Hey Bob, SS may be a bit delayed in his response. With a 5DIV and not money limit, the 24-70 f/2.8L II is the best choice. It's as sharp as Canon's primes at the same focal lengths and apertures. Your high MP sensor provides options for cropping that may offset the missing focal length offered by the 24-105 II. The 24-70 II offers maximum image quality in all situations, and particularly in low light if you're shooting f/2.8 to f/4. The 24-70 f/4L IS and the 24-105 f/4L IS II are both excellent performers, enhanced by IS.

You asked about an extender, but I'm unsure of the purpose of this question. The Canon 1.4x and 2x extenders cannot be physically attached to any of the 24-xx zooms nor any EF-S lens being discussed.

Converting a JPEG from 8-bits in sRGB color space to 16-bit TIFF in a wider gamut color space such as ProPhoto RGB will give you ADJUSTMENT GRANULARITY. In other words, as you change levels (lighten, darken, adjust color), instead of the stair-stepping you normally get by adjusting in 8-bits, you shift to intermediate tones available in the 16-bit TIFF. When you finally convert the TIFF back to 8-bits, and the color space back to sRGB, the result is a subtly smoother image, especially in skies, shadow edges of portrait faces, etc. You get less posterization, stair-stepping, and banding.

A side benefit is that you can save the TIFF several times during your edit process without losing data (unless you clip the highlights or plug the shadows). And you don't do any compression destruction in TIFF. Saving the TIFF once to a high quality JPEG at the end of the process will provide maximum possible quality.

We used this technique in a pro lab I helped set up. It worked wonders on marginal images. NO, you can't get something from nothing, but you can preserve and protect what you have, and modify it in more subtle ways than editing a JPEG.

You have to try this with some images to see its benefits...

Checking the subfolders will add another layer of subfolders to your existing structure. Since you will be adding what is already on your hard drive to your catalog, and your structure is all ready organized by year, date and folder number, there is no need to impose LR's folder dating by clicking include sub folders. It is redundant and unnecessary.

You don't want to COPY anything anywhere. You just want to ADD the image names and folders to your catalog. Leave your structure intact. It is fine the way it is.

Well, the answer is both easy and hard. Photoshop is an industry standard used by millions of creative people to edit photos and create graphic images. Elements is a baby version that was introduced as a low-cost entry point to Photoshop editing. Initially it was considerably cheaper than Photoshop, which cost $800.

Lightroom was introduced by a subgroup of product developers, as a professional raw converter and cataloging tool, by photographers for photographers. It boasts a really fast and smooth workflow, a way to integrate plugins, external editors, and offers a few creature comforts like book publishing, direct uploading to social media, emailing, metada editing, gps tagging and printing. Besides being a very powerful image management tool, one of it's strongest features is the fact that just about anything you do to an image can be saved as preset to be used again. As far as fast and easy to use, I typically can download, cull and edit to proof stage 1000 images (like from a wedding) in about 2 hours. Raw converters that are workflow-oriented are like that. For final image finessing, such as when you are preparing images for printing, or delivery to a client, Photoshop is the tool to use. You can take the image that comes out of Lightroom that final 10%-15% that makes a great image say WOW!

Today, for $10 a month, you can get Photoshop and Lightroom. There are tons and tons of free tutorials and videos to help you learn both. But the limited command set makes LR the first choice for someone who wants good results fast. PS is for someone who wants to reveal the potential in an image that is beyond LR's capabilities.

My suggestion is that you consider the subscription, as millions of pros and enthusiasts have, and learn how to use them. You'll be better off than learning all sorts of free software that is not in the same class as the PS/LR CC software. And it is only $10/mo. I think when all is said and done, you'll be happy you did.

BTW, nothing that came out of Picasa could ever touch even PSE. I know that you may find that hard to believe because you were happy with your results, but I teach photography and post processing, and had to deal with students that felt as you did, that Picasa was all that the needed. That is, until I would take an image and run it through a few quick adjustments in LR/PS. There eyes would open wide and they instantly became converts. Well, most of them did, in any case.

I fully understand the frustration of learning Photoshop. After 16 years, I am still learning it's little secrets and new ways to do things. It is powerful, and anything that you can imagine you would want to do with an image you can do with PS. The key is to view an image as a creative director, or a teacher, or a gallery owner, or a judge at a photo competition might look at it. Recognizing the flaws that need to be addressed, and the potential that can be unlocked are things that will come in time. And this recognition is fluid - you will look at images you did 5 yrs ago with your current knowledge and experience, and the first thought that comes into your head will be, "What on earth was I thinking when I did that?"

One of the really nice things about working with LR and PS, is that you can use raw files easily. These are far easier and faster to edit than working with jpegs, and the results are always better. Always.

I hope I've inspired you to take another look. If you need some sites to help you get started with either, send me a PM and I will pass them along.