Thursday, 7 February 2013

Bokeh comparison @ 20mm and 19mm

The Sigma 19mm f/2.8 EX DN lens can be an interesting alternative to the Lumix G 20mm f/1.7. It focuses significantly faster for both stills and movies, and while it is not as sharp as the 20mm lens, it is still sharp enough. It also comes at a much lower price.


In this article, I'm looking at the out of focus rendering of the lenses, the bokeh. I also threw the Lumix X 12-35mm f/2.8 into the comparison.

The comparison was done by focusing on a close object, the box at about 50cm distance in the left foreground:

Sigma 19mm @ f/2.8 Lumix G 20mm @ f/2.8 Lumix X 12-35mm @ f/2.8

Here are some 100% crops from the centre:


And from the extreme right border:


The Lumix G 20mm f/1.7 features asymmetrical out-of-focus rendering outside of the centre of the frame: The further from the centre, the more elliptical the bokeh highlights become. You can see the same phenomenon in this study. This property is also shared with the Lumix-Leica 45mm f/2.8 1:1 macro lens.

The Lumix X 12-35mm f/2.8 also has some minor disturbance in the border: The out-of-focus highlights are rendered somewhat non-circular. When stopping down, this becomes less of a problem. However, this is a very minor issue.

Overall, I think the Sigma 19mm f/2.8 EX DN probably has the most pleasing out of focus rendering in this high contrast scene.







6 comments:

  1. Bought the 19mm last week bc I have always wanted a 35mm FOV and 38mm equivalent is good enough. I already have the Pana 14mm and PanaLeica 25mm. The 19mm is really wonderful lens to add to my bag and definitely worth more than just $99. It may not have the sharpness of my PanaLeica, but I think I can live with it. I love the FOV of 35mm and 50mm. Thanks for the comparison. Now I feel better about my choice and don't feel bad about not investing in the 20mm.

    ReplyDelete
    Replies
    1. The Lumix 20mm f/1.7 pancake is a very good lens. But the Sigma 19mm f/2.8 is a perfectly good alternative. That is my conclusion so far.

      Delete
  2. It looks like excuses why you bought that cheap bulky and slow aperture lens. It's a monstro. ))

    ReplyDelete
  3. Not everyone needs the speed! The Panasonic has very unsure edges to the out of focus areas. Thanks for testing.

    ReplyDelete
  4. Would that mean "in focus" area on the edges of the 20 mm are also distorted? Also how many iris blades are on the sigmas? Thanks!

    ReplyDelete
  5. The Sigma lens has seven iris blades. The Lumix 20mm lens does not have distorted corners when in focus. It is only the bokeh which is non-round and blocky when out of focus.

    ReplyDelete