The picture looks to be plenty sharp, which is one of the most important points for good resolution. But what size is your original photo? This one you attached here on the forums is only 985×657 px which is very small to try to make a large canvas print from…
Do you have a link to the gallery so we can see what the client is seeing and downloading? If you’re not comfortable posting it here publicly, you can email it to me and I’ll be happy to check it out for you.
Your camera is capable of ~22 megapixels (5760 × 3840) so you just need to make sure that it was actually taking photos at that resolution, and then send them that file (after edits of course).
Unfortunately, I may have shot it in JPEG by accident… I had to clear my settings and MAY have forgotten to turn it back to RAW… but does it really make that big of a difference when you go to blow up & print? I’m hoping not, but perhaps I may have just learned a good lesson?
Keep in mind that “quality” is very subjective. A JPG file might theoretically have less “quality” (in terms of color and noise) than a RAW file (if you’re pixel peeping), but they’ll usually both have the same resolution.
Canvas does not provide a very high quality printing experience to begin with, so you can probably get by with less than the industry standard of 300 dpi, especially if it’s large and intended to be viewed from a distance. If you can tell us what size of canvas your client wants to print, we can give you some more precise guidance on just what dimensions your photo needs to be.
