It’s a pain to hold. The BF’s control scheme may be refreshingly straightforward, but it’s accompanied by some baffling ergonomic decisions that suggest Sigma’s engineers were a little too focused on form over function.
For one thing, the BF’s precisely machined aluminum edges are surprisingly sharp. They won’t cut you, but they aren’t comfortable over a long day of shooting. On top of that, the front side of the camera offers no grip, aside from a diamond pattern etched into the metal, and it has just a small lip for your thumb on the rear.
I found that lip unexpectedly useful, but nevertheless I almost always found myself carrying the BF by the lens barrel when I wasn’t actively shooting. Doing so simply felt more natural and comfortable.
Even more frustrating is the fact that the screen doesn’t tilt or articulate in any way. It’s fixed, like that of an early digital point-and-shoot. And it doesn’t get especially bright: On a cloudless New Mexico winter day, I bumped it up to the maximum brightness setting, and the battery promptly drained before my very eyes, which were still fighting horrendous glare just to make out the image on the screen.
This camera calls for a pancake lens or two. Unfortunately, there is just one tiny lens available for L-mount, and it has a rather restrictive f/8 fixed aperture. Most L-mount lenses are chunky and heavy, which leads to a front-heavy feeling on a small body like the BF.
Even the smallest i-series Sigma lenses, such as the 17mm f/4 and 45mm f/2.8, are all metal and thus fairly heavy for their size. That gives confidence in their build quality but doesn’t lead to the best shooting experience with this camera.
I encountered a few image-quality issues. Although I loved the BF’s output in general, I did notice a few problems that Sigma may or may not be able to address with firmware updates.
To start with, the automatic white balance and exposure both got fooled on several occasions, delivering overly warm color rendering under mixed incandescent and LED light, blowing out bright areas in some shots taken under noonday sun, or delivering unusually dim results in others.
Ben Keough/NYT Wirecutter
I also noticed some moiré patterns with certain i-series lenses. That result speaks to their sharpness, and it isn’t particularly surprising considering Sigma’s choice of a sensor lacking a low-pass antialiasing filter, but it also leads to less than desirable JPEGs in certain scenarios. Other cameras without antialiasing filters manage to avoid this issue, so hopefully Sigma can correct it.
Finally, I experienced some issues with the rendering of JPEG files on macOS. Specifically, when using the Preview app to examine JPEG files, I found that highlights sometimes appeared extremely blown out, almost posterized.
I didn’t see this problem in DNG files or in the same JPEGs when I opened them in a third-party app like Photoshop, so this seems to be a problem related specifically to macOS system-level rendering, perhaps due to the fact that the BF outputs 10-bit JPEG files, as opposed to the more standard 8-bit variety.
The camera has no viewfinder and gives you no way to add one. The screen issue wouldn’t be a serious problem if the BF had a viewfinder, but it doesn’t. It also lacks a hot shoe (or even a cold shoe), so you can’t add an electronic or optical viewfinder accessory. And since it has no wireless connectivity, you can’t use your phone as a viewfinder, either.
This is a huge miss.
You can forget about image stabilization. The Sigma BF doesn’t include in-body image stabilization, as many other mirrorless cameras do. That wouldn’t be problematic if Sigma’s L-mount lenses were optically stabilized, but only its extreme telephoto zooms have that feature. As a result, this camera is harder to use in low-light situations than many of its rivals, and it has to rely on higher ISO sensitivity settings to compensate for its inability to shoot at slower shutter speeds.
Panasonic and Leica (the two other major lens makers in the L-mount alliance) do offer stabilized glass, but Leica lenses are prohibitively expensive for most people, and the only stabilized, non-telephoto lenses that Panasonic produces are the Lumix S 28–200mm f/4–7.1 Macro OIS (3.7 inches and 0.9 pounds) and Lumix S 24–105mm f/4 Macro OIS (5 inches long and 1.5 pounds). Neither lens is a particularly good match for the tiny BF.
The battery life is atrocious. Sigma suggests that you can expect to get about 280 shots out of the BF on a full charge. Judging from my experience, that claim seems optimistic—especially if you have to boost the screen brightness.
Shortly after receiving the camera, I took it for a 20-minute walk around my neighborhood and watched with growing anxiety as the battery level dropped by 20%.
You have a few ways to mitigate the battery drain: You can tap the power button to put the camera into sleep mode or long-press it to turn the camera off completely. I found that the battery still drained, slowly, in sleep mode, but turning it off between shots was a great way to eke out more life.
As usual, we recommend picking up another battery or two if battery life is a concern for you.
Seriously … why is there only one strap lug? This one we don’t understand at all. Dual strap lugs are a standard feature on serious cameras. Only the cheapest disposables tend to come with a single point to attach a strap, and that makes sense there since those cameras are so lightweight and, well, disposable.
For a solid-aluminum camera that costs $2,000 and weighs a full pound without a lens? Yeah, nah.
Having just one strap lug basically forces you to use a wrist or hand strap rather than a neck strap, which means one of your hands is always occupied while you’re walking around with this camera. I happen to be a fan of wrist straps, even with a heavier camera like this, but why remove the choice?
