Zoon lens minimum focus

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With a zoom lens, does the minimum focus remain the same at all zoom ranges? i.e.; is the 5.9 foot min. focus for the 100-400mm IS the same at 100mm as it is at 400mm? Thanks, and thanks to Ming Kuo and Isaac Sibson for their previous answers in this forum. They were a great help to me.

-- Charlie Spiekerman (cfs5558@aol.com), March 07, 2002

Answers

yes. doesn't change.

-- m. lohninger (anavrin@mac.com), March 07, 2002.

Depends on the lens....some lenses do change, some don't.

For example, the Canon 35-350L has its highest magnification ratio at 135mm, after which it can not focus so closely. As far as I'm aware, this is not the case with the 100-400IS, but the answer to your general question is that it depends on the lens.

Another example of this was my old Sigma 70-300mm APO Macro. It had a close focus of 1.5m throughout the range, but at 300mm you could move a switch, which would allow it to focus down to 0.95m. This locked the zoom mechanism, however, because the lens was not capable of this at shorter focal lengths, so to zoom back out, you had to focus back to a point 1.5m or further away, and move the switch back to the normal position.

-- Isaac Sibson (isibson@hotmail.com), March 07, 2002.


hmm... i didn't know that. thanks for clearing that up, isaac. all zooms i've ever used had constant minimum focus throughout their range.

-- m. lohninger (anavrin@mac.com), March 07, 2002.

Upon testing, my EF 100-400mm L IS USM is parfocal (i.e. no focus change when zooming) at all focus distances. My other EF zooms are varifocal: e.g. the EF 28-135mm IS USM is able to focus closest at around f=80mm, closer than the 50 cm Canon spec.

'Tis better to remain silent and be thought a fool, than open one's mouth and remove all doubt.
Samuel Johnson


-- Julian Loke (elan7e-owner@yahoogroups.com), March 07, 2002.

Thanks for the information on zoom lens min. focus. Since that one foot difference in min. focus between the 300f4IS and the 100-400IS is so little, I have pretty much made up my mind to go for the 100- 400 as my next lens, even though the 300 is apparently a little sharper. By the way, I assume the 300f4IS & 100-400IS don't have the third sensor mode to detect tripod use as do the big primes. or do they?

-- Charlie Spiekerman (cfs5558@aol.com), March 08, 2002.


Yes, unfortunately the Image Stabilizer does not have a tripod sensing mode on the EF 100-400 (and the EF 300 f/4 L too, from what I read).

I was told by a Canon sales rep in a store I was visiting to try Mode 2 (panning) on the 100-400 when shooting from a tripod. Anyone had any success with this strategy?

-- Julian Loke (elan7e-owner@yahoogroups.com), March 09, 2002.


Neither the 300 F4L IS nor the 100-400 have the tripod mode.

There are several generations of IS technology. The first generation is the single-mode, 2 stop gain, as found in the 75-300 IS and the 28-135 IS. The second generation is the 2-mode, 2 stop gain, as found in the 300 F4L IS and 100-400 IS. The third generation is 2- stop gain, two mode with tripod, as found in the 300 F2.8 IS, 400 F4 DO IS, 400 F2.8 IS, 500 F4 IS and 600 F4 IS. The latest generation, found only on the 70-200 F2.8 IS is two-mode with tripod, three-stop gain.

Using mode 2 on a tripod might work, but there's less reason to use IS on a tripod.

Charlie- If you go for the 100-400, I doubt you'll be disappointed, but do remember that, although it is similar weight to the 300F4L IS, the weight is at the front, and when the lens is zoomed, it is quite long, and can seem heavier than it is (it's acting as a lever). My advice would be to go to a shop that has both, and handle both on your own camera body.

Whichever lens you buy, you'll get some great shots, and happy shooting!

-- Isaac Sibson (isibson@hotmail.com), March 09, 2002.


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