snubbr.com

Resolving the 'triangulation' issue when center focusing.
I typically like to center focus w/ my DSLR, and then adjust the frame accordingly. However, I'm (re)discovering the depending on the distance you are to the subject, that slight movement could cause your subject that you locked in on to become no longer in focus, as you've re-directed the camera likely with turning your hips and not moving your legs..

Other than trying to move laterally to stay parallel with the subject (if you're close enough to begin with for this to help you re-frame), what other options are there?.

I'd love to hear any thoughts on this subject..

Thanks!..

Comments (5)

I don't think there's a 100% solution to this..

The biggest error, as you point out, comes from moving the camera, and most of that comes not from rotating as such, but from rotating about the wrong place - often the spine of course. The trick is to rotate around the entrance pupil of the lens, which is generally somewhere near the middle of the lens or a little forward of that. For instructions on finding it exactly, google for tips on panoramic photography, because it is the same point that eliminates parallax error. In practice this is not really necessary, though, as anywhere around the middle of the lens is likely to be close enough..

Then there's the smaller error you referred to in your subject line. This is partly compensated for by a weakness in most lens designs. Although they should be 'flat field', which would create a perfect triangle, in practice the field is usually a little curved which reduces the focusing error..

Finally, some people claim to have acquired the knack of leaning back ever so slightly as they rotate, to compensate for the remaining slight back-focus. I suppose if you are (for example) taking studio portraits using the same set up day after day it becomes predictable enough to do that sort of thing..

If you do all that and it's still not good enough, I think you will need to manual focus...

Comment #1

Why not move the focusing point in the viewfinder to the left or right off center?..

Comment #2

That would often do it but sometimes the subject, say a energetic 4y old boy isn't sitting still long enough and I'm just happy to get him in the frame... .

My current camera:http://www.amazon.com/exec/obidos/ASIN/B000V5P90K/02-4686-20Some of my pix:http://haroldandpod.com/p826419914/..

Comment #3

Generations of photographers happily focused and recomposed. But about a decade ago "bokeh" became all the rage, and suddenly flocks of amateurs are having trouble with recomposing..

One easy solution is to forget the "bokeh" stuff and stop down enough that the shift in subject distance isn't an issue. Take a look at the work of pro photogs in magazines and the like. Aside from long-lens paparazzi shots where small depth of field is unavoidable but recomposing doesn't significantly affect subject distance, you won't see many shots with limited depth of field..

Another easy solution is to not recompose. Instead, shoot a bit wider and crop to the desired composition..

As mf999 already noted, another approach is to use an appropriate AF point to reduce or eliminate recomposing...

Comment #4

Doug Pardee wrote:.

Generations of photographers happily focused and recomposed. Butabout a decade ago "bokeh" became all the rage, and suddenly flocksof amateurs are having trouble with recomposing..

One easy solution is to forget the "bokeh" stuff and stop down enoughthat the shift in subject distance isn't an issue. Take a look at thework of pro photogs in magazines and the like. Aside from long-lenspaparazzi shots where small depth of field is unavoidable butrecomposing doesn't significantly affect subject distance, you won'tsee many shots with limited depth of field..

Another easy solution is to not recompose. Instead, shoot a bit widerand crop to the desired composition..

As mf999 already noted, another approach is to use an appropriate AFpoint to reduce or eliminate recomposing..

Yes to all of that. In a sense I answered the wrong question, even though it was the one that was asked!..

Comment #5

Click Here to View All...

Sponsored Amazon Deals:

1. Get big savings on Amazon warehouse deals.
2. Save up to 70% on Amazon Products.


This question was taken from a support group/message board and re-posted here so others can learn from it.

 

Categories: Home | Diet & Weight Management | Vitamins & Supplements | Herbs & Cleansing |

Sexual Health | Medifast Support | Nutrisystem Support | Medifast Questions |

Web Hosting | Web Hosts | Website Hosting | Hosting |

Web Hosting | GoDaddy | Digital Cameras | Best WebHosts |

Web Hosting FAQ | Web Hosts FAQ | Hosting FAQ | Hosting Group |

Hosting Questions | Camera Tips | Best Cameras To Buy | Best Cameras This Year |

Camera Q-A | Digital Cameras Q-A | Camera Forum | Nov 2010 - Cameras |

Oct 2010 - Cameras | Oct 2010 - DSLRs | Oct 2010 - Camera Tips | Sep 2010 - Cameras |

Sep 2010 - DSLRS | Sep 2010 - Camera Tips | Aug 2010 - Cameras | Aug 2010 - DSLR Tips |

Aug 2010 - Camera Tips | July 2010 - Cameras | July 2010 - Nikon Cameras | July 2010 - Canon Cameras |

July 2010 - Pentax Cameras | Medifast Recipes | Medifast Recipes Tips | Medifast Recipes Strategies |

Medifast Recipes Experiences | Medifast Recipes Group | Medifast Recipes Forum | Medifast Support Strategies |

Medifast Support Experiences |

 

(C) Copyright 2010 All rights reserved.