400 Nikkor and felt it was very clumsy to operate in that application and while the lens did produce decent outcomes I got better results with the 200 mm Micro-Nikkor. I don't have the 180-600mm but it is reported to give its maximum magnification of 0.25x at 180 mm.
I am not saying the longer minimum focus distance is never an issue, as I've run into that problem when photographing grebes: the bird once familiar with my presence (I was lying on my stomach for a long time repeatedly on many evenings) eventually swam so close that I couldn't focus on it using the 500mm PF which has 0.18x max magnification factor at 3.0 m distance. A 100-400 would have handled that particular situation better, but most of the time the distance to bird was greater and the 500mm (or the 600mm f/6.3 which didn't exist at the time) was a better fit. However, the 100-400 is not that fast focusing when it comes to close subjects and can often need manual intervention to achieve focus, and the primes tend to focus faster though they do not achieve such close focus. A VCM-equipped long macro lens would probably be ideal for such applications, but it seems the manufacturers are not interested in producing a dedicated lens for such a specialized market. The 105 MC is wonderful but its focal length is quite short. Perhaps Nikon will eventually make a Z MC 200mm f/4.
I noticed your cherry-picked list doesn't include any other lenses that are 600mm with an aperture of f6.3... .
Your suggestion that a 105mm macro lens is a substitute for a 600mm telephoto for bird photography suggests you don't know a great deal about the subject, but nice try, though.
I listed fixed focal length 600 mm lenses of major manufacturers. I also noted that some long zoom lenses have the ability to focus closer by sacrificing focal length, and gave examples of that. But then those zooms are no longer 600 mm lenses at those focus distances, so at equal focus distance (e.g. 4 m) they give less magnification and less detailed images than the prime. Nikon's suggestion of cropping the images from these extremely sharp prime lenses (600/6.3) is perfectly valid for smaller subjects at a distance. If the subject comes too close for the 4 m distance, then the zoom has a benefit since shots can be taken but since the focal length is so short at maximum magnification, one might as well look at the 300 mm PF or a long macro lens.
I did not suggest the 105 MC for bird photography; the reason I brought it up was because it is currently the longest Nikon macro lens in the Z system. A dedicated long macro lens (such as a 200 mm implemented with SSVCM) might have the desired qualities of fast focusing and high magnification at close focus, but Nikon does not make one for the Z system yet and the existing F-mount 200 (AF) Micro requires manual focusing if used on a Z camera (and even on a DSLR it does not have focusing comparable with the fastest motors today). You might be amused at the short focal lengths of the macro lenses but the reality is that the zoom lenses also have short focal lengths at their closest focus distances and the macro lenses are sharper, so the gains from use of those zooms for close-up photography are not as obvious as one might think merely looking at the nominal focal lengths of the lenses. I've looked at the 100-400 and 200 micro for the same subject in the same situation (though the subjects were frogs, not birds) and by far preferred the outcomes and handling of the latter.
If Nikon implemented a 600 mm prime lens which became a 200 mm at minimum focus of 0.25x, I think people would be quite upset. With the zooms, such drastic loss of focal length and the associated slow focusing (as in the 180-600 and 100-400 zooms) is accepted since the lenses are so versatile and relatively inexpensive, such things can be more easily forgotten and forgiven. However, in 600 mm primes, people expect high performance across the range of focus distances, very little loss of focal length when focused close, and very fast focusing. With these requirements, the minimum focus distance is as it is. All the manufacturers have the same physics to deal with so they end up with similar maximum magnifications when the other requirements are similar.
Jan 02, 2026 at 04:38 PM
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