Originally Posted by
Kayaker72
First off, enjoy the concert.
In terms of lenses, I would echo what Joel said, bring your fastest lens.
The images you linked were shot at 1/30, f/9, ISO 6400 and 1/40, f/5.6, ISO 6400, so these are actually ~1 stop different exposures. Both shots, the photographer used a slower shutterspeed than the 1/focal length would indicate (it seems their lens has VR/IS). Also, they were using a FF sensor.
Going to a crop body, my guess is that you will want a lower ISO, but that is the first thing I would look at. Likely around ISO 1600, or 2 stops lower. Then, unless you are also using a IS lens, you will need to make sure your shutterspeed is high enough to minimize blur, likely around or above 1/focal length, so you will need another 1/3-1 stop. The place that you could make up that difference is in aperture. Going from f/9 to f/2.8 is 3.3 stops, so you would be able to use your 40 mm f/2.8 from f/2.8-f4.5 at ISO 1600. That may be your best lens. The 18-55 will give you IS, but you'll likely have issues, as you will get motion blur at slower shutter speeds than 1/40 used in your links. But, I would probably take those two lenses.
For what it is worth, I took a few pics with my EOS-M and M18-55 lens at a concert in early July. Nothing amazing, but I got some ok shots 1/30-1/80, f/4-8, ISO 1600.