Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-16-2010, 06:54 AM   #1
Veteran Member




Join Date: May 2009
Location: North Carolina
Photos: Albums
Posts: 612
K7 Native ISO

Anyone know the native ISO of the K7? It isn't necessarily the lowest ISO in the menu. Is it 100 or 200?

01-16-2010, 07:18 AM   #2
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,962
It is 100, the same as the K20. The Kx on the other hand has a base iso of 200 -- expandable to 100.
01-16-2010, 08:57 AM   #3
Veteran Member
Raybo's Avatar

Join Date: Dec 2007
Posts: 871
IIRC it's iso 200, iso 100 is firmware based.
01-16-2010, 09:13 AM   #4
Senior Member




Join Date: Sep 2007
Location: Colorado
Posts: 173
If you look at the dp review, the K-7 has better DR at ISO 100 than 200, whereas the K-x has better DR at ISO 200 than 100. It isn't definitive, but it seems to indicate that the K-7's base ISO is 100.

01-16-2010, 09:26 AM   #5
Veteran Member
Raybo's Avatar

Join Date: Dec 2007
Posts: 871
QuoteOriginally posted by Kirivon Quote
If you look at the dp review, the K-7 has better DR at ISO 100 than 200, whereas the K-x has better DR at ISO 200 than 100. It isn't definitive, but it seems to indicate that the K-7's base ISO is 100.
Here's a quote from DP when they did the K20 review, i'm guessing it also has to apply to the K-7.

"Enabling D-Range doesn't appear to change the exposure yet is only available from ISO 200 upwards which suggests the sensor's native sensitivity may be ISO 200, hence offering slightly improved dynamic range at that setting."
01-16-2010, 09:28 AM   #6
Veteran Member
pcarfan's Avatar

Join Date: Sep 2007
Location: Dayton, Ohio
Photos: Gallery | Albums
Posts: 2,958
Native iso is 100 for the K-7
01-16-2010, 09:31 AM   #7
Veteran Member
pcarfan's Avatar

Join Date: Sep 2007
Location: Dayton, Ohio
Photos: Gallery | Albums
Posts: 2,958
QuoteOriginally posted by Raybo Quote
Here's a quote from DP when they did the K20 review, i'm guessing it also has to apply to the K-7.

"Enabling D-Range doesn't appear to change the exposure yet is only available from ISO 200 upwards which suggests the sensor's native sensitivity may be ISO 200, hence offering slightly improved dynamic range at that setting."
DPR got that assumption wrong. The only reason the k-7 limits the iso to 200 with extended dynamic range, is with that option the image is actually taken with 1-stop less iso than what you set in the camera. So, if you choose iso1600 and take a shots with extended dynamic range, then the shot is actually taken at iso800. So, the minimum iso for this feature has to be 1-stop higher than the lowest iso possible, and has nothing to do with native iso. this was studied and explained by Gordon Good in DPR.

Hope this helps.
01-16-2010, 09:38 AM   #8
Veteran Member
Raybo's Avatar

Join Date: Dec 2007
Posts: 871
QuoteOriginally posted by pcarfan Quote
DPR got that assumption wrong. The only reason the k-7 limits the iso to 200 with extended dynamic range, is with that option the image is actually taken with 1-stop less iso than what you set in the camera. So, if you choose iso1600 and take a shots with extended dynamic range, then the shot is actually taken at iso800. So, the minimum iso for this feature has to be 1-stop higher than the lowest iso possible, and has nothing to do with native iso. this was studied and explained by Gordon Good in DPR.

Hope this helps.
Now I know!
Thanks for the info pcarfan.

01-16-2010, 10:28 AM   #9
Veteran Member
blende8's Avatar

Join Date: Feb 2007
Location: Bremen, Germany
Photos: Albums
Posts: 1,484
DXO mark writes that the lowest ISO of the K7 (100) equals about real ISO 85.

K7
01-16-2010, 04:13 PM   #10
Veteran Member
jeffkrol's Avatar

Join Date: Sep 2006
Location: Wisconsin USA
Photos: Gallery
Posts: 8,434
QuoteOriginally posted by Kirivon Quote
If you look at the dp review, the K-7 has better DR at ISO 100 than 200, whereas the K-x has better DR at ISO 200 than 100. It isn't definitive, but it seems to indicate that the K-7's base ISO is 100.
One of the definitions of base iso is the one with the most dynamic range... so yes it can be "definitive". That said most cameras will not fulfill this exactly at the iso notches presented. It may be 123 or 237 ect...
Of course all this is subject to interpretation like iso itself....... The wiki article is quite good...
Film speed - Wikipedia, the free encyclopedia
The ISO standard 12232:2006[14] gives digital still camera manufacturers a choice of five different techniques for determining the exposure index rating at each sensitivity setting provided by a particular camera model. Three of the techniques in ISO 12232:2006 are carried over from the 1998 version of the standard, while two new techniques allowing for measurement of JPEG output files are introduced from CIPA DC-004...................
The saturation-based technique is closely related to the SOS technique, with the sRGB output level being measured at 100% white rather than 18% gray. The saturation-based value is effectively 0.704 times the SOS value.[17] Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically TIFF—and not to output files in raw image format. It is not applicable when multi-zone metering is used.
....................
Despite these detailed standard definitions, cameras typically do not clearly indicate whether the user "ISO" setting refers to the noise-based speed, saturation-based speed, or the specified output sensitivity, or even some made-up number for marketing purposes. Because the 1998 version of ISO 12232 did not permit measurement of camera output that had lossy compression, it was not possible to correctly apply any of those measurements to cameras that did not produce sRGB files in an uncompressed format such as TIFF. Following the publication of CIPA DC-004 in 2006, Japanese manufacturers of digital still cameras are required to specify whether a sensitivity rating is REI or SOS.[citation needed]
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, iso, k7, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Macro Black Native Bee............. eaglem Post Your Photos! 2 10-22-2010 04:12 PM
Macro Black Native Bee eaglem Post Your Photos! 2 08-20-2010 07:34 AM
Show your native places Mindaugas Post Your Photos! 15 07-29-2009 06:07 PM
Native ISO of the 14.6 MP CMOS Sensor (with !shocking! attempt to lighten mood!) solar1 Pentax DSLR Discussion 22 01-27-2008 06:15 PM
Native ISO in the K10D Michael Rothman Pentax DSLR Discussion 5 01-11-2007 05:44 AM



All times are GMT -7. The time now is 09:21 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top