Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Jan 28, 2010, 1:25 PM   #1
Senior Member
 
Eetu's Avatar
 
Join Date: Jan 2010
Location: Jyväskylä, Finland
Posts: 2,212
Default What happened to the low ASA's / ISO's

Hi all! Say, does anyone have an idea of what today's DSLR's begin with 100 ISO/ASA instead of the lower ASA's/ISO's on film cameras. I remember taking Kodachrome slides with 25 and 64 ASA... Just curious... Thanks for whatever answers you might provide or suggest.

Take care and all the best.

Ned Brockwell
Jyväskylä, Finland
Eetu is offline   Reply With Quote
Sponsored Links
Old Jan 28, 2010, 2:38 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Sensors have a base ISO Sensitivity, and you have to amplify the signal for more sensitivity to light at you increase ISO speed (and this amplification can increase noise levels). So, you tend to see sensors for dSLR models starting out at around ISO 100 or ISO 200 now in order to allow better results at higher ISO speeds (which is what most users are going to want in order to achieve faster shutter speeds for a given lighting level and aperture).

But, you could use a Neutral Density Filter to reduce the light seen by the camera if you have a need for slower shutter speeds than you're getting at a camera's base ISO speed and don't want to close your aperture down anymore than necessary for whatever reason (diffraction, wanting a shallower depth of field, etc.). For most types of images, faster shutter speeds are more desirable (so higher ISO speeds are better for that purpose).
JimC is offline   Reply With Quote
Old Jan 28, 2010, 2:59 PM   #3
Senior Member
 
Eetu's Avatar
 
Join Date: Jan 2010
Location: Jyväskylä, Finland
Posts: 2,212
Default

Hi Jim,

Hey, thanks for your reply and kind answer, indeed. I understand that now. And thanks for your words on a neutral density filter. Good to know.

All the best.

Ned Brockwell
Jyväskylä, Finland
Eetu 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 6:38 AM.