Quote Originally Posted by Squidy View Post
Hi all,

coupled with the slow shutter speed I still got blur. If I sped up the shutter then I got close to still motion... but very, very little light. Then when I raise the exposure in Lightroom... Oh boy.
Ya I guess we've all been there. When the available light isn't enough for action-freezing exposures / shutter speeds... and you're already maxed out on the ISO (physically at the limit or just averse to using high-noise ISOs) ... the only option remaining is to add more light. At an aquarium ... shooting thru glass .... yikes. Faster glass will certainly help. An f/1.4 or 1.8 lets in much more light than your f/4 - more than twice as much.

Will that be enough? Does LR do a good job reducing noise in high-ISO shots? I'm more familiar with Photoshop/Camera Raw. It does a great job and plugins like Noise Ninja and Neat Image can work wonders.

As far as autofocus, so much depends on the body/lens combo that I don't think anyone can make a general statement. Many bodies have focus points on their sensors that are designed to be more sensitive at f/2.8 and wider so if anything you might say in general that faster glass focuses faster.

My f/4 vs f/2.8 story is about shooting tennis. Bright sunshine at the U.S. Open, a Canon 40D and two 70-200s, one f/4 and one 2.8IS. The f/4 locked on quickly, just as fast at the 2.8 but the images - probably 60-70% of them - were OOF. Not by much but enough. The in-focus shots looked great but the keeper rate was much lower compared to the 2.8. (the IS wasn't used as all shots were at least 1/500th). Maybe it was the extra-sensitive 2.8 sensor...that's all I can assume. My technique was the same, the conditions were roughly the same. But the 2.8 was far superior to the f/4. Since then I've sworn off f/4 lenses. I know the 24-105 is great, the IS etc. But f/4 is just too slow!