Sony FX2 vs FX3: Why Native ISO Matters

If you’re here wondering if you should purchase the FX2 or the FX3a, you can learn a lot more about those cameras here. When it comes down to it, the higher native ISO on the FX3 is going to be the deciding factor. As a production company that does everything from working on sets with controlled lighting to covering events in all types of lighting situations - we will always pick the FX3. If you are a run and gun documentary style shooter than you should be picking up the FX3. If you are always finding yourself in a controlled lighting environment, or focus mostly on stills and want to get into video - the FX2 is probably the right choice for you! Whereas the blog I linked above is a really good overview of both cameras, this one just focuses on what I think is the most important part- Native ISO.

Let’s Jump In

Native ISO lives in the fine print, but it’s the secret sauce for clean low-light footage - long story short this matters a lot. It’s where your sensor and processor work in perfect harmony, delivering rich highlights and deep shadows without producing a lot of noise. Push past it and you’ll wrestle grain, crushed blacks, and color shifts in post. Nail it, and even handheld, run-and-gun setups under tungsten bulbs or neon signage stay crisp and cinematic. Here’s how the FX3’s 800→12,800 jump stacks up against the FX2’s 800→4,000 spread and why those numbers should guide your camera choice.

What Is Native ISO?

If you shoot video, you should ONLY be shooting in your native ISO if you’re looking for an imagine without noise. Native ISO refers to the sensitivity settings where your camera’s analog-to-digital converter and sensor design are optimized for the cleanest output. Unlike extended or boosted ISO, which digitally amplifies the signal (and the noise), native ISO modes let you push your sensor without compromising dynamic range or color fidelity. Staying at or near a camera’s native ISO ensures you’re capturing the maximum latitude in your highlights and shadows.

Sony FX3 Native ISO Modes

The FX3 gives you two S-Log3 base ISOs:

• ISO 800 for rock-solid mid-range latitude and minimal noise

• ISO 12,800 for ultra-dark scenes and highlight retention

That 4-stop separation unlocks run-and-gun flexibility: switch to ISO 12,800 when you’re rolling handheld under street lamps or in a candlelit bar, then dial back to 800 for controlled interview setups. The FX3’s fan-cooled body handles long takes without overheating, and at just over 1 lb 9 oz body-only (about 2 lb 4 oz with XLR handle and battery), it’s ideal for gimbals or shoulder rigs. Expect around 95 minutes of continuous recording on a single NP-FZ100 battery.

Sony FX2 Native ISO Modes

Sony’s FX2 also offers dual S-Log3 ISOs, but with a tighter spread:

• ISO 800 for the cleanest shadows and max dynamic range

• ISO 4,000 for a 2-stop boost when the lights dip

That narrower separation ensures exceptionally clean midtones at ISO 800 and a reliable bump at 4,000 without a huge noise penalty. The FX2’s upgraded sensor and graphite-cooled design mean sustained 4K 59.94p recording without rolling-shutter artifacts or shutdowns. And since it shares the FX3’s S-Log3/S-Gamut3.Cine color science, mixing footage between bodies is painless.

Choosing Your Setup

For fast-moving, unpredictable lighting - trade shows, pop-ups, or street-style promos - the FX3’s ISO 800→12,800 jump gives you the ultimate run-and-gun edge. If you’re building a controlled narrative - testimonials, product demos, cinematic interviews - the FX2 might be the right choice for you. Ultimately if you can ALWAYS control the light the FX2 is a viable video camera option - but with that said I will always go for my FX3.

Your shoot’s style should dictate your camera’s native ISO strategy. Pick the FX3 when agility and maximum light sensitivity rule. Opt for the FX2 when you’ve got grip, lights, and a story that calls for the cleanest possible imagery and you’re looking to snag some photos. Either way, understanding and respecting native ISO will elevate your work from noisy compromises to crisp, cinematic visuals.

Ready to dial in the perfect native ISO for your next project? Reach out to Bunker Hill Media to craft a video tailored to your story. Let’s make every frame count.