It’s most noticeable in very strong areas of contrast, as shown in these crops: Panasonic camera used on the left, Olympus on the right, top images show crops from JPEG, underneath the raw images processed in Adobe Camera Raw – the Panasonic image is automatically corrected in ACR, while the Olympus image needs purple fringing correction to be switched on manually.

The only other prime designed specifically for micro-four thirds at the time of writing, the Olympus 17mm is a slower lens (ƒ/2.8 instead of ƒ/1.7) but offers a slightly wider field of view. The lens is slightly smaller than the Panasonic 20mm and the Panasonic easily bests it in terms of sharpness, resistance to chromatic aberration, and distortion. To its favor, the Olympus shows less corner shading than the Panasonic. The focus isn't all that brisk, and it's not exactly silent. The focus-by-wire system (common to all mFT lenses) makes manual focus less pleasant than it might be.

Introduction

Overheat, thanks! I am also interested in those old C-Mount lenses. I have seen some interesting things with an E-P1/2/GF1 and those lenses. I shot with the G1 inside of B&H and liked it. The EVF was no better than the E-P2’s though and from what I remember, the E-P2’s EVF is slightly better. BUT I could be wrong a as I only shot with the G1 for a few minutes. Even when shooting with the included lens hood attached, artifacts from lens flare can be pretty distracting with this lens. You may notice ghosting when shooting directly into the sun, usually manifesting as a multiple-color haze or purple blobs. i love the 25 1.4 the first prime i bought for m43 which ive been using the last few days on my pen f .. been my take out camera for a few days .. ive also bee n sing the 80mm contax g 2.8 with customized by focal l stabilization of amazing ability When shooting bright light sources at stopped-down apertures – like in the F16 shot above – the 'spikes' of the sunstar are soft-edged and not all that well pronounced. Lateral and longitudinal chromatic aberration (fringing)

Over our review period, we’ve come to really appreciate the 20mm f1.7 II lens. It’s built and feels super solid with a metal exterior that works well with both the OMD EM5 and the GH4. When it comes to manually focusing though, you’ll only be working with a small sliver of a focusing ring. Granted, this lens isn’t weather sealed nor does it really need to be.

Design

I was a bit surprised that you bothered to take the time to shoot comparison shots with the D3x and the cheapo lens. Didn’t you have a better lens to use? Would have been more fun to see the comparison with a decent lens on the Nikon. The Nikon 50 1.4 D is cheaper than the Panasonic 20 1.7 but might have performed better than the Nikon 1.8. Diffraction limiting technically starts in at ƒ/8, but isn't statistically noteworthy until ƒ/11. In practical usage, you won't see a difference unless you use the lens fully stopped-down at ƒ/16, where we note about 2 blur units of sharpness across the frame. Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more. The original Panasonic Lumix G 20mm f1.7 ASPH was one of the most prized lenses for both Panasonic and Olympus users and the announcement of a revamped model with the same optical construction was a surprise.

Any comments on how the 20 fairs AF wise on the new OM-D? I’m looking at building a MFT kit (I’m tired of waiting on sony lenses for my NEX). I’ve got the 12, 14, 20 and 45 in my sights. The 45 is a given, the rest of the equation is either the 14 and 20 for 2 smaller lenses to travel with or to combine them into just the 12mm. One of my biggest concerns is AF speed, my second being size. So if the Panasonics do well on the OM-D I’ll go that route, but if they’re not I’ll go with the larger 12mm and call it a day. Any help is greatly appreciated. Any for reference I’m using this setup to shoot my kits around the house, so it’ll be low light (3200 f/2 and 1/90th). That being said, stopping down just a bit to F2 or F2.8 will result in the sharpest output. But sharpness will drop quite visibly by even F5.6 and certainly by F8, due to diffraction (remembering that F5.6 - F8 on Four Thirds is F11 - F22 in full-frame terms). So it's better to crank your shutter speed in bright light, rather than go beyond those apertures, if possible. Vignetting and distortionThe overall image quality from the 20mm f1.7 II lens from Panasonic is truthfully pretty damned good. There is a healthy amount of sharpness, contrast, and overall solid color rendition built into this lens. When you couple this with its great build quality and focusing abilities you’ve got yourself quite the winner. It doesn't mean anything for optical performance, but in 6 month your lens and camera will *look* like it's been through a war zone, even if it was just bouncing around in a padded camera bag. Although the original was highly regarded, the range of rival offerings has increased dramatically. Olympus introduced a high-grade 17mm f1.8 model to compete directly, and Panasonic added a Leica branded 25mm f1.4 that must surely be tempting sales away from the diminutive 20mm. Considering this is the focal length am using most out of 14-42 mm range, this lens is very practical for me. I gave my kit lens on this one and am keeping this lens since it was released and used it extensively. Many times only this lens in my camera bag. I’m absolutely convinced of the quality of this lens. But… what about the focal length? 35 mm is my favorite focal length landscape/context shooting. And I prefer to jump to 70-85 mm for portraits/details. The 40 mm Pana is, as you say, “in between the two great classic focal lengths, the 35 and 50.” But isn’t that a bit problematic? It is neither fish nor flesh. Neither a landscape lens nor a portrait lens. It falls in a “no man’s land” where some photographers may find difficult to work.