Fast prime

As my daughter's grow (2 and 4), I find I want a lens that is a bit faster than my Tamron 24-70 2.8 G2 and Canon 70-200 2.8 v2 and longer than my Sigma 35 1.4. main use is low light action IE dance recital and martial arts, both of which flash is not permitted for obvious reasons.

I am contiplating the following options:
85 1.4 of sorts
Sigma 105 1.4 Art
Sigma 135 1.8 art

I like the idea of a 1.4 but worried the 85mm might end up a little short in length on the 5D due to the distance the subject will be (50' but could sit an extra row back), on my 7D it would probably be great. Last recital I used the 5D with the 70-200 and most shots were right around 150-180mm. Full stage shots I used the 24-70 with 5D as the 35mm was not wide enough where I was sitting.

The 135 on the 5D I think would be ok as I could crop a little and still have great shots.

The 105 is seemingly a great mix of both speed and length, obviously I would have to crop more on the 5D but the 7D might be perfect.

While money is not pouring from my pockets, I don't mind spending the $1600 that the 105 would cost.


So... What would you do?

I think you could still buy new 6D for 1600 and get enough ISO for f2.8 or even f5.6 indoors.
One thing is the photo studio where you could dictate the distance, another is anything else, where zoom is huge convenience.

Shaun, you're kidding me, right? You have an incredible kit right now. The 5DMkIII (which your profile says you have), along with the 70-200 f/2.8 II (which I'll assume is IS) is a powerful combination. You don't need to spend $1,600 on a "faster" lens. What you need to do is push yourself and your kit.

Below is a link to a set of photos from my daughter's last year in high school. I was the chair for our Band Boosters Photography & Media group. Photos in here include ISOs up to 25,600. Typically at night I'd shoot M at f/5.6, 1/500s, and ISO 12,800 with the Canon 70-200 f/4 IS. I went to f/5.6 to ensure I'd catch more than one band member. (The photos in the album below include the Canon 24-105 f/4L IS, 70-200 f/4L IS, and the 100-400 f/4-5-5.6L IS, all Mk I versions.)

http://grahamglover.ze​nfolio.com/p927460208

Dance? Link below. The aforementioned 70-200 was used. Settings in M were mostly f/4, 1/320s, and ISO limited to 12,800, and all were shot from the lighting booth. Was there noise? Sure. Did I correct for it? Mostly. The ballet company seemed to like them.

http://grahamglover.ze​nfolio.com/p499654316

What would I do? I'd push my camera and lenses to their limits. The 5DMkIII has high limits, especially with the 70-200 you have.

Yes the 5D mkiii and a good 2.8 do a nice job. But I can't help to think a 1.8 or even 1.8 could allow for more.

This was taken with that combo.


The 7D mkii is noticably noisier, I'd say a little over 1 stop. That's where I think the 1.4 or 1.8 would really shine.

When shooting at an actual f:stop of 1.4 or 1.8, depth of focus becomes very narrow (thin/shallow). Just something to keep in mind when the subject is 1-2 feet or more deep.

Understand.

105mm with F/1.4 at 50'

7D mkii = 3.5' with 48% front (5D mkiii at 40' is the same)
5D mkiii = 5.6' with 47% front