If the camera body is a box that holds a rectangle, the lens is the part that turns that rectangle into meaning.
Adams opens this chapter by basically saying: lenses are magic—not because they’re mysterious, but because they extend what our eyes can do. And if you care about making photographs (not just taking them), you need to know what your lenses do so well that you’re not thinking about them at the moment of exposure.
Here’s the part I keep chewing on in 2026: modern lenses are ridiculously good. Adams notes that by his time, lens performance had already improved dramatically (and that the design work was aided by computers). He even makes the point that lenses can out-resolve the limits of film and paper. Translation: the bottleneck isn’t usually “sharpness” anymore—it’s the photographer’s choices.
Focal length isn’t “zooming with your feet”
One of the biggest misunderstandings Adams tries to clean up is the difference between:
- changing focal length, and
- changing your distance to the subject.
He points out that if you swap lenses without moving the camera, everything in the frame scales equally. Perspective doesn’t magically change just because you mounted a longer lens—what changes is how much of the scene you include (and how big it lands on the film/sensor).
That’s a 2026 reminder I want tattooed on my workflow: perspective comes from position. Lenses decide framing and scale; you decide viewpoint.
Short lenses, long lenses, and the cost of each choice
Adams breaks down lens families in plain-language consequences.
Short focal length lenses:
- help when you need to include a broad subject area (landscapes, interiors)
- tend to give a greater depth of field
- are more forgiving for hand-holding (again: not permission to be sloppy)
He also gets into the practical mechanics: on SLRs, very short lenses create clearance issues with the mirror, so designers use retrofocus designs to make them workable. And on view cameras, you may need recessed boards and a bag bellows if you want movements with short glass.
Long focal length lenses:
- narrow the angle of view
- enlarge distant subjects
- are often preferred for portraits because they encourage a comfortable working distance (and a more “pleasing” spatial rendering)
But you pay for that reach:
- depth of field drops fast
- camera vibration becomes a bigger enemy
- stability becomes non-negotiable (sometimes even needing extra support for the lens itself on a view camera)
As someone who lives mentally in the 28mm world, this chapter reads like validation: a wider field of view isn’t just a look—it’s a whole set of handling advantages and compositional habits. And it’s also a warning: wide doesn’t save you from bad positioning. It just gives you different problems to solve.
Sharpness isn’t one thing
Adams makes a distinction that still matters: there’s “resolution,” there’s “acutance,” and there’s the feeling of sharpness in a print. He gets very practical about why images lose snap: internal reflections, flare, imperfect shading, and the need to check whether your lens shade is vignetting your corners.
And then there’s the trade-off photographers love to forget: stopping down increases depth of field… until diffraction starts taking its cut. In other words, “smallest aperture” isn’t automatically “best.
Focus as a creative decision, not a technical checkbox
There’s a line elsewhere in the book that echoes Chapter 5’s spirit: if something is going to be out of focus, it should be clearly out of focus. The halfway, slightly mushy zone is the one that nags at the viewer.
That’s the mindset shift: depth of field isn’t “coverage,” it’s emphasis.
The nerdy stuff that quietly saves photographs
This chapter also gets wonderfully unglamorous—in a way I respect.
Adams talks about:
- converters (teleconverters) increasing effective focal length but cost light and potentially quality
- supplementary close-up lenses (diopters) vs better options like bellows/macro lenses
He warns that lens design is critical enough that “bolt-on optics” can easily degrade results unless they are properly matched.
He also raises two classic large-format realities:
- aperture markings can be wrong (especially at smaller stops), which can create real exposure errors
- close-up work needs bellows extension compensation, because the f-stop only tells the truth at “normal”
This is the kind of stuff digital convenience makes easy to ignore… until you’re doing macro, product, or controlled-light work and suddenly the old physics shows up like a bill you forgot to pay.
Optical flaws: what matters, what doesn’t, and what stopping down can’t fix
Adams runs through aberrations not to scare you, but to give you a mental map:
- coma, curvature of field, astigmatism: often improved by stopping down
- distortion: generally not fixed by stopping down (it’s baked into geometry)
That last point is a big one for photographers who shoot architecture, street, or anything with strong lines: sometimes your “problem” isn’t technique—it’s simply the wrong lens for the job.
Movements for small cameras: shift/tilt as “convergence control”
Adams also mentions “perspective-control” lenses for 35mm SLRs, but he argues a better name is “convergence-control”—because what you’re really managing is geometry, not reality.
Shift to keep the camera level for architecture. Tilt to align the plane of focus for landscapes with deep foregrounds. Same view camera ideas, just miniaturized.
My 2026 takeaway
Chapter 5 is Adams reminding me that lenses aren’t a shopping category—they’re a discipline.
The modern world wants to solve lens problems in software. And yes, we can fix a lot now. But Adams is pushing a deeper point: when you understand your lens, you stop reacting and start pre-visualizing. You choose the look on purpose.
Tomorrow: Chapter 6 (Exposure). Same plan—one chapter a day, until I’ve worked through all three books.