Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-02-2013, 12:21 AM   #1
Senior Member




Join Date: Apr 2012
Location: Sweden
Posts: 185
EV in practice?

Hi Guys,

The meter range of a K-5 is '0 to 22 EV'.
1. Please suggest a simple(beginners) way of understanding the EV in terms of when one is out in the field with just a camera and wanting to make the best exposure possible. What should be my first thoughts and steps towards the best possible exposure knowing the '0 to 22 EV' information on a K-5?
2. Also, how does dynamic range relate to EV?

02-02-2013, 12:32 AM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 40,942
QuoteOriginally posted by voyager13 Quote
Hi Guys,

The meter range of a K-5 is '0 to 22 EV'.
1. Please suggest a simple(beginners) way of understanding the EV in terms of when one is out in the field with just a camera and wanting to make the best exposure possible. What should be my first thoughts and steps towards the best possible exposure knowing the '0 to 22 EV' information on a K-5?
2. Also, how does dynamic range relate to EV?
The 0-22 figure just gives you the boundaries within which the camera's light meter works reliably. Less than 0 ev is a very dimly-lit room, while over 22 ev is close to the brightness of the sun.

If you have 14 stops of dynamic range then everything no part of the photo will be over or under exposed if and only if the difference between the lightest and the darkest point in the photo is less than or equal to 14 EV. In other words, say you're shooting outdoors and the darkest area is a rock at 5EV. So then everything from 5EV to 19EV would be kosher. You can buy a light meter that tells you the EV value, or it can be calculated based on shutter speed, ISO, and aperture.

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:

02-02-2013, 12:51 AM   #3
Senior Member




Join Date: Apr 2012
Location: Sweden
Posts: 185
Original Poster
QuoteOriginally posted by Adam Quote
The 0-22 figure just gives you the boundaries within which the camera's light meter works reliably.
QuoteOriginally posted by Adam Quote
If you have 14 stops of dynamic range
I feel I need to have a good, thorough read on understanding dynamic ranges and EV's in practical terms, especially where those concepts are explained clearly using photographic examples. Any suggestions?
02-02-2013, 01:20 AM   #4
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 40,942
QuoteOriginally posted by voyager13 Quote
I feel I need to have a good, thorough read on understanding dynamic ranges and EV's in practical terms, especially where those concepts are explained clearly using photographic examples. Any suggestions?
I'm going to bed now, otherwise I'd like some samples. Try looking for photos of the sky or photos of blag dogs. That's when you really need dynamic range!


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:

02-02-2013, 03:00 AM - 2 Likes   #5
Veteran Member
TenZ.NL's Avatar

Join Date: Feb 2012
Location: Below sealevel
Photos: Gallery | Albums
Posts: 1,100
In short:
DR is the intensity of light between pure black and pure white measured in stops (EV). 1 EV is a set lightlevel (say a lightbulb), so +1 EV is twice as bright as the initial lightbulb (if your lightbulb was 20Watt to begin with, it`s now 40Watts). So -1 EV is like cutting the lightintensity in half, like you dim the lightbulb by 50% and your lightbuld is now 10Watts.
Now in photography not all scenes have the same dynamic range. A landscape on a bright sunny day has more DR (EV stops) than the same scene on a cloudy day. Because the sunlight is stronger the shadows are deeper and the highlights are brighter, thus the total range of EV (stops) is bigger/wider.

Here`s something without getting too technical: Why understanding dynamic range is vital for travel photography - Photography - 25 Days Off | Make the most of your time off work! Travel itineraries and photography tips for full time workers.
And this one has some interesting links at the bottom: What is Dynamic Range? | The Circle of Confusion
And one more if you can`t get enough
The Online Photographer: More on Dynamic Range


Edit:
Also, EV (exposure value) is used to designated the luminance of a scene. To get the full out of a given scene the DR of that scene must not exceed the DR of the camera. (check your histogram)
(Shameless copy from Wikipedia)
Attached Files
File Type: xml EV.xml (13.0 KB, 105 views)

Last edited by TenZ.NL; 02-02-2013 at 04:56 AM.
02-02-2013, 07:12 AM   #6
Senior Member




