Olympus M.Zuiko 100-400mm vs Panasonic Lumix 100-300mm

I have had the first generation Panasonic Lumix G Vario 100-300mm F4.0-5.6 ASPH for a few years now and recently described my experience with this lens' optical image stabilization in a blog post.  I have often felt that I was missing out on those extra 100mm of focal length and a better overall image quality of a more modern and hopefully better lens, prefereably from the Olympus lineup to better work with my two E-M5II and E-M1III bodies. And when I recently saw Olympus M.Zuiko Digital ED 100-400mm F5.0-6.3 on sale on Amazon.ca for $1,657.13 Canadian (about $370 off its normal price) I couldn't resist and ordered one.

I wasn't buying a completely unknown lens as I thought I already knew enough about it from online reviews, blog posts and YouTube videos, most of which described it as a major step up in terms of image quality. Turned out, either those reviewers were wrong or I ended up with a really bad copy. This post is about my descent from the intial elation upon unboxing the lens to disappointment a few short days later.

First Impressions

I am not going to go into the details of the specs and features of Olympus M.Zuiko 100-400mm because those are widely available on the Internet. 

This lens is really big and heavy by MFT standards!  Its considerable weight (1,325g with and 1,120g without the tripod adaptor) immediately makes one feel assured of its solid build and reliability. 

The zoom and focus rings felt nice and grippy, but the zoom ring was unusually tight.

A major annoyance was the noticeable rotation play when the lens was mounted on the camera body. I was alarmed at first until I saw other users commenting on this issue and figured it must be a feature, not a bug after all. Although one would imagine that a precision optics instrument such as a telephoto lens made by a reputable brand such as Olympus would be engineered with tighter tolerances.

Sharpness and Image Quality

I immediately stepped out into my backyard to shoot some test frames for a side-by-side comparison of the new lens vs my old one using a wall calendar. I fully anticipated to be blown away by the improvements in sharpness and overall image quality. Alas, it wasn't meant to be as Olympus 100-400 utterly failed to beat my old Panasonic 100-300 pretty much at every combination of focal length, aperture and speed both in handheld and tripod tests.

Given all the positive reviews of Olympus 100-400 I assume I am simply unlucky to have received a particularly bad copy of the lens. Up until now I have always held Olympus in very high regard when it comes to the quality of their lenses, but my experience with the 100-400 has shaken my confidence in the brand.

The Olympus 100-400 will now go back to Amazon for a full refund.

Test Images

The full-res versions of my test images can be found in the following Google Photos albums (also linked from the tables below):

Olympus 100-400 vs Panasonic 100-300 (tripod with OIS and IBIS disabled)

Olympus 100-400 vs Panasonic 100-300 (handheld with both OIS & IBIS enabled)

All the test frames were shot in fairly bright light and in conditions resembling the real life shooting environment.  

All tripod test images in the first album were made using a compact Manfrotto tripod and the OI Share app to remotely trigger the shutter. Both the OIS in the lenses and the in-body IS were turned off.

In the case of the second album I was shooting handheld while sitting down with my elbows resting on a table, one hand gripping the camera and the other holding the lens by the hood to minimize the amplitude of its shake.  Both the OIS and IBIS were turned on, with the latter in lens priority mode (my usual setting).

To compare apples to apples I tested the lenses at 100, 200 and 300 mm focal lengths, each at three different apertures representing the entire practical range: 

1. Wide open (f/5 for Olympus 100-400 and f/4 for Panasonic 100-300)
2. Sweet spot (f/8 for Olympus 100-400 and f/7.1-f/8 for Panasonic 100-300)
3. Smallest aperture at which sharpness remains largely unaffected by diffraction (f/11 for both lenses).

At every focal length and aperture I made two short series of burst shots using digital shutter in the "silent low" (L-heart icon) mode, each series focused somewhere in the centre of the calendar page. Then a single sharpest image was chosen for each focal length and aperture combination. 

Finally, the chosen best images were exported from the original RAW files as JPEGs with no adjustments, sharpening or resizing.

The final conclusions of my pixel peeping into the matching pairs of images is summarized in the following tables. Click on the words winner, loser and tie to see the actual photo and don't forget to zoom in for a closer look.

Shooting from a tripod

TRIPOD	Olympus M.Zuiko 100-400	Panasonic Lumix 100-300
100mm
wide open	loser	winner
sweet spot	loser	winner
f11	loser	winner
200mm
wide open	loser	winner
sweet spot	loser	winner
f11	slight loser	slight winner
300mm
wide open	loser	winner
sweet spot	loser	winner
f11	loser	winner

The biggest surprise of my tripod testing was at 300mm where I fully expected the Olympus lens to beat the Panasonic hands down because the latter is at the very top of its range whereas the former still has another 100mm of focal length to work with. But Panasonic consistently delivered results that are considerably crisper and sharper than its competitor.

Shooting handheld

HANDHELD	Olympus M.Zuiko 100-400	Panasonic Lumix 100-300
100mm
wide open	tie	tie
sweet spot	tie	tie
f11	slight loser	slight winner
200mm
wide open	tie	tie
sweet spot	tie	tie
f11	slight winner	slight loser
300mm
wide open	tie	tie
sweet spot	loser	winner
f11	slight loser	slight winner

The handheld tests were less conclusive than the tripod tests in terms of differences in sharpness between the two lenses. However, the overall image quality of the Panasonic 100-300 appears to be slightly better as Olympus 100-300 images typically look muddier and less contrasty.

Moreover, I expect the handheld tests of Panasonic 100-300 would have shown better results had I disabled the lens' OIS and let the E-M1III's IBIS do all the stabilization.  Why?  Because as I have showin in my blog post Test of Panasonic Lumix G Vario 100-300mm with Olympus E-M1III, the combination of this lens with Olympus bodies produces sharper images with IBIS alone even at 300mm.