[Leica] leica d-lux 6

[Zach Rosen]

Hi I have a Leica d-lux 6 which I bought new several years ago.
I would like to blow up to poster size some of the photos I have taken.
For example, the Hudson River and George Washington Bridge.
After I have submitted the image to the lab (MPix) they tell me that after
a certain size, usually 11 x 14, that the image is too grainy or loses
detail.

When I use my Nikon, however, I am able to blow up the prints to poster
size without losing detail.

Am I doing something wrong on my Leica or is the Leica limited in being
able to blow up prints to poster size?

Thank you.
Zach