Intro
With smaller mirrorless cameras dominating the market, there has been a surge of popularity for compact street photography bodies. In the last several years, the usual cameras I'd recommend to someone in this area of photography would have been the Ricoh GR series, Fuji X100 cameras, and the amazing Leica Q2 with its beautiful 28mm Summilux lens and astounding 47megapixel sensor.
Recently, companies like Sony and Sigma have been releasing new compact lenses. These lenses bridge the gap between the original cheap and plastic Sony FE lenses and the incredibly expensive Sony GM and Sigma Art series for professionals.
Sony released an interesting trio of lenses: the 24mm f/2.8 G, 40mm f/2.5 G, and 50mm f/2.5 G lenses. Oddly, Sony opted to release a 40mm lens instead of a 35mm. Not wanting to spend thousands of dollars on switching to a new camera system, I picked up the 40mm f/2.5 G and mounted it on my Sony A7C for my new EDC (everyday-carry).
Specs
Focal Length: 40mm
Sony FE Mount (Full Frame)
Minimum Focus Distance: 28cm/.28m
Max Aperture: f/2.5
Minimum Aperture: f/22
Optics: 9 Elements in 9 Groups; 7 Diaphragm Blades
Weight: 173g
Dimensions (Diameter x Length) 68mm x 45mm / 2.7" x 1.8"
Filter Size: 49mm
Weather Proofing: Dust and moisture sealed
Price: $598 USD
Build Quality
The 28mm, 40mm, and 50mm all share the same outer lens construction. If you placed all three lenses side-by-side, they'd look virtually identical until you read the focal length indicator. The 40mm f/2.5 G lens has a very solid metal build quality which is a huge improvement over the plastic on the Sony Zeiss prime lenses that tend to scratch very easily. The only odd part of the lens is not even an issue with the actual lens build itself but with the flimsy plastic lens hood.
Personally, I really desired something that looked sleek like the square hoods on the Fuji X100V and Leica Q2 so I found a square hood online and filed down the plastic mount so it would fit onto the Sony lens. The setup resembled the Leica Q2 Summilux lens in the end and I have to say that I think this looks much better than the stock lens hood that Sony decided to provide.
The lens has a slew of manual controls including a manual aperture ring with a de-click switch, a custom function button, and a AF/MF switch. Having all these controls when shooting street photos is invaluable when you want full control of your photo in the moment. I found myself using the manual aperture ring and AF/MF switch quite often and never felt like I was going to damage the lens if it accidentally bumped into something. Sony claims the lens is dust and moisture sealed and it has a thin rubber ring at the mount to prevent anything leaking onto the sensor.
The optical design of this lens consists of 9 glass elements in 9 groups with 7 diaphragm blades which might show slightly disappointing bokeh (if bokeh is a priority to you). Unlike the Sony 24mm G and 50mm G, this lens does not have ED (Extra-low Dispersion) glass elements to reduce chromatic aberration. This doesn't mean the lens has horrible chromatic aberration, but it won't be able to avoid purple and green fringing in certain situations where the 24mm and 50mm might have been able to perform better.
Performance
The 40mm f/2.5 G looks like it was specifically designed to live on the Sony A7C. The compact nature of the lens and slim profile of the A7C makes it a fabulous option for discreet street photography. The lens has two linear focusing motors for fast focus and, more importantly, virtually silent autofocus. You'd have to put the lens up to your ears to hear the motors operating at all and I love that there was no sacrifice to the autofocus speed for this attribute.
The lens is quite sharp, but I can't say this is the sharpest Sony FE mount lens I've ever used. It won't rival something like the amazing Sony Zeiss 55mm f/1.8 or the Sigma 24-70 f/2.8, but having the sharpest details in a lens like this isn't necessarily the best image quality to have. You definitely don't want muddy details, but for general street photos or everyday-carry, usability is the most important trait to have. With the 40mm, getting a great (and not amazing) image quickly, is the most important factor to me. I even attached a Moment 10% Cinebloom filter to create some diffusion and remove some of the digital sharpness. A lot of my resulting images had clarity but had more flattering results for people and bright lights.
Vignetting nor distortion are problems for this lens, considering you have automatic lens correction on in your camera. Flaring isn't an issue either but the fact that the Sony 40mm f/2.5 G lens is missing the Extra-low Dispersion glass elements means that chromatic aberration can be apparent in some images. I don't believe it's significant enough that I wouldn't use any image, but you might want to consider it if you're using this lens for professional purposes.
If you're very strict about your preference in bokeh quality, you'll be quite disappointed with the 7 aperture blades. The bokeh isn’t the most spherical and has some obvious onion ringing going on. That said, it's not the worst bokeh I've seen but you might want to avoid the Sony G trio if creamy out-of-focus areas are your thing.
I will say this lens can still produce suitable portraits if you're careful with the background depth of field. It's not a f/1.2 or 1.4 lens but in traditional street photography it's generally better to be shooting at lower aperture values like f/8 or f/11 to capture deep focus of all subjects in your image.
Again, I think it's important to know that the Sony 40mm f/2.5 G is very good at general purpose photography but most multipurpose lenses won't excel at one area of photography.
Sample Images
Click on the photo to view a larger image.
Final Thoughts
Overall, this is one of the most practical and well-built Sony FE lens that has been released. Excellent build quality, great sharpness, useful focal length, and quick autofocus are all obvious signs that this lens is a must-have for any Sony street photographer or someone looking for an everyday-carry setup.
I didn't have any similar focal length lenses like the 50mm f/1.4 or 35mm f/2.8, but my intention was specifically to pair this lens with my A7C to create a sleek and efficient setup whenever I wanted to have a small camera while on the go.
Pros:
Excellent build quality
Manual aperture ring, custom function button, AF/MF switch
Very fast and quiet autofocus
Useful focal length
Great sharpness
Dust and moisture proof
Cons:
7 aperture blades produces unappealing bokeh
Chromatic aberration at times
Rating: 3.5/5
It feels unfair to give this lens the same grading system as any other lens I've experienced considering it is very purpose-driven. I won't be taking this lens for portraits or landscape projects, but it'll definitely live on my Sony A7C when I want convenience, but more than just an iPhone camera. I'd highly recommend any Sony shooter who's looking at street photography options to check out the Sony 40mm f/2.5 G lens. You can save yourself a considerable amount of money by having a relatively affordable and proficient lens instead of having a separate camera system by switching to something like the Fuji X100V or Leica Q2. The Sony 40mm f/2.5 G is quietly one of the best lenses that Sony has released for the everyday photographer.