planning an upgrade

[Amateur]

I am thinking of upgrading from DRebel to 20D and looking at lenses.
I have a 28-135mm IS and really like the IS.

Still the lenses I am looking at are:

Sigma 18-50mm f2.8 EX (29-80mm effective)
Sigma 70-200mm f2.8 EX (112-320mm effective)
Sigma 1.4 or 2x TC (448 & 640mm effective)

I am thinking that between the large aperture and 20D's high ISO capability I can handle the same low-light situations I now shoot with the IS.

One feature I really like is the internal focusing and zoom of the Sigmas.

The 28-135, though a really nice lens, often leaves me wanting on the wide end. For this reason I am thinking that the 18-50mm will be my walk-around lens. I expect to carry the 70-200 and TC for reach but not planning to carry the 28-135.

Anybody think the 50-70mm gap between these two lenses is too big?

Also, any thoughts on trading IS for f2.8? (that Canon 70-200 f2.8 IS looks sweet but $$$$ and #)

Thanks,
David

[NHL]

This is just my opinion...
When I look at an f/2.8 lens, I value its 'Bokeh' at the larger aperture more than its speed: Remember photography is all about the 'mastering' of light - you can snap a shot in lower light with a faster lens, but to get a memorable image, it's all in the lighting!

Many people can recommend you the 70-200 f/2.8; However I have some reservation about the need of an 18-50 f/2.8 - The 18-125 f/3.5-5.6, even though not an EX (Sigma's pro designation) is more flexible and you don't lose much 'Bokeh' at 18mm (@ 125 the 70-200 f/2.8 will cover it!): http://www.fredmiranda.com/forum/topic2/143791

... and since everyone mention MTF's nowadays :G

[Mr_Saginaw]

I'm one of the many people who can recommend the Sigam 70-200 f2.8 EX.... This lens is my main lens... I shoot mostly indoor sports with no flash. I don't shoot much wide angles but when I don't use my 70-200 i usually use a Tamron 28-75 f2.8 XR Di which has turned out to be great lens at a good price...

[peripatetic]

Ha ha ha... your selection is where I started out...

I went through 3 posts with lots of help from the forum:
Cunningly Original Question,
Cunningly Original Question MkII,
Cunningly Original Purchase

Looking forward to seeing what you end up buying. Good luck on your journey.

[Amateur]

NHL, your opinion is always worth consideration, thank you. Good points. Good Bokeh is important and is one of the reasons for considering these lenses. Low light is also important to me for different reasons. Most of the low-light shooting I speak of is family or event stuff. I just want to be able to shoot unobtrusively. I will certainly take a closer look at the 18-125mm, what a great range for a 1.6 sensor!

I gather that you are saying that the larger aperture has less impact on bokeh at shorter focal lengths? I haven't ruled out the 17-85 f4.0-5.6 EF-S IS either.

Mr_Saginaw, Thanks for your input. There's hardly a discouraging word about the 70-200. Do you use a TC with it?

Peripatetic, Thanks to you too. I read your post "Cunningly Original Purchase" and will again probably. I wasn't aware of the previous ones, I will certainly read those too. I know you are enjoying your 17-85mm and 70-300mm DO, both contenders for me too.

Do you suppose the price will fall on the 20D soon after the PMA or not? Think Canon has any surprises in store?

David