Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-24-2010, 02:49 PM   #31
Loyal Site Supporter
imtheguy's Avatar

Join Date: Mar 2009
Location: Virginia Beach
Photos: Gallery | Albums
Posts: 2,950
QuoteOriginally posted by dlacouture Quote
Well, on the DxO site, there is an explanation to this. In fact, it can be found by using some mathematical models analyzing the noise... Cannot explain more, but that was a really interesting reading.

Here it is : DxO - Noise reduction
Thanks for posting that link. It filled in a number of gaps in my understanding. I used to be a DxO customer and never knew of all those short lessons they post.

03-24-2010, 03:04 PM   #32
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
FWIW, I *do* prefer restricting my ISO choices to just full stops. Anything less than that I don't mind finessing with shutter speed or aperture or just adjusting in PP. I just got tired it taking so many clicks to get from, say, ISO 200 to ISO 800.
03-24-2010, 03:10 PM   #33
Veteran Member
GoremanX's Avatar

Join Date: Dec 2009
Location: Georgia, VT
Photos: Albums
Posts: 1,653
QuoteOriginally posted by Marc Sabatella Quote
FWIW, I *do* prefer restricting my ISO choices to just full stops. Anything less than that I don't mind finessing with shutter speed or aperture or just adjusting in PP. I just got tired it taking so many clicks to get from, say, ISO 200 to ISO 800.
I can flick through the dial so quick to go from 200 to 800, it doesn't typically bug me. But the real reason why I really like having those extra ISO steps is that I don't mind my K-7's performance at ISO 2500. I've found many pictures at that sensitivity to be perfectly usable. But most pictures I take at ISO 3200 turn out like crap. So being able to select ISO 2500 gives me an extra 2/3 EV of low-light usability that I wouldn't otherwise have.
03-24-2010, 05:06 PM   #34
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,216
QuoteOriginally posted by GoremanX Quote
You wouldn't have noticed, the "full" ISO steps stay the same regardless of whether you're using 1/2 or 1/3 steps. The series of ISO sensitivities goes like this:

In 1/3 EV steps:
100 - 125 - 160 - 200 - 250 - 320 - 400 - 500 - 640 - 800 - 1000 - 1250 - 1600 - 2000 - 2500 - 3200 - 4000 - 5000 - 6400

In 1/2 EV steps:
100 - 140 - 200 - 280 - 400 - 560 - 800 - 1100 - 1600 - 2200 - 3200 - 4500 - 6400

(the full ISO steps are bolded)
I know--that's what freaked me out.

That that "little" setting in sensitivity, two choices, opens up all of the options if you choose the correct one.

I still have it set for 1/2 stops, because enough's enough.

03-24-2010, 05:53 PM   #35
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,256
QuoteOriginally posted by GoremanX Quote
Honestly, I'm not sure how we can confirm or deny this claim. Since there's no way to have a RAW file at ISO 3200 that doesn't have noise reduction, we have nothing to compare it to. I'm sure there's some technical reason why GordonBGood made that claim, but I'm not aware what it is.
Yeah ... this is somewhat confusing. I always shoot in RAW, so what exactly should I set this K7 at for making it behave better at high ISO? I try to be cautious with exposure, even try to expose a bit more "to the right" when in RAW mode. Should I also set the threshold at ISO800 and forget about everything else?
Frankly, I also try not to go higher than ISO640-800 most of the time, unless I am in a bind and must use higher settings.



Your keyboard is set to English/US. The question mark is found at the bottom-right, where the é key is. You need to hold shift while pressing that key. (consequently, you've lost the é key). Switch back to a French/CA keyboard layout to put the keys back where they belong.
Oh! I didn't notice that I could have, inadvertently, switched to a different keyboard layout! This only happens when I am using the laptop instead of this PC here.
Thanks for the advice.
03-24-2010, 06:02 PM   #36
Veteran Member
GoremanX's Avatar

Join Date: Dec 2009
Location: Georgia, VT
Photos: Albums
Posts: 1,653
QuoteOriginally posted by jpzk Quote
Yeah ... this is somewhat confusing. I always shoot in RAW, so what exactly should I set this K7 at for making it behave better at high ISO? I try to be cautious with exposure, even try to expose a bit more "to the right" when in RAW mode. Should I also set the threshold at ISO800 and forget about everything else?
Frankly, I also try not to go higher than ISO640-800 most of the time, unless I am in a bind and must use higher settings.
If you shoot in RAW, then you have no control over noise reduction. The settings in the Custom Function menu are for JPG output only. When it comes to RAW, there is no noise reduction applied by the camera, except apparently at ISO 3200 and above (if GordonBGood is to be believed). I'm sure the noise reduction applied at these sensitivity settings is minimal anyways, I wouldn't worry about it. And in any case, you have no control over it.
03-24-2010, 06:16 PM   #37
Site Supporter




