philo Loc: philo, ca

On the side of my Canon 100-400 there are a number of settings. The one I'm not clear of is.........1.8m or 6.5mso my question is .....what is the difference and when is the best time to use either.
Thanks

CHG_CANON Loc: the Windy City

They control the minimum distance where the lens can / will try to focus. It can help in 'focus speed' so the lens doesn't rack back n forth between 3-feet (ish) and infinity. Their use depends on your situation, where say you're tracking players on the soccer pitch. If nothing is ever close, you might set the distance limit to the further distance setting. Of course, you sometimes forget, and can't figure out why you miss focus on close subjects.

philo Loc: philo, ca

so if something is close i would use 1.8 and for anything is over 6 feet away i would use 6.5. is this correct?

Retired CPO Loc: Travel full time in an RV

Yes. It just limits how far the lens has to go when searching for a good focus.

CHG_CANON Loc: the Windy City

Limiting the focus distance range can improve focus lock times and reduce focus hunting. The setting is not based on any specific subject, but rather, how does the lens behave in dynamic focus situations. Not 'on any specific subject', unless of course, that subject is inside the minimum distance limit setting. I've encountered every so often this error where I find the lens won't focus on something close it should be capable of capturing, only then to note I have the switch to the wrong setting.

philo Loc: philo, ca

So you have it set for 6.5m most of the time, and then switch to 1.8 if something is close?

CHG_CANON Loc: the Windy City

I adjust the setting when I think the lens is not locking fast enough on more distant and moving subjects. I said soccer before, but an airshow is more accurate. Never will the planes be closer than 3-meters as they fly by. The limiter won't allow the lens to waste time mistakenly searching for something close to focus on.

robertjerl Loc: Corona, California

It does not effect the focus itself, just the distance it will try to focus to make focus on distant subjects faster. You don't have to use it at all. I almost never use it anymore since I found that when doing a series of pictures of things at aprx. the same distance the lens almost always just snaps into focus without any hunting.

As said something like an air show I might use it but being me, what if I saw a butterfly or flower near me I wanted and image of.

LittleRed

I think it will depend on what your normal taking of photos consists of. Unless there is a reason for the need of a super fast focus I tend to set my lens to the “full” setting on my lens. I only reset it to the “3m - infinity” mark when I’m working with items that are moving (like sports or wildlife) where speed in getting a focus is critical or I know all my pics will be closer to infinity. That way if you see a swan swimming on a pond or a pretty flower at your feet your ready fo either one if your on the “full” setting. But if you see the same swan flying overhead you’d best be on the second setting.
I should also mention that the stated minimum focus distance in the lens specs is 59 inches but in use it will actually focus down to approx 38 inches. In fact I have found that if you set the lens to the minimum 100mm I can get a good focus at close to 30 inches. This is a remarkable lens and you should have many pleasures for many years to come.
Stay safe and keep a’shooting.

LittleRed (Ron)

LittleRed

[quote=LittleRed]I think it will depend on what your normal taking of photos consists of. Unless there is a reason for the need of a super fast focus I tend to set my lens to the “full” setting on my lens. I only reset it to the “3m - infinity” mark when I’m working with items that are moving (like sports or wildlife) where speed in getting a focus is critical or I know all my pics will be closer to infinity. That way if you see a swan swimming on a pond or a pretty flower at your feet your ready fo either one if your on the “full” setting. But if you see the same swan flying overhead you’d best be on the second setting.
I should also mention that the stated minimum focus distance in the lens specs is 59 inches but in use it will actually focus down to approx 38 inches. In fact I have found that if you set the lens to the minimum 100mm I can get a good focus at close to 30 inches. This is a remarkable lens and you should have many pleasures for many years to come.
Stay safe and keep a’shooting.

My bad😵‍💫😵‍💫. The stated minimum focus distance is 5.9 feet, not 59 inches. Problem of leaning on my 8th decade and not proof reading your own stuff.

LittleRed (Ron)

amfoto1 Loc: San Jose, Calif. USA

Those are meters... not feet. "M" = meters.

Chg_Canon and others have described the purpose of this feature well and given some examples.

But there's a big difference between meters and feet (there are about 39" or more than 3 feet per meter).

It's called a "Focus Limiter" and this particular one has two possible settings:

1.8m to infinity...the full range possible with the lens, it can focus on subjects from as close as approx. 6 feet (1.8m) and all the way out to infinity.

6.5m to infinity... subjects must be approx 22 feet (6.5m) or farther away to be able to focus upon them.

Normally you'd leave the lens set to the first.... 1.8m to infinity... to be "ready for anything" near or far.

But sometimes you may wish to use the second... 6.5m to infinity... for faster AF and/or to avoid possible AF "hunting", when you know the subjects will be more distant.

robertjerl Loc: Corona, California

[quote=LittleRed]

The Canon posted spec minimum focus distance of 5.9ft is for the old "trombone zoom" style mk1 of the 100-400L, the mk2 (current model) is 2.75ft
The minimum focus distances are measured to the sensor(formerly film) plain, not to the front of the lens.

tgreenhaw

I leave mine at 1.8. One time I was worried that my lens wouldn't focus until I found that control

LittleRed

That’s the problem when you’ve had both versions of this lens. Your correct about my quote being for the older model. According to the data I found online the correct quote is “The minimum focus distance of Canon EF 100-400mm f4.5-5.6L IS II USM is 0.98m (3.21’)”. That’s pretty close to your call. But I think that perhaps the 2.75 measurement possibly only occurs when the lens is set at 100mm. Either way it’s a helluva lens even though it set me back close to $3000

LittleRed (Ron)

robertjerl Loc: Corona, California

The 2.75' is from a review by a wildlife photographer on his actual results with his lens. I have gotten just a hair over that with mine at the 400mm setting.
But I still sometimes am too close - like the time a small butterfly I was getting ready to photograph on a flower in the yard took off and landed on my own knee, then the lens's hood and finally the camera itself. After which it took off and went over the fence into the yard next door. @#$@&*^!