D300 auto-ISO in P and A mode

[JediKnight]

I have a burning quesion with regards to auto-ISO selection by D300 in P and A mode. I have set the default ISO as 200 and max ISO to be 1600. On several occasions and many times, the camera like to choose the max ISO 1600 even if it is relatively bright. I am using matrix metering.

Example: Beach shot of my son playing sands with no direct sunlight (f22, 1/250s, ISO1600 in P mode) and outdoor building with sunlight (f16, 1/1000s ISO1600).

Wondering if any D300 users have similar encounters/experience as I am not sure if it was due to some other settings on the camera affecting this behaviour.

[chris667198]

Your 3D matrix metering is working fine.

[soeypixels]

why u want to shoot in f16 or 22?

[chris667198]

Originally Posted by soeypixels why u want to shoot in f16 or 22?

He is new to photography. Spare him.

[kkcharles82]

Yupz. . why F22, that aperture setting will not fair any better than F11. In fact, it may cause the shot to turn out softer than you expect.

[postman]

Your camera reacts correctly.

To see the effect of the auto, you need to change 2 settings.
Assuming that u are using A mode now.
1) set the min shutter speed in the auto ISO settings slower (maybe 1/100 or even lower 1/60)
2) set ur aperture to a bigger one (maybe f/5.6)

If the aperature is too small, that is f/22, you camera will boost up the ISO to the max, followed by changing the shutter speed accordingly.

As for me, usually i use auto-ISO only during indoors, when no flash can be used or when it is quite dark. If i use flash or when the sun is bright, i dont use it

[tanhb]

You set max ISO to 1600, so what did you set for minimum shutter speed?

From what I understand, in P and A mode, ISO won't change until the exposure reaches the extreme ends of the shutter speed range. Minimum shutter speed set by user(if you have not made any changes, the default is 1/30sec), maximum shutter speed set at 1/8000sec.

Auto ISO is turn off automatically if you are using flash.

[postman]

Originally Posted by tanhb Auto ISO is turn off automatically if you are using flash.

Auto ISO is NOT off if you are using flash. When the flash does not have enough power, the higher iso will kick into to compensafe. I just tried mine with flash and with my lens against a dark object and the iso fluctuates.

[JediKnight]

I usually use A mode. Even a recent outdoor shoot of childrens with no direct sunlight but still bright, set A mode at f/8 and camera pick shutter at 1/500s and still chose ISO1600. P mode and camera pick f/9, 1/250s and ISO1600. Somehow noticed the camera always like to pick smaller aperture (most of the time) in P mode and the highest ISO set. It seems like camera look at what is the max ISO and then decide aperture and shutter speed.

I have no issue in M mode with f/5, 1/320s with Auto-ISO and camera auto chose ISO200.

[Cannotanyhowonela]

I don't have any problem with D300 auto-ISO.

Firstly Auto-ISO will not use any ISO lower than then ISO sensitivity that you set. The auto-ISO automatically adjust the ISO Upwards if the ISO you set is not sufficient to achieve the sufficient exposure using the Min. shutter speed set. It WILL NOT adjust downwards even if ISO lower than the ISO you have set previously is sufficient to a shuttle speed greater than the min. shuttle speed that you have set in auto-ISO.

So i supposed what happened is you already preset your shuttle speed to ISO 1600 when you took the shot at the beach, therefore ISO1600 is used.

Just set your ISO to ISO200/400 when you really want to use the auto-ISO feature will do.

[tanhb]

Originally Posted by postman Auto ISO is NOT off if you are using flash. When the flash does not have enough power, the higher iso will kick into to compensafe. I just tried mine with flash and with my lens against a dark object and the iso fluctuates.

I didn't really do a test to see whether auto-iso is active or inactive when flash is used, but I remembered I did notice auto-iso on my D300 was automatically became inactive when I mounted my SB800 on it and turned on.

If you have set auto-iso to ON and is active, when you power on your camera you will see the 'auto-iso' indicator blinks.
If you have set auto-iso to ON and is inactive, when you power on your camera you will see the 'auto-iso' indicator but it will not blinks.

My D300 is sleeping soundly in her dry palace and I am also too lazy to wake her up for a test. Will test it the next time I bring her out for a walk.

A check on Nikon web site also shows that ISO will be fixed to the value selected by the user when flash is used and auto-iso is on.
http://nikonasia-en.custhelp.com/cgi...i=&p_topview=1

Quote from Nikon Website below.

Originally Posted by Nikon Under the following circumstances Auto ISO will not work: On the D2 series, ISO Auto cannot be switched on if the sensitivity is on 'Hi-1' or 'Hi-2'. Similarly 'Hi-1' or 'Hi-2' cannot be selected if ISO Auto is ON. If a flash is used when ISO Auto is on, ISO will be fixed to the value selected by the user.

[postman]

Originally Posted by tanhb A check on Nikon web site also shows that ISO will be fixed to the value selected by the user when flash is used and auto-iso is on. http://nikonasia-en.custhelp.com/cgi...i=&p_topview=1 Quote from Nikon Website below.

Certainly what the Nikon says is not wrong. When i use flash in normal conditions, when my flash is fully charged, it will be fixed to the value selected by me. That's why i say "When the flash does not have enough power, the higher iso will kick into to compensate".

Just sharing what i know

[postman]

Originally Posted by tanhb I didn't really do a test to see whether auto-iso is active or inactive when flash is used, but I remembered I did notice auto-iso on my D300 was automatically became inactive when I mounted my SB800 on it and turned on.

Maybe auto-iso works differently on my D700 as compared to the D300. My "ISO-AUTO" icon still there even with flash.