As it shares much of the same specification as the V3, we had anticipated that the J4 would have very similar image quality to its sibling.
Happily, that means very good image quality. JPEGs straight from the camera are bright and punchy, and contain a decent level of detail – especially for a camera with a one-inch sensor. Like the V3, the J4 has no anti-aliasing filter, which makes it more capable of resolving detail than its predecessor, the J3.
It's still fair to say that in terms of detail resolution at least, this camera struggles to compete with cameras that have much larger sensors, such as the Micro Four Thirds range, or APS-C cameras from Sony and Fujifilm.
However, if you are looking for something very small and you're familiar with other Nikon cameras, then this is very appealing. The overall impression of detail when looking at images at normal printing or web sizes is good, it's only when looking at 100% that image smoothing starts to become a problem – the average user of this camera is unlikely to be pixel peeping to that level though.
The camera's metering system does a decent job of producing accurate exposures in the majority of conditions. Occasionally in very high contrast conditions, using general purpose metering can confuse the camera a little, in which case using spot metering can help, or dialing in some exposure compensation.
Similarly, automatic white balance does a good job of coping with mixed lighting or artificial lighting conditions, producing accurate colours in the majority of conditions. It's easy enough to switch to a more appropriate white balance though if you find the camera is struggling a little.
In most conditions, autofocus speeds are very quick, locking onto the subject quickly and easily. You can get relatively close to a subject, but this is not really a camera designed for macro work without the addition of a dedicated macro lens.
Sadly, there are none of those available in the proprietary Nikon 1 mount, though you could attach an F mount optic via the additional lens mount. If you're shooting in lower light conditions, the lens will often take a little while longer to focus than in bright conditions.
Overall, the 10-30mm f/3.5-5.6 kit lens is a good performer, and makes for a good carry-around lens even if you decide never to purchase any additional optics. Examining an image taken at a mid-range aperture of around f/8 allows you to assess lens sharpness, and this lens does well to produce reasonably sharp images, dropping off just a little in the corners of the frame.
During my testing I also used the 18.5mm f/1.8 lens, which gives a roughly equivalent 50mm in 35mm terms, and the 32mm f/1.2 lens, which gives a rough equivalent of 85mm. Both are excellent lenses, but the 18.5mm is a good 'classic' length lens and is great for portraits, streets and anything that requires a shallow depth of field.
Noise levels are good throughout the sensitivity range, but at 100% you can see some loss of detail at ISO800. That loss increases further if you push sensitivity up to ISO3200, but it shouldn't be a problem unless you're printing at very large sizes.
If you favour detail over noise reduction, shooting in raw format allows you to add your own reduction post-shoot. Looking at equivalent raw format images shows how much noise reduction is applied to JPEG images – it's quite heavy handed, but that helps to keep the image looking clean.
The digital filters available on the camera are reasonably interesting, if you like that kind of thing. It's worth experimenting with them to see if you like them – my favourite is the Cross Process set found under the Creative Mode. I also like shooting in Monochrome using the Picture Control element in semi-automatic or manual mode. It's worth giving the Creative Palette a go, too.