id this a good package

So the non IS lenses are sharper than the IS? So what does the IS do? I know it is Image Stabilization or whatever, so what exactly does it do?

Sorry to get off topic here...
 
Hmm I am making this up as I go so bare with me:

Outstretch you thumb. Touch the next finger and your thumb nail to nail. It should look like an "OKAY" hand signal or a classy "number 3". The main point is that your fingers make a big circle.

Now stretch your arm a decant distance from your face and place your avatar inside that circle. Try to hold your hand steady on the black spot to the left of the fish eye. I bet you'll notice no matter how hard you try, you can still see your pretty fish head moving up, down, and side to side.

Now take your other hand and make a small circle by touching your thumb and the next finger nail to nail. Place your hand in front of the circle you already have and counteract your shaking hand.

It worked for me but I can see a large margin for error on this example so I'll just try to explain what is going on.
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Your holding the camera but your hands are a little shaky. Inside your lens, the IS tries to predict your shaking and shakes with you. As long as you don't shake too much, hopefully it will counteract your shaking and keep the image on the sensor steady. It can only do so much though.

To accomplish this, the light has to pass through this complex shaking system and you loose some detail along the way. If the image was going to be a blurred mess without it, the good far outweighs the bad. Assuming a 70-200 f/4 and a 70-200 f/4IS were both placed on the same camera on the same tripod in exact same conditions with IS off (even if it isn't doing anything its still there), the subject on the IS lens will be slightly blurred compared to the non IS lens when viewed at full size.

So if you don't need it, IS will degrade the image compared to what it would be without and IS system. Of course the whole reason for having it is that sometimes you can't get a useable image without it. A tripod is the ultimate image stabilizer and works better than any IS system will ever be able to. Sometimes you just don't have a tripod. 75% of the time when hand holding a lens, IS will improve quality more than it will degrade it. With a tripod this is never true. In fact, IS must be turned off on a tripod or the IS will be shaking around with nothing to shake against. The 70-200 IS (both) and the 55-250 IS all know if they are on a tripod and turn themselves off in case you forget. IS also uses battery power at a noticeably faster rate (turning IS off uses no extra batter power).
 
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That is very interesting... Actually that's pretty much what I thought... but you made it sound even better! :D Thanks again man! I will be bugging you a bit more in the next couple days I am sure ;) I am THIS close to pulling the trigger...

So if I get both the 18-55mm IS and the 55-250mm IS then that will pretty much cover your basic close/portraits and further/zoom/scenery pics right? so all I need is a good macro?
 
And a good flash! This should be purchased much later once you figure out why you need it. You will also understand all about cameras and lenses by then and be ready to learn about something new and exciting anyway. Flash is your friend (especially with f/5.6 lenses). I think that camera coupled with those three lenses will keep you satisfied for some time.
 
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oh thank you kind sir for returning my thread to me, but you did ask the questions i was gonna ask. and titusvile are you saying that the falsh on the XSI is very inadequate, inadequate, or it will do its job somewhat
 
Built in flashes of all DSLRs are inadequate regardless of make or model. The cheaper DSLRs are the only ones that even have it in the 1st place. The more expensive cameras (5D and up) assume you have a real flash and don't even bother having it.

The build in flash will do its job somewhat...mainly for emergencies when it is dark outside and something really cool happens but you just don't have a real flash. You aren't going to take much of anything spectacular in the way of photographs with it though. It is especially bad for me because my lenses are so big that you can see a round shadow where no flash hit at all. I don't think you'll have any problem with this but you really should get a nice flash down the road.
 
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That camera's flash has a guide number of 43' at ISO 100

To figure out range the equation works like this:

guide number = f/stop x distance or distance = guide number / f/stop

So at f/4, for example, that flash has an effective range of about 11'
 
One more thing... Amazon offers a free lens filter with the zoom lens (or a credit of $6.99 towards one..). What is a good useful filter? The one that is free is a UV filter but wont ship for 3 weeks and delay my order. Or I can get the Tiffen 58mm Haze-1 Filter for an additional $6. Should I? Sounds like it might be useful for tank photos? Thanks!
 
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