TTArtisan AF 17mm F1.8 C レンズレビューVol.2 解像チャート編

広角レンズの定型チャートテストで、周辺・隅の結果が低下することは珍しくありません。本レンズは広角レンズの中でも画質低下が顕著。球面収差に加え、非点収差や像面湾曲の影響が目立ちます。
周辺部は像面湾曲なのでピントを合わせたて絞ったらシャープな結果が期待できます。しかし、隅はそもそも非点収差が強すぎるため、絞ってもソフトなまま。近距離のパンフォーカスは諦めたほうが良いでしょう。F11-16まで絞って許容範囲内に収まるかどうか。

In standard test charts for wide-angle lenses, it is not uncommon for image quality to deteriorate towards the edges and corners. Among wide-angle lenses, this particular lens exhibits a notably significant drop in image quality. In addition to spherical aberration, the effects of field curvature are also conspicuous.
As image curvature is a problem in the periphery, sharp results can be expected if the focus is set and the aperture is stopped down. However, in the four corners, the image curvature is simply too severe, so the image remains soft even when the aperture is stopped down. It is best to give up on achieving pan-focus at close range. If the aperture is stopped down to f/11–16, results within an acceptable range can just about be achieved.

*当ブログのレビューは冒頭に断りが無い限り、自費購入となっています。