We have already discussed about ISO and its pros and cons in my previous post. Now lets discuss about ISO settings for Nikon D90. There is no doubt that Nikon D90 is very powerful and semi-pro camera for most of the case. It is also one of the first DSLR camera which records HQ video with sounds.
Anyway, I am not going to discuss about it’s movie feature here. Lets save that topic for the future discussion. D90 is also considered as one of the best camera to capture variety of rich colors on your subject if you use proper exposure. We know that shutter speed, aperture and ISO are the main three fundamentals to control your exposure settings. And we discussed about exposure compensation using different techniques like exposure lock, bracketing etc and we will discuss more about proper combination of shutter speed and aperture for proper exposure. But now lets discuss about ISO settings that affects exposure.
When you press the Menu button at the left panel on the back of your camera, you will get bunch of menu options. Click on the Shooting Menu (camera icon) and then you will see ISO sensitivity settings there. When you go inside that menu, there are mainly two things to be considered, one is ISO Sensitivity which is available with all exposure modes and another one is ISO Sensitivity Auto Control which is available in PAS modes.
ISO Sensitivity option allows you to specify the ISO settings. It’s a same thing as you press ISO button on the back of D90 and rotate main command dial. In Nikon D90, ISO can be set AUTO which camera pick automatically as necessary or you can specify any value that ranges from LO 1 (equivalent to ISO 100) through 3200 to HI 1 (equivalent to ISO 6400). ISO sensitivity auto control menu lets you specify how and when your camera will adjust the ISO value for you automatically under certain conditions. When Auto ISO is activated, the camera set ISO value whenever it’s necessary if current ISO settings won’t allow you for optimal exposure. There are three main features to be considered when you enable ISO auto control option. I have written short notes on them below.
1. ISO sensitivity auto Control ON/OFF
This button will let you set ISO sensitivity auto control ON or OFF. If it’s OFF then it will prevent camera from changing ISO automatically when there is necessary. If you turn this feature off, you have to increase or decrease ISO value manually.
2. Maximum Sensitivity
This option is used to set the highest ISO value your camera can set automatically before it starts lowering shutter speed to get proper exposure.
3. Minimum shutter speed
This setting allows you to set D90 how slow the shutter speed can be before ISO is boosted up by camera automatically to higher value to get proper exposure. Default value is 1/30th of the second and it’s not recommended most of the time to set shutter speed below that unless you are using tripod. If you are using telephoto lens then may be you want to set Minimum shutter speed to 1/250th of the second and if you are using wide angle lens for landscape, you might want to set below 1/30th of the second.