missjtiger wrote in post #14863181
I have the 70-300mm f/4-5.6 IS USM ( I don't have a clue what all that means) but I'll learn.
First of all, you mention you now have "Mark II" but not which "Mark II". 5D Mark II? 1D Mark II? 1D Mark IIN? 1Ds Mark II? Folks seem to be assuming it's a 5D Mark II, but I didn't see specific mention of that and our recommendations might be different, depending upon which camera.
Regarding the designations you see on your lens...
70-300mm is the focal length range of the lens (which you probably already know). f4-5.6 is the size of the lens' largest aperture, at the two extremes of the focal length range. It's a variable aperture lens (larger f4 at 70mm to smaller f5.6 at 300mm), which makes for a more compact and less expensive lens. A zoom lens that's labelled with just a single aperture designation such as f4 is a non-variable design. A "fast" lens is one with a bigger aperture. In zooms, the largest available for Canon and generally is f2.8. An f2.8 zoom, non-variable, can let in twice as much light as your lens at the 70mm setting and four times as much light at the 300mm setting (note: a 300mm f2.8 lens is very large and heavy... not to mention expensive). A larger aperture, especially on a longer focal lengths, allows more blurred backgrounds. Also, a larger aperture allows more light to reach the camera's focusing sensors, which can make for faster and generally better performing autofocusing. It's a trade-off, though, with size and price. (Note: practically all lenses can be stopped down to smaller apertures, to increase depth of field and reduce background blur. Some, such as macro lenses, allow for very small apertures such as f32 or f45... but using really small apertures comes at a cost, too.... very slow shutter speeds and the risk of diffraction effects that lose fine detail from images. With lenses and optics, it's always a trade-off of some sort!)
Your lens also has the EF designation on it, which simply means it fits the EF mount used on all EOS cameras since the late 1980s. Your 18-55mm has an EF-S designation, which means it only fits the APS-C "crop sensor" DSLRs since the original Digital Rebel or 300D onward. But you found that out already, didn't you? EF-S lenses can be smaller, lighter and less expensive, since they don't need to cover as large an image area as a full frame lens.
IS stands for Image Stabilization. That corrects for minor movements while shooting, allows you to use somewhat slower shutter speeds than might normally be required. But, as someone else posted above, it can't help with subject movement, so at time you still might need the faster shutter speed.
USM stands for Ultrasonic Motor is the type of focus drive the lens uses. Canon now has three types and USM is the fastest and most accurate. For most general types of photography, USM is the best choice and most USM lenses are at least mid-grade build quality. Non-USM lenses use a Micro Motor to drive focus. These tend to be slower, noisier and hunt more. The 50/1.8 is an example of this type lens. Recently Canon has been introducing another type called STM, which stands for Stepper Motor. Only a few of these have been introduced so far, but the main purpose for them appears to be to allow focusing while shooting video with a DSLR. They will work on all Canon DSLRs, but only certain camera models seem to have ability to take full advantage of them, such as the T4i. I don't use my DSLRs for video and haven't used any STM lenses yet, but suspect their performance is close to that of USM, perhaps even quieter.
You also might want to know that "L" stands for "luxury" and are Canon's premium quality lenses. They are fully compatible with all EOS cameras past, present and future (so there are no L EF-S lenses and never will be, no matter how good the EF-S lens might be). They are built to the highest professional standards for durability and performance, and all feature exotic lens elements of at least one type or another, used to achieve very high image quality. All L-series lenses I can think of use USM, aside from a few special manual focus models. Some non-L lenses simply don't need fancy glass to do their job extremely well, though they appear very comparable in all other respects (the 100mm macro is an example).
There are also a few "DO" lenses, which stands for Diffractive Optics. This is a special... and expensive... optical design that allows for a much smaller lens design. There is a 70-300mm DO lens that would surprise you, how small it is next to your lens. it's considerably more expensive, though.
Canon USM lenses that aren't L-series mostly have a gold stripe on them (there are some exceptions). L series lenses have a red stripe. And DO lenses have a green stripe.
That's the general info about Canon EF/EF-S lenses... If you want to know more, Google for the Canon Europe website and the pdf version of "Canon Lens Work" book that they have posted there for download. Or if you prefer, hardbound versions of that book can be found. It's loaded with a great deal more info about Canon lenses, though older copies of the book might not reflect some of the more recently introduced lens models.
Regarding the kit you are putting together....
24-105mm will be a good "walk-around" lens, whichever Mark II you've got. That will replace the kit lens you used on your Rebel quite nicely... And it will be a huge upgrade in quality... both build and image quality.
Personally I would not have recommended the 50/1.8 II... I'd have suggested the 50/1.4 at least. It's a considerably better made lens that offers a number of subtle but nice image quality improvements. But, for occasional use, the 50/1.8 might be adequate. It's capable of pretty darned good images... better than it should be considering the price!
If portraits are a big deal, I might have suggested an 85mm lens instead... and for tight portraits on the full frame cameras the 135/2 is a superbe lens... but it depends upon your style and how you want your images to look. A 50mm or even wider can be useful for portraits, too.
Your 100mm macro will be fine on any of the above camaras. No worries there.
The 70-300mm might be fine, too. It depends upon your expectations. You mentioned some sports situations where personally I'd prefer to have one of the 70-200s with IS (some will try to tell you IS isn't important for sports, but having used IS lenses for ten years - a lot of the time for sports/action photography - I completely disagree and recommend it so long as budget allows). The f4 versions of 70-200 are smaller and lighter, but less usable in lower light situations. The f2.8 versions are pretty big and heavy.
If using the 5D Mark II... well it's not really a sports/action-oriented camera... so either the 70-300mm would be fine and you might make do with it for occasional use. But if you are very serious about the sports/action shooting, then a 5DII will need all the help it can get and one of the 70-200s might become more important. Indoor sports (basketball) might require a fast (big aperture) lens. Daytime football can need a longer focal length (min 300mm and up to 400mm and 500mm). Night football can need both a fast lens and longer focal length.
I'd just suggest using the 70-300mm for a while, then see where you feel it's coming up short. That will best tell you what you need.
As a newby who's jumping into the deep end of the pool, I'd suggest a stop over at Amazon.com and look for one of the guide books specific to your particular camera, to help you get the best out of it. Those books sort of pick up where the instruction manual leaves off. I'd also recommend getting a copy of "Understanding Exposure" by Bryan Peterson. That might be the best $16 you ever spend on your photography.
Have fun with your new gear!