Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-24-2009, 08:55 AM   #1
Junior Member




Join Date: Aug 2009
Photos: Gallery | Albums
Posts: 27
K7 Noise at ISO800

Hi All

(Ground rules first:
1. For all practical purposes this can be considered as my first post.
2. The K7 is my first DSLR - I know many will consider that ambitious (or even stupid)
3. I understand the fact that I have a lot to learn. I have a few books I'm busy working through, but thought I will also benefit from learning from other users.
4. I LOVE this camera - I havent used a SLR for many years and were instantly reminded of how satisfying it is to shoot with a decent camera that was clearly made for enthusiasts! I therefore acknowledge that most of my current problems is most probably down to me!)

Right, now on to ISO and noise.
This subject is fairly new to me as I have never before used a DSLR.
I restricted all my shooting with P&S to the lowest ISO.
However, the advantages of a higher ISO is very desirable and I started experimenting.

The following photo was taken at ISO800. (EXIF hopefully intact)

ISO 800 Sample - Flickr Page

ISO 800 Sample - Original Size
(This JPEG is straight from the camera)

I find the level of noise in the blue (sky) parts quite high.

Can anyone spot any obvious mistake I made here?
Is this level of noise to be expected?

I tried using Noise Ninja to reduse noise, but I lose so much IQ that I'm either using the program incorrectly, or the noise is just too much.

Any input will be greatly appreciated.

Regards CX

P.S.
I have not played too much with in-camera NR.
I have not shot using RAW yet.
I did not play around with Sharpness settings at all.


Last edited by CX15; 10-25-2009 at 05:11 AM.
10-24-2009, 10:19 AM   #2
Senior Member
chedoy's Avatar

Join Date: Dec 2006
Location: Chicago, IL
Posts: 143
Wow, I'm dismayed, but maybe it's the settings and exposure. I don't own a K-7, but I would look at the NR settings. If you're going to shoot in JPG, you probably want to have some in--camera NR turned on. How much is up to you.

This is based on what I do for my Olympus E510, which s a very noisy sucker. Turn the in-camera NR up higher for JPG shots. I assume it's not off right now? Or turn it off for higher ISO shooting and post process it out. Also, under-exposure really aggravates noise.

Most of the time, mild noise doesn't print anyway, and is not noticeable in a screen shot.

Here's a 100x crop from your flikr image, right side run thru Adobe Elements with Noiseware plug-in. It's not all that sharp on either side, being a hazy shot anyway.
Attached Images
 
10-24-2009, 04:47 PM   #3
Banned




Join Date: Jun 2009
Location: Massachusetts, USA
Photos: Gallery
Posts: 84
I don't get this fixation with "noise". Consider this, your sensor is much closer in size to a 110 film negative than it is to a 35mm neg. Would you expect "noiseless" results if you shot this on an 800 speed 110 cartridge??? It's been many, many moons but my guess is the results would be dismal, at best. Film grain was perfectly acceptable, but digital grain is not. I just don't get it!!
10-24-2009, 05:26 PM   #4
Junior Member




Join Date: Aug 2009
Photos: Gallery | Albums
Posts: 27
Original Poster
QuoteOriginally posted by billtin59 Quote
I don't get this fixation with "noise". Consider this, your sensor is much closer in size to a 110 film negative than it is to a 35mm neg. Would you expect "noiseless" results if you shot this on an 800 speed 110 cartridge??? It's been many, many moons but my guess is the results would be dismal, at best. Film grain was perfectly acceptable, but digital grain is not. I just don't get it!!
Here we go again...

This was a test shot in hazy conditions - I did not expect to get a perfect picture. The same shot was taken at lower ISO settings as well and produced much better results. Taking a picture of a mountain in ISO800 in bright sunlight is probably not standard practise anyway and I would definately not have tried it in the film days as you say.

The purpose of my original post was simple: It was in no way a complaint about noise!! It was simply a question to more experienced photographers to help me - i.e. can anyone spot an obvious mistake with my settings. I am trying to figure out how ISO works with this camera, that's all.
If this level of noise is normal for the conditions, then so be it - I am not expecting any miracles here...

