Should I swap or not

[modchild]

I've recently got a 5DMkII to compliment my 7D and am left with a little problem. I've got a 100-400 L that goes perfectly with the 7D range wise (640 equivalent) but seems a little bit short when used on the 5DMkII. I've been thinking whether or not to trade the 100-400 for either a Sigma 150-500 OS or a Sigma 50-500 OS. I know the IQ is roughly the same but if you were in my position what would you do.

 

[scottthehat]

my advice is go try both the 50-500mm os and 150-500mm os, personally i think the extra for the 50-500mm os is worth it and its my fav lens sharp as on the d300 and even better on the d700, the os i think you will find knocks the spots of the canon 100-400mm and the af speed is about the same.
but if you go try one you can see if you will gain much as some people say there not 500mm more like 460mm, cant really say myself but my 50-500mm was the same as my 150-500mm os and my 170-500mm.

 

[modchild]

Thanks Scott, I had a chance to shoot a few shots with the 150-500 when I had my 550D and was impressed by the results, I then borrowed a 100-400 L at an airshow and was amazed by the results when I got them on the computer. Then I was left some money and decided to go for the 100-400 not just for the IQ but a bit for the prestige as well. I've obviously matured somewhat since and wish I'd gone for the most practical instead, which would of been the 50-500 OS for me.