![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG20230913111040-1024x768.jpg)
This is the Nikon 180mm F2.8 AIS ED F2.8 Lens from the 80s I recently got and I wanted to do a quick test using my DSLR to find its sweet aperture spot! Here I am looking at sharpness and Chromatic Aberrations. I went through all the apertures on a simple scene near window light.
Watch the Video!
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG20230913111146-1024x768.jpg)
Full Frame (My focus spot was the 28mm lettering on the lens)
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2092-1-1024x682.jpg)
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32
Sweet Spot
Normally a Lenses “Sweet Spot” is 2 stops down from its widest aperture. In this case f/5.6.
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2092-2-1024x682.jpg)
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2093-2-1024x682.jpg)
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2094-2-1024x682.jpg)
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![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2096-2-1024x682.jpg)
So for me this lens is best at f/8 at the closest focus distance.
Chromatic Aberrations.
Nikon say “Chromatic aberration is a phenomenon in which light rays passing through a lens focus at different points, depending on their wavelength.”
You can see it in these images real close. Like a purple edging.
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2092-3-1024x682.jpg)
f/2.8. You can see the purple banding on the FM3a logo and the strap clip and also along the top plate.
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2093-3-1024x682.jpg)
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2094-3-1024x682.jpg)
![](https://www.rogerlowe.co.uk/wp-content/uploads/2023/09/IMG_2095-3-1024x682.jpg)
So I would definitely say my sweet spot for this lens and camera is f/8. And I shall remember this for using this lens on other cameras knowing safe that I can still shoot F/5.6 with still quality results.
Even at f/2.8 and f4 were good.