QuoteQuote:
Turn the in-camera NR up higher for JPG shots. I assume it's not off right now? Or turn it off for higher ISO shooting and post process it out.
Good question. NR is set to Medium (Option 1, Item 19 in menu C3) and to start at ISO800 (Option 1, Item 20 in menu C3). However, Im not sure if the NR will start at ISO800 or only at ISO1600. The manual states that Item 20 sets the NR start ISO, but the camera states: "NR is activated when ISO sensitivity is set to higher than 800"

I will play around with that the in camera NR a bit more when I have time and see if I can produce different results.

QuoteQuote:
Also, under-exposure really aggravates noise
Looking at the histogram, I cannot see any glaring mistake here, but please correct me on this if I'm wrong...

QuoteQuote:
, being a hazy shot anyway
Can haze actually be mistaken for noise? It was fairly hazy on that day - I will upload an ISO200 shot of the same scene for comparison purposes...

ISO 200 Sample - Flickr Page

ISO 200 Sample - Original Size

-Thanks for the inputs so far-


Last edited by CX15; 10-25-2009 at 05:10 AM.
10-24-2009, 05:31 PM   #5
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,944
I don't know the K7, but I have heard that some of the sharpening that is done in-Jpeg increases noise significantly. The other thing that I have seen on the K20 bump noise is using the "enhanced dynamic range" feature. The other thing is that I probably wouldn't have used iso 800 in this setting. In bright daylight, you should be able to shoot iso 100-200, f8 and have a decent shutter speed.
10-24-2009, 10:31 PM   #6
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by CX15 Quote
a question to more experienced photographers to help me - i.e. can anyone spot an obvious mistake with my settings. I am trying to figure out how ISO works with this camera, that's all.
Flat areas of color like skies tend to show noise more than areas with texture or detail. And I've also heard that the blue channel tends to be noisier than the red or green. So that suggests a blue sky would be the worst place for noise.

As the previous poster said, also be sure not to be applying too much sharpening, or using the various noise-enhance modes like D-range.

QuoteQuote:
Can haze actually be mistaken for noise?
I suppose. Also seems that condensation and salt deposits on the front of the lens wouldn't help.
10-25-2009, 03:24 AM   #7
Junior Member




Join Date: Aug 2009
Photos: Gallery | Albums
Posts: 27
Original Poster
Thanks Marc & Rondec!

QuoteQuote:
As the previous poster said, also be sure not to be applying too much sharpening, or using the various noise-enhance modes like D-range.
Both D-Range Settings was on: Highlight correction and Shadow Correction to Med.

I will definately try shooting without them and see if there is any difference.
10-25-2009, 04:17 AM   #8
Inactive Account




Join Date: Oct 2007
Location: Brisbane, QLD, AUS
Posts: 3,262
I honestly can't tell difference...because the samples are so friggin' small.

I can tell the difference with the FOV, that's about it.

10-25-2009, 05:12 AM   #9
Junior Member




Join Date: Aug 2009
Photos: Gallery | Albums
Posts: 27
Original Poster
QuoteOriginally posted by lithos Quote
I honestly can't tell difference...because the samples are so friggin' small.

I can tell the difference with the FOV, that's about it.
Hi Lithos - I simplified the links provided to include a direct link to the original size pics.

Let me know if you still can't see them properly.
10-28-2009, 12:14 PM   #10
Junior Member




Join Date: Oct 2009
Location: Wash DC
Photos: Albums
Posts: 36
Any cropped sensor dslr is going to show noise at iso 800 in a shot like that. Theres no reason to be shooting at such a high iso there. You are probably so alarmed because the noise is so apparent, but I bet other camera brands would show similar amounts of noise.

