Hi, I was wondering how copyrights are applied to rendered still images in the industry.

For example, I've used Vue 6 Infinite's objects, features and other 3rd party objects (purchased from the Internet) to create a scene.  I then rendered it as a still image.  

In this situation, do I have the copyrights?  If not, who owns it?

I'm not a specialist in the field, but I would say you have the copyrights over the rendered image only. The objects you used for your scene, unless created by you are copyrighted to their maker.
Licence agreements are part of the files you buy and are stated as a readme file most of the time, take some time to read them. You normally buy the right to use objects you buy, but the objects remain their maker's property.

Thanks for your reply.  When I mentioned copyrights, I'm referring to the rendered still image only.  

Having said that, what happens if I sell the still image to agencies?  Do I have to pay royalites to e-on software and other 3rd party vendors for their objects that I've used in the scene?

you can use any of the objects from vue in your own scenes but not the premade- scenes to make images that are completely yours. if you aquire 3d virtual objects from elswhere then read the readme with them - if u buy the object the readme normally says commercial use of renders is okay love esther

No, you don't have to pay royalties to e-on or other 3d party vendors. Almost always, use of 3d models is "royalty free" for "publications" or renders made with the objects.

If it were only that easy!

All software companies own the Intellectual rights to their software including the content and their use by the consumer of that software.  Which means that, yes they could control the manner in which you sell any reproduction or artwork based on the use of their software. However, these companies rarely do so, as they cannot sell software if they prohibit the use of such, so as long as you do not infringe on their base copyright, they almost always look the other way.  Their base copyright is the distribution and redistribution of software and content, their personal property. 

Third Party Vendors are another matter, and one must be cautious and knowing of the stated stipulations between both parties related to the use of such content.  Many parties are not well informed about copyright law which often results in bad judgment or flawed Disclaimers by the content artist. Typically the content artist makes a statement telling you how you can use the content you purchase.  Again, typically, the content artist requests that you not use the content for any purpose other than personal, commercial rights not included, or commercial right may be included.  This usually covers the distribution of the content, but may also include the sale of works of art created by you the user.  Please remember this all depends on the agreement in the EULA or whatever statement or agreement that binds the seller and purchaser.   

Ordinarily, this means even though the artwork is yours, you can use the content to create artwork for personal use only.  If you do not have commercial rights then that may mean that you cannot sell any artwork that contains the artist content without his or her consent or possibly remuneration. 

Even if you purchase Royalty Free work, which often requires that you give credit to the content artist as a condition of use, this can be a whole new area of concern.  AS many apprach the rights is a different light.

Read the Copyright Law and always Read the EULA or Agreement carefully when purchasing software, and if in doubt ask the artist and get a written statement to cover your backside.   If you do not know the limitations of Copyright a law suite can be devastating.   There are many more categories of interest contained in the law than “First Rights”, “Work for Hire”, "Royalty Free", etc.  Now them if you want to sleep comfortably at night!