Nikon has unveiled its first full-frame SLRs, aimed at photo enthusiasts and professionals.
The long-awaited launch poses a challenge for Sony, who has had this segment of the market for itself.  The motion allows Nikon to create advanced cameras less volume than before, giving the opportunity to develop new types of lenses.
But the disadvantages of the technology include a higher charge on battery power.
Many industry looking at relocation is crucial to the future of the Japanese company, at a time when smartphones have declined the demand for digital cameras with fixed lenses.
The sale of mirror-based DSLR cameras has also been weakened.
"Increased competition between non-camcorders will lead to greater credibility for the segment, wider consumer awareness, increased support from retailers and reasonable prices, which will ultimately be useful to consumers and professional d users," said Arun Gill, a analyst at the Futuresource consultancy office.
High-end cameras have traditionally shown a mirror to bounce light into the viewfinder. This allows the user to review the lens when composing a shot.
Nikon's electronic viewfinder is an OLED panel with 3,690,000 dots giving 100% coverage of the image
. In contrast, mirrorless cameras are a digital searcher. This releases space in the camera housing, making it more compact, providing more space for sensor-stabilizing technology and other electronics.
Digital display lenses originally could not match optical equivalents for quality, but the higher resolution displays have reduced gaps.
But their power requirements mean that camcorders tend to take fewer pictures before they require a battery replacement compared with DSLR.
Nikon experimented earlier with mirror-free technology in 2011. But the new Z7 and Z6 marks the first time It has combined innovation with a full-frame image sensor, as big as 35mm format film.
Full-frame sensors occupy more light than smaller versions – but require larger lenses to do so.
Having such a large sensor helps capture more light, making it easier to shoot sharply and helps to shoot lightly.
Other advantages of mirror-free technology include:
- A quieter camera, since it's not necessary to turn a mirror when taking a photo. This is useful when taking pictures for weddings and golf tournaments, such as
- ability for manufacturers to improve brast modes, where multiple images are taken quickly one after another
- reduces camera weight
One of the compromises is that existing DSLR- Lenses can not be fastened without adapter because there is a smaller gap between the mounting and the sensor.
Nikon will sell an adapter to work with existing F-mount lenses – but in some cases, owners will lose the ability to use auto focus and auto exposure with third party devices.
Nikon will sell an adapter for F-mount lenses that have a smaller diameter than the new Z-mount system
However, the company has announced three native lenses for its new Z-mount system and say that another six will come in 2019.
And it has said that because the new assembly has a larger diameter than before, it can develop new types of high performance alternatives.  Among these are a 58mm f / 0.95 lens, which says it will be the "fastest in Nikon story" – which means that a very shallow plan of the image can be placed in focus, with objects on the back and the front made unclear for artistic effect.
Nikon v Sony
Of the new cameras, the Z7 is the higher end model and costs around £ 3,500. It provides:
- 45.7 megapixels
- 493 focus points
- up to nine frames per second (fps) in burst mode
Z6 will be around £ 2,100 and offers:
- 24.5 Megapixels
- 273 focus points
- up to 12 fps in burst mode
Z6 captures lower resolution images but can take them faster
Both cameras shoot 4K video at up to 30fps and have a touchscreen which lashes but does not fold out, meaning that vlogers who are filming may need their own screen.
They use the XQD memory card format for storage.
Their closest equivalents are Sony's A7RIII and A7III.
Sony's A7RIII was announced in October 2017
The Z7 is higher resolution than the A7RIII and has more focus points and a slightly larger touchscreen. But it is £ 500 more expensive and heavier.
The Z6 can take more subsequent burst mode images than the A7III and has a much higher resolution. But Nikon's camera has less than half of the focus points, is heavier and is £ 100 more expensive.
Sony also benefits from having a much wider range of native lenses made by themselves and others.
In addition, Sony's cameras have two SD card slot. This means they can spend much cheaper storage and let owners choose between making a backup of each image for the security or storage of photos and videos on different cards.
The Z7 is 33% lighter than Nikon's D850 and has a more advanced sensor
"Nikon has been very competitive in terms of specifications and feels like it takes this category seriously," said Jon Devo, co-editor of Gadgetsboy newsgroup.
"Nikon has admitted the Z7 sensor is superior in its own D850. And to challenge their own DSLR flagship is a very bold step.
"But Z7's price and lack of a double card slot are especially the biggest issues it will encounter when it comes to adoption."
He added that Sony was thought to be a manufacturer of Nikon's sensors so it would benefit of the new-style sale anyway.
Attention will now be made to Canon, which is expected to launch new, non-cameras in itself in the coming months. The existing M Series allows owners to swap lenses but does not include a full frame model.