Focal length for 50mm lense


bluebaby

New Member
Sep 20, 2006
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#1
Hi, I am using a newbie and trying out a 50mm lense, when I'm using auto focus, I can't focus on the subject if its less than 1.5m, but my 50mm focal length is 0.45m, have I missed out any setting? Thanks.
 

CasualBear

New Member
May 4, 2013
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singapore
#2
1. Go search focal length on camera lens..
2. Read the stickies articles on newbie section.. this should b sufficient..
 

Yutaka Go

Senior Member
May 22, 2010
983
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SG
#3
Hi, I am using a newbie and trying out a 50mm lense, when I'm using auto focus, I can't focus on the subject if its less than 1.5m, but my 50mm focal length is 0.45m, have I missed out any setting? Thanks.
The focus length of 50 mm lens is 50 mm.

I think you mean the lens minimum focus distance is 0.45 m

If there are insufficient light, you will also have problem focusing.

You may want to switch to Aperture priority mode and set aperture to F1.8 or F1.4
 

Rashkae

Senior Member
Nov 28, 2005
19,105
12
0
#5
Hi, I am using a newbie and trying out a 50mm lense, when I'm using auto focus, I can't focus on the subject if its less than 1.5m, but my 50mm focal length is 0.45m, have I missed out any setting? Thanks.
Please read up on the difference between focal length and minimum focus distance. They are not the same thing.
 

catchlights

Moderator
Staff member
Sep 27, 2004
21,903
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Punggol, Singapore
www.foto-u.com
#6
Hi, I am using a newbie and trying out a 50mm lense, when I'm using auto focus, I can't focus on the subject if its less than 1.5m, but my 50mm focal length is 0.45m, have I missed out any setting? Thanks.

I think you mixed up minimum focusing distance aka closest focusing distance with focal length.

http://en.wikipedia.org/wiki/Canon_EF_50mm_lens

anyway, it could be you are shooting in low light, or the subject has no contrast, or too tiny, so the camera unable to do auto focus.
 

Mythmaker

New Member
Oct 8, 2011
1,011
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Buangkok MRT
#7
It's more to do with your shooting I think. When you go close (in your case, lower than 1.5m), everything becomes bigger. When things are bigger, finding a spot that has contrast is tougher. You need that contrast for AF to lock on. You just can't randomly pick a spot and pray it will focus on.
 

rhino123

Moderator
Staff member
Sep 1, 2006
5,243
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#8
Hi, I am using a newbie and trying out a 50mm lense, when I'm using auto focus, I can't focus on the subject if its less than 1.5m, but my 50mm focal length is 0.45m, have I missed out any setting? Thanks.
1) What subject are you focusing on?
2) Have you try manual focusing, if yes, can you get a sharp focus?
3) Set your camera + lens on a tripod and take your time to 'test' focusing on different subject at less than 1.5m (subject like pebbles, flowers, cactus or even yourself), see if there is a problem with locking focus on all these subjects or was the camera seemingly 'selective' locking on.

If you tried different subjects, some can lock on focus, some cannot, then most probably, it might be those subject that you are shooting are very low in contrast with the surrounding (e.g a blank piece of white paper). If everything also cannot focus, then it might be some issue with your lens and you might want to bring it down to the service centre.
 

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