Review: Sigma BF | Minimalist Full-Frame Mirrorless Camera

The Sigma BF is a minimalist full-frame mirrorless camera that takes a different approach. Ahead of its April 2025 release, MPB's Connor Redmond and Amy Moore took the Sigma BF to Porto, Portugal and Uckfield, UK. In Amy's full-length video and Connor's in-depth review, the MPB team reviews the camera's unique design, simplified shooting experience and real-world performance as a street and travel camera. Co-written with additional images by Jillian Lenser.

Amy Moore was sceptical of the Sigma BF, with its poor battery life and lack of viewfinder. Beyond the Sigma BF's limitations as a workhorse, Amy began to grow fond of the camera, appreciating its solid autofocus and unique aperture control system. But what does Connor Redmond think of the Sigma BF? Over to you, Connor.

Many people tout the Sigma BF as ‘if Apple made a camera,’ but the reality is much better. The new Sigma BF is unlike any other camera I’ve ever used. Sigma has opted out of the spec race, inviting us to imagine a different digital photography experience. The experience of using the Sigma BF is part calming point-and-shoot, part luxury fashion camera accessory like the Leica Q3 and part appreciation of its tactile industrial design. 

Let’s agree on one thing before diving in: This camera is simply not intended to replace high-end cameras or compete with existing cameras on the market, where increasingly ‘do-it-all’ cameras dominate. This is not a camera meant for professional work. This is best described in my opinion as a luxury ‘everyday carry’ camera.

The entire philosophy here is to rediscover the joy, inspiration and discovery that have always defined photography. Modern spec-monster cameras can make you feel distant from these things, with a lot of distracting features shoehorned in. But, Sigma is saying no to that here with the BF. The BF stands for ‘Beautifully Foolish’ – which, I think, sums up the camera perfectly.

Sigma BF Key Specs

Machined from a single piece of aluminium, available in either black or silver, the Sigma BF features a 24.6-megapixel full-frame CMOS sensor.

Design & Build Quality

The first thing you’ll notice about the Sigma BF is its stark, minimalist design. It looks like a piece of modern art. Sigma has opted to do things the hard way in pursuit of an uncompromising design. Each camera is milled from a single aluminium block, giving the BF a solid, weighty feel.

Shooting Experience

There are just three buttons and one dial on the rear of the Sigma BF, and one shutter button on top. You get a playback button, an on/off button and a button to bring up the menus. That is all you have for interacting with the camera. The LCD screen is a touchscreen but can only be used for focus and certain menu functions. 

Every button or dial interaction provides satisfying haptic feedback, a small but pleasant detail. This minimal design dramatically reduces clutter compared to most mirrorless cameras on the market, which tend to have a lot of different mode dials and buttons for various functions. If you are used to many buttons and dials, the Sigma BF can be a jarring shift, but after a while of use, it felt quite freeing, like spring cleaning.

The absence of a viewfinder is a bold decision from Sigma, which means you will compose and review via the LCD screen only. Whether that’s a pro or con depends on your process. For me, the experience felt limiting at first, but I did get used to it, and it felt a lot like shooting with the Ricoh GR III, which is a camera I adore. But that camera is much easier to hold and use with one hand. Read our Ricoh GR III review.

No matter how bright your screen can get, it can never beat the great fiery orb in the sky. This presents problems when you consider that you are likely to take this camera to sunny places. The glare of the rear screen can become intense, almost making the camera unusable when it is particularly bright out. 

While shooting with the Sigma BF in Porto a few times, I experienced too much screen glare. It wasn’t completely unusable, but some moments made framing the shot quite tricky, which a viewfinder would have solved — like the Sigma LVF-01 viewfinder you can get for the Sigma FP-L. It would be great if Sigma considered making some interesting attachments for the BF, but there are no possible mounting points apart from the tripod screw. 

