I like my lens stable across the board. There is honestly not one lens that is irrelevant, nor one that does not offer a point of strength. This may be weight, price, performance, versatility, power or simply that I like it, but no matter the lens, there is a point to owning it.
However!
My prime lenses, more often than not, take my best images. This has nothing or little to do with optical quality of zooms, it is all to do with the strengths of prime lenses and the way they make me work.
The Leica 15mm cuts out subjects better than any zoom I own.
Their first strength, lens speed (meaning aperture setting). All of my prime lenses (except my 300 which is a special case) are faster than f2. This means they have more depth of field options and produce consistently better quality images in low light.
his image had no depth of field issues, as it was shot on my 9mm, but the benefit of f1.7 allowed a low ISO image in an environment that usually eats light.
An example of this was my shoot today for the school. Mostly shot in the school gym or classrooms, the Leica 12-60 (G9) and Oly 40-150 f2.8 (EM1 mk2) did the lions share, but the couple of dozen images I took with the 15mm on a lowly EM10 mk2 stood out. Better sharpness (lower ISO and cleaner separation), better contrast (same, but also the lens), more keepers (same). Even a weaker camera did not stop it doing a better job, in fact this combo keeps surprising.
Their second strength is seen by many as a weakness, so bear with me. Using a prime (i.e. non-zoom) lens forces you to move your feet and think differently, but I have found this comes with a healthy dose of clarity of purpose. I grab a camera with a prime and feel instantly empowered by the single mindedness of the gear. No standing flat footed and just popping shots, it makes me really think about my other options other than simply changing focal length. I usually find myself moving soon after picking this more limited kit.
I also have the added problem of running two brands that zoom in opposite directions, meaning I need to create work processes to avoid operational confusion. To this end I have limited my standard working kit zoom lenses to Olympus where possible, using Pana/Leicas for personal use and the occassional school job. Even then, I miss the odd shot, zooming the “wrong” way. You can set the focussing to match, but not the zooming.
The power of a long and fast lens against a messy background.
Thirdly, but by no means least importantly, the Bokeh or “draw” of a prime lens is a predictable thing. A prime takes care of angle of view, then you get to know it and use the lens character to suit. A zoom has a lot of different personalities, making it much harder to predict and simply stops me from thinking that way. Generally the only predictable Bokeh behaviour zoom lenses have are negative and equally, most primes show strong Bokeh characteristics (not always, but mine do).
My 9, 15, 17, 25, 45, and 75mm’s are known quantities and are used to highlight their strengths. The crop of excellent zooms I have unfortunately do not work like that. They take great images, but they make me take them differently and in some cases actively avoid some backgrounds where possible.
Finally, their form factor generally aids in camera handling and general movements. This is not as clean-cut as above as some of my zooms are quite small, but there is no doubt, when comparing my best/biggest/heaviest zooms with my primes, there is a mile of difference. My largest fast prime, not counting my 300mm is the same size as my smallest pro zooms.
The reality is, I am never far from commiting to a primes only dynamic. The fact I already own some great zooms is the only hurdle. The convenience of zooms cannot be forgotten, especially for fast moving situations, but primes only can get the job done even gaining some of the above benefits, you just need more than one camera.
What would I use as my ultimate primes kit?
9mm Leica the little ripper that only just came into my life. This fixes the wide end.
15mm Leica the slightly technically better of the two semi-wides, but a more logical focal length.
25mm Oly the nifty fifty that is closer to a 45mm, my ideal “one lens” focal length.
45mm Oly my favourite regular portrait lens, but I would likely switch to the 42.5 f1.7 Pana for better close focus.
75mm Oly the ultimate long portrait and indoor sports lens.
200mm Leica with matched teleconverter. This is effectively my 300 f4 with another option.
Lacking the 200mm, I guess I can make do with the 300 ;).
After writing this today, I shot a pair of basketball matches with my 75 and 17mm f1.8’s with great results. the school gym I shot in is quite dark needing f1.8-f2 for 1/1500-2000th at ISO 6400 (slightly over exposed by a half stop for cleaner files).
Sharp, clean and well separated, this file could have been shot with my 40-150 f2.8, but at a 2 stop cost, so either a risk of some movement blur, some noise or a bit of both. No ON1 No Noise was applied, but would have made the image very high quality.