Voigtlander Nokton 35 mm f/0.9 Aspherical
6. Distortion and field of view
Field of view
A rectilinear 35 mm lens on the smaller APS-C/DX sensor should provide an angle of view amounting to 44.1 deg. The Fujifilm X sensor is slightly smaller than the classic APS-C/DX so the field of view value in official specifications of the lens is also a tad narrower, reaching 43.8 deg.We decided to take a reality check. In order to measure it we took photos of starry sky and saved them as JPEG files with distortion correction switched off. Then we transformed the pixel layout (X,Y) from the photo into the equatorial coordinate system (right ascension and declination), which locates a star on a celestial sphere. That way we could determine the field of view of the lens with utter precision and in the right way, so for rays of light coming from infinity. Our transformation was based on over 115 stars positioned evenly across the frame and average mesh-fitting error amounted to just 8 seconds of arc.
The field of view, determined that way, amounted to 43.2 degrees, with measuring error not exceeding 0.1 of a deg. It is a value a bit lower than the official declarations of the producers but, with such parameters of the lens, the difference hardly matters.
Distortion
Constructors of optics for mirrorless systems sometimes give up on distortion correction, turning it over to software of a camera. In case of angles of view on a level of standard lenses, distortion correction is not that difficult; that's why we hoped that Voigtlander optics would face the challenge.
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. |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Unfortunately, our hopes proved ill-founded. RAW files show barrel distortion of -1.27%. It's not a high level but you have to remember that contemporary standard lenses that are no longer a 6-7 element double gauss constructions, are able to correct this aberration practically to zero.
It's worth also mentioning that on corrected JPEG files distortion decreased to a level of -0.61%.
| Fujifilm X-T2, 35 mm, JPEG | |||
|
|||
| Fujifilm X-T2, 35 mm, RAW | |||
|
|||
