Updated: Aug 16, 2019
There is a lot of hype in the media that you can take pictures on a phone and you will get good quality pictures. If this was true, then why do press photographers, fashion photographers and wedding photographers still use Digital SLR cameras and not start using phones?
This is one case where size does matter. Digital cameras have a sensor which records the image. You will have heard the term 3 million pixel cameras but what does it mean?
Inside the average phone the size of the sensor can be seen below in this illustration. On the left it is the sensor in a phone. On the right it is the sensor in a professional camera.
If the phone sensor has 3 million pixels, they are incredibly small whereas the professional camera will usually have around the 23 million pixels region.
Certain phone manufacturers claim they can print big posters from their phones, but unreality it isn't quite true. I would say the majority of people taking picture son their phones, myself included, only ever look at them on their phones, sometimes upload to a computer and in some cases make prints, but usually only quite small, which is fine.
Generally speaking we take hundreds of pictures but rarely print anything. Most of the pictures are posted online to social media and they look great!
So to come back to the question, using a high quality camera in the hands of a professional who knows how to use it, I can safely say that if you want a poster sized picture for your wall it will be no problem whatsoever.
A professional DSLR (Digital Single Lens Reflex) camera will enable you to print poster size pictures at a high level of quality and they look great!