m4/3 primes are "stellar"?: distortion comparison to other lenses

Started Jul 3, 2013 | Discussions thread
jalywol Veteran Member • Posts: 9,314
Re: disappointing

walkaround wrote:

ohmydentist wrote:

I kind of suspected this, but didn't know it was that much worse. I love OM-D 12-35mm 2.8 combo, but I noticed distortion was very noticeable and made portraits somewhat unflattering.

From Photozone:

"Traditionally this (distortion) is a bit of a weak point of MFT lenses because the system relies on an auto-correction here and as such it isn't really a design priority. You may argue, of course, that this is not relevant from a user perspective because all the applied corrections are done "under the hood". This is also something that we can confirm - standard JPEGs or conventionally converted RAW files don't show a significant amount of distortion throughout the zoom range.

That said it is still interesting to look a bit behind the scenes by using an "unsupported" RAW converter like e.g. RAW Therapee. This converter reveals the native barrel distortion level of about 5.8% at 12mm. This is excessive - and as such it is highly disappointing for such a lens. Please note that the correction of such an amount of distortion is lossy due to the required image stretching and interpolations."

Panasonic 12-35mm 2.8
12mm: 5.78%
20mm: 1.00%
35mm: 0.70%

One of the BASIC premises of M43 was to design small lenses for a small system, and think a bit outside the traditional box, as it were, to optimize size and quality. To that end, Panansonic and Olympus designed small lenses with high quality optics with PREDICTABLE distortion characteristics that were then software correctable. These lenses were not designed to be used uncorrected, so when testing sites like Photozone test them without the designed correction, it is the equivalent of testing a fully optical design lens without one of its integral glass lens elements!

Unfortunately, Photozone still does not seem to understand this concept, and grumps about at the distortion levels in the uncorrected lens measurements.

The simple fact is, when you use native M43 lenses on native M43 cameras, you will get extremely low distortion results. It just does not matter that one element of the lens formula is software based, and the lenses are actually designed around that capability.....they just work.

If it bugs you, then there are a lot of other systems out there that use all glass to get their results. However none of them have small  AF lenses with the quality of M43. Can't fight physics, you know?


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