Many people will not even consider this camera because it does not have a built-in viewfinder, and that is fair enough, but not having one can certainly put you in a different headspace while shooting. In this case, Sigma has opted to go without a viewfinder to maintain the camera's simple design philosophy and keep the camera's shape charming.

I think that no viewfinder means, in a way, you are more ‘connected’ to your immediate surroundings. These are subtle things, but I think that Sigma has designed the BF to be used in a certain way. It can’t ever be considered an ‘all-rounder’ or ‘do-it-all’ camera. So, to get the most out of the Sigma BF, I think you should try and shoot the way Sigma intended.

Sigma BF Menu System

The Sigma BF menu system is worth discussing because it’s so basic. The BF has four very sparse menus. Sigma wants you to focus on the picture-taking here, with the menus sitting right at the very back.

Clear View Shooting: While shooting, you can bring up this overlay of basic functions like white balance, aspect ratio, autofocus setting, file type, and a switch to video button.

Playback Menu: Activated by pressing the button with the triangle, the playback menu works well and is noticeably quick because of the speedy 230 GB SSD inside. The information about the picture you can bring up is shown in the image above. 

Shooting Aids: Pressing the three dots brings up a menu that allows you to toggle different shooting aids, such as guidelines. This is also how you get to the system settings menu. 

System Settings Menu: The Sigma BF's settings menu is refreshingly light and easy to navigate. There isn’t that much here to fiddle with or get overwhelmed with. Good job, Sigma. 

Context Window

I really liked the little context window at the top right of the camera. It felt smart and was useful in several scenarios. 

By using the dial below it, you can quickly change the setting you want to change on the fly. I used exposure compensation the most out of them as I was shooting in aperture priority most of the time. 

Checkered Texture Grip

Each Sigma BF is cut from one solid block of aluminium. Sigma claims it can only produce nine of them a day at their factory because of this. Each BF takes seven hours to cut, but the result is a precise block of beauty. 

To help with the camera's handling, a checkered-textured grip is also etched into the right side of the front. This helps make the camera feel more grippy. See the close-up of the fine texture below. 

This texture does feel interesting and helps the camera handle it. However, after prolonged use, my hands would get quite clammy, which made the camera more difficult to hold with no rubber present apart from on the bottom of the camera. It is a struggle to try and use this camera one-handed, I wouldn’t recommend it. 

Internal Storage

The nightmare-inducing era of forgetting your memory card is officially over. Instead of an SD card, the BF has a solid-state drive (SSD) with 230GB of internal storage. That’s enough for roughly 14,000+ JPEGs, 4,300 RAW images, or 150 minutes of high-bitrate video—more than enough for a day’s shooting. You offload files via a USB-C port, which also charges the camera. 

I think it’s time for camera manufacturers to start including internal memory on all cameras, don’t you? 

L-mount Lens Compatibility

There are many lenses available for the Sigma BF, which can only be a good thing; all budgets are covered. The BF uses the L-mount lens system. This means the BF is compatible with a whole spectrum of excellent lenses from Sigma, Leica, Samyang, Sirui and Panasonic, which form part of the ‘L-mount Alliance’, which is a unified lens mount standard across multiple brands.

Sigma i-Series ‘Premium Compact Prime’ Lenses 

At the time of the Sigma BF release, nine prime lenses (to rule them all) match the style and colour of the Sigma BF. These are called the ‘Sigma i-series’, and Sigma describes them as “premium compact primes for mirrorless users that combine superb optical performance with a level of compactness.” The available focal lengths are: 

• 17mm f/4 DG DN L

• 20mm f/2 DG DN L

• 24mm f/2 DG DN L

• 24mm f/3.5 DG DN L

• 35mm f/2 DG DN L

• 45mm f/2.8 DG DN L

• 50mm f/2 DG DN L

• 65mm f/2 DG DN L

• 90mm f/2.8 DG DN L

All of these i-series lenses feature the same beautiful compact all-metal build and material finish in both black and silver. They all feature a smooth aperture ring and an auto/manual focus switch.

