Will the difference between an achromatic, semi-apo, and apochromatic refractor be noticeable? We test some small refractors by photographing a simple daytime target.
A simple test to see the differences of some small refractors
There are 3 basic categories of refractors in the market: the achromatic, semi-apo, and apochromatic refractors. Achromats correct for 2 colours, semi-apos correct for 3 colours only for low magnifications, and full apos correct for 3 colours over most of its operating range. Well, at least that's the theory. I decided to put some refractors to the test to see if I could capture the differences photographically. The following refractors were all coupled with a Canon 550D at prime focus, and the raw results as well as a cropped and zoomed photos (to aid comparisons) were made.
Hope you enjoy seeing the results as much as I did getting them !!
And the winner is...
For this test, I would say the William Optics Zenithstar 66 Apo performed the best in terms of colour/contrast, lack of fringing, and level of detail given its diminutive aperture. The runner up would the the Orion ED 80mm, which performed exceptionally well given its price. At the zoom levels concerned, it exhibited unnoticeable fringing, which were readily apparent in lesser scopes.
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