I have all three of the lenses you mentioned.
I use the 16-85 lens for group travel, when I expect to travel pretty light and shoot handheld and 'on the fly', in situations where lens changes will be few and far between. I feel that the image quality is quite good, but not quite up to the standard of the other two lenses. I'd prefer a faster aperture than 5.6 on the long end, but 5.6 is acceptable for a travel lens for me. The 16-85 is paired with a 55-300 lens and my KP body for travel - I semi-seriously refer to this as my 'B-Team' kit. If this kit was lost or stolen, I'd be unhappy, but it wouldn't be a major financial loss; both KP bodies and the lenses are available used.
The 16-50 PLM is for my serious work, when I want the best quality I can get from a zoom, and don't mind carrying the extra weight and bulk. The 16-50 is paired with a 60-250 and K-3 III and I refer to this as my 'A Team'. Loss or theft of my A-Team kit would be a serious financial hit. Because of this there are some places I won't take my A-Team kit.
The 20-40 is my day to day 'go-to' normal zoom lens. I feel it takes excellent images and - for me - both it's zoom range and aperture range is more than enough for most of my shooting. Toss a 15mm and 70mm into the bag, add a tripod and I'm ready to photograph almost anything I normally shoot - albeit with more lens changes than I would need with the 16-85. I shoot this lens kit with either my KP or my K-3 III depending on what and where I'm shooting.
Last edited by wm_brant; 06-29-2022 at 05:49 PM.
Reason: Wordsmithing