Join Date: Apr 2012
Location: Sweden
Posts: 185
Original Poster
Those are great links you sent me Tenz, THANKS.
02-02-2013, 02:13 PM   #7
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,814
You can use the camera's spot meter when you're out in the field with just the camera. In M mode, the bar meter shown is in Ev. In Av or Tv with a fixed ISO, you'll have to convert the displayed value to stops or Ev. For example, in Tv mode, the display says f2.8 at one point and f11 at another point. That's a 4 Ev difference. You can calculate the difference in any mode but when you allow more than one parameter to change, it's easy to run out of fingers and toes to count on. Remember the spot meter is designed to ignore everything except that spot. The other meter modes are looking at the whole frame and suggesting an exposure for that scene. The spot meter readings are only for the spot, so you have to consider how they'll work for the whole scene before shooting.
02-02-2013, 10:38 PM   #8
Senior Member




Join Date: Apr 2012
Location: Sweden
Posts: 185
Original Poster
QuoteOriginally posted by Just1MoreDave Quote
You can use the camera's spot meter when you're out in the field
That's what I always try to do to measure the exposure, and than refer to the histogram to confirm if the exposure has been achieved within the confines of the camera's histogram, which also confirms that the dynamic range present is captured for that scene.
What I have been curious about is how to calculate the EV in any given scene (if I don't have a light meter) and apply that knowledge confidently knowing I must have captured the best possible exposure. I know one can do that using the zone system, but what if I am not comfortable(and confident) using the zone system, there must be some other way?

02-02-2013, 11:16 PM   #9
Pentaxian




Join Date: Sep 2011
Location: Nelson B.C.
Posts: 3,211
Ultimate Exposure Computer

This is one way to do it. Another is to use a grey card, take a meter reading off of that, then set your camera.
02-03-2013, 12:23 AM   #10
Senior Member




Join Date: Apr 2012
Location: Sweden
Posts: 185
Original Poster
Excellent. Thanks for the link guys
02-03-2013, 12:36 AM   #11
Loyal Site Supporter
SteveM's Avatar

Join Date: Jan 2009
Location: Vancouver Island, BC, Canada
Photos: Gallery
Posts: 3,295
I've been shooting Pentax since 1981....and every camera has it's advantages but it's been a little wonky as of late. What I mean is EV from my K10d is not the EV from my K5. I can drop the shot 2 or 3 stops and push post processing with a K5 beyond my K10d.....which means sensitivity (Dynamic Range) means everything for EV.
02-04-2013, 06:10 PM   #12
Junior Member




Join Date: Oct 2012
Location: Grand Rapids, MI
Posts: 45
I'm still trying to grasp the concept here. Is exposure bracketing the same as EV bracketing?
02-04-2013, 11:22 PM   #13
Pentaxian




Join Date: Sep 2011
Location: Nelson B.C.
Posts: 3,211
QuoteOriginally posted by arcturus Quote
I'm still trying to grasp the concept here. Is exposure bracketing the same as EV bracketing?
Yes. When you bracket, you set the camera to take say 5 shots. -2/3 -1/3 0 +1/3 +2/3. It refers to -1/3 of a stop or EV.

The exposure mechanism of the camera measures the light and sets the exposure as if the measured part of the scene is 18% grey. That gives a baseline exposure settings, and from there you either expose more or less.

I often take shots of birds against a cloudy sky. Even with center metering, much of the portion of the scene that is metered is bright white, so the camera exposes to make that match 18% grey. The subject I'm shooting ends up being a dark blob. I have found that over exposing by +2.3 or +2.7 gives me proper exposure of the bird.

To make it easy, lets say +2 ev. I'm wide open at F4 on my lens, say starting at 1/1000 at iso 200. So to get the exposure I want, I would want 2x2 more light, so I would get twice as much by going 1/500. Another twice by going iso 400. The shutter is open twice as long, and the sensitivity of the sensor is doubled. That would produce and exposure at +2 EV, or two stops.
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, ev, exposure, k-5, pentax help, photography, range
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ev Compesation in Manual mode Swapnil Pentax K-r 20 02-06-2014 04:45 AM
Why no EV in M mode? Also, DOF with long focal lengths ChooseAName Troubleshooting and Beginner Help 27 09-07-2012 01:49 AM
kM ev values in manual mode GaryJarvis Troubleshooting and Beginner Help 2 07-29-2012 04:28 PM
Misc Practice photography in life. [01] atomboy Post Your Photos! 3 04-01-2010 10:44 AM
Tamron 70-200: IQ in practice Ash Pentax SLR Lens Discussion 5 12-15-2009 12:58 PM



All times are GMT -7. The time now is 07:16 PM. | 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