The flash will light things at 100ft. Doesn't look great but it will work. It's best to use the flash at 20ft or less. The shadows cast with the flash at more than 20 feet is terrible. If you're using the flash to light a person making a speech at 100 ft., it will work but the picture is awful. Do some test shots.
Quantums are great but I just bought a Bolt from Amazon. Cheaper than quantum and uses Lithium batteries. I have used Quantums for years and have them refurbished a few times but the Bolt is a great battery. 4000 flashes per charge. Check it out!
I shoot a lot of weddings and my main lens is the 24-70 2.8. This covers over 90% of the shots. For the ceremony a 70-200 will cover that part. Other than that 2 lens will work most of the time. Good luck and the less is better.
A good not too expensive durable lens is the 50 1.4. Costs around $350 but it is fast and sharp. The 1.8 takes similar pictures but it is plastic. It costs around $100 and if you are low on cash then the 50mm 1.8 is a good and fast lens. My go to lens is the 24-70 2.8 for most of my stuff. It's fast enough and if you need to bump the ISO by a stop or two, the lens is way sharp and fast.
The G12 is an awesome camera but it may be too much camera for your son. It has all the features that a DSLR comes with in a small camera. Very sharp pictures, great video and the camera can shoot raw or jpeg. It has the latest processor so the colors come out great without much post processing. I recently went to Hawaii using the G12 and it worked perfectly. Your son will learn photography with this camera and then he can buy a DSLR for his next camera. Good Luck!
I use the 100 mm lens in manual focus all the time. To get the bokeh I want I usually shoot f 5.6 or wider and depth of field is very shallow. I then use aperture priority and let the camera figure out the shutter speed. However, you could use manual mode but it's faster to shoot in P or A mode. Also a tripod works great when shoot small objects like bees, flowers or rocks. Also this lens is a fantastic portrait lens Creates nice bokeh.
If you have a cropped sensor, 28-70 is not wide enough. Otherwise lens don't usually wear out unless it was dropped. I use my 24-70 all the time with my 50D and if I need wider I switch to my 17-40. If your sensor is cropped, the 17-40 is a good lens to buy and f4.0 isn't bad as it's only one stop different. Just change your ISO one stop and you're the same as f2.8. Keep looking and have fun shopping!
That lens was popular back in the film days. If it's in good condition, it may be a great buy. If your camera is full frame, then this lens would be great. I use a 24-70 on my 5D and a 17-40 with my 50D. Pretty close to the same spread and both lens are very sharp.
A fast way to test a lens is to glue a newspaper to poster board. Set your camera up on a tripod. I would use available light if possible. Window light works good or outdoors in open shade. Set the lens at the widest aperture f2.8. Take a few shots and check the focus. Be sure the camera is exactly perpendicular to the newspaper. You will notice if the lens is good or not. Look at the image on your computer screen and zoom in. The blemish may show up. Good luck!
A good, fast walk around lens is the 24-70 L Canon lens. Also works as a macro. My go to lens for just about everything.
If your lighting and exposure is dead on then jpeg works fine. I use an expo disc to get a custom white balance first then shoot jpeg. There is less post production shooting jpeg but the problem exists when the lighting changes or shooting in different locations. That's when raw is better. Fixing a jpeg image if you messed up in exposure you probably have only a stop adjustment in exposure. Shooting raw, you have about 4 stops of adjustments which means if you blew the exposure you can fix it. Shooting in raw, you will need to convert that image after post production which is an extra step in getting an image that other's can view or to print.
I use a lens hood all the time. Outdoors, it prevents lens flare even on cloudy days. Indoors using window light or strobes, it also prevents light from hitting the lens causing more lens flare. Your pictures will be a lot cleaner using a hood!
Another reason to use a hood is to protect the front glass from damage if you drop or bump the lens. The glass is way more expensive to replace then a lens hood.
I use tripods when shooting macro of bugs and flowers since you're so close to the subject any movement of the camera will make the image out of focus so the tripod really keeps the camera still. When shooting with a long lens, over 300mm a tripod is useful here also. You will need a solid tripod with a good ball head. I also use Bogen tripod with a bogen head. A ball head could set you back more than the tripod itself. I then use a L bracket to switch from horizontal to vertical quickly. Check out Really Right Stuff for heads and stuff.
When I shoot weddings with my Canon 550 EX I normally bounce the light off the ceiling with a Stofen light modifier. However it does suck power so recycle time is slow on batteries. I use a Quantum Turbo battery pack. One pack will last about 400 shots with less than 1 second recycle times. Great for shooting multiple flashes quickly. You will need a special cord to hook to your flash and flash either mounts to your hot shoe or a bracket. I use a bracket to keep the flash high above the camera to eliminate red eye.