Which lens should I choose ??

[oldamateur]

hi. I hope someone can help me, i apologise in advance as i'm sure this Q has been asked 100's of times. I'm a novice when it comes to photography, I started taking pictures 12mths ago.  I own a canon EOS 5d mk II & AF 35-105mm L IS USM lens.  I'm ready to purchase a new lens and for the last few months I've been reading every article and review I could find, I've read so much my brain is nearly fried due to information overload. Once upon a time i would have argued that you can never have too much information (that was before the mighty internet ;o)). It's difficult to decide when there are so many choices and each review contradicts the last. As most of the photos i take are of sports (league, union, swimming, surfing, motor cross & dirt bike racing etc) and wildlife, I was looking at buying the canon EF 100-400mm L IS USM lens ($1650.)  I'm also considering the Canon EF 2X II extender camera lens.
I took into account performance and cost, from cheapest to most expensive these lenses have a price difference of $200 / $300 between each, I ended up with the following list.                                             EF 100-400mm f4 L IS USM :          EF 70-200mm f2.8 L USM :          EF 70-200mm f4 L IS USM :            EF 70-300mm f4.5-6 L IS USM :      EF 70-200mm f2.8 L IS USM II (most expensive $2200)
Canon 70-300mm f4.5-5.6 DO IS USM :  
One canon review suggested sigma lenses as a cheaper alternative, they had good reviews and are cheaper.
Sigma 120-400mm f4.5-5.6 APO DG OS HSM :          Sigma 150-500mm f5-6.3 APO DG OS HSM :
Sigma 50-500mm f4.5-6.3 APO DG OS HSM :
If anyone knows how they compare to canon I would appreciate your thoughts.  Any comments or suggestions would be appreciated. I know the EF 70-200mm f2.8 L IS USM is the best in this list, I'm wondering if it was used with the extender lens would the quality suffer? I'm teetering between this and the  EF 100-400mm L IS USM - any suggestions or if any one of the others in the list stand out your comments will be welcome.
                                                        Thanks

[Bob Atkins]

If you don't need the f2.8 speed, then I'd say that for your sports/wildlife photography your best choice would be the 100-400/4.5-5.6L IS USM.

Canon 100-400/4.5-5.6L IS USM - $1499

It's a very good lens, sharp, fairly fast focusing, and has image stabilization. You can add a 1.4x TC or 2x TC but you will loose AF when you do. The image stabilization will still work, but your best best for focusing with a TC attached will be using live view. I have a full review of it here - http://www.bobatkins.com/photography/reviews/ef_100_400_l_is_review.html

The EF 70-200mm f/2.8L USM  - $1299 is a good lens but it isn't stabilized and I'd regard that as a significant drawback if you're thinking of shooting handheld, possibly with an extender. If you want IS, it will cost you a lot more EF 70-200mm f/2.8L IS II USM - $2199 and even more if you want to add a Canon 2x TC - $449. Both lenses work fairly well with a 2x TC, but you do lose some sharpness.

I've tested the Sigma 50-500mm f/4.5-6.3 APO DG OS HSM and it's not a bad lens at all, but it gets a little soft at 500mm (and at 500mm it's f6.3) plus at $1509 it's actually a few dollars more expensive than the Canon 100-400 right now.

I don't think either the "L" or "DO" versions of the Canon 70-300 are very good value, nor are they very long. They are however small and light (expecially the DO version) if that matters. If you only needed 300mm and you were OK with the speed range, I'd recommend the Tamron AF 70-300mm f/4.0-5.6 SP Di VC USD as a good, inexpensive, telephoto zoom.

[oldamateur]

Hi, I truly appreciate the swift response and the advice . . . Thanks.  For months I've being going round & round reading reviews, comments etc.  For me this is a huge decision, more so because I'm a beginner with LIMITED knowledge, I'm a retailers dream customer.  I have (once or twice  ) been talked into purchasing the most expensive item rather than the one best suited to my experience and needs.  A brief example, after buying my camera gear I enrolled in my first photography class, at 1st I was a proud to be the only one to have the same camera as the instructor, then it turns out I was embarrassed when we discovered I had an item or two which was more expensive/superior to the instructors.  A classic example . . a few filters, a memory card . . my card was faster with triple the memory, I felt a bit silly when I explained the reason I bought such an expensive card was the salesman had told me anything less would greatly hinder the speed of my camera, the quality of my photos blah, blah all of which defeated the purpose of a good camera.  Don't laugh but it was greatly exaggerated, he saw an opportunity to sell the most expensive card in stock.  My thoughts this time was plenty of research, go in armed with knowledge . . . ha!!! with so much info at my finger tips I ended up more confused then ever.
Anyway, I was caught between two, the EF 100-400 f4.5/5.6 L IS & the EF 100-200 f2.8 L IS, I think I'll go with EF 100-400 L IS which is the one i was leaning towards.  I hesitation was my trying to work out if the EF 100-200mm L IS with 2X TC would give me so much more thus making it worth the extra $$. 
Again thanks for the quick reply, this is advanced warning . . . . . brace yourself . . . . . you'll be hearing a LOT more from me, I can already predict there will be a heap more questions in the future.  .  Especially after i purchase this all important lens . . . . Cheers 

[Bob Atkins]

Both the 100-400 and 70-200/2.8 are good lenses. The choice depends on what you shoot. If was doing portraits and weddings most of the time, I'd certainly go with the 70-200/2.8, but if I was shooting sports and wildlife I'd go with the 100-400 for the longer reach and more rapid zooming. While you can add a TC to the 70-200 to get to 400 you do lose a little image quality, zooming the 100-400 is much faster and you'll get a lot more shots if you are trying to capture near and far action.