Image Quality & Performance

At the heart of the Sigma BF is a 24.6-megapixel full-frame sensor that is neither revolutionary nor outdated; it is just as you would expect a decent modern camera sensor to be. For an ‘everyday carry’ type camera, it’s an excellent option for quality without settling for a crop sensor. 

On paper, the Sigma BF might look like a lesser version of the Sony A7C II, the Sony A7CR or the Panasonic DC-S9 compact camera. For example, the BF’s 24 megapixels are less than half of the Sony A7CR’s  60 megapixels. However, it is only by using and feeling the Sigma BF that you quickly realise how different the Sigma BF is from its closest competition. The type of photographer that this camera interests is unlikely to be super critical of the resolution and pixel peeping. 

Autofocus

The autofocus system is speedy in bright light and tracks subjects steadily. In dimmer conditions, it occasionally hunts, which is on par with many other mirrorless bodies. But I appreciate how quick and quiet the autofocus motors are, especially with Sigma’s latest lenses.

The Sigma BF has three autofocus modes available: single point, area and subject tracking, which can track humans and animals. I found that the area and subject tracking autofocus were impressive. Their performance is on par with Sony’s autofocus, which is a high bar to clear. 

ISO and Low Light Performance

The BF has an ISO range of 100-102,400. It can handle dim indoor scenes or dusk landscapes without turning every shadow into a grain festival. I did see some noise when I pushed the ISO up toward the higher limits, but it’s a pleasant, fine grain that’s relatively easy to handle in post-processing.

Colour

The Sigma BF’s main menu has 13 built-in colour modes, which you can cycle through like film presets. The camera offers 13 different colour modes: Standard, Rich, Calm, Powder Blue, Warm Gold, Teal and Orange, FOV Classic Blue, FOV Classic Yellow, Forest Green, Sunset Red, Cinema, 709 Look, and Monochrome. 

Jillian Lenser took the Sigma BF out in New York and tested out the camera’s colour modes.

Left: Rich | Right: Calm

My personal favourite is the “Warm Gold” colour mode; it adds elegant warmer tones without severely altering the colour too much. Cycling through colour modes is as easy as turning a dial and watching the screen and context window, so I surprisingly switched them up frequently to find the right one for each scene.

Left: Teal & Orange | Right: Cinema

Of course, you can shoot in DNG+JPEG so that the RAW photo is retained if you want that later, but the JPEG will have the colour mode applied to it, which can be useful for getting a general look or if you want to share quickly with no editing. 

Left: Powder Blue | Right: Warm Gold

Aspect Ratios

Using the BF's main dial, you can quickly cycle through aspect ratios and see them change on the screen. In real-time, as you cycle through them, you will see the ratios change on the screen. The ratios go from 21:9, 16:9, 3:2, Asize (full sensor), 4:3, 6x7 to 1:1. 

At first, I thought this might be a useless feature that I’d never use. I can just crop the image in post? But in reality, I found myself cycling through the aspect ratios a lot, depending on the scene in front of me. I found it a refreshing experience that unlocked a bit of creativity in me. I found myself thinking about composition a lot more than usual, which I enjoyed. 

I kept gravitating back towards the ridiculous 21:9 aspect ratio. Which feels like shooting through a letterbox. The frame is so horizontal and restricted, I found it fun and challenged myself to stick with it and try and actually get some decent images with it. Again, it had me thinking about composition in ways I hadn’t before. 

In the 21:9 case, I thought much more like a cinematic director of photography than a bog-standard 3:2 photographer. This aspect, combined with the camera's portability, just wandering around Porto's streets, made it a unique and enjoyable experience to try to find unusual frames among the city and its patrons. 

As you can tell, I enjoyed playing with the long evening shadows the sun was casting on the promenade by the banks of the river Douro. The 21:9 aspect ratio had me thinking in different ways.

