Unexpected Behavior of Nikon D3100 in A Mode

[bhaur]

I Have Nikon D3100. When I choose Aperture priority mode, choose ISO to be 100 and shoot some still object in very dim light (of course using a tripod), I suppose the shutter should open for a considerably longer time and the picture should be of good quality. But what happens is that shutter opens for lesser time, and the picture is very dark. When I check ISO value of picture, it is indicated to be 3200 and this number appears in red. Couldn’t understand what is happening. Would anyone guide?

Uzair

 

[Geenphoto]

There is a setting on Nikons that automatically adjusts the ISO setting in the menus. Make sure this is not set to auto in the menu.


Sent from Mordor using an iPhone.

 

[PJM]

Hi Uzair, It sounds to me like you have auto ISO setting enabled. In this mode the camera will make its best guess for exposure by adjusting both the shutter speed and the ISO. The red ISO number indicates that the camera changed the ISO from the value of 100 that you set. If you want the specific value of 100 for ISO then go through your menu system and find the auto ISO menu and turn it off. With auto ISO disabled the camera will use the ISO value you set and then adjust the shutter speed appropriately. I hope this helps.

 

[bhaur]

Thank you GlenGleen and PJM,
There is a setting in which some time ago I opted Auto ISO sensitivity, which overrode my ISO ordinary setting. I have changed it now.

Uzair