Fed Up with EF-M 18-150mm

J Peters wrote:

Thanks everyone. I did some more tests last night (albeit brief). Comparing the 18-150 to at the long end to my 55-200 was an open and shut case. The 18-150 is pretty lousy by comparison - though not as bad as the first copy I had. Even things that are supposedly in the plane of focus are blurred when I look critically, and there's noticeable chromatic aberration. I've compared these two before though, and this was no surprise.

What shocked me though is when I compared the short end to my 18-55. The 18-150 was better! And by quite a margin. I wasn't expecting that at all. I don't think I'd run that comparison before.

If the 18-150 behaved like that through the range, I'd be very happy. However mine seem to fall apart around about 70mm, and over 100mm it's useless for critical shots, or where any cropping is needed. I am now wondering if it's worth buying a third copy (third time lucky?). I'd be grateful if someone can post an example of their 18-150 at or near 150mm with no post processing (by which I mean no contrast or chromatic distortion correction). That should help me judge if mine's a lemon.

You should definitely read this article: https://www.lensrentals.com/blog/2017/03/rogers-law-of-wide-zoom-relativity/

Roger has written other similar pieces over the years, but his takeaways are the same:

• Zooms have lots of copy-to-copy variation (even the most expensive ones);
• You can never have a zoom with peak performance at all focal lengths - you can either have one excellent extreme and a crappy one, or mediocre performance all over;
• Zooms suffer even more from differing quality at different focus distances than primes, and so distance to subject can have a massive impact on their focal plane characteristics, aberrations, and general resolution;
• Burning through copy after copy of zooms is mostly a waste of time because, unlike primes, you can never have peak performance at all focal lengths and distances.

Keep in mind two other things as well: each one of us examines images on different monitors, different software, with different eyesight and different criteria. What constitutes “sharp” to me can be “mush” to you, or vice versa. Also, better zoom lenses do exist; the newest 70-200mm f/2.8 lenses, for example, still do have a better focal length and optimal focus plane distance, but their baseline performance is so good that they just feel “super sharp all around” to most users. This is not the case with cheapo consumer zooms, like, ever.