Battery

Battery life on the Sigma BF is quite frankly appalling. These days, I rarely have to worry about battery life, I usually get a day's worth of shooting with the majority of the cameras I review. But the Sigma BF? I was watching that battery go down in disbelief. It uses a new proprietary BP-81 battery, which Sigma developed for the BF, and it’s about the size of a lipstick. It has a CIPA rating of 260 shots, which is really low. 

As I was shooting DNG+JPEG, the battery life felt even lower. Combined with max screen brightness, there were certainly a lot of anxiety-inducing moments. I felt like I had to charge the camera every time I sat down near a plug. 

It is worth noting that you can use the Sigma BF while it is charging, so you could charge it on the go with a powerbank—if you don’t mind the extra bulk. 

Video Capabilities

You wouldn’t buy this camera to shoot video, but the specs are as follows: 6K video up to 30p, 4K up to 30p, 1080 up to 120p with a Leica L-Log profile. We have a readout speed of 20.9ms, which isn’t terrible and means that rolling shutter in video should be fine for most people. 

6k video is fun, but it's really all par for the course for modern mirrorless cameras, which must always have some video functionality. I can’t envision anyone using the video other than for quick snaps or moments in front of them, to be posted on social media. So, for this use case, the Sigma BF is perfectly fine. But the camera’s lack of WiFi hinders itself in this regard, as you can’t quickly zip a video you just took to your phone; you have to plug it in via the USB-C port. It feels like a weird miss on Sigma's part, not including the built-in WiFi. 

Four Alternatives to the Sigma BF

Sony A7C II

If you are interested in what the Sigma BF offers but feel you still can’t quite live without a viewfinder, IBIS, dials and a mechanical shutter, then get yourself a Sony A7C II, which offers all of these features for a similar price point. 

If you aren’t fond of the Sigma BF's megapixel count, consider the 61-megapixel Sony A7CR. For a deep dive, check out our Sony A7CR review as well. 

Fujifilm X100VI

Similarly, the Fujifilm X100VI offers more features than the Sigma BF and, in my opinion, a superior shooting experience, with better colours straight out of the camera. It is also more comfortable to hold, and still does not lack in style points either. 

Read our full Fujifilm X100VI review to understand why I think it is the better buy. 

Panasonic S9 

For a cheaper alternative, perhaps consider the Panasonic S9, which suspiciously might use the same sensor and innards as the Sigma BF. They have very similar specs, but the Panasonic is cheaper, less stylish and nice to look at. It’s also compatible with L-mount lenses. 

Olympus PEN-F

If you prefer the retro camera look over the modern super minimalist look, then the Olympus PEN-F has you covered. It has a premium design, 5-axis image stabilisation, picture profiles like the Sigma BF, and it is small and lightweight due to being a Micro Four Thirds camera. 

Sigma BF Sample Images

Sigma BF Verdict

Upon reflection, the Sigma BF is a unique camera. Sigma set out to create a camera that feels different, and in my experience, they succeeded. 

The sheer amount of interest in the Sigma BF’s release challenges the notion that more buttons, deeper menus or bigger specs automatically make for a better camera. Instead, it focuses on thoughtful design, intuitive menus and a durable construction. The Sigma BF has proven to be a breath of fresh air in a crowded mirrorless market. Not everything has to be a hybrid camera, does it? 

I would like to see more niche and weird tools in photography, and the Sigma BF is certainly one of those.

FAQs

Who is the Sigma BF for?

The Sigma BF is a great option for a person looking for a pared-down shooting experience for travel photography or taking street pictures.

Is the Sigma BF pocketable?

The Sigma BF is portable with the right lens, if you attach a pancake lens to the camera, perhaps. 

How heavy is the Sigma BF? 

The Sigma BF weighs 446g, including the battery. 

Is the Sigma good for street photography? 

The Sigma BF is an excellent option for street photography with the right compact lens, like a 35mm or 50mm. 

Read more camera gear guides on the MPB content hub.