EF 100-400mm f/4.5-5.6L IS USMThe Big Gun

It’s quite large and fairly weighty. That’s why the tripod mount is on the lens for better balance and no undue stress where the lens mount meets the camera.

Yes, I’m using a plastic green army man for size context. I wonder if there are any plastic green army women anywhere?

I’ve had this telephoto lens for some years now and consider it a staple in the lens line up.

My purpose was mainly for outdoor nature photography and great for outdoor portraiture when you want a blurry background.

Brass Tacks – What’s It Got To Offer?

It’s not a fast lens. Fast meaning a really low f-number like 2.8 (the Image Stabilizer on this lens helps compensate). A faster lens going to mean a much  higher price with this range of focal length (100-400mm). Just bump up the ISO to turbo boost the shutter speed and use Topaz DeNoise and you’ll still get tack sharp results.

  • Image Stabilizer for horizontal panning or regular use
  • L series professional glass – superb quality
  • Leather zippered carry case, lens hood
  • Trombone style focal length adjustment
  • Very responsive AF
  • Filter size 77mm

Shutter Speed Tips Using Telephoto Lens

EF 100-400mm f/4.5-5.6L IS USMWith any telephoto lens, when you’re fully zoomed and taking a hand-held shot, all slight movements are amplified just like those UFO video clips where the shooter wanted to zoom in all the way. This is why I think of this as an outdoor lens if doing handheld shots, because ample natural light helps.

  • Fully zoomed at 400mm, suggest a shutter speed of about 1/600 for hand held shots
  • Starting at 100mm, suggest a shutter speed of about 1/200 for hand held shots
  • Using a tripod with remote release, shutter speed of no concern but you must have a strong and steady tripod. I first tried this on a inexpensive tripod and it wouldn’t settle with a constant jiggle.
  • When hand holding, grip the lens with your left hand the camera with the other

The IS (Image Stabilizer) helps buy you a f/stop.

I’ve had this lens for some years now. I consider this a keeper, a basic.

It’s designed for full frame digital sensors but can be used with your Rebel. It’ll just be cropped giving the artificial effect of even greater zoom. I purchased this lens when I had a Canon Rebel anticipating I would eventually upgrade to a full frame. It’s well below $2000 and could be around $1500 with rebates sometimes.

Reach versus Speed with Professional Lenses

Just to give you a flavor on price. The newer Canon EF 70-200mm f/2.8L IS II is a fast telephoto lens. Not only a huge agperture at f/2.8, but with the added IS (Image Stabilization) that’s pretty incredible performance. A favorite for photojournalists. Not as much reach as the Canon 100-400mm.  The 70-200mm price will be significantly more than the 100-400mm. But you can see the how the speed of the lens affects price. If Canon had the 100-400mm as an f/2.8 with IS, it would also have a much bigger price tag attached to it.

F/number Basics with Lenses

Variable Aperture

Canon EF 100-400mm

f/4.5-5.6 – When a lens spec quotes two f numbers like this lens 4.5-5.6 that means at 100mm the smallest achievable aperture is f/4.5 and at 400mm the smallest achievable aperture is f/5.6. If you set to the smallest aperture at 100mm and zoom out to 400mmm, you’d see the aperture change to 5.6.

Constant Aperture

Canon EF 70-200mm

F/2.8 – When a lens spec quotes one f number like this lens at 2.8 the means the smallest achievable aperture is 2.8 and constant from 70 to 200mm. Therefore described as a constant aperture through the entire focal length.

Apertures 101

When beginning to learn about apertures, it could be confusing.

Here are all the follow through effects of smallest or largest f/number:

Smallest f/number

=largest aperture

=more light through the lens

=faster shutter speed

=narrower depth of field

Largest f/number

=smallest aperture

=less light through the lens

=slower shutter speed

=longer depth of field.


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