@coachboz68 wrote:
@TCampbell wrote:
Pop-up flashes are not great - these are very weak flashes and you have very little control over them. The 6D II doesn't have any flash at all. It would require an external flash -- but you can get a lot more power and control when using an external flash.
Just something else to keep in mind about pop-up flashes that bit me when I first started acquiring good lenses: the larger lenses (and/or their hood) will often obstruct the light from the pop-up flash and cast a shadow on the bottom of the pic. Quite frustrating the first time someone experiences it.
I'll second that! It happened to me once (on a 7D with the 17-55mm f/2.8). Very embarrassing. 
I read through the back and forth looking for info about what you need to shoot and how yuou need to use the images..... These should be your first concerns and will likely determine what camera & lens(es) would be best for your purposes. If you'll be shooting portraits, that would call for one thing... If you'll be shooting sports, entirely different gear would be recommended. If you are shooting for large prints, that's a lot more demanding than if the images will primarily be used on a website in fairly small size.
The only specific type of photography I've seen mentioned is theater... And although much of a stage is dark, often the subjects are pretty well lit so might not require f/2.8 zooms. Especially when you have a camera capable of shooting at very high ISOs, which the full frame 6D Mark II certainly can. Recent APS- C format like 80D and 7D Mark II are very good, too... much better than your older T3i... though of course the full frame camera is even bettter.
How high ISO you can use depends a lot on what you'll be doing with the images. While a very high ISO image from a 24 to 26MP camera may be "full of noise" at 100% on your computer screen... it might make an 8x10 or 8x12 print with little problem. And it almost certainly would be usable in smaller size and lower resolutions online.
For example, this is a test shot done with one of my 20MP 7DII at ISO 16000 (not a typo, ISO sixteen thousand)...
Above would print fine up to 8x10 or 8x12, even though it shows some noise when viewed at ridiculously large magnification. It certainly would be fine for even larger display online at Internet resolutions. (Note: "100%" vieiwing of a 24MP images on most modern computer monitors is equivalent to making a 5 foot wiide by 3.5 foot tall print, then viewing it from 18 to 22" away.) Here's a highly enlarged detail from the above image...
Yes, there's noise in this image, shot at ISO 16000 by the light of a single 60W CFL bulb and small window, each 8 or 10 feet from the subject (both can be seen in the catchlight in the cat's eye... handheld, Canon 100-400mm II lens at 158mm and wide open at f/5). It was shot RAW (no in-camera noise reduction) with some care to avoid under-exposure and the RAW file was converted in Lightroom 6 with default noise reduction setting, only a minor boost in contrast and adjustment of the black point were done to the image. Normally wiht high ISO images I do more extensive NR in Photoshop, with Noiseware plug-in.... but didn't in this test because I wanted to see "worst case". I regularly use ISO 3200 and 6400 with my 7DIIs without concern. And sometimes even higher ISO when necessary... depending upon what I'll be doing with the images. 80D is a little higher resolution than 7DII... but it's also a little newer model. I'd expect it to have similar high ISO performance. Full frame 6DII is probably good for one or two stops higher ISO... I believe it's native ISO range goes to ISO 40000 (I generally avoid using the extended ISOs on any camera, unless I absolutely have to use it and perhaps am planning to convert the image to black & white).
My point is that depending upon your "real world" uses of your images, you might be able to use much higher ISO than you do now with your older camera. And maybe those f/4 zooms would be fine. And, for that matter, so might an APS-C format camera. You also could "complement" a pair of f/4 zooms with one or two smaller/lighter, relatively affordable primes such as EF 28mm f/1.8, 35mm f/2, 50mm f/1.4, 85mm f/1.8 or f/1.4, 135mm f/2. Not only are they comparatively compact, these prmes area also one to two stops faster than those bigger/heavier, more expensive f/2.8 zooms you're considering.(I shoot a lot of sports, so mostly use USM lenses for their fast focus and good tracking ability).
Don't get me wrong.... the f/2.8 zooms are great. Just want to point out that you may have alternatives. The Canon EF 24-70mm f/4L IS USM lens can double as a macro lens (closest focusing of all their zooms.... with up to .70X magnification possible). It's also Image Stabilized (the f/2.8 version isn't). I haven't used the new 70-200mm f/4L IS USM "II" yet.... but I use the earlier version of that lens frequently (as well as an f/2.8 version). The f/4 lens is roughly 1/3 lighter and smaller than the f/2.8 lens.... not to mention considerably lower priced. (Note: I bought the f/4 as a backup for my f/2.8, one of my most used lenses shooting sports... But I soon found myself using the f/4 lens more often than the f/2.8, because it's a great lens and my hands, arms and shoulders are a lot less sore at the end of a 6 or 8 hour session!)
But a lot depends upon your particular needs... what you have to shoot and how you'll be using the images.
If it were me, I'd be deciding my lenses first, then choosing the most affordable camera that has the features and functions I need, to use with them.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & ZENFOLIO
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