Sony FE 85 mm f/1.4 GM II
5. Chromatic and spherical aberration
Chromatic aberration
In the front optical system of the Sony FE 85 mm f/1.4 GM II there are two elements made of low dispersion ED glass. It suggests the lens might correct well both variants of chromatic aberration.Photos shown below, made with the help of the Sony A7R IIIa and the Sony A7R V show that indeed, there are no slip-ups here. Longitudinal chromatic aberration is very low up from the maximum relative aperture.
 |
Please Support UsIf you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free. |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 |
It's clear the results are excellent as well. At the maximum relative aperture that aberration's level amounts to zero in practice, then it reaches its peak by f/2.0-2.8 and then slowly decreases. Even at that maximum very low results mean you certainly won't notice this aberration in real life photos.
The relatively fast increase of aberration from zero by f/1.4 to maximum values by f/2.0 and f/2.8 might be one of the reasons why the lens shows such a quite untypical resolution performance on the edge of the frame close to the maximum relative aperture, a feature we mentioned in the previous chapter.
| A7R IIIa, RAW, f/1.4 | A7R IIIa, RAW, f/2.8 |
|
|
Spherical aberration
In first photos of this chapter it would be difficult to notice any focus shift effect, even after taking a closer look. Still, in circles of light we got before and behind the focus you can spot some traces of poorer correction of spherical aberration. In the first case you see soft edges and in the second one – a brighter rim. Still this effect is not especially distinct.As you see, problems with spherical aberration are accented but we think the optics constructors cared more about a nice appearance of out-of-focus areas. It seems that spherical aberration is kept well in check due to the lack of focus shift and a very good image quality by f/1.4.
| A7R IIIa, f/1.4, before | A7R IIIa, f/1.4, after |
|
|
