Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-05-2014, 04:25 PM   #1
Junior Member




Join Date: Aug 2012
Location: Minnesota
Posts: 37
ISO newbie

Hi all!
I've been trying to practice off and on all summer and was reasonably successful on my trip to the United Kingdom and even got a few Puffin shots. BUT very amateur struggles are my routine. I have the k30 and I can never understand the relationship between ISO and aperture and shutter speed. I kept having to set the ISO way too high I am sure. Like 600, 800, even 1200 to get anything to work. Maybe I'll attach some shots, but I'm kind of chicken
We have no photography classes anywhere near here so I just find what I can online over the years.
Thanks!

11-05-2014, 04:34 PM - 1 Like   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,147
The ISO determines the sensor's sensitivity to light. The higher the ISO, the more sensitive the sensor, and the less light you'll need. Thus, faster shutter speeds and/or smaller apertures can be used at higher ISOs.

The catch is that image quality (dynamic range and detail) deteriorates as you crank up the ISO. You probably won't start noticing this until 1600 or higher, though, so it's safe to use the ISOs you mentioned.

In daylight, you'll often want to stick to ISO 100 for the best image quality. But at night, for sports, or indoors, you may need to crank up the ISO to use a shutter speed that's fast enough to avoid motion blur/camera shake.

Oh, and one more thing: every time you double the ISO number, you can reduce the shutter speed/aperture by one stop.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

11-05-2014, 04:34 PM - 1 Like   #3
Veteran Member
flaviopetrone's Avatar

Join Date: Aug 2014
Location: Reggio Emilia
Photos: Albums
Posts: 1,150
It is something a little bit complicated to explain in few words, you should try to give a search over the net.

ISO is sensor's sensibility, so the more is high, the more the image is lightened but lose in quality.
You should try to set aperture and shutter speed in the way that the ISO stays the lower possible. Try to make some tests in TAv mode.
11-05-2014, 06:44 PM - 1 Like   #4
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon
Photos: Gallery | Albums
Posts: 10,770
May I suggest "Understanding Exposure" by Brian Petersen. Should be in alsmot any library, or available new or used anywhere. it is now in the 4th edition and has been updated a bit more for digital. The foundation of photography (well the technical part) is understanding the exposure triangle and how to achieve the exposure and look you want.

11-05-2014, 08:36 PM - 1 Like   #5
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,107
There is an excellent SLR camera simulator at the following link, that can help you see the interactions across shutter, aperture and ISO...
11-05-2014, 09:21 PM - 1 Like   #6
Pentaxian
esrandall's Avatar

Join Date: Feb 2014
Location: Sumner, WA
Photos: Albums
Posts: 965
QuoteOriginally posted by interested_observer Quote
There is an excellent SLR camera simulator at the following link, that can help you see the interactions across shutter, aperture and ISO...
That's a pretty cool little thing to mess with, actually. I've never been able to explain exposure to my wife, but as she is definitely a tactile learner, you could see her gears turning as he was messing around with that little sim.
11-05-2014, 10:41 PM   #7
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,862
Here is an example of what happens to image quality at high ISOs:



There are three types of noise here. Color noise causes that speckled impressionistic look. Luminance noise causes graininess. Pattern noise causes visible lines or grids where there shouldn't be anything. Noise reduction tries to reduce each type without losing the detail that was supposed to be there. Color noise can also happen on long exposures for a different reason. That noise is less random and can be processed out by dark-frame subtraction, what your camera calls "Slow Shutter Speed NR".

At the same time, raising ISOs reduces the dynamic range, the difference between the lightest and darkest tones. Digital technology has hard limits at the brightest or darkest tones - you can't get darker than a string of zeros, or brighter than all ones. So when the possible number of tones between the limits starts to drop, the image looks less like you saw, more processed. It looks like everything is high contrast when it shouldn't be.

