There are several steps in getting a product to market, and it sounds as though you are well on your way. First, I want to emphasize that hardware design in inherently more risky than software design, so you should first learn about systems engineering from someone who has put a product such as this together. If you tell yourself that you can do the software, make sure you are equally confident that your team can put the hardware together. It has been my experience that the hardware itself can be one of the most challenging as well as one of the most expensive aspects of the system design process.
First, you must think from the system level about the product both in terms of the overall design specifications and the engineering required to meet your specification to meet a particular cost model. You will need someone to handle software (it sounds as though you have that covered), electronic design, mechanical design, PCB layout, sensor and optical system requirements, and how you will put it all together.
Since you asked about PCBs, it is absolutely necessary that you find an experienced PCB engineer, either by hiring one (the market is great for this right now, if you have the money to hire) or by finding someone with hardware design experience to work as a consultant and could select the components, layout the board, and then work with a mechanical engineer to package the system for the mass market. There are many companies that are more than happy to contract with you to do this, but beware that they have different focuses in terms of quantity, reliability, and, most importantly, cost.
The design process prior to going to a Chinese manufacturer will usually include a working prototype, a couple of design iterations, and a final (usually several copies) of the final test prototype for verification and comparison to the Chinese production model. Simply put, you donâ(TM)t want to order 50000 buggy boards. Express PCB will print the board itself, but you will need another shop to drop the components and solder them to the board. Iâ(TM)ve had luck with a couple of companies that are local to me and you will likely be able to find a shop that can provide you with PCB finishing services. Your PCB engineer will likely help you select components (probably from DigiKey) and whatever sensor you are using (likely directly from Kodak, depending on the sensor, or from a vendor that will give you a complete OEM camera (that is usually a better option if you have no sensor integration experience, but will typically cost more per unit, so if you are going to mass market the camera, youâ(TM)ll want to look into other options).
In summary, your team will need to work on the product design from different perspectives, both the systems/business/cost side and the design/fabricate/testing side.