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12-14-2009, 11:05 PM   #1
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DOF ,EV

is DOF distance of focus?

is EV enhanced vision? <- and what is EV used for ? i used it and i do see theres a lil diffference but not sure what it is... please help me

ehh and i was wondering, whats a good Flash for portrait? i like it so taht when i use the flash it looks like theres nature white light, not the flash from the normal cameras where it looks too artificial
does this mean i need to get a disfusser thing? (is that the white plastic thing that goes on a flash to make it more whiter?)

12-14-2009, 11:47 PM   #2
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QuoteOriginally posted by jolee1990 Quote
is DOF distance of focus?

is EV enhanced vision? <- and what is EV used for ? i used it and i do see theres a lil diffference but not sure what it is... please help me
DOF = Depth of Field. See Depth of field - Wikipedia, the free encyclopedia

EV = Exposure Value. This is a combination of Aperture, Shutter Speed & ISO setting. A change of 1 EV = a change of 1 stop. So if an exposure meter (there's one in the viewfinder of a Pentax DSLR in M mode) shows -1EV, to get the correct exposure of 0 EV you would need to:

1. Increase aperture from say F5.6 to F4 - lets in twice as much light (smaller F-numbers on the same lens means a larger opening - think of light photons as rain drops -you have to get a certain volume of rain drops to get the correct amount of water in a bucket).

or

2. Slow down shutter speed from say 1/125s to 1/60s - lets in twice as much light

or

3. Increase ISO from say ISO 100 to ISO 200 - makes the camera twice as sensitive to the light (like turning up a volume control on an amp - turn it up too much and you bring up the noise floor - photo becomes noisy, particularly in the dark parts - or you clip the amp on the loud parts - blow out the highlights)

or

4. A combined change of 2 or 3 of the above, say increase aperture 1/2 stop from F5.6-> F4.5 & decrease shutter speed 1/2 stop from 1/125s to 1/90s.

See the interactive calculator at
Exposure: Exposure: Glossary: Learn: Digital Photography Review

This calculator only works in 1 Stop/EV steps, but cameras can change settings in 1/2 or 1/3 stop increments.

Typical EV values for daytime shooting are in the range of 12 EV to 16 EV, so the 0 EV I'm taking about in the camera's viewfinder is the camera's way of say "correct exposure for this scene".

You can also use the EV compensation control to over-ride the camera's chosen exposure. Say you have someone inside a house standing in front of a window. They will be overly dark unless you either:

1. Dial in some EV comp, say +1 or +1.5 (EV)

2. Use fill-flash.

See also: Exposure value - Wikipedia, the free encyclopedia
Exposure (photography) - Wikipedia, the free encyclopedia
Exposure compensation - Wikipedia, the free encyclopedia
F-number - Wikipedia, the free encyclopedia


Dan.

Last edited by dosdan; 12-15-2009 at 01:36 PM.
12-14-2009, 11:51 PM   #3
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You will need to do some reading on the fundamentals of photography.
Start with the forum's articles section with articles like:

https://www.pentaxforums.com/forums/photography-articles/23232-learning-basic...echniques.html
https://www.pentaxforums.com/forums/photography-articles/62522-exposure-shutt...rture-iso.html
https://www.pentaxforums.com/forums/photography-articles/49478-what-focal-length.html
https://www.pentaxforums.com/forums/photography-articles/39743-understanding-...-kit-lens.html

DOF = depth of field
EV = exposure compensation value (also called exposure bias), telling the camera to bias its metering by the number of stops of light stipulated. See http://www.planetneil.com/tangents/exposure-metering/
Good flash for portrait? I suppose you mean how to create soft lighting to make flash not look like flash. See http://www.planetneil.com/tangents/flash-photography-techniques/
Diffusers are only a small part of the story - there's so much more you can do to get good quality light for portraiture, but first read up on the above articles, and perhaps: http://www.strobist.blogspot.com/2006/03/lighting-101.html

edit: I see Dan beat me to it - sorry for the repitition...
12-15-2009, 12:08 AM   #4
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QuoteOriginally posted by jolee1990 Quote
ehh and i was wondering, whats a good Flash for portrait? i like it so taht when i use the flash it looks like theres nature white light, not the flash from the normal cameras where it looks too artificial

does this mean i need to get a disfusser thing? (is that the white plastic thing that goes on a flash to make it more whiter?)
The problem with direct flash is that it washes out any shadows and can create a sharp shadow of its own. This can make a face look harsh. A diffuser can increase the apparent area the flash light is coming from. Bouncing a flash light off a light-coloured wall or ceiling will also diffuse the flash, greatly softening the artificial lighting.


Dan.

12-15-2009, 12:01 PM   #5
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wow thank you soo much to all for the help, i will do my research with the information given.
and ill try to post some pictures up later for critic, thank you again!
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