Go Back   Steve's Digicams Forums >

LinkBack Thread Tools Search this Thread
Old Jun 17, 2006, 12:17 AM   #1
Senior Member
Log's Avatar
Join Date: Feb 2006
Posts: 394

just going through reviews and whatnot... i found something about ISO and dont understand what they mean? it says "Sensitivity:100 to 800 (ISO equivalent); HI-0.3, HI-0.5, HI-0.7, HI-1 and HI-2 available" what does the
HI-0.3, HI-0.5, HI-0.7, HI-1 and HI-2 available

no big deal just curious.

thanks in advance

Log is offline   Reply With Quote
Sponsored Links
Old Jun 17, 2006, 1:04 AM   #2
Senior Member
rey's Avatar
Join Date: Oct 2005
Posts: 949

I never noticed it before, so I got curious. But it looks like "HI-1" is set to high ISO (1600 or 3200, depending on the camera), probably just to make it clear to "EXPECT NOISE! I HOPE YOU KNOW WHAT YOU'RE DOING! MAY GOD HELP YOU!" (or something like that)

HI-2 is one full stop above Hi-1. while the decimal values are a fraction (1/3 or so) stops below HI-1.

Just my conclusions from what I've gathered.

rey is offline   Reply With Quote
Old Jun 17, 2006, 8:00 AM   #3
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378

Digital Camera Sensors are analog devices. When light hits the photosites on a sensor, they generate a signal.

When you increase ISO speed, the camera is amplifying that analog signal, prior to the analog to digital converter in most cases.

But, for "Extended" ISO modes (or "ISO Boost" modes), what tends to happen is that the values generated by the photosites are multiplied after the Analog to Digital Converter (they only amplify them so far prior to that). ISO 3200 is an "Extended" mode in most models that have it available.

In some models (for example, the Nikon D200), the Extended ISO speeds can be increased in smaller increments, so that you don't need to go straight from 1600 to 3200. D200 ISO speeds:

HI 0.3 = ISO 2000
HI 0.5 = ISO 2200
HI 0.7 = ISO 2500
HI 1.0 = ISO 3200

JimC 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 On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 6:04 AM.