Friday, 9 July 2010

Bokeh comparison, ZD50 and PL45

The Olympus Zuiko Digital 50mm f/2 macro and the Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 macro lenses are somewhat similar. The 50mm is a Four Thirds lens, and requires an adapter to be used on Micro Four Thirds (MFT) cameras. The Lumix Leica 45mm, on the other hand is a native MFT lens.

The Olympus 50mm is not optimized for Contrast Detection Autofocus (CDAF), and will autofocus slowly on MFT cameras, and not at all on the first series of Panasonic MFT cameras (G1, GH1, GF1). The Olympus has an edge when it comes to maximum aperture, one full stop faster than the Lumix Leica. On the other hand, the Lumix Leica has optical image stabilization built in.

Both lenses are useful both for macro photography and portrait photography.

This study looks into the bokeh (out of focus rendering) for a typical portrait setup. In the comparison, the subject, which is not a face in this case, is about one meter away from the camera. This corresponds to a headshot distance. The background foliage is about five meters from the camera. When taking a portrait under these conditions, it is important that the background is nicely blurred, and does not stand out to distract from the main subject.

I have previously compared the bokeh of the 45mm f/2.8 macro with two zoom lenses at 45mm, and looked at the bokeh for the 45mm f/2.8 macro at various apertures.

Here is the full image, taken at maximum aperture with both lenses. The images were taken within less than five minutes, so the lightning is mostly similar. I used a tripod, and ISO 100 in all the images. I used the P exposure mode, and auto white balance. The camera used was Panasonic Lumix GH1.

For both lenses I focused manually using the maximum enlargement. The images were rescaled and sharpened. Click on the image to view it larger.

Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8

Olympus Zuiko Digital 50mm f/2

What's more interesting in terms of bokeh, though, is to compare 100% views of various regions at the same aperture.

Here is the centre at f/2.8 (click to enlarge):

The centre at f/4 (click to enlarge):

The centre at f/5.6 (click to enlarge):

Here's also 100% crops from the lower left corner. Since the field of view is not exactly the same for the two lenses, the crop might not be from exactly the same area.

The corner at f/2.8 (click to enlarge):
The corner at f/4 (click to enlarge):
The corner at f/5.6 (click to enlarge):
Conclusion

Honestly, I was expecting the Olympus 50mm lens to perform best in terms of bokeh. This study, however, shows that the bokeh is somewhat smoother with the Lumix Leica 45mm. The highlight circles have harder edges with the Olympus 50mm.

Both lenses are certainly very capable, though.

2 comments:

  1. another nice and helpful comparison!

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  2. Thanks for doing this interesting comparative study. I invested in the Olympus 50mm lens, the Panasonic adapter, and the Olympus extension tube before the Panasonic-Leica 45mm lens was available.

    The price of the 45mm has come down significantly by now, but even at current prices, I still saved $70. Granted, the 45mm is a native MFT lens, is smaller and lighter, has faster autofocus, and has image stabilization built in -- that means you get a lot for your $70!

    As you've pointed out in your blog, autofocus speed is not usually an issue for studio portraits or macro work. I use my Olympus 50mm on my Olympus E-P1, which gives me in-body image stabilization. I don't miss OIS with such a moderate telephoto lens. (My tests of the Panasonic 45-200mm telephoto zoom at 200mm showed me that OIS really is better than IBIS at 200mm, though.)

    For me, the big advantage of the 50mm over the 45mm is the extra stop of speed. I really prefer the greater isolation of the subject in your 50mm crane photo. I think the isolation is noticeably more effective than the 45mm crane photo.

    As for the shape of the blurred highlights, I actually prefer the Olympus bokeh to the Panasonic-Leica bokeh. I *like* that you can make out distinct circles in the background -- my academic training is in mathematics, so perhaps that's why it pleases me so much to be able to make out distinct geometric shapes. :) I don't really like the indistinct fluid blur of the Panasonic-Leica background.

    In the end, I think it's very much a matter of personal taste as to which bokeh you prefer. There is no right or wrong -- good people can disagree on this issue. :)

    Thanks for another fine article,

    Fred Chapman
    Bethlehem, PA

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