Problem with my 100mm Macro lens


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Sun_Of_The_Beach

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I have a query, or should I say a problem on using the canon 100mm Macro lens. I try to describe the problem as best as I can:

When I switch to auto focus mode and half press shutter, the lens keeps zooming in and out of the object, and it reaches the point of no focus. (totally blur image)

I half to press multiple times half shutter button, to reach certain degree of sharpness, and then do another half shutter, then the image is sharp.

Am I doing it the wrong way, or is there some problem with the lens focusing? Pls help.
 

n0d3

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Was the subject sufficiently illuminated/sufficient contrast for the camera to obtain an AF lock? What focusing mode was your camera set on?
 

Ris Goh

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clean the electrical contacts..... which 100 macro (non-USM or USM version) is that and which cam you using?
 

Sun_Of_The_Beach

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n0d3 said:
Was the subject sufficiently illuminated/sufficient contrast for the camera to obtain an AF lock? What focusing mode was your camera set on?
I put the lens to AF mode and camera at AI focus.

Lighting shouldnt be a problem, as I was trying in out in my room, brightly lit. I not too sure about the contrast, as it was a grey blower, on my yellow bedsheets. (not yellow stained, just to emphasize.):)
 

Sun_Of_The_Beach

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Ris Goh said:
clean the electrical contacts..... which 100 macro (non-USM or USM version) is that and which cam you using?
Its a USM version, and just got it today, and I am using it on my 350D.
 

n0d3

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The 100mm f/2.8 macro?

http://www.fredmiranda.com/reviews/showproduct.php?product=47&sort=7&cat=2&page=2

Hmmm, some people say fast focusing but I think it tends to hunt a bit if the AF can't lock on due to insufficient contrast. Try focusing on something else or try it outdoors tomorrow. Read the comments, some people find that you're better off using manual focus in some cases.
 

Ris Goh

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AI focus?! switch to one shot AF mode and the problem should go away...

If I remember correctly in AI mode the cam will keep searching for focus when there's a slight change in the object as it'll try and AF....

AF should be pretty fast for USM version in medium to far distances but will sometimes get a bit erratic at macro distances as the DOF gets very shallow at such distances...
 

Ris Goh

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one more thing.... the canon AF system sees objects in black and white only, ie contrast differences.

a grey blower on a yellow bedsheet is like a grey object on a light grey back ground... contrast may not be high enough for the AF to work properly....
 

Sun_Of_The_Beach

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I tried out a few methods, and some helps. Here are what I have tried:

1) Change of object
Tried a more contrast object, a black color pen on a white A4 size paper. The focusing is still errantic.

2) Changing of focus mode on camera
I changed from AI focus to one shot focus. Focusing is slightly faster.

3) Change from AF to MF on lens
Will be out, coz the focusing is much more slower. Due to user issue. :)

4) increase object distance
I did a far distance, medium distance and near distance shot on the same object. It seems that the far distance focusing is fantastically fast, while the near distance shot was erratic focusing for a while before it image is clear.

What is the minimum distance for the 100mm macro? Yes, n0d3, Its the f2.8L one.
 

Goldenstars08

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Nov 21, 2004
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Sun_Of_The_Beach said:
What is the minimum distance for the 100mm macro? Yes, n0d3, Its the f2.8L one.
You can try manual focus. Turn your lens's focus ring to 1:1 life size ratio, walk from far to close to your subject. Once your subject is sharp & clear that is the minimum distance for the 100mm macro lens...;)

For a macro lens learn to manual focus. For my Tamron 1:1 90 Macro AF for far away object is ok. For close up object it run in & out trying to focus. Very slow. So I switch to manual focus. Quiet fast...:)

I think this is what you facing too...:think:
Hope this help...:D
 

Sun_Of_The_Beach said:
I have a query, or should I say a problem on using the canon 100mm Macro lens. I try to describe the problem as best as I can:

When I switch to auto focus mode and half press shutter, the lens keeps zooming in and out of the object, and it reaches the point of no focus. (totally blur image)

I half to press multiple times half shutter button, to reach certain degree of sharpness, and then do another half shutter, then the image is sharp.

