lens for 5D

[Joan]

I have a 5D Mark 2....What is the best affordable lens to use to photograph large groups (100-150) of students inside gyms or auditoriums?

[pjmacd]

Wow! That's a tough assignment. Assuming you want to get everyone in the photo at the same time, you will need a fairly wide-angle lens that can cope with difficult lighting (inside a school gym). On a full-frame sensor camera like the 5D Mark 2, you might want to look at something like the Canon 16-35mm f/2.8, but it's expensive (~USD 1600). I haven't checked, but there should be similar lenses from Sigma, Tokina and Tamron that are more affordable, but check reviews on image quality before you buy.

[amfoto1]

You might take a look at the Canon EF 20/2.8... It's a very nice lens and quite wide on a full frame 5DII.

If they give enough coverage, the Canon EF 24/2.8 or 28/1.8 are also pretty good.

All these prime lenses range in price from around $400 to $500 US.

If this is a one-time project, or something you only need to do occasionally, you might want to consider renting a lens for the purpose.

Using a wide lens to photograph people, you have to be careful about the edges of the images in particular. People too close to the edge of the frame will show anamorphic distortion effects, unavoidable with wide lenses. All you can do is try to keep people away from the edges.

Prime wide lenses often show less distortions than wide zooms, though the Canon 16-35 and 17-40 are pretty well corrected.

Shooting such a large group, you might need a step ladder and several flashes!

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[ebiggs1]

I do this all the time  as I photograph the pictures for the school yearbook.

The lens of choice is the 17-40mm f4 L. It is a wonderful lens that doesn't change f ratio. And it does not change it's length as it zooms. Two very desirable attributes. Pay attention Canon!

I shoot it on a 5D Mk II. I use LR5 and tether the camera to a 17" laptop so I can confirm the photo before I let the kids go! Otherwise you will be disappointed, trust me on that one!!!!!!!!

[ebiggs1]

BTW, you will also need a small step ladder.

[TCampbell]

The 17-40 zoom will probably give you the most wiggle room to work.  

Keep in mind that as you lower the focal length, a wide angle focal length also has the effect of stretching the length of the room.  That means those people near the back of the pack will appear to be REALLY far back (and very tiny).  While you will need a wide-angle lens for a group this large, try to use the longest focal length that will work.

Since you'll have a bit of a crowd, use a depth of field calculator to find the DoF that will work best.  Normally you'd use a high focal ratio to increase the depth of field, but it turns out wide angle lenses naturally stretch the depth of field so you don't actually need a particularly high f-stop.  

For example:  If you set the focal length to 24mm, use f/4, and focus the lens to a distance of 16, then everything from 8' away to infinity will be in acceptable focus.  If you did the exact same thing with a 50mm focal length, then only subjects between 13 and 20' would be in focus -- the wide angle focal length really helps the depth of field. 

At 24mm f/4 and focused to 16' means you're not focusing on the person in the front row of the crowd.  You're focusing several rows back.

There's also a website you can use:   http://dofmaster.com/dofjs.html

If you were doing this type of shot all the time then I'd suggest getting a tilt-shift lens such as the TS-E 24mm f/3.5L II.  But I don't recommend you try this lens if it's just for one event -- I don't even recommend that you rent the lens for one event (not unless you rent the lens and practice heavily with it for weeks in advance).  A tilt-shift lens has a learning curve.  Nothing is automatic on the lens.  The lens has the ability to alter the plane of focus so that you can shoot a crowd of people and everyone's heads will be in tack-sharp focus (even at low focal ratios and it doesn't matter that they're all at different distances from the lens).  BUT... learning to adjust the tilt angle to achieve this is more challenging that one might guess (there's a math formula that calculates the correct tilt angle and there's also a method that will get you pretty close without doing any measurements or doing the math.  But without practice, you'll find you miss the focus more often then you nail it.)