Minimum focus distance with Canon 600mm f/4.0L

[alain hogue]

Hi,

 

I have already posted a question of this type some time ago about a

Nikon product. Things are more clear to me but now I would like to

talk about a Canon product and be a little more specific.

 

The minimum focus distance with a Canon Telephoto 600mm f/4.0L EF IS

USM is 18 feets. I would like to know what will be the EXACT minimum

focus distance if I use an extansion tube of 12 mm. or still if I use

an extansion tube of 25 mm.

 

I would also like to know if the loss of light is important when

using the 12mm or the 25mm extansion tube. How many f stop?

 

Alain Hogue

 

Birds in the Wild - http://www.rocler.qc.ca/hogalain/oiseaux/

 

Bird photography - http://www.rocler.qc.ca/hogalain/

 

Quebec Landscape - http://www.rocler.qc.ca/hogalain/Site-web-paysage/

[bob_royse]

According to the manual, the minimum focusing distance of the Canon 600/f4L IS lens is 4.777 meters with the 12mm tube, and 4.182 meters with the 25 mm tube. You lose roughly 1/2 stop with a tube.

 

In reality, you'll seldom need tubes with that lens. Since getting it, I've used the 2x to shoot at 1200mm for 95% of passerine shots, something I certainly wouldn't attempt without IS! It's razor sharp. 18 ft. is more than adequate magnification at 1200mm for all passerines, including warblers.

 

Here's one of the few times I used an extension tube on that lens. I attached a tube (I forget which, but probably the 25mm) along with the 1.4x. The light was too low for an f/8 lens, and the bird was close so I could use a "short" 840mm lens on it. As you can see, minimum focusing distance really isn't an issue with that lens.<div></div>