Hello,
A quick question I was wondering about...
What's the difference between a zoom lens and I believe they're called a Prime lens.
Canon has a 100mm-400mm Zoom lens and Prime 400mm lens. The zoom lens seems to be a little more expensive and has Image Stabilizer.
From reading other posts, it sounds like a person can use a 1.4x telephoto converter and still get good shots but not with the zoom lens.
So what is the real difference between the two lenses (besides IS).
Thanks (My girlfriend just bought a Canon XTI and I'm trying to help her out)
The prime lens is a fixed lens of 400mm.
The 100-400 mm zoom can be used at 100mm to 400mm and anywhere in between.
Because zoom lenses are more complex with more glass elements, usually they are a little softer focus than prime lenses so by adding a teleconverter you magnify this softness.
The 100-400mm is a very high quality zoom lens, one of the best money can buy, however it's not quite as sharp as the 400mm prime lens. The zoom is a little bulkier, heavier and the autofocus a tiny bit slower but minimum focus is a lot less and the zoom range makes it a more versatile lens.
It's swings and roundabouts between them depending on what you mainly want a lens for.
There's a bit more (actually a LOT more) to this in that Canon produce three 400 mm prime lenses: the 400mm f/5.6, the 400mm f/4 and the elite 400 mm f/2.8. The f/2.8 is the fastest of the bunch and costs around £5,250 which is more than six times the cost of the f/5.6.
Serious glass costs serious money and the f/2.8 (a very fast telephoto lens) is a superb lens which works with both 1.4x and 2.0x TC's.
The 100-400 zoom is a very popular and very good lens which will work reasonably well with a 1.4x TC, especially in good light. It would be a good choice with your girlfriend's XTi/400D and can be bought for about £1,000 if you look around.
Colin