The image with the blue sky is simply noise prone in general. Shoot iso 800 in a different setting and i'm pretty sure it won't be as bad.
10-28-2009, 01:22 PM   #11
Senior Moderator
Loyal Site Supporter
Parallax's Avatar

Join Date: Apr 2008
Location: South Dakota
Photos: Gallery
Posts: 15,103
Just to put things in perspective:

With a K-7, or in my case K20D we are starting with a sensor 23.5mm across. A typical 22" widescreen monitor is 475mm across and 1680 pixels. My monitor would have to be 1320mm wide to display the the 23.5mm 4668px wide image at "actual pixel" resolution (or what I call PPV; Pixel Peep View ). That gives an enlargement of roughly 56x (1320/23.5=56.17). If I shot a picture on Tri-X, or even Plus-X and printed the FF film image as a 56"x37" print I might expect to see just a wee bit of grain.

Last edited by Parallax; 10-29-2009 at 06:56 AM.
10-28-2009, 03:10 PM   #12
Pentaxian
emalvick's Avatar

Join Date: Feb 2008
Location: Davis, CA
Photos: Gallery
Posts: 1,466
Given the brightness of the day, the shot does seem a bit noisy, but there are a couple of points I'll re-emphasize from others as well as suggestions.

The blue channel does tend to be noisier than others. I still only have the K10d, and I can often find even ISO 200 shots to be noisy in the sky if I'm not careful. I shoot raw, so I avoid any camera noise removal.

When I do have some noise, I tend to utilize Noiseware. Given that noise tends to show up in the sky the most in my shots (I often darken shadows so that noise is often less of a distraction), I will often mask my noise reduced layer so that the noise reduction on the sky is in view but the remainder of the image has not been noise reduced (i.e. the detailed zones). I can essentially pick and choose with a decent mask where detail is saved and noise reduction is important.
10-29-2009, 03:50 AM   #13
Veteran Member
StarDust's Avatar

Join Date: Apr 2008
Location: Uppsala, Sweden
Posts: 400
QuoteOriginally posted by Marc Sabatella Quote
Flat areas of color like skies tend to show noise more than areas with texture or detail. And I've also heard that the blue channel tends to be noisier than the red or green. So that suggests a blue sky would be the worst place for noise.
I sure miss those summer green skies.
(I just couldn't resist).
10-29-2009, 11:09 AM   #14
Veteran Member
Jasvox's Avatar

Join Date: Oct 2007
Location: Melbourne, Australia
Posts: 3,110
Why would you shoot this at ISO 800 anyway? Bright sunny day, stationary objects except for waves which will be no problem since your speeds should be more than fast enough to freeze them at ISO 100.

Jason
10-29-2009, 12:14 PM   #15
Junior Member




Join Date: Aug 2009
Photos: Gallery | Albums
Posts: 27
Original Poster
QuoteQuote:
Why would you shoot this at ISO 800 anyway? Bright sunny day, stationary objects except for waves which will be no problem since your speeds should be more than fast enough to freeze them at ISO 100.

Jason
As I mention in my second post: This picture was taken at these settings purely as a TEST. I was playing around with the different ISO settings to see what the results will look like.

The reason for my post is: To find out if the amount of noise is to be expected with settings like that, or if I made an obvious mistake.

As some posters suggest (thanks mtags24 & emalvick) this is actually normal for any dslr with these settings.
So it actually comes as a relief!!
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, iso800, k7, k7 noise, level, noise, pentax help, photography, sample
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K20D @ 300mm ISO800 vulcanman Pentax SLR Lens Discussion 12 07-24-2010 07:54 AM
So horrible at ISO800 henryjing Pentax DSLR Discussion 42 04-17-2010 10:26 AM
Fish-eye in flight and ISO800 and more MightyMike Post Your Photos! 14 03-13-2009 03:26 PM
Watch Macro with K20 and ISO800 palmor Post Your Photos! 0 06-13-2008 08:13 AM
K200D vs *ist DS at ISO800 ogl Pentax DSLR Discussion 7 04-26-2008 09:13 AM



All times are GMT -7. The time now is 05:20 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