If I were to ask you which one would you prefer more? One piece or A Certain Magical Index? Sword Art Online or Naruto? or let’s say Fairy tail or Shakugan no Shana? what would your answer be? well…of course some answers may automatically come with the anime quality and story arcs in mind,but let’s ignore that,in a more general sense the answer would inevitably be “They are very different” and you wouldn’t be wrong ,after all their source materials have all been written very differently. If you google,”what is the difference between manga and a light novel?”,the search result that comes up is
A manga is a comic book or graphic novel – a story told in sequential art. A light novel is a prose book with illustrations. Called “light” because the content tends to be easy-reading and the size is small and portable.
In general manga provides a storyline involving the main characters and it’s setting using art as a medium. The various panels are drawn using various tools like G-pens,skin tones and calligraphic SFX text to convey the complete information to the reader.The panel sizes are often altered to emphasise a certain event or present a scene in the grandest manner possible. The best example would be One Piece,story and art by Icchirio Oda, the manga of One Piece probably has one of the best panel work in the history of manga making.The huge action panels and scenery panels convey the grandness and the epic(also sometimes weird) architecture of the cities,and also do a very good job of etching the most epic scenes in to the readers memory.Some of the other notable works are Boku no Hero Academia,though done partly digitally and partly traditionally does a very good job of making the best of both mediums. Naoshi Komi’s Nisekoi employs many backgrounds commonly found in romantic Shoujo manga’s or romance manga in general to convey the character’s feelings.
Coming to Light Novels,while just like manga they are also a primary source material for anime making,the techniques employed are obviously very different. Light novels also contain illustrations but are usually very scarce, they generally contain coloured illustrations for the most important events that take place in that volume and also manga-like illustrations for the action scenes sometimes or some other key events.The text lays more emphasis to what’s going on in the surroundings rather than the character itself, the description of the buildings,the feel of the surroundings, what’s going on in the character’s heads,but most importantly the dialogues,as the whole situation has to be conveyed effectively through them.They can be excessively fun to read,though a bit lengthy in some cases but there are some very good works out there, the best and probably the most frequently updated is of course A certain magical index,where the author Kazuma Kamachi has super human writing abilities(writing one volume a month since September 2014) and writing four other series in parallel to that,the stories of Light novel usually turn out to be much more creative but Harem based when compared to Manga however during the making of anime a lot of details can be skipped,dialogues can be cut short and ultimately story arc’s may be changed slightly or skipped,which in manga’s case however all the existing material is used and additional filler arcs if necessary to buy time.
So, in general both mediums are different and have their own specific features, they are both loved by their respective fans.Personally I think both the mediums are excellent and their story telling ways are very different,and since they are so different,these tiny nuances make them all the more special.