Free Shipping on ALL Products
camera reviewsbest cameraslens reviewsphotography tipscamera forumvideo toursphotography bookssupport me
It is currently Sat Aug 30, 2014 5:00 am

All times are UTC




Post new topic Reply to topic  [ 4 posts ] 
Author Message
 Post subject: Help with focusing
PostPosted: Tue Apr 29, 2008 11:41 pm 
I'm a brand new owner of the Canon 40d and new to this site. I've had the camera about two months now and am having some serious trouble focusing. IE, I'll have one of my son's eyes in focus and not the other one. Ugh! I have toggled the focus points and still can't get a clean pic. I have two toddlers that are always on the go so that is also a challenge. What tips can you offer to help me achieve better in-focus pictures? Also, should I be using AI Focus since they are stopping/starting all the time? I have the 50 1.8 and Tamron 28-75 2.8. I know I can take an in focus pic b/c I've done so with stationary objects. It's especially hard for me when I'm around 2.8 or lower.

Any help would be so appreciated! I'm feeling so discouraged!


Top
  
 
 Post subject:
PostPosted: Wed Apr 30, 2008 12:02 am 
Offline
Moderator
User avatar

Joined: Sat Sep 30, 2006 4:30 pm
Posts: 9815
Location: UK
Hi kgreen3,

May I offer you a warm welcome to the CameraLabs forums.

It sounds as though your issue is Depth of Field and my guess is that you are letting the camera do it's own thing rather than shooting in Av (Aperture value = Aperture Priority) mode. If you are shooting indoors in low light the camera is probably selecting the fastest available f-number which gives the shallow depth of field. Though neither is specifically tailored to your problem have a look at the two video workshops How to get more in focus and How to blur portrait backgrounds over at our sister site DSLR Tips.

A good technical resource, which includes a depth of field calculator, is Understanding Depth of Field over at CambridgeInColour. I hope this helps.

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


Top
 Profile  
 
 Post subject:
PostPosted: Wed Apr 30, 2008 7:22 pm 
Thanks for the welcome, Bob. I have been shooting in AV mode-mostly. I've watched the videos and they have explained a lot. However, I'm still having issues getting all my subjects in focus. I usually use the center focus point and recompose or toggle. The hardest part I can't figure out is when I want both my kids in the shot and in focus. Always, one of them ends up being out of focus and that'll be at f4.0. I'm beginning to wonder if it's the camera or lens or something?


Top
  
 
 Post subject:
PostPosted: Wed Apr 30, 2008 7:51 pm 
Offline
Moderator
User avatar

Joined: Sat Sep 30, 2006 4:30 pm
Posts: 9815
Location: UK
.
Well, at f/4 with 50mm focal length and a focus distance of 4 metres the depth of field is about 1 metre. If you focus on one of the kids who is at 4 metres the other one only has to be a bit more than half a metre closer or farther away and you are out of the really sharp zone. For the same settings but with the focus distance of just 2 metres the depth of field is only around 60cm so focussing on one kid means the other has, ideally, to be less than 30cm closer or farther. If you must shoot at f/4 then you probably need to focus manually halfway between them or, if you are nimble enough, use AF but then recompose and move yourself forwards or back as appropriate half the distance between the kids. :?

Try shooting in Av mode at f/8 and, if the shutter speed gets too slow and you end up with motion blur, bumping up the ISO to compensate. You might end up have to do a little extra post-processing to reduce sensor noise but that is a better option than starting off with an out of focus subject.

Maybe maximising depth of field in family portraits where flash isn't an option might be a suitable topic for another of Gordon's DSLR Tips workshops?

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  

All words, images, videos and layout, copyright 2005-2012 Gordon Laing. May not be used without permission.
/ How we test / Best Cameras / Advertising / Camera reviews / Supporting Camera Labs

Webdesign by Alphabase IT
Powered by phpBB® Forum Software © phpBB Group