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Exposure Value ?
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May 21, 2019 19:17:17   #
Greer Loc: SOUTH GEORGIA
 
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.

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May 21, 2019 19:19:14   #
Longshadow Loc: Audubon, PA, United States
 
In what context?

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May 21, 2019 19:23:24   #
Old Timer Loc: Greenfield, In.
 
I would suggest you go to Youtube and or do a search with google. Also there are some good books explaining the exposure triangle. It is not easy to explain in a few sentences. Unless you want to shoot auto you need to learn the basics and then it will start to come together as you study and practice/

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May 21, 2019 19:27:19   #
Haydon
 
I'd recommend buying this book. It will give you all what you need to know on this subject, or at least for now :)

https://www.amazon.com/Understanding-Exposure-Fourth-Photographs-Camera/dp/1607748509

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May 21, 2019 19:46:35   #
rmalarz Loc: Tempe, Arizona
 
Greer, could you more specifically show examples of what you're mentioning regarding manufacturers claims.

I'm sure that because the word exposure is mentioned in the post, you'll get the usual litany of exposure books and youtube videos to use as reference. I'd prefer to address your issue with the specific manufacturer's quotes.
--Bob
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.

Reply
May 21, 2019 21:29:13   #
selmslie Loc: Fernandina Beach, FL, USA
 
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.

The Wikipedia article on Exposure value covers the question thoroughly. Note that the EV recommendations are based on ISO 100. Higher ISO settings call for higher EV.

You can read more about this in Exposure Value - No metering used.

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May 21, 2019 21:44:16   #
TriX Loc: Raleigh, NC
 
Where I usually see EV values in camera specs, it refers to the lowest value where the AF is functional (AF sensitivity). Is that what you’re referring to? EV values of -3 or -4 are typical.

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May 22, 2019 03:26:54   #
Pablo8 Loc: Nottingham UK.
 
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.


The EV will give you a setting for the amount of light recorded on a (Hand-Held ) Light meter. This EV can bet set on any Hasselblad lens, and with the EV locked-in, any combination of shutter speed and aperture will give you the same exposure density. EV's are a universal scale, my meter ranges from -8 to 24.

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May 22, 2019 05:51:39   #
BebuLamar
 
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.


Those specs are related to the minimum EV for the AF to work. The range that the meter can work from minimum EV to maximum EV.
They also used to specify the number of EV that the exposure compensation can work.

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May 22, 2019 06:18:03   #
CO
 
Nikon compiled this AF module reference table. This is just part of it. See the entire list here:
https://nikonrumors.com/2016/12/30/nikon-af-modules-reference-table.aspx/

Check the EV range column
Check the EV range column...

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May 22, 2019 07:18:48   #
billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
 
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.


I have always used the phrase Exposure Equivalent's. ie. say for example if the correct exposure is F8 at 1/125 sec., then exposure equivalent's from this exposure include, F11 at 1/60 sec. or F16 at 1/30 sec. or F22 at 1/15 sec. going the other way, F5.6 at 1/250 sec. , or F4 at 1/500 sec., or F2.8 at 1/1000 sec.
All are exposure equivalent's of the original exposure of F8 at 1/125 sec. In other words, they will all be the correct exposure, but you can pick if you want a higher or lower shutter speed or a higher or lower F stop.
On my Hasselblad, once you set the correct exposure, it locked in the F ring and shutter ring so as you changed either the F stop or shutter speed, it automatically changed the other for you. COOL.

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May 22, 2019 07:20:57   #
pila
 
selmslie wrote:
The Wikipedia article on Exposure value covers the question thoroughly. Note that the EV recommendations are based on ISO 100. Higher ISO settings call for higher EV.

You can read more about this in Exposure Value - No metering used.


Checking your reference. Thanks.

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May 22, 2019 07:48:04   #
GGerard
 
CO wrote:
Nikon compiled this AF module reference table. This is just part of it. See the entire list here:
https://nikonrumors.com/2016/12/30/nikon-af-modules-reference-table.aspx/


Thanks for posting this CO. I can see how someone might choose a D500 for better low light autofocus vs other full frame models!

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May 22, 2019 07:56:27   #
rond-photography Loc: Connecticut
 
Greer wrote:
I'm a newbie and as I understand it, exposure value (or EV), gives one(1) figure for f/stop and shutter speed combined to meter the target light. I understand the purpose is to be able to set your f/stop and shutter speeds from this value, but what do claims of lower EV numbers (or higher) by camera manufacturers mean exactly? Please explain this to me and why it's important.


I think in terms from my film camera days. EV is a stop. +1 is exposure of +1 stop; -1 is exposure of -1 stop. As others have pointed out, manufacturers like to point out how well their AF works and if it works from -3 EV to whatever, you can be sure it will focus in light that poor.

Mostly though, once you own the camera, you are only concerned with getting the correct exposure for your situation, and the EV is just a value you dial in with the exposure compensation dial to get the exposure you want ( when you think the camera has not decided correctly).

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May 22, 2019 08:20:57   #
selmslie Loc: Fernandina Beach, FL, USA
 
pila wrote:
Checking your reference. Thanks.

Here is some more information:

Manual Exposure without a Meter

Exposure triangle Spreadsheet and Exposure Triangle Calculator (documentation)

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