Question about MF

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stevet1 Senior Member • Posts: 1,100
Question about MF

I guess I have three questions:

1) Is the lens IS tied to autofocus?

2) If I switch to MF, does the IS in my lens still work?

3) If you are using MF, does it make a difference turning off the IS when using a tripod?

Steve Thomas

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Dunlin Senior Member • Posts: 2,317
Re: Question about MF

stevet1 wrote:

I guess I have three questions:

1) Is the lens IS tied to autofocus?

No.

2) If I switch to MF, does the IS in my lens still work?

Yes.

3) If you are using MF, does it make a difference turning off the IS when using a tripod?

Not entirely sure.

Traditional advice is to always turn IS off when using a tripod, although various sources I've read (eg. Ken Rockwell) say most IS systems are smart enough to notice when they are on a tripod and turn off automatically.

I always turn IS off just to be safe.

Steve Thomas

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Len Philpot
Len Philpot Contributing Member • Posts: 500
Re: Question about MF

Jethro B-UK wrote:

3) If you are using MF, does it make a difference turning off the IS when using a tripod?

Not entirely sure.

Traditional advice is to always turn IS off when using a tripod, although various sources I've read (eg. Ken Rockwell) say most IS systems are smart enough to notice when they are on a tripod and turn off automatically.

I always turn IS off just to be safe.

Same here. My Canon EF 70-300 IS USM is about 15 years old and it does not recognize the tripod. It's just a single switch - Get in the habit of turning if off when on a tripod.

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Len Philpot
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OP stevet1 Senior Member • Posts: 1,100
Re: Question about MF

Jethro and Len,

Thank you for your replies.

A poster on another forum told me that the IS is in the lens and the autofocus is in the camera. He also said that when you flip the switch and turn on MF, it disables the IS.

What say you?

He also recommended turning off the IS when mounting the camera on the tripod.

If the IS has been disabled when switching to MF, why would I nee to also turn off IS?

Steve Thomas

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Dunlin Senior Member • Posts: 2,317
Re: Question about MF

Len Philpot wrote:

... My Canon EF 70-300 IS USM is about 15 years old ...

My EF 100-300mm USM is around 30 years old! It doesn't even have IS.

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Dunlin Senior Member • Posts: 2,317
Re: Question about MF

stevet1 wrote:

A poster on another forum told me that the IS is in the lens and the autofocus is in the camera. He also said that when you flip the switch and turn on MF, it disables the IS.

What say you?

That's incorrect for canon DSLRs. All canon DSLRs have AF built into the lens, not the body.

Some brands (eg. nikon, pentax) have AF built into the bodies. (the lowest range nikons don't have AF built in, and so are incompatible with some older nikon lenses.

He also recommended turning off the IS when mounting the camera on the tripod.

👍

If the IS has been disabled when switching to MF, why would I nee to also turn off IS?

As far as I know (a.k.a. canon) that's incorrect.

Steve Thomas

Jethro Busby

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OP stevet1 Senior Member • Posts: 1,100
Re: Question about MF

From what I've read, the image stabilization in your lens fights with the autofocus in your camera; and the reason your turn off IS when mounted on a tripod, is that you want your camera to be completely motionless.

But if I have disabled the autofocus by switching to MF, what does the image stabilization have to fight with? Surely the electronic IS can't reach up and manually turn your focus ring.

My thinking is that if you are on a tripod, and your turn on the manual focus on your lens, you don't have to mess with the IS switch at all.

Steve Thomas

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Len Philpot
Len Philpot Contributing Member • Posts: 500
Re: Question about MF

stevet1 wrote:

From what I've read, the image stabilization in your lens fights with the autofocus in your camera; and the reason your turn off IS when mounted on a tripod, is that you want your camera to be completely motionless.

But if I have disabled the autofocus by switching to MF, what does the image stabilization have to fight with? Surely the electronic IS can't reach up and manually turn your focus ring.

My thinking is that if you are on a tripod, and your turn on the manual focus on your lens, you don't have to mess with the IS switch at all.

Steve Thomas

I guess IS could maybe fight with AF (depending on the implementation), but IS moves in an X-Y plane and AF along the Z axis (viewed from behind). In other words, left-right / up-down vs. forward-backward.

So IS has nothing to do with focus, at least on my Canon system. You don't want it wandering when the camera is on a tripod, so that's why it should be turned off.

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Len Philpot
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OP stevet1 Senior Member • Posts: 1,100
Re: Question about MF

Len Philpot wrote:

stevet1 wrote:

From what I've read, the image stabilization in your lens fights with the autofocus in your camera; and the reason your turn off IS when mounted on a tripod, is that you want your camera to be completely motionless.

But if I have disabled the autofocus by switching to MF, what does the image stabilization have to fight with? Surely the electronic IS can't reach up and manually turn your focus ring.

My thinking is that if you are on a tripod, and your turn on the manual focus on your lens, you don't have to mess with the IS switch at all.

Steve Thomas

I guess IS could maybe fight with AF (depending on the implementation), but IS moves in an X-Y plane and AF along the Z axis (viewed from behind). In other words, left-right / up-down vs. forward-backward.

So IS has nothing to do with focus, at least on my Canon system. You don't want it wandering when the camera is on a tripod, so that's why it should be turned off.

Len,

I think I understand a little better.

The lens IS is a gyroscope and operates whether your camera is autofocusing or not.

I read my manual and it says IS is working all the time to correct camera shake, not focus.

It recommends turning off IS when mounted on a tripod only to preserve battery life.

My basic premise was wrong.

Steve Thomas

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