Is canned pumpkin and pumpkin puree the same thing?
Essentially yes. There are pumpkins called "pie pumpkins" that give a sweeter, softer flesh.In my experience there is more water with cooked fresh pumpkin puree than with the tinned kind. If you are making pie, this could influence the recipe. There is a definite difference in taste and it's a personal preference whether the extra work of cooking the pumpkin is worth it to you.
Yes, I agree with SweetTea in that fresh pumpkin puree is wetter. Strain it for a few hours if you make it yourself.
I agree with mrslarkin and SweetTea. I generally used canned pumpkin as a time/effort saver. If you are using canned pumpkin you can get rid of the "tinny" flavor by cooking it in a saucepan for 5-6 minutes over medium-high heat. You need to stir it constantly, making sure to scrape the bottom of the pan.
As long as the label on the does not say "pumpkin pie filling," you can substitute canned pumpkin for pumpkin puree in equal measure and your recipe will turn out fine. (You can also "roast" canned pumpkin by spreading it on a baking sheet and putting it in a 350-degree oven for 15 minutes.
100% pure pumpkin not pumpkin pie mix
My understanding is that canned pumpkin is not made of pumpkins but another type of winter squash- I doubt anyone can tell in a made dish, though.
I use butternut squash myself. If it seems a little watery, cooking it down in a saucepan for a bit will get rid of the excess liquid.