ISO Sensitivity

[parky]

Hi, folks, something is bothering me since day 1 when i got my D90.
In the specification, the ISO Sensitivity states that
ISO 200 - 3200 in 1/3, 1/2 or 1 EV steps with Lo-1 (0.3, 0.5, 0.7 and 1 EV (ISO 100 equivalent) under ISO 200), and Hi-1 (0.3, 0.5, 0.7 and 1 EV (ISO 6400 equivalent) over ISO 3200)
what is meant by one-third, half, one EV steps ? would anyone care to elaborate. thanks in advance.

 

[Octarine]

EV = Exposure Value. Explained in the newbie guides.
More to read also here in Wikipedia: https://secure.wikimedia.org/wikipedia/en/wiki/Exposure_value

 

[parky]

EV = Exposure Value. Explained in the newbie guides.
More to read also here in Wikipedia: https://secure.wikimedia.org/wikipedia/en/wiki/Exposure_value

ic tks, how come some pics indicates "1EV under 200" while others "ISO 200" , what is the diff ?

 

[Edwin Francis]

Exposure (ISO, Shutter speeds, aperture) is based on a logarithmic scale, not a linear one. Every Exposure Value step (or one stop) either doubles (+1EV) or halves (-1EV) the exposure. It's essentially a base-2 log scale.
+1/3 EV step - increase exposure by 1.26 (2^1/3)
+1/2 EV step - increase exposure by 1.414 (2^1/2)

Smaller steps just allow finer control of your exposure. Many (if not most) DSLRs allow you to vary the three exposure parameters in either 1/2 or 1/3 steps.

 

[parky]

Exposure (ISO, Shutter speeds, aperture) is based on a logarithmic scale, not a linear one. Every Exposure Value step (or one stop) either doubles (+1EV) or halves (-1EV) the exposure. It's essentially a base-2 log scale.
+1/3 EV step - increase exposure by 1.26 (2^1/3)
+1/2 EV step - increase exposure by 1.414 (2^1/2)

Smaller steps just allow finer control of your exposure. Many (if not most) DSLRs allow you to vary the three exposure parameters in either 1/2 or 1/3 steps.

ic, does this applies to WB as well ??

 

[daredevil123]

ic, does this applies to WB as well ??

WB is measured in kelvins... not steps or stops.

 

[parky]

WB is measured in kelvins... not steps or stops.

hi, daredevil, my ISO sensitivity is not set to AUTO, but fixed at ISO200.
is it ok if some pics indicates "1EV under 200" while others "ISO 200"


same goes to WB ==> auto,
is it ok if some pics will indicate AUTO A1. 0 and other will not.

 

[parky]

Auto White Balance on my D90 is horrible, it just cannot cope with anything other than sunlight or flash. Everything else gets a strong color cast to it. does
this applies to all D90 or i am just the unlucky one.
when i shoot at orange tungsten light, WB set to auto, it will give strong orange color which my naked eye tells me otherwise.
the pic reading indicates WB AUTO B3, M1.
Dont know what to do now, anyone care to help.

 

[Diluted]

Hmm.. why don't u try custom wb instead of leaving it in auto to get more accurate wb?? :think:

 

[daredevil123]

Auto White Balance on my D90 is horrible, it just cannot cope with anything other than sunlight or flash. Everything else gets a strong color cast to it. does
this applies to all D90 or i am just the unlucky one.
when i shoot at orange tungsten light, WB set to auto, it will give strong orange color which my naked eye tells me otherwise.
the pic reading indicates WB AUTO B3, M1.
Dont know what to do now, anyone care to help.

I find D90's AWB to be quite good.

BTW, is this D90 your first DSLR?

 

[daredevil123]

hi, daredevil, my ISO sensitivity is not set to AUTO, but fixed at ISO200.
is it ok if some pics indicates "1EV under 200" while others "ISO 200"


same goes to WB ==> auto,
is it ok if some pics will indicate AUTO A1. 0 and other will not.

There are no magic settings. You need to change settings when the situation demands it.

Sometimes I shoot at ISO200.

Sometimes I turn auto ISO on, min ISO 200, min shutter speed depends on the lens used at the time. max ISO depend on the light conditions, usually on 1600.

 

[Ted888]

Auto White Balance on my D90 is horrible, it just cannot cope with anything other than sunlight or flash. Everything else gets a strong color cast to it. does
this applies to all D90 or i am just the unlucky one.
when i shoot at orange tungsten light, WB set to auto, it will give strong orange color which my naked eye tells me otherwise.
the pic reading indicates WB AUTO B3, M1.
Dont know what to do now, anyone care to help.

Buy a gray card for WB and learn from it.

 

[ZerocoolAstra]

Auto White Balance on my D90 is horrible, it just cannot cope with anything other than sunlight or flash. Everything else gets a strong color cast to it. does
this applies to all D90 or i am just the unlucky one.
when i shoot at orange tungsten light, WB set to auto, it will give strong orange color which my naked eye tells me otherwise.
the pic reading indicates WB AUTO B3, M1.
Dont know what to do now, anyone care to help.

it's ok on mine.
Quite good accuracy.

If you aren't satisfied with the results, either use another WB mode (eg. colour tempeture in K), or best shoot in RAW and correct in PP later.

 

[Octarine]

when i shoot at orange tungsten light, WB set to auto, it will give strong orange color which my naked eye tells me otherwise.
the pic reading indicates WB AUTO B3, M1.

[GUESSING MODE]
B3 could be Blue, 3 steps. M1 could be Magenta, 1 step
[/GUESSING MODE]
Blue and Magenta are base colours used for White balance adjustments.

Anyway, do note that your naked eye and your camera 'see' differently. Human eye can overcome colour casts, the brain starts filtering such lights out or (in other words), our sensitivity towards a certain colour can get reduced. Easy to try: Look at any reddish lamp for a while and then look at normal daylight or fluorescent light. Both will appear greenish initially, then it fades back to normal. The camera will always record what is there in terms of light. There are complex algorithms trying to sense what is correct and they can fail.
It needs neutral reference for the camera to determine the correct White Balance - provided there is only one type of colour cast. If you have tungsten light and shoot with flash (without any gel) there is no way to balance both colour temperatures. If the in-camera functions (either Auto or presets) cannot help you then it's time for a grey card or White Balance cap (e.g. Expodisc or other cheaper products). Use them to get at least close to a correct settings, do the rest at home with a profiled monitor. Also, it is not always good or necessary to achieve technically correct White Balance. We tend to perceive images with a slightly warmer WB as more pleasing, compared to a technically neutral WB.

 

[parky]

B4 calibration, wb set to tungsten, color way too warm.

after White Balance fine tuning
setting tungsten WB to 2650k , as recommend by kenrockwell
i got the photos i want right out of your D90.

many thanks to all esp the suggestions from ZerocoolAstra, it really helps

 

[ZerocoolAstra]

:embrass:

glad I could be of help.

When you set to Tungsten, the camera might have been expecting really 'warm' lighting. But as you can see from your photo, most of it is dark sky. So the camera could have then mis-calculated.

 

[wcljack]

seach in yuotube.... got alot there.

 

[daredevil123]

seach in yuotube.... got alot there.

ooooo someone trying to up their post count... :bsmilie: