Got some question to ask about macro lens


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rysouke

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Apr 25, 2009
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#1
Hi All,

I got some questions to ask about macro lens....

1) why macro lens has a focal length since their MFD is pretty short..so the focal length is for what use..?? for example .. a prime length 50mm f1.8..MFD is 45cm..and for a macro lens 100mm f2.8 got a MFD 31cm...so what the focal length of a macro lens mean??

2) For example...when we want to shoot a snake..and we cant go near it to shoot and how does the macro lens work then?? In order to do a close up shoot of the snake??

3) Any good macro lens to recommend??
 

nysheng

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Sep 11, 2006
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#2
u are confusing MFD and focal length. they have nothing to do with each other. the focal length is how near/far u see the object, while the MFD is how far u have to be at least from ur object to get in in focus.

obviously using a 100mm lens (macro or not), ur object will appear alot closer compared to a 50mm. difference is that a macro lens allows u to shoot a 1:1 shot. meaning, ur photo will appear life size. the advantage of a 100mm macro over a 50mm macro is that u dun get bitten by the snake u are trying to take if u want a life size shot.

canon has i think 3 macro lenses. 50/60mm(which allows up to 1:5 reproduction. meaning ur object can appear 5 times bigger than life size), 100mm as well as 180. difference being how far u can stay away from ur object AND STILL able to get a 1:1 reproduction.
 

rysouke

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Apr 25, 2009
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#3
u are confusing MFD and focal length. they have nothing to do with each other. the focal length is how near/far u see the object, while the MFD is how far u have to be at least from ur object to get in in focus.

obviously using a 100mm lens (macro or not), ur object will appear alot closer compared to a 50mm. difference is that a macro lens allows u to shoot a 1:1 shot. meaning, ur photo will appear life size. the advantage of a 100mm macro over a 50mm macro is that u dun get bitten by the snake u are trying to take if u want a life size shot.

canon has i think 3 macro lenses. 50/60mm(which allows up to 1:5 reproduction. meaning ur object can appear 5 times bigger than life size), 100mm as well as 180. difference being how far u can stay away from ur object AND STILL able to get a 1:1 reproduction.
so does it mean i stand 100mm away from my object..and lens will adjust till 1:1 production..before i release the shutter???
 

ahbian

Senior Member
May 23, 2006
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#4
so does it mean i stand 100mm away from my object..and lens will adjust till 1:1 production..before i release the shutter???
The 100mm is the focal length, not the distance from the object to your lens.

If the mimimum working distance is around 15cm, loosely put, when your object is 15cm from your lens, then you get 1:1 production.

Edit: change Minimum focus distance to minimum working distance
 

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jlkk76

Senior Member
Dec 28, 2006
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Tampines
#5
to solve ur problem, go rent the macro lens n test it urself...:cool:

or simply find some1 for has it and let u try.. ;)
 

nysheng

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Sep 11, 2006
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#6
so does it mean i stand 100mm away from my object..and lens will adjust till 1:1 production..before i release the shutter???
no! pls do not confuse focal length with minimum focal distance.
if u are using for example a canon 100mm macro whose MFD is abt 31cm. when the tip of the lens is 31cm from ur object, u will get a 1:1 reproduction. if u decide to move further away because ur composition is too tight, u will get lesser than 1:1 reproduction.

if u want a 1:1 reproduction, the best way is to adjust ur lens using manual focus to 1:1 (ur lens should have a meter/dial of some sort), den adjust ur distance from ur object until it is in focus.
 

Rashkae

Senior Member
Nov 28, 2005
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#7
so does it mean i stand 100mm away from my object..and lens will adjust till 1:1 production..before i release the shutter???
Please read the newbies guides to photography posted here as well as searching online for "photography basics" and "focal length".

Focal length is NOT the same as "distance from subject". It affects your angle of view.
 

ahbian

Senior Member
May 23, 2006
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#8
no! pls do not confuse focal length with minimum focal distance.
if u are using for example a canon 100mm macro whose MFD is abt 31cm. when the tip of the lens is 31cm from ur object, u will get a 1:1 reproduction. if u decide to move further away because ur composition is too tight, u will get lesser than 1:1 reproduction.

if u want a 1:1 reproduction, the best way is to adjust ur lens using manual focus to 1:1 (ur lens should have a meter/dial of some sort), den adjust ur distance from ur object until it is in focus.
Slight correction, because I made the mistake also. From tip of lens to object is minimum working distance, not minimum focusing distance.
 

rysouke

New Member
Apr 25, 2009
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#9
no! pls do not confuse focal length with minimum focal distance.
if u are using for example a canon 100mm macro whose MFD is abt 31cm. when the tip of the lens is 31cm from ur object, u will get a 1:1 reproduction. if u decide to move further away because ur composition is too tight, u will get lesser than 1:1 reproduction.

if u want a 1:1 reproduction, the best way is to adjust ur lens using manual focus to 1:1 (ur lens should have a meter/dial of some sort), den adjust ur distance from ur object until it is in focus.
Ok..i got what you mean by now....
 

nysheng

New Member
Sep 11, 2006
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#10
Slight correction, because I made the mistake also. From tip of lens to object is minimum working distance, not minimum focusing distance.
sorry..my fault...

the miminum working distance is distance from tip of lens to object. the minimum focusing distance is distance from ur sensor to object.

To TS: take the MFD - (the length of ur lens) = minimum distance from lens tip to ur object.

hope it's clearer now..
 

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