Maximum effective ISO is an estimate of the highest sensitivity at which a camera can capture excellent quality photos.
Cameras with higher effective ISO will be better choices for indoor photography, night shooting, and indoor sports photography, especially if you intend to make large prints.
You can learn more at our glossary entry.
Maximum effective ISO test data courtesy of DxO Mark.NX1 test data on DxO Mark GH4 test data on DxO Mark
Excellent still image quality for its class; Fantastic, highly-detailed video quality; Superior video recording chops with 4K video (both Cinema 4K and Ultra HD); Responsive all-around performer with great AF performance and burst shooting; Rolling shutter is minimal with 60p and 30p video; Splash- and dust-proof magnesium alloy body; Built-in Wi-Fi with NFC.
High ISO performance not as good as some APS-C models (IQ drops quickly past ISO 3200); Overall still image quality not significantly better than the GH3; Sluggish buffer clearing with RAW files; Rolling shutter noticeable on 4K video; Not as compact as most mirrorless cameras.
Very good, high-resolution image quality; Excellent high ISO performance with RAW files; Very good dynamic range; Blazing fast 15fps full-res burst mode; Deep buffer; Great build quality & comfortable ergonomics; Lots of physical controls; Great battery life; Fast single-shot AF.
Continuous AF performance still not as robust as competing DSLRs; Aggressive JPEG noise reduction at high ISOs; JPEG colors and saturation less pleasing at higher ISOs; H.265 video codec can be difficult to work with.