I have now spent the weekend testing Lightroom Beta 3, and have come across something interesting in how Lightroom handles upsizing of images. If I choose to export an image from Lightroom (File > Export), I can enter ANY dimension for width or height, as well as ANY resolution. This is a level of customization I have never seen before in an imaging software.
Similarly, if I edit the same image in Adobe Camera Raw, under Workflow Options, the dimensions are limited by the type of file (I am guessing its total megapixel count). For example, my Canon 10D files can only be upsized to 4096x6144 (25.2 MP), which at optimum resolution (360) results in a file roughly 11"x17".
What I'd like to know is, is it better to upzise an image using Lightroom or Adobe Camera Raw, and, in the case of Lightroom, is there any drawback to setting the output size to something largerthan is normally possible with Adobe Camera Raw?
(Sidenote: While experimenting this weekend with Lightroom and ACR, I threw in Canon's DPP software for kicks. Turns out, Canon too sets an "upper limit" on upsizing. However, I can easily upsize to 16"x24" at 360 using DPP, which is a significant gain over Adobe Camera Raw)