You shouldn't avoid using higher ISOs, because it will really limit the shots you can take - especially if you don't have costly lenses. The ISO can be expanded to go up to 25600 on your camera, and sometimes you might use that. Just be aware of the tradeoffs. Exposure should be as close as you can get to perfect, because the image will just start to look worse if you want to make it brighter in processing. Noise will look worse in shadow or black areas. Noise reduction settings in the camera or using separate software can be effective most of the time, possibly risking detail. Remember the risk to dynamic range.

Ultimately, shooting in DNG and processing on a computer with good software is better and more flexible. You might even use different settings on several parts of the image.

You should figure out the limits of the camera, where the shots turn from OK to terrible. It's a personal decision, maybe including the software and processing ability you have. Take practice shots at different settings (remember to return the camera to normal after you're done).
11-06-2014, 12:41 AM   #8
Forum Member




Join Date: Mar 2014
Posts: 79
On the K-30, I find that 1600 or 3200 seems to me the acceptable limit. Any higher and the ISO gives too much noise that can hurt the picture. I'm sure others can explain to you better than I can, so I can only give you my opinion on this. Limiting your ISO depending on the time of the day helps. During daytime, I limit it to 100-800 Auto ISO, whilst during night I change it to 100-3200. The darker it is, the higher the ISO you need to maintain your Aperture and Shutter Speed.
I hope this helps.


Last edited by Anthen; 11-06-2014 at 01:00 AM.
11-06-2014, 02:14 AM   #9
Pentaxian
schnitzer79's Avatar

Join Date: Jul 2013
Photos: Albums
Posts: 1,095
QuoteOriginally posted by jatrax Quote
May I suggest "Understanding Exposure" by Brian Petersen
Excellent suggestion. the first book I read when I first started.

2 other great books are :

David Busch's Mastering Digital SLR Photography
Learning to See Creatively by Bryan Peterson (again)

also there are tons of youtube tutorials on correct exposure and photography in general
11-06-2014, 02:39 AM   #10
Pentaxian




Join Date: Mar 2014
Location: Sydney
Photos: Gallery
Posts: 442
I've set up my K5 so when I'm in AV mode the rear dial controls aperture and the front dial controls ISO. I'm constantly experimenting with combinations of each. It's a quick way to learn. You should be able to customise the K30 the same way.
11-06-2014, 02:44 AM   #11
Junior Member
Tony Lens's Avatar

Join Date: Nov 2014
Posts: 26
here i found a nice video on youtube,
11-06-2014, 08:14 AM   #12
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,107
QuoteOriginally posted by Just1MoreDave Quote
Here is an example of what happens to image quality at high ISOs:
We have an IGgy sighting!!!!!!

11-06-2014, 09:38 AM   #13
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon
Photos: Gallery | Albums
Posts: 10,770
QuoteOriginally posted by officiousbystander Quote
I've set up my K5 so when I'm in AV mode the rear dial controls aperture and the front dial controls ISO.
+1 Both my bodies are set the same way, also in Tv, Sv, X and Bulb. The ISO is on the front dial and the other variable on the back. Makes it intuitive no matter what mode you are using.
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!
aperture, camera, change, helps, hope, iso, limit, night, pentax help, photography, shots, shutter, speed, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Newbie Armature, Newbie to Pentax jgirl57 Welcomes and Introductions 5 08-31-2014 09:31 AM
Newbie, how to balance ISO vs. shutter speed in the moment? Newtophotos Photographic Technique 10 08-22-2013 07:48 AM
Newbie Question 2 - Auto ISOs Sage97 Troubleshooting and Beginner Help 23 05-02-2012 07:11 PM
Some newbie questions on RAW processing kcobain1992 Digital Processing, Software, and Printing 4 09-17-2011 01:45 PM
K-x newbie questions hray Troubleshooting and Beginner Help 10 02-10-2011 03:52 PM



All times are GMT -7. The time now is 08:45 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