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Forum: General Discussion Sep 8, 2010, 8:15 AM
Replies: 59
Views: 5,691
Posted By JohnG
Another quote from you Brian: I point...

Another quote from you Brian:


I point this out only because you are so adamant earlier. This is photo manipulation now - so is DOF locked in at the time the shot is taken or can it be altered...
Forum: General Discussion Sep 8, 2010, 8:13 AM
Replies: 59
Views: 5,691
Posted By JohnG
Brian - you said earlier: This method...

Brian - you said earlier:


This method simply puts multiple photos together - like a panorama. It's editing photos after the fact. Which is it Brian - is DOF locked in when the photo is snapped...
Forum: General Discussion Sep 2, 2010, 10:26 AM
Replies: 59
Views: 5,691
Posted By JohnG
TCAV - I submit we will never agree because I...

TCAV - I submit we will never agree because I believe we are using two fundamentally different definitions of what DOF is. It is my belief you are using a definition espoused on the DOF master page:...
Forum: General Discussion Sep 2, 2010, 9:33 AM
Replies: 59
Views: 5,691
Posted By JohnG
By the way, the first and second shot also help...

By the way, the first and second shot also help illustrate the concept of sensor size and it's affect on DOF. Whether the 'crop' happens because the recording media is smaller or because you crop...
Forum: General Discussion Sep 2, 2010, 9:24 AM
Replies: 59
Views: 5,691
Posted By JohnG
Let us look again at the definition of depth of...

Let us look again at the definition of depth of field:


By definition, perception is part of it. If I perceive something as in focus and then step forward and now perceive it as not in focus,...
Forum: General Discussion Sep 2, 2010, 9:19 AM
Replies: 59
Views: 5,691
Posted By JohnG
oh and when the crop image is displayed and I...

oh and when the crop image is displayed and I move back 20 feet the 5 & 6 look the same. depth of field has changed.
Forum: General Discussion Sep 2, 2010, 9:17 AM
Replies: 59
Views: 5,691
Posted By JohnG
TCAV - I believe this shows exactly what we are...

TCAV - I believe this shows exactly what we are talking about. The 1st and 2nd photo came from the same image. In the first photo, the '5' and '6' mark on the ruler appear about the same when I...
Forum: General Discussion Sep 2, 2010, 9:02 AM
Replies: 59
Views: 5,691
Posted By JohnG
tclune - I submit you mistake what the DOF...

tclune - I submit you mistake what the DOF calculations do. They are not calculating a scientific fact. It isn't like calculating velocity. They are attempting to model a subjective phenomenon...
Forum: General Discussion Sep 2, 2010, 8:50 AM
Replies: 59
Views: 5,691
Posted By JohnG
Actually TCAV, the DOF calculations are based on...

Actually TCAV, the DOF calculations are based on some ASSUMPTIONS as the article Craig listed points out. There are assumptions about image size and viewing distance. What the DOF calculator is...
Forum: General Discussion Sep 2, 2010, 6:55 AM
Replies: 59
Views: 5,691
Posted By JohnG
exactly - you have to remember, it's about how a...

exactly - you have to remember, it's about how a person PERCEIVES something to be sharp or not. And remember, it's not like anyone is saying you're going to dramatically change what is considered in...
Forum: General Discussion Sep 1, 2010, 1:27 PM
Replies: 59
Views: 5,691
Posted By JohnG
I'll play along - my understandings mimic Mark's....

I'll play along - my understandings mimic Mark's. Which is also why I think there was disagreement between the parties in the other thread. Here is my understanding:
Given same distance, focal...
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