Photoshop vs Illustrator...keeping it vector

Question

Hi all,
I use photoshop ALL the time and love every feature. However, I've been forcing myself to use Illustrator (love it, but find it's limited compared to photoshop for many projects I do). I'm hoping you all can help with two questions that I have.....
Question 1: I've often heard people starting a project in illustrator then "bringing it in to photoshop" to do other effects....this might seem like a dumb question, but won't that rasterize the work you did in illustrator? And if that's the case, why not start and end the project in photoshop?
Question 2: I started a project in illustrator that involved a lot of pathfinder work and gradient mesh. I'm sure I could have airbrushed in photoshop to get a similar technique but like i said, I want to stick and learn illustrator than always depending on photoshop. I'm currently at a impasse because now I want to use certain parts of a jpg image to mask into the objects i created in illustrator (see link below for example of my objects in question) at lower opacities (in PS I would create a layer with the image i want to use,  make a layer mask, lower the layer opacity and soften the hard edges and around the areas I don't want). I tried the clipping mask in Illustrator and it SORTA does the job but not quite.
What i create in Illustrator is very similar to this:
http://vector.tutsplus.com/tutorials/illustration/design-wedding-rings-using-adobe-illustr ator/
What i want to do now is to clip certain parts of other photo images into these rings to make them look part of the ring (in photoshop i would use masking, warping, opacity, layer blending etc). When I created the mask in illustrator, it sorta worked but there's hard edges from the image i made the clipping mask from that i would like to smooth out....among other issues i would normal not encounter in photoshop.
Should I just take it into photoshop and finish it off or is there a way to get my end result in illustrator? And if the answer is to take it into photoshop, then my first question comes into play. I hope this makes sense
any help would be appreciated. Thanks

Answer 1

I've often heard people starting a project in illustrator then "bringing it in to photoshop" to do other effects....won't that rasterize the work you did in illustrator?
Yes, it will.
And if that's the case, why not start and end the project in photoshop?
First, because just as there is a multitude of things you can do by editing raster images, there is a multitude of things you can do in vector-based drawing that you can't do in raster imaging.
Second, the resolution independence of vector graphics is not a matter of whether your work will be rasterized; it's a matter of when. Everything eventually gets rasterized. When you print vector graphics, they are rasterized by the printer. When you display vector graphics on a monitor, they are rasterized by the monitor. In fact, even while you are editing vector paths, you are viewing what you are doing as a raster image on your screen.
Third, raster imaging is lossy by nature; not just in terms of resolution but also in terms of color conversion and color correction. So it's quite common to create a vector-based graphic and keep it as a master which you then rasterize and/or enhance with effects for specific final uses. In other words, it's quite common to create and keep a vector-based file to maintain lossless editability and then "nail it down" to specific rasterization settings optimized for a particular use.
When I created the mask in illustrator, it sorta worked but there's hard edges...
Crisp, sharp edges  are naturally germane to vector graphics, just as detailed, noisy texture is germane to raster imaging. That's why both exist. When it comes down to it, vector graphics are mathematically-described shapes; therefore, by nature, sharp edged. When Photoshop needs scale-independent sharp edges, what does it do? It resorts to vector-based paths. Inversely, when Illustrator needs soft fuzzy drop shadows and blurs, or highly-textured fills, what does it do? It resorts to raster imaging.
You can do the things you describe in Illustrator. It has features for raster-based masks, transparency, etc., as do other vector drawing programs. Just as with raster imaging, some programs are better at specific things than others in the same category. Xara Designer Pro, for example, is another vector drawing program, but it does live raster-based feathering far better than does Illustrator.
Many things which appear to be raster-based (reflections, transparency, realistic grads, glows) can, in fact, be rendered entirely with vector-based drawing and thereby retain true resolution independence. For example, you mention mesh grads; an entirely vector-based construct. Soft drop shadows were built entirely from vector-based blends long before raster-based effects appeared in programs like Illustrator.
This is a detail taken from an entirely scaleable vector-based drawing. Some of the object-level feathering and noise texture is raster-based, but mathematically rendered on-the-fly; and therefore scaleable when needed for different output purposes:
JET