Sony has confirmed plans to sell two stand-alone lenses that connect to smartphones by wi-fi, allowing them to take higher-quality photos.
The devices are compatible with Android and iOS handsets and mark the creation of a new product category.
The Japanese company announced the products alongside a new smartphone which features a 20.7 megapixel camera and a larger-than-normal image sensor.
The launches should help the firm challenge Nokia's top-end handset.
Sony told the BBC it would target its Z1 handset at a wider audience than what it called the Lumia 1020's "super-premium category".
It confirmed details of the devices at the Ifa consumer tech show in Berlin - much of the information had already leaked via tech news sites.
One analyst suggested the lenses in particular would struggle to find buyers.
"The concept is interesting, but when you think about using it, will users want to carry them around?" asked Francisco Jeronimo, mobile devices research manager at tech consultancy IDC.
"The problem is that for those wanting top-quality photographs, the experience of having a DSLR [digital single lens reflex] offers a better experience than a phone with an add-on camera.
"Meanwhile having the lens attached to a phone makes it feel quite bulky compared to a compact camera or stand-alone handset.
"If the lenses were priced under £100, then I could see photography geeks buying it, or operators bundling it with the phone, but these lenses will be quite expensive."
Sony itself acknowledged that it did not know how strong demand would be.
"Always we're discussing: 'How many pieces should we prepare,'" Yosuke Aoki, a digital imaging spokesman for the firm, told the BBC.
"We're waiting for after the Ifa announcement to see what the feedback will be to the models."
Making a statement
The QX10 lens offers a 10x optical zoom and 18.2MP resolution which Sony says makes it ideal for taking shots of distant landmarks or close-ups of people. It will cost about £170,
The QX100 features a smaller 3.6x zoom but a bigger sensor with a resolution of 20.2MP. Its aperture goes as wide as f1.8 - allowing more light in - meaning it should be more adept at taking photos in low light or with a very shallow focus. It also offers manual focus as an option which is not possible on the other lens. It will cost about £380.
Once fitted with a battery and memory stick, the QX10 weighs 105g (3.7oz) and the QX100 179g (6.3oz).
- include technology that compensates for shaky hands
- activate a link-up to a phone or tablet if it has an NFC (near field communication) chip
- can attach to different-sized handsets via an extendable clip, or - in the case of the Z1 - using a special case
- can be operated while a short distance away from the smart device
Neither has a built-in screen.
Sony Mobile's head of sales and marketing said they were intended to send a message to consumers, including those who would never buy them.
"It's a statement as one piece of many things that are starting to come together under the umbrella of Sony," said Dennis van Schie.
"The PlayStation 4 is coming out. In 4K [ultra-high resolution] TVs, we're the leader - from the formats to the cameras to recording capabilities [that will appear] quite soon in mobile.
"Now we're the first ones to dare to create a lens-type camera with a new kind of user interface. It contributes to what Sony is standing for."
Sony posted a 3.5bn yen ($35m, £23m) profit in the April-to-June quarter, reversing a 24.6bn yen loss the previous year.
Stronger sales of smartphones helped achieve the turnaround.
However, IDC says the firm still only had a 4.1% share of global smartphone shipments over the three months, putting it behind Samsung, Apple, LG, Lenovo, Huawei and ZTE.
Sony is hoping the new water-resistant Z1 handset will help it boost that figure.
It says the device features an exclusive sensor which is the same size as that found in its Cybershot cameras.
It also features new software including the ability to provide live video streams to Facebook, and Info-eye - an app that provides information about books, wine and landmarks among other objects the phone is pointed at.
The company is also taking advantage of its other assets to help the device stand out from the Android crowd. UK shoppers are promised five Sony movie downloads and a selection of free PlayStation mobile games.
"They've done quite a good job of differentiating the phone," said Mr Jeronimo.
"That's what operators want - to be able to provide additional value from what Sony offers.
"That's why they are looking at Sony as a better prospect for the future than other vendors like Blackberry and HTC."