Quote:
Originally Posted by Aurorae
Thanks JA for your detailed feedback. The Nikkor 300mm f/4 AFS is a good option because I can combine it with wildlife photography, but I question the difference between the AF-S and the updated PF version, which is half the weight at about 750grams.
This review by Mansurov does not show much distinction, however notes that the PF version is sharper in the centre which, when considering cropping (as I am using a full-frame) would probably be the better option because i'll have a sharper image. |
Yes i'd read that review: wide open at f/4 the PF is ~11% sharper in the centre of the frame, but the AF-S is ~17% (!!) sharper mid-frame and ~23% (!!!) sharper in the corners. At f/5.6 the results are even better with the AF-S. The sharpness across the entire frame is FAR more even with the AF-S than the PF lens, indicating much better field flatness with the AF-S lens. But sure the PF lens is ~700 g lighter.
Quote:
Originally Posted by Aurorae
With any lens, the capabilities change when doing deep space objects, and it seems like the PF would be the better option, but that it unfortunately becomes the more expensive option. The cost is far higher with the optically better VR2.
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I can't say that I agree, for the reason of flatness of field etc, as stated above, but if you want to try one let me know. It did see it objectively tested against the Redcat51 and where the Nikon 300mm f/4 AF-S was found better, not the least of reasons for its aperture i would say; 75mm v 51mm and also a superior resultant image, higher sharpness and better star roundness/less eccentricity than the Redcat 51.... is lighter and can be had used for ~$700.
Quote:
Originally Posted by Aurorae
I just find it questionable whether the 300mm is necessarily suitable for astro imaging, but may be better if I combine it with daytime photography, which likely will not happen all that often as I prefer night photography and landscape.
Something like AT60ED with a reducer can reach that 300mm range and is very cheap and lightweight, but again, leaning to the RedCat simply because people vouch for it and it can also be used for wildlife photography too. The synthetic fluoride glass helps with FF images that are nice and flat.
Happy to get into more details on this if you feel I am leaning in the wrong direction with my POV.
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Whether something around 300mm for The Nikkor or the 250mm of the Redcat51, is enough for you is only a question you can answer, but with the tiny pixels, by camera standards, of the Z7ii, you can easily crop on a good sharp lens. I initially chosethe 300mm as something of a compromise in performance and weight for your travel scope desires on targets like Andromeda.
As stated, the Nikon 300mm f/4 AF-S is sharper, gathers more light (116% more) and is objectively (on test) sharper and much less distorted than the Redcat 51 in terms of star ovality/roundness. It is also a little more up-close than the 250mm focal length of the Redcat 51, that you're considering. For $700, in astro terms, it's for free.
Best
JA