I have a Nikon D90 and would like to set the aperture to f/1.4 and the shutter speed to around 1/60, all while having the camera compute what ISO is required for the current light conditions. I am choosing these settings to get the most possible light without worry that an unsteady hand will cause picture blur due to movement.

I have the "A" setting where aperture and ISO are held and shutter speed varies as well as "Auto" where all three are set by the camera and it doesn't ever seem to choose f/1.4.

  • \$\begingroup\$ What lens are you trying to do this with? \$\endgroup\$
    – dpollitt
    Commented May 6, 2011 at 1:25
  • \$\begingroup\$ Sigma 50 mm f/1.4 EX DG \$\endgroup\$
    – WilliamKF
    Commented May 11, 2011 at 2:07

3 Answers 3


It sounds like you are interested in an Auto ISO type mode, that Pentax refers to as TAv mode. This allows you to manually adjust the aperture and shutter speed, and the camera determines the optimal ISO.

Nikon does not have a special name for this mode, but you can achieve the same results by putting the camera into "M" for manual mode, and setting your ISO to Auto ISO. In your case, just set it to "M" mode, Auto ISO, with an aperture of f/1.4 and a shutter speed of 1/60.


Assuming you have a lens that can do f/1.4, set yourself to manual, with aperture at 1.4, shutter speed to 1/60, and then turn on auto-iso (in the menu; I use this on the d300 all the time, but I'm sure it's in a different location in the d90).

That way, the aperture and shutter speed will be constant, but the iso will fluctuate as you like. I set my auto iso to go in 1/3 steps.

  • 1
    \$\begingroup\$ My standard mode for any party where I pick out people :) (although only 2.8 max here) Only thing that really annoys me is that I have to go to the menu for turning Auto ISO on/off. At least it is always in my "Last used options"-list (can't be added to the customized list in the D90). \$\endgroup\$
    – Leonidas
    Commented May 6, 2011 at 2:01
  • \$\begingroup\$ Fortunately, the D7000 fixes that oversight, and it can be added to the last-used-options list. You can also program one of your user modes, but those save all your settings, including WB, focus modes, etc. \$\endgroup\$
    – Evan Krall
    Commented May 6, 2011 at 5:40
  • \$\begingroup\$ Wow I didn't even know there's an auto ISO mode. Thanks! \$\endgroup\$
    – rabbid
    Commented May 6, 2011 at 7:15

Camera companies could do photographers a favour by calling this 'Shutter+Aperture Priority' auto mode instead of presenting it as a manual mode with auto ISO. By carrying over the film terminology, they are failing to communicate that in digital, there are THREE ways of controlling exposure.

Therefore, you already have what is effectively an auto mode where the photographer controls the shutter speed as well as the aperture and still gets auto-exposure because the camera can vary the ISO.

In fact, most cameras' auto ISO is a step ahead of auto shutter or auto aperture because one can limit the range within which the camera can vary the ISO. I'd love to be able to do the same with shutter or aperture.

  • \$\begingroup\$ FWIW, that's what Pentax does. See @dpollitt's answer. \$\endgroup\$
    – mattdm
    Commented May 7, 2011 at 4:05
  • \$\begingroup\$ Nikons do too, and I guess so do others. The problem is the terminology. Despite the 'M' on the screen, this is an auto mode and should be presented as one. \$\endgroup\$
    – Vivek
    Commented May 7, 2011 at 16:57
  • \$\begingroup\$ No, I mean Pentax does what you want. They call it TAv - shutter time + aperture. \$\endgroup\$
    – mattdm
    Commented May 7, 2011 at 18:06

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