Olympus 25 mm f2.8 pancake lens review: small really is beautiful

Olympus 25 pancake
I love pancakes. There is no better breakfast. But surely there have to be much better lenses than the flattened and presumably optically compromised pancake lenses that the likes of Pentax and Olympus are serving up? With that in mind, I set out to get a taste of the Olympus 25mm f2.8 pancake lens made for the four-thirds mount, which, given the 2x crop factor due to the four-thirds sensor size, translates into the equivalent of a normal 50 mm lens on a 35 mm full-frame camera.

From a practical point of view, small is nearly always more desirable when it comes to portability but, almost inevitably, in photography small is a signal that image quality has been sacrificed on the altar of convenience.

There is no denying the lens deserves to be called a pancake lens. It is remarkably flat, sticking out barely 2 cm when mounted on the camera. And it is light at 95 g. The widest aperture is 2.8, which although not especially fast, is respectful, even surprisingly so, given its size.

And always it seems, one is bound to be doing that: excusing aspects of its performance or design because of its size. Kinda like “Allen Iverson is an okay basketball player for his size.”

To be honest, when you first see the Olympus 25 mm pancake lens, it appears to be a toy. It is so small that you think to yourself that it cannot be for serious photography. And my initial test did little to dissuade me of that: the lens has pronounced barrel distortion that is evident when photographing objects up close or where there are straight lines near the edge of frame, such as when doing any form of architectural photography.

To assess just how bad the performance of the pancake lens was, I did some side-by-side shooting with a Leica 25mm f1.4 lens – one of the finest lenses available in the four-thirds mount and one of the finest normal lenses available in any mount.

At the end of the day I threw the raw images into Apple’s Aperture and examined them on my computer – and immediately I regretted purchasing the pancake lens. Why had I bothered to get it? Image quality was clearly not up to the other lens, so why would I consider using it just because it was smaller? And then a very strange thing happened: when I checked the Expanded Exif data in Aperture, I discovered that the images I had assumed were from the Leica, because of their superior sharpness and contrast, were actually from the pancake lens! Impossible!? But I checked back through all my images and the same pattern was repeated time and again.

Admittedly all the shots were taken between f3.5 and f8.0 (wide open the Leica is a superlative performer and it operates at apertures where the pancake cannot even dream of going), but these were the results that I got consistently:
• The pancake is sharper overall than is the Leica, particularly at the edges of the frame.
• The pancake has similar but slightly better contrast.
• The pancake has a warmer, slightly yellow colour cast.
• At similar apertures, the pancake produces shutter speeds that are about a third of a stop faster.
• Purple fringing is not apparent and, if anything, chromatic aberrations are controlled even better in the pancake than in the Leica.

Bottom line: this is a lens that gives up only speed (with its widest aperture topping out at 2.8) in exchange for its size. The truth is that, just like Allen Iverson, the Olympus 25mm pancake lens is simply great irrespective of its size.

Olympus 25 mm pancake lens on E3: ISO 100, f8, 1/250

Leica 25 mm f1.4 lens on E3: ISO 100, f8, 1/200

100% crops from Olympus 25 mm pancake (left) and Leica 25mm (right)