Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon Lenses

Reply
 
Thread Tools Search this Thread
Old Apr 4, 2005, 10:03 AM   #1
Senior Member
 
matthew2000tx's Avatar
 
Join Date: Mar 2005
Posts: 1,451
Default

With the EF-S lenses do you still have to use the 1.6X factor with the 20D or if a EF-s says 20mm then it is 20 mm???
matthew2000tx is offline   Reply With Quote
Sponsored Links
Old Apr 4, 2005, 10:24 AM   #2
Moderator
 
Join Date: Aug 2004
Posts: 8,529
Default

You still use 1.6x for the conversion factor.
JohnG is offline   Reply With Quote
Old Apr 4, 2005, 8:46 PM   #3
Member
 
Join Date: Apr 2005
Posts: 52
Default

You still apply the crop factor. The digital lenses reduce the image circle by cropping, not by reducing the magnification.
Humrme is offline   Reply With Quote
Old Apr 5, 2005, 10:28 PM   #4
Senior Member
 
matthew2000tx's Avatar
 
Join Date: Mar 2005
Posts: 1,451
Default

So if I buy a 20mm EF-s Lens will it appear the same as a 20mm lens on a 35mm SLR. will it be just as wide??
matthew2000tx is offline   Reply With Quote
Old Apr 5, 2005, 11:23 PM   #5
Junior Member
 
Join Date: Apr 2005
Posts: 12
Default

A 20mm EF-S lens (say for your 20D) will functionally serve similarly as a 32mm focal length on a standard 35mm film camera.

20 x 1.6 = 32

However, keep in mind that you are NOT getting a longer focal length and you are not "zoomed in closer" - the sensor is smaller and simply recording less of the overall "image" as compared to what a 35mm film camera would capture.

In other words... It is still a 20mm lens... you have an increase in the perceived focal length by using the 20mm on a DSLR rather than a Film SLR. (It's simply a 20mm lens on a digital sensor that is smaller than the equivalent technology used in a standard 35mm film camera. )

Does that make more sense than all the tech talk?

Just take a few steps backwards and you will never notice the difference.


CDesperado is offline   Reply With Quote
Old Apr 6, 2005, 3:05 AM   #6
Super Moderator
 
peripatetic's Avatar
 
Join Date: Nov 2004
Posts: 3,599
Default

CDesperado wrote:
Quote:
A 20mm EF-S lens (say for your 20D) will functionally serve similarly as a 32mm focal length on a standard 35mm film camera.

20 x 1.6 = 32

However, keep in mind that you are NOT getting a longer focal length and you are not "zoomed in closer" - the sensor is smaller and simply recording less of the overall "image" as compared to what a 35mm film camera would capture.

In other words... It is still a 20mm lens... you have an increase in the perceived focal length by using the 20mm on a DSLR rather than a Film SLR. (It's simply a 20mm lens on a digital sensor that is smaller than the equivalent technology used in a standard 35mm film camera. )
True, but the implications of all of that are not particularly obvious.

http://www.stevesforums.com/forums/v...25&forum_id=65

http://www.photo.net/learn/optics/dofdigital/

For most purposes there's little harm in simply multiplying by 1.6 to get the 35mm equivalent and leave it at that.

With the proliferation of different sensor sizes I'm actually in favour of starting a movement whereby we quote the angle-of-view of the lens instead of the focal length.
peripatetic 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 11:58 AM.