Sony has been releasing some very tasty, high-end lenses in the past few years. However, there’s always the case for a more cost-effective prime lens, that still provides great optics at a more palatable price point. The Sony DT 35mm f/1.8 SAM is built specifically for APS-C Alpha cameras and features the A-Mount.
The lens provides an equivalent focal length of 52.5mm, which is a touch over the standard 50mm. And being so lightweight, it should be a great walkaround lens. Lots of potential applications here, especially with the f/1.8 aperture, so let’s dig in and see what this lens can do in the real world.
Anybody familiar with the Canon 50mm f/1.8 STM will see a similar concept here. Lightweight and simple to use, but to fit a certain price point, there had to be cutbacks in certain areas. Most noticeably is the all-plastic construction which feels nowhere near as robust as higher-end lenses. The construction is fine for general, everyday use, but along with no weatherproofing, it’s not the type of lens that can be treated roughly.
The inner lens tube extends and rotates during focusing, but the filter ring stays in place. The rest of the lens barrel is a very simple design, with the only external features being an AF/MF switch and the distance scale printed around the lens. The front of the lens has a 55mm filter thread and fits the securely locking lens hood, which snaps in place with a quick turn.
Inside the lens are six elements arranged in five groups with a seven-blade rounded diaphragm. The aperture range goes from f/1.8-f/22 (f/2.7 on a 35mm equivalent) and weighs in at a very lightweight 170g. The lens also has a reasonably close focusing distance of 23cm.
Lastly, the SAM bit in the name stands for the Smooth Autofocus Motor. This isn’t the most rapid operator in the Sony lens lineup, but it should still be adequate enough for general applications.
Sony DT 35mm f/1.8 SAM in Use
The Sony DT 35mm f/1.8 SAM is a definite lightweight and if nothing else, it’s a joy to use when you’re coming from heavyweight zoom and prime lenses. As you would expect from this price tag of a lens, it does have its anomalies, but they’re not as detrimental as expected. There is some barrel distortion, which is most noticeable with horizontal and vertical lines, but this is easily correctable in software.
The lens can suffer from 1.5EV of vignetting when the aperture is set at f/1.8. Light falloff in the corners is noticeable up to f/2.2, but by f/2.8, things clean up nicely and by f/4 vignetting is hardly noticeable. Chromatic aberration is lower than expected at f/1.8. Slightly visible in very high contrast areas, with everything cleaning up nicely by f/4.
With an f/1.8 aperture, you would expect some quality background blur or bokeh, which the lens can deliver. However, the seven-blade aperture can only push things so far, with less than circular highlights, but at least they are not harsh or onion-shaped in appearance. Vignetting cuts down on the effects in the corners at f/1.8, but can still be reasonably smooth by f/4.
The autofocus system is relatively quick to snap into place, but it can start to struggle in very low light conditions. There was some focus hunting at times and some audible workings of the motor, meaning it might not be the best application for video, but it’s still relatively efficient and gets the job done.
The overall resolution of this lens is better than expected when wide open. At f/1.8 center sharpness is very good, with softer edges, but by f/2.8 sharpness across the frame clears up and by f/5.6 is very clear across the frame. Contrast levels are slightly reduced when the aperture is wide open, but stopping down to f/5.6 provides the best contrast overall.
The overall image quality of the Sony DT 35mm f/1.8 SAM shows its best results in the middle of the aperture range and in good lighting conditions. The lens provides a good deal of contrast and saturation at its optimum settings and even some pleasant shallow depth of field images. Bokeh may not be as artistic looking as a top-end prime, but still very pleasing for this price point of lens.
How Does It Compare?
As the choices here are going to be from the Sony camp and within a certain price range, the Sony DT 55-200mm f/4-5.6 SAM could be a possible alternative. It may be a zoom lens, but in this scenario, it’s the most optics you can get for your money that counts. You get the benefit of a 55-200mm range, but the downside of the variable apertures of f/4-5.6, which won’t make it as good a low light performer as the 35mm f/1.8.
Because there’s not much between the two lenses concerning price, the question is, which will provide the best optics for the money. The 35mm f/1.8 will be the better option in this regard and with a better low-light performance, is arguably the more useful all-rounder. This will also stand true if you only need a general-purpose prime.
|Sony DT 35mm f/1.8 SAM||Sony DT 55-200mm f/4-5.6 SAM|
|Optics||6 elements/ 5 groups||13 elements/ 9 groups|
|Diaphragm Blades||7 rounded||9 rounded|
As with the initial comparison with the Canon EF 50mm f/1.8 STM, the Sony DT 35mm f/1.8 SAM is aimed at being a cost-effective, prime lens, with good optics for the price. The center sharpness of the Sony is solid at f/1.8, with the only letdown being soft corners and a slight reduction in contrast. Stopping down to f/4 gets rid of most of the anomalies and by f/5.6, is where the lens looks its best.
The bokeh is reasonable, even when the aperture is completely wide open, with only minimal amounts of chromatic aberration. Again, stopping down a little to f/2.2 seems to get rid of the effects. The lens has obviously been built to a certain price point, but considering what you get for the money, this lens is a great little performer and there’s no reason why it can’t be a general-purpose backup lens in everybody’s kit bag. The biggest takeaway, Great value for money.