Kit zooms vs upgrades
What do you get for your money if you splash out a little more?
Some kit zooms feel like they’re built down to a price. Most don’t feature a focus distance scale and the three DX format options aren’t supplied with a hood. Only the AF-S DX 18-140mm f/3.5-5.6 ED VR has a metal mounting plate, also adding a weather-seal. Shift up to a full-frame kit lens and build quality feels better. The AF-S 24-120mm f/4 ED VR for SLRS has excellent handling and high-end features, so the lines between standard and upgrade lenses is a bit more blurred. The Z 24-70mm f/4 S kit lens for mirrorless cameras takes a further step up in quality and performance.
One common theme in top-grade standard zooms is they tend to have faster apertures. For full-frames, this is usually f/2.8, making them an f-stop faster than favoured current kit lenses. All have a constant-aperture design, so the same aperture is available throughout the entire zoom. Nikon’s latest and greatest DX format standard zoom for SLRS bucks the trend. It still has a faster aperture rating than kit lenses, but its aperture shrinks from f/2.8 to f/4 as you stretch through the zoom.
Faster lenses with wider aperture ratings enable a tighter depth of field at any given focal length, great for blurring the surroundings and making the main object of interest stand out. They also enable faster shutter speeds under dull lighting. The flip side is that faster zooms are bigger, heavier and more expensive. This is mainly because the glass elements need to have a wider diameter, to let in more light. Upgrading from the AF-S 24-120mm f/4 ED VR to the AF-S 24-70mm f/2.8e ED VR, you’ll gain an extra f-stop but lose out on telephoto reach. Even so, the f/2.8 lens is about 50 per cent longer and 50 per cent heavier than the f/4.
Back in DX land, every millimetre counts at the short end of the zoom. With the 1.5x crop factor, 16mm and 18mm focal lengths equate to 24mm and 28mm, in full-frame terms. That makes a big difference to how much you can shoehorn into the frame.
One thing to be aware of, when it comes to F-mount lenses, is that AF-P (Pulse, stepping motor) autofocus systems and/or ‘E’ designations (Electromagnetically controlled diaphragms) are not compatible with older cameras.