Best possible settings for team indoor pictures

I'm afraid this will not work.
The filter size from the Nikon is 67 mm. and your vivvitar had a 52 mm tread. The step down convertor from 67 to 52 will block to much to use the wide-angle convertor.
I think you still will see a wider part in the centre of the frame, but in the end, the vignetting that takes place, will leave you with only a part of the picture to use. What stays will be smaller than what you pick up with the lens in the 18 mm setting.

Just try what you see, when you just hold the vivitar in front of the lens and shoot a picture. Take care you don't scratch the front lens of your 18-135. put a cheap UV filter, when you want to test.
See you only have a circular picture with this test.

I have a 12-24 lens and only use it once a year, so if you don't have a special purpose for a wide angle, don't bother buying one.

That depends on what you're taking a picture of. The best setting for a landscape picture won't necessarily be the best setting for a group portrait. You might want to use different settings for a daytime landscape than for a sunset. That's why the camera offers different settings. The camera is a tool. You're the photographer.

If by a "normal" lens, you mean a 35mm or 50mm fixed focal length - often called "prime" lens, that is to be expected. The additional and internal rotating optical elements all contribute to loss of clarity, color loss, and increased chromatic aberration that starts to become noticeable when compared to use of a prime lens. It's a trade off; less number of lenses to carry and lower cost when using wide angle zoom lenses as opposed to a prime lens for even just a few of the focal lengths offered by the wide angle zoom types.

You can minimize the unwanted effects by staying away from both the extreme wide angle and zoom focal lengths as well as the widest aperture settings. If you can stay 2 or 3 stops smaller from wide open, you can limit these destractions from your pictures. This is recommended advice for nearly every lens: Keep away from the extremes.

Good luck!

What is most important is that unless there is a slave flash or a more flash the subject might look quite blurred in the distance . You might need a SLR with a wide angle to get such pictures perfectly. Try to light up the area when it is indoor and see the result.

Edge to edge focus is an ongoing debate with every photographer that has run into it. A flat field of view is possible if you have deep pockets, a tilt shift lens, view camera in 4x5 or computer programing that will pull this out in post processing. I'm not trying to give you a smart answer but the amount of Barrel distortion and pin cushion effects on an 18mm wide angle lens will be difficult to correct. What I've done with huge groups to minimize the problem is use rows of people Kneeling, sitting and standing to minimize the effect and try to shot it loose then crop in. What this does is uses more of the center of the lens and also use F8 or F11

The cap is a plastic disk, usually black or silver, that snaps on at the end of the lens to keep the lens clean. Some lenses have two caps, one for each end when not attached to the camera.
Some cameras don't use a "loose" cap; those cameras generally retract the lens into the camera body and "close" a door in front of the lens.
Many, if not most, camera users do not use a cap (my guess).

The wide angle lens is generally an "optional" lens that can be used for group or scenery pictures when you want to shoot a "wide" picture. A "normal" lens is generally around 50mm (plus / minus 5mm). A wide lens is anywhere from 17mm to 24mm (or so).

I recommend obtaining a wide lens... with a cap.

Hope this helps!

There are lenses available to add with an adapter ring. I have the wide angle lens (which I LOVE) and a 2x telephoto lens. The wide angle lens allows me to macro from several feet away. It is an amazing lens. The telephoto lens is something you really need to use with a tripod. But yes, there are lenses you can add to your camera.

Had this problem before and i found this guide online

1. Turn off the camera.
2. Remove the lens, battery, and CF card.
3. Allow the camera to sit without power for approximately 20 minutes.
4. Insert a fully charged battery, and turn on the camera.
5. Depress the shutter button as you would to take a picture.
Does the “ERR 99′ message appear? If it does, then the camera should be
serviced. If it does not, then please proceed to the next set of steps:
1. Turn off the camera.
2. Insert the CF card.
3. Turn on the camera.
4. Format the CF card in the camera.
5. Depress the shutter button as you would to take a picture.
Does the “ERR 99′ message appear? If so, then the CF card is the most
likely source of the issue. Try using a different card.
If the message does not appear, please complete the following steps:
1. Turn off the camera.
2. Clean the lens contacts by gently rubbing them with a pencil eraser
or soft cloth. Be careful that you do not let any debris fall into the
camera body.
3. Reattach your lens.
4. Turn on the camera.
5. Depress the shutter button as you would to take a picture.
If the “ERR 99′ message only appears when one particular lens is
attached, then that lens should be examined by a service technician.
If you see the “ERR 99′ with a different Canon lens attached, then the
camera should be serviced.

It really depends on what kind of photography you want to do.
I own both of those bodies, and the 5D is great for landscapes, portraits, and other artsy stuff.
However, the 3 frames per second doesnt compare to the 5FPS of the 30D, so if you're shooting sports, the 5D will do better.
Also, 5D is better for wide angle shots.

If you do decide on the 30D, again, lens choice really depends on what kind of shooting you plan on doing.

Here you will find the tips for taking better photos with less camera shaking. Tips 1. Composing and holding the camera with less camera shaking. For clearer images, hold the camera firmly not to cause camera shaking. 1) For maximum stability, hold the camera firmly well over the grip and keep your right elbow lightly pressed against your body. 2) Support the lens or the camera body with your left hand from below. 3) Look into the optical viewfinder as if pressing your forehead to the camera. 4) Do not stand straight, but with one foot stepping forward for taking better balance of your body. 2. Change the composing and holding the camera according to the situation for securer photographing. (Particularly when you take photos using the LCD monitor.) 1) Lean against the wall. 2) Put the camera on a fixed object like a table. 3) Ensure the camera holding by pressing the elbow against the handrail. 4) Use the tripod. 3. Move the zoom control towards wide-angle if your camera has the zoom function. Moving the zoom control towards tele-angle, camera-shaking will easily happen. If your camera has the zoom function, we advise you to take photos by zooming towards wide-angle. 4. Higher shutter speed will produce better images. Slower shutter speed may produce more possible camera-shaking. If your camera has a choice of shutter speeds, we advise you to select higher shutter speed for less camera shaking.