I'm seeking advice on taking photos on the go in low light conditions. I recently went to AFA which was held at the Suntec Convention Halls. As it was my first time using a Nikon D80 with 14-24mm f/2.8 lens, which my friend lent me without even advising me on anything, I happily went around shooting photos like a compact =_=''' Initially there wasn't much problem in the main hall due to the sufficient lighting but matters got alot worse when I ventured outside to take photos of the cosplayers. Due to the poor lighting I decided to use the in built flash which cause alot of harsh lights on the subject and not the mention due to the massive lens hood I ended up with a shadow patch at the bottom of the photo D: Learning that mistake, I decided not to use flash and noticed that quite a few photos I took came out blurry due to low shutter speed.
Recently I purchased a Nikon D7000 with the same lens (14-24mm f/2.8), and I'm interested in getting a speedlight. Would the SB700 be enough ? Or should I go for the bigger SB900 ? Since I'm anticipating I will be having the same issues as I faced in AFA, is the diffuser and bounce card sufficient(in cases where I can't find a suitable wall or ceiling to bounce) ? Considering I need to be mobile without too many accessories to lug me down, not to mention limited movement due to the huge amount of photographers around.
Has anyone used the orbis ringflash ? Is it any good ? Though I am worried it might not fit with the lens I have at the moment.
Any feedback or advice will be appreciated. Thank you.