Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Thread Tools Search this Thread
Old Apr 27, 2005, 1:14 AM   #1
Senior Member
gwei's Avatar
Join Date: Apr 2005
Posts: 120

Camera: istDS

When I use manual focusing, I zoom up to the details of the object and manually focus to it. I then zoom back to compose the picture.

Is this operation correct? Somewhere inthe user manualgave me the impression that when you change zoom, the focus may change.

gwei is offline   Reply With Quote
Sponsored Links
Old Apr 27, 2005, 11:29 AM   #2
Senior Member
Catbells's Avatar
Join Date: Nov 2004
Posts: 874

Suggest that you try it4 ways -Auto Focus & Manual Focus at the composed shot & repeat at Full zoom then recomposing using the zoom on both Auto Focus & Manual Focus. Compare the results to see how they perform.

I would imagine that the focus should remain OK but there may be a slight change as the glass changes relative position within the lens during zooming.
Catbells is offline   Reply With Quote
Old Apr 27, 2005, 3:15 PM   #3
Senior Member
ennacac's Avatar
Join Date: Mar 2005
Posts: 4,198

I only find that necessary if I am using a fast lens like my 85mm 1.4 wide open since the depth of field is so shallow.

ennacac is offline   Reply With Quote
Old May 3, 2005, 10:00 PM   #4
Junior Member
Join Date: Mar 2005
Posts: 5

Seems to me that the focus may or may not change depending on the lens. My lenses seems to lose a little focus when I do what you suggested.

I do know that some lenses are designed as parafocal lenses and are designed to maintain their focus throughout the zoom range(the Tokina ATX Pro series touts this).

You'll need to try it out and if the results are good, then go with it.
geiim is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 5:03 PM.