Am I doing it the wrong way, or is there some problem with the lens focusing? Pls help.
i sometimes experience this problem

i think it is because if you were using the lens as a normal 100mm and you aim at something really close (for macro), the lens elements have to move alot to adjust... which results in it hunting.,

so i dont think you or your lens has a problem
hope that is more assuring
 

blow

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you don't shoot macro with AF. Stick to MF for precise focus on the subject.
 

Sun_Of_The_Beach

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haagen_dazs said:
i sometimes experience this problem

i think it is because if you were using the lens as a normal 100mm and you aim at something really close (for macro), the lens elements have to move alot to adjust... which results in it hunting.,

so i dont think you or your lens has a problem
hope that is more assuring
Based on your own experience, so how do you actually minimise such problem?
 

Sun_Of_The_Beach said:
Based on your own experience, so how do you actually minimise such problem?
how i do it?
this method works for me.

when i suddenly decide to shoot from far to macro (near)
i turn the focusing ring till its suitable for close up.
i will then AF and it mostly would lock on.. (ie. it wont hunt and swing into focusing at infinity)

or like someone says. you can MF
but my pooreyesight doesnt help me MF well
:confused:
 

Sun_Of_The_Beach

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Manual focus for macro?

I tried to, but find it pretty slow to focus. Or is it that I doing the wrong way? :) I have to turn quite a few rounds on the focus ring before the image gets sharp.
 

n0d3

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Feb 3, 2003
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Ris Goh said:
AI focus?! switch to one shot AF mode and the problem should go away...

If I remember correctly in AI mode the cam will keep searching for focus when there's a slight change in the object as it'll try and AF....

AF should be pretty fast for USM version in medium to far distances but will sometimes get a bit erratic at macro distances as the DOF gets very shallow at such distances...
Wrong, thats AI Servo.

Sun_Of_The_Beach said:
I tried out a few methods, and some helps. Here are what I have tried:

1) Change of object
Tried a more contrast object, a black color pen on a white A4 size paper. The focusing is still errantic.

2) Changing of focus mode on camera
I changed from AI focus to one shot focus. Focusing is slightly faster.

3) Change from AF to MF on lens
Will be out, coz the focusing is much more slower. Due to user issue. :)

4) increase object distance
I did a far distance, medium distance and near distance shot on the same object. It seems that the far distance focusing is fantastically fast, while the near distance shot was erratic focusing for a while before it image is clear.

What is the minimum distance for the 100mm macro? Yes, n0d3, Its the f2.8L one.
I don't recall it being a "L". ;p

Sun_Of_The_Beach said:
Manual focus for macro?

I tried to, but find it pretty slow to focus. Or is it that I doing the wrong way? :) I have to turn quite a few rounds on the focus ring before the image gets sharp.
Eh, few rounds? You just need to turn it from left to right, you don't need to make full revolutions.
 

Sun_Of_The_Beach

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n0d3 said:
I don't recall it being a "L". ;p
Sorry, typo. Guess I been thinking of all the L lens....Yes, there is no L. Its a 100mm Macro f2.8 AL. (Almost L);)


[/quote] Eh, few rounds? You just need to turn it from left to right, you don't need to make full revolutions.[/quote]

Yea, I have to make at least 1 full revolution to get a clear image for manual focus.:( Thats why dun know whether is it user issue.
 

n0d3

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Hmmm, I think theres nothing wrong with your lens. Like blow said, stick to MF for macro subjects. And you said that AF worked fine for subjects further away sooooo, time to work on your MF skills!
 

Sun_Of_The_Beach

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n0d3 said:
Hmmm, I think theres nothing wrong with your lens. Like blow said, stick to MF for macro subjects. And you said that AF worked fine for subjects further away sooooo, time to work on your MF skills!
Thanks!

One more question. Is flash a requirement for macro? If yes, can use the built in one instead of external flash?
 

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