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05-22-2010, 04:06 PM   #16
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I thank all of you for your responses. It seemed like a case of underexposure. I've looked through other of my photos and there are always noise in the black, purple and dark blue areas....but I thought it shouldn't happen at lowest ISO?

Nonetheless, I will do a EV+1 and test out further.

05-22-2010, 05:42 PM   #17
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Just FYI and FWIW, the 18-55 II kit lens is actually quite good, capable of commendable resolution for a kit lens, and generally good optical performance.

Have a look at this review of the lens to optimise your use of it:
Pentax smc DA 18-55 mm f/3.5-5.6 AL II review - Introduction - Lenstip.com
For example the best resolution is obtained at all focal lengths if you stop the lens down to between f5.6 and f11. And note also for example at the frame edge the lens is softest at 18mm when shooting wide open.
05-22-2010, 06:04 PM   #18
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QuoteOriginally posted by noel Quote
...but I thought it shouldn't happen at lowest ISO?
With my K7 at 100, I see noise, but it easily cleans up. I do shoot in RAW, but have not tried straight JPG to see how it behaves.
05-22-2010, 06:59 PM   #19
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You shouldn't be able to notice noise in a RAW image from any Pentax DSLR at ISO 100 without any edits made, if you do then I'm not quite sure why. You can see pixel grain, but that's different.

05-23-2010, 07:15 AM   #20
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QuoteOriginally posted by noel Quote
I thank all of you for your responses. It seemed like a case of underexposure. I've looked through other of my photos and there are always noise in the black, purple and dark blue areas....but I thought it shouldn't happen at lowest ISO?

Nonetheless, I will do a EV+1 and test out further.
I believe shadow and highlight correction can generate noise at low ISO.

You can't add +1 Ev all the time and expect good results. Depending on the scene, you may need no Ev, positive or negative Ev, and weak or strong settings. You have to get to know how your camera exposes and adjust as required. Make your best guess, then use your histogram to review and correct the next shot if needed.

Last edited by audiobomber; 05-23-2010 at 07:29 AM.
05-23-2010, 07:35 AM   #21
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There are some incorrect directives here IMHO.

IMHO the lens is fine at f/7 unless you're right on the edge and at 55mm.

As for no noise in RAW at base ISO .... no way. You'll see it alright, especially in RAW because no NR has taken place. It's almost always there in the shadows on every camera, you need to apply noise reduction before exporting to jpg.
05-23-2010, 04:23 PM   #22
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QuoteOriginally posted by Alfisti Quote
As for no noise in RAW at base ISO .... no way. You'll see it alright, especially in RAW because no NR has taken place. It's almost always there in the shadows on every camera, you need to apply noise reduction before exporting to jpg.
That is exactly what I've been doing. One thing that I do find strange, is that I never really noticed it on my *istD, but it could have just been a setting turned on / off on either of the cameras. Could also be the higher resolution makes it more noticeable.
05-23-2010, 08:03 PM   #23
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As for the increased resolution making it more noticeable, I was having that exact thought when I read your post! :-) I would have liked to have seen some comparison shots -- the subject of this thread compares the K-x to a P&S: how 'bout some shots taken with a P&S of similar resolution, and the K-x, then show 100% crops of both -- or do some more experimenting with the two, side-by-side.

I used to think that base ISO should be noise-free across the frame, in all situations. I found from both experience and reading that dark colors, shadow regions, etc. are indeed prone to noise -- so little light reflected from such dark regions, I think. I still have a bunch to learn... thanks for participating in this great thread, everyone! I am looking to get a K-x sometime soon... that high ISO performance is wooing me sweetly...

05-25-2010, 03:02 PM   #24
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to elminate any effect of possible noise reduction coupled with smear of detail, maybe you want to shoot in RAW + JPG. I have noticed the degradation of detail in shots you probably refer to in sampe shots and was actually quite shocked by the smeary look of many of the high ISO shots published in the Internet prior to purchasing my own Kx, but when I took first shots with it, I found, that deactivating high ISO and long exposure NR helps gaining a more natural look of the JPGS under those conditions. Still my impression was, that Kx does more havy-handed NR that any other Pentax DSLR I owned before. Therefore, I prefer shooting RAW. BTW, JPGs taken with K20D also tend to have this special "smeary" appeal to them, when light is dimm and no exposure correction is set. The same would probably be the case with shots on film, if you compared.
05-28-2010, 09:01 PM   #25
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QuoteOriginally posted by noel Quote
Here's 2 more crops from different sections of the photo.



Below: Notice the loss of details especially on the collar of the man facing us.
The top picture of the yellow bottom railing is pin sharp and detail is there, but the 2 vertical railings are a bit OOF.

THe 2nd picture is off centre. What is your focus setting? Centre, or all 11 points? If it is in the centre then the centre will have more detail.
05-28-2010, 09:33 PM   #26
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it's a kit lens and I was a big point and shoot fan but I noticed that if I really concentrated on keeping the camera still when I snapped the photo problems you show would happen very often. I also had much better results on auto with a tripod (anti-shake off) - lots of good advice here. If you bought your camera at a camera shop and let them help you. If not then, keep shooting, have fun and expect things to improve. Betcha' it will!!!!
05-30-2010, 02:06 PM   #27
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QuoteOriginally posted by Ira Quote
What does ROT mean?

I'm terrible with acronyms.
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