Join Date: Jan 2008
Location: NC
Posts: 787
Original Poster
K7 jpg's w/ LR 3.0

i did a few quick tests w/ LR 3.0 NR. i'm impressed.

all at iso3200 jpg straight out of camera. NR medium

original


+2/3 EV


+2/3 EV w/ NR 25 luminance and color


for comparison kx at 3200 no NR


100% crops

orig


2/3


+2/3EV nr




--
'when 900 years you reach, look as good you will not'
-- master yoda

Zenfolio | Jordan Paw Image Arts

Last edited by opiedog; 03-24-2010 at 06:40 PM.
03-24-2010, 07:43 PM   #38
Site Supporter
jpzk's Avatar

Join Date: Jan 2009
Location: Québec
Photos: Gallery | Albums
Posts: 7,256
QuoteOriginally posted by GoremanX Quote
If you shoot in RAW, then you have no control over noise reduction. The settings in the Custom Function menu are for JPG output only. When it comes to RAW, there is no noise reduction applied by the camera, except apparently at ISO 3200 and above (if GordonBGood is to be believed). I'm sure the noise reduction applied at these sensitivity settings is minimal anyways, I wouldn't worry about it. And in any case, you have no control over it.
Thanks, Frank.

That settles the issue at hand, for me.
Nice to know that I don't have to fiddle with more settings; I like to take pics, not so much like to play computer with my cameras.

JP

03-25-2010, 05:00 AM   #39
Senior Member




Join Date: Aug 2007
Location: Perth, Australia
Posts: 268
Hi, I saw another poster from another forum sharing his settings to obtain a "low noise" JPEG.
Can the k7 handle the noise ??? - Photo.net Pentax Forum

I've tried, and it really works!! The only downside is that I get a lot more highlight clippings, which also mentioned by the OP. Enable Highlight Correction helps. Maybe with a bit more tweaking,we can really get some low noise picture.

Anyway, the settings I've applied are:
1. Selected Bright Mode
2. High/Low Key Adj - All the way to the left
3. Contrast Shadow Adj - All the way to the left
4. Fine Sharpness 2 - All the way to the left
5. In Camera NR - Low
6. EV +1

I find if I left sharpness defaulted at +1, the picture is a bit soft, but lower perceived noise. If I use Fine Sharpness, the picture appears sharper, but more noise, so I tone it down by using the minimum FS2 settings.

What not have a go and see what you get?

Mike

Last edited by mcjm78; 03-25-2010 at 06:41 AM.
03-25-2010, 10:40 AM   #40
Site Supporter




Join Date: Jan 2008
Location: NC
Posts: 787
Original Poster
thanks for the link, mike. i'm going to try these settings.
in the mean time...
i did a little test using his sample + LR3 b2.

that's pretty impressive for iso6400, me thinks

03-27-2010, 02:29 AM   #41
Senior Member




Join Date: Aug 2007
Location: Perth, Australia
Posts: 268
My Tests

Ok.. I spend a bit of time today to test the different between the default Bright mode settings to Ian's settings.

Camera NR is set to Low.
The default bright mode setting is using normal sharpness.
Ian's settings only changes the High/Low Key Adj, Contrast Shadow Adj and EV +1

The original scene using default bright mode iso 800


The 100% comparison of the 4 photos from ISO 800 to ISO 1600.
Top Left - ISO 800 Default
Top Right - ISO 1600 Default
Bottom Left - ISO 800 Ian
Bottom Right - ISO 1600 Ian



As you can see, in the default settings, the grain size is apparent even under the reduced size. Ian's method basically produces jpeg thats a lot smoother with tighter grains. The sharpness is reduced using Ian's method, hence I've opt to fine sharpness 2 with -4 setting to give a "sharper" picture.
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, contrast, dslr, iso, k7, noise, photography, settings, sharpness
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
High Noise at Low ISO? JGB Troubleshooting and Beginner Help 19 11-11-2010 07:39 PM
K-x high-ISO noise reduction: use it or do it in PP instead? richardm Troubleshooting and Beginner Help 5 10-28-2010 08:45 AM
K7 high iso noise comparison cyy47 Pentax DSLR Discussion 24 08-02-2010 02:19 AM
More to KX high ISO than low noise telfish Pentax DSLR Discussion 1 02-11-2010 02:22 PM
K20D - High ISO Noise Reduction - How? How much? When? ksignorini Pentax DSLR Discussion 4 04-13-2008 01:14 PM



All times are GMT -7. The time now is 09:30 PM. | See also: NikonForums.com, CanonForums.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