How to Choose a Camera Lens: Focal Lengths, Apertures and the Best Picks for Sony

By the CamTech Compare team · Updated October 2026

Most photographers notice a bigger jump in image quality from a better lens than from a new camera body. The problem is that lens names are packed with numbers and abbreviations. This guide explains what those numbers mean in practical terms and then recommends lenses from our catalog for the most common types of photography. Our picks focus on Sony's E-mount because it has the widest choice of first- and third-party lenses, but the principles apply to every system.

Focal length: how much of the scene you see

Focal length is measured in millimeters. Lower numbers show more of the scene; higher numbers bring distant subjects closer.

• 16 to 35mm (wide): landscapes, architecture, interiors and vlogging at arm's length.
• 35 to 70mm (standard): everyday photos, street, events and environmental portraits.
• 85 to 135mm (short telephoto): flattering portraits with soft backgrounds.
• 200mm and beyond (telephoto): sports, wildlife, aviation and anything you cannot walk closer to.

One important detail: APS-C cameras crop the image, so a lens behaves as if its focal length is about 1.5 times longer. A 50mm lens on an APS-C body like the a6400 frames like a 75mm lens on full frame.

Aperture: light and background blur

Aperture is written as an f-number such as f/1.8 or f/4. A smaller number means a wider opening, which lets in more light and creates a shallower depth of field, so backgrounds melt into blur. Fast lenses (f/1.4 to f/2.8) are best for low light, indoor events and portraits. Slower lenses (f/4 and above) are smaller, lighter and cheaper, and perfectly fine outdoors in good light.

Some zooms list two apertures, such as f/4.5-6.3. That means the maximum aperture gets smaller as you zoom in.

Primes vs zooms

A prime has one focal length. Primes tend to be sharper, brighter and lighter for the money, and they encourage you to move your feet and think about composition. A zoom covers a range and saves lens changes, which matters at weddings, on safari and when traveling.

Stabilization, autofocus motors and weather sealing

Look for "OSS" (Sony) or "VC" (Tamron) to identify optical stabilization, which helps with handheld telephoto shots and video. Linear or "XD" style focus motors are quieter and faster, which is valuable for video. Weather sealing adds peace of mind outdoors but raises the price.

Our recommendations

Your first prime: Sony FE 50mm F1.8

Inexpensive, light and bright, this is the classic way to learn what a fast lens can do. Expect a big jump in low-light performance and background blur compared with a kit zoom. Autofocus is not the fastest, but for portraits and everyday shooting it is excellent value.

Best everyday zoom for APS-C: Tamron 17-70mm f/2.8

A constant f/2.8 aperture, stabilization and a useful wide-to-portrait range make this the lens we would put on an a6400 or a6700 and leave there. It is one of the most popular third-party lenses for good reason.

Best travel all-in-one: Tamron 18-300mm

From wide landscapes to distant wildlife without changing lenses. Image quality is a step behind specialized zooms, especially at the long end, but the convenience is hard to beat on a trip.

Best for video on APS-C: Sony E PZ 18-105mm f/4 G

The power zoom gives smooth, controllable zooms during recording, and the constant f/4 aperture keeps exposure steady. It is a favorite among vloggers and event videographers.

Best full-frame standard zooms: Sony FE 24-105mm F4 G and Sony FE 24-70mm F2.8 GM

The 24-105mm covers more range and is lighter, which suits travel and general shooting. The 24-70mm f/2.8 GM gathers twice the light, which matters at indoor events and weddings, at the cost of weight and price.

Best portrait lens: Sony FE 85mm f/1.4 GM

The 85mm focal length flatters faces and separates your subject from the background. At f/1.4 the blur is creamy and low light is rarely a problem.

Best telephoto zooms: Sony 70-200mm F2.8 GM II, Sigma 70-200mm f/2.8 Sports and Tamron 70-300mm

For professional sports and events, the Sony GM II is the benchmark, and the Sigma Sports version offers similar f/2.8 performance for less money. If you want reach on a budget for wildlife or kids' games outdoors, the Tamron 70-300mm is light and affordable. On APS-C, the Sony 70-350mm G gives even more reach.

Quick picks by subject

Compare apertures, weights and prices on our lens category page, or read mirrorless vs DSLR if you have not picked a camera yet.

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