Sony FE 20-70mm F4 G Review
The Sony FE 20-70mm F4 G (SEL2070G) is an ultra-wide standard zoom lens for Sony Alpha full-frame E-mount mirrorless cameras.
It will also work with APS-C sensor cameras with an effective increase in focal length to 30-105mm due to the 1.5x crop factor.
The optical construction features 16 elements in 13 groups including three ED elements, two AA elements, one ED aspherical element, and one standard aspherical element.
It has a near-circular 9-blade diaphragm which creates an attractive blur to the out-of-focus areas of the image, a fluorine coating on the front lens element, a minimum focusing distance of 0.25m / 0.82ft and a maximum magnification of 0.39x, two XD (extreme dynamic) linear motors for fast and quiet autofocusing, and it's also dust and moisture resistant.
The Sony FE 20-70mm F4 G lens will be available in March 2023 priced at £1400 / $1099 in the UK and the US, respectively. It is made in Thailand.
Ease of Use
Weighing in at just 488g /17.3 oz. and measuring 10cm in length, the hybrid metal and plastic bodied Sony FE 20-70mm F4 G is very light and compact for a standard zoom lens that offers such a wide angle of view.
It proved to be a perfectly balanced partner to the the Alpha A7R IV camera that we tested it with, as shown in the photos below.
It's significantly lighter than all of its main rivals, which include amongst others the Sony FE 24-70mm F2.8 GM II (695g), the Sony FE 24-105 f/4 G OSS ^663g), and the Sigma 24-70mm F2.8 DG DN Art (830g).
This new lens does extend when zoomed from the minimum 20mm focal length to the 70mm focal length, by almost 5cms when zoomed from 20mm to the 70mm focal length.
The overall build quality is veery good, which is something of a relief given the high price-tag, with this very modern lens utilizing a hybrid metal and plastic construction.
This lens has a sealed dust and moisture resistant design utlising silicon seals around all the buttons and switches and a rubber gasket around the lens mount, which makes it well-suited to life in both the field and the studio.
There's also a a fluorine coating on the front lens element to help repel water, oil, and any other contaminants, as well as making it easier to clean.
It has a metal lens mount and accepts 72mm filters via metal threads.
The Sony FE 24-70mm f/2.8 GM has two round Focus Hold Buttons for easier access when shooting in either a horizontal or vertical orientation.
By default they keep the lens locked to the current focusing distance, useful if you're auto-focusing and don't want the lens to try and find focus again. An alternative function can also be assigned to either of these buttons through the camera's custom settings.
There is a slightly narrow ridged focus ring at the end of the lens. Manual focusing is possible by using the dedicated AF/MF switch to toggle between AF and MF.
There are no hard stops at the ends of the range, making it harder to set focus at infinity. Polariser users should be pleased that the 72mm filter thread doesn't rotate on focus.
The lens utilizes two XD Linear Motors for satisfyingly fast, smooth and precise auto-focusing, and it's very quiet in operation making it well-suited to shooting video.
An internal focusing design ensures that the overall lens length remains constant during focusing.
When it comes to auto-focusing, this lens is a really quick performer, taking less than 0.10 seconds to lock onto the subject when mounted on the Sony Alpha A7R IV that we tested it with.
We didn't experience any "hunting" at all, either in good or bad light, with the lens accurately focusing virtually all of the time.
It's also a very quiet performer, which makes this lens equally well-suited to both video recording and more candid stills shooting.
This lens has a dedicated aperture ring with 1/3EV stops ranging from F2.8 to F22. It can be switched between smooth and notched rotation using the dedicated Click On/Off switch on the bottom of the lens barrel.
Using the Iris Lock switch on the lens barrel, it can also be locked to either the Auto or F4-F22 settings to prevent accidental movement of the aperture ring.
The generously sized zoom ring sits in the middle of the aperture and focusing rings and rotates through approximately 80 degrees. It has six different focal length markings - 20, 24, 28, 35, 50 and 70 mm.
This lens does not feature optical image stabilisation, so it relies on the camera body's own built-in stabilisation, which is fine unless you're an owner of an early Sony Alpha camera.
The Sony FE 20-70mm F4 G lens is commendably supplied with both a good quality soft case and plastic petal-shaped lens hood (ALC-SH174) which rotates through 90 degrees then snaps into place (there's no lock button as on some more premium hoods).
The 20mm focal length provides an angle of view of 94 degrees.
The 70mm focal length provides an angle of view of 34 degrees.
Chromatic aberrations, typically seen as purple or blue fringes along contrasty edges, are not a problem for the Sony FE 20-70mm F4 G lens, even in areas of very high contrast.
With the lens set to its maximum aperture of f/4, there is some light fall-off in the corners, requiring you to stop down by at least 3 f-stops to completely prevent it.
The Sony FE 20-70mm F4 G exhibits some barrel and pincushion distortion, as you can see in the photos below, which will you need to correct in post-processing.
Sunstars and Flare
The Sony FE 20-70mm F4 G is capable of producing very nice sunstars when stopped-down to f/16 or f/22, as shown below, and the lens doesn't exhibit very much flare even when shooting directly into the sun, provided that you have the supplied lens hood fitted.
The Sony FE 20-70mm F4 G offers very good close-up performance for a standard zoom lens, with a close focus point of 30cm / 0.99ft from the sensor plane at 20mm and 25cm / 0.82ft at 70mm and and 25cm / 0.82ft throughout the zoom range when focusing manually. It offers a maximum magnification of 0.39x.
Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc.
Sony have paid close attention to this aspect of lens use, employing a 9-segment diaphragm with rounded blades for more pleasing bokeh.
In our view, their efforts have been pretty successful for a standard zoom lens - see the examples below to judge for yourself.
In order to show you how sharp the Sony FE 20-70mm F4 G lens is, we are providing 100% crops on the following pages.