Back in November 2025 I wrote about my experiences with the OM System 100-400 mk ii, and it is fair to say that they weren’t very positive. Since then a lot has happened and I’ve had a couple of requests for an update so here we go.

First of all I’d like to take the time to thank Aaron Harivel Product and Sales Specialist at OM Digital Solutions Australia for his help and patience in bringing this matter to a resolution. On 21st January 2026 I picked up a new copy of the lens.

My main problems with the original copy were that the autofocus was very bad – it just wouldn’t find focus or when it did it would not hold it. It was a very frustrating experience. My other cause for concern was that the lens was soft wide open and didn’t improve until I stopped down to f11. So I was interested to see whether the new copy was any better.

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Optical Performance

I didn’t bother testing the lens at all focal lengths I just concentrated on the 400mm end. So pointing the lens at a test chart with the camera mounted on a tripod and using the self timer to trigger the electronic first curtain shutter I found that the new version wide open at f6.3 was softer than the first copy – only by a gnat’s whisker, but none the less it resolved less fine detail. But, more importantly the performance at f8 was way superior to that of the first lens even when that was stopped down to its best aperture of f11. Not ideal, but I can work with it if I can get the lens to focus accurately and consistently.

 

 

 

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Autofocus

 

 

The day after I collected the lens I took it out and gave it a simple test – taking a sharp photo of a Laughing Dove sitting on a railing from a distance of about 10m. I fired a burst of shots using single point continuous auto focus and held my breath waiting for the buffer to clear before looking on the back screen of the camera. When I looked I saw to great relief that every shot was perfectly in focus – something the first copy could not achieve. I carried on walking along the riverbank taking photos of a variety of different birds in as many different lighting scenarios as I could find using either single point CAF or subject tracking and the lens performed flawlessly. The video I shot was also in focus. I’ve even tried it in combination with the 1.4x teleconverter and it works well in brighter light, but struggles a little bit when the light levels are low and lack contrast. It was better than I expected.

 

 

I’ve taken it out of subsequent occasions with the same results.

 

 

 

 

 

 

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In Summary

Well when I posted the original post about the first version and the accompanying YouTube video I was amazed at the supportive comments. Most people it seemed were happy with copy of the lens, but there quite a few who definitely had problems with theirs and were unhappy. In my first write up I recommended the Panasonic Leica 100-400mm over the OM version. I had a few comments from people who had the opposite experience to mine and felt that they could not share my recommendation. It would seem that there is quite a lot of sample variation with camera lenses, although this is my first problem in this regard in 40 years of photography.

All I can suggest is that you be persistent with your dealer or local distributor if your lens doesn’t function like it should and work to a satisfactory resolution.

As to how I feel about the lens now I have a satisfactory copy. Well I’ve got some exciting trips lined up this year and the lens will be coming with me.