If you use an extender lets say a 2x what change will that make in f stops? I was trying to figure out what would be the cheapest way to set up a camera, as far as lens ,iso speeds etc ..I want to be able to shoot sports both indoor and outdoor , mostly basketball, wrestling, softball and football.I am on a limited budget but want to able to get the best printable results for my money .I want to be able to print an 8x10- 11x14 that is clear and fairly crisp. Right now i get a lot of grain and lack of good fine detail. So iwas wondering what would create the best printable picture , for example would a dslr at iso400, with a 70-200mm zoom 2.8 produce a better shot than say a 70-200mm 3.5-5.6 at iso 800-or 1600?I ususally hand hold the camera. With all things taken into consideration where would be the best place to focus on ? Like image stabilization? if so what can i expect for the money and what are the cons? Higher speed lenes or higher iso speeds? I still havenet chossen the camera yet ,and this is all factoring into it. I am thinking between the d 70, the 20d or minoltas maxxum 7d. I want to have a set up i can grow with and as money allows me to be able to expand.Liek with iso speeds when is it to fast , i mean will you really loose qaulity over 1600 , over 800 ,where does the noise start having a big factor? Like with my 35mm and 70-200mm 3.5-5.6 zoom takes fairly clean pictures but they are very dark when zoomed and shooting indoors and sports. For sports photography what are the most important things to look at ? Does any one have any books they recommend or web sites on this topic ... Thanks Bill B