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

Reply
 
Thread Tools Search this Thread
Old Aug 13, 2006, 4:25 PM   #21
Senior Member
 
bilybianca's Avatar
 
Join Date: Nov 2005
Location: Hassleholm, Sweden
Posts: 3,435
Default

nlp239 wrote:
Quote:
Anyhow, would the image below describe what we're saying?

Yeah, it's all clear to you now!

Kjell
bilybianca is offline   Reply With Quote
Old Aug 14, 2006, 7:27 AM   #22
Senior Member
 
nlp239's Avatar
 
Join Date: Jan 2005
Posts: 719
Default

Thanks for ALL the PATIENCE.
nlp239 is offline   Reply With Quote
Old Aug 14, 2006, 8:14 AM   #23
Senior Member
 
Monza76's Avatar
 
Join Date: Jul 2004
Posts: 4,095
Default

nlp239, one more comment, you keep referring to a crop factor of 1.6, for the Pentax it is more like 1.5. Canon uses a slightly smaller sensor which is why their cameras have a 1.6X factor, Pentax Nikon and I believe Sony use a sensor with a slightly larger area to give a 1.5X factor.

The diagram you used is perfect because it shows exactly what happens, if the whole picture represents a 35mm frame the red box defines the digital sensor size, so it only "sees" what is inside the box. Therefore lenses have a narrower field of view when used on the small sensor camera.

A"normal" lens for Pentax dSLR would be about 33mm, a normal for 35mm film would be about 50mm and a normal for square medium format is about 80mm. The rule of thumb is that a lens with a focal length equal to the diagonal of the image frame will give a view most like normal vision, thus a normal lens. For 35mm film the frame is 24mm by 36mm so the diagonal is about 43mm, how that grew to a 50mm standard I am not certain, for a while 55mm was all the rage.

Ira
Monza76 is offline   Reply With Quote
Old Aug 14, 2006, 8:48 AM   #24
Senior Member
 
nlp239's Avatar
 
Join Date: Jan 2005
Posts: 719
Default

Thanks Ira, I stand corrected - I was under the incorrect impression.
nlp239 is offline   Reply With Quote
 
Reply


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 11:33 PM.