I am using D5100 for around 6 months. I have basic ins-and-outs understandings of the camera, including A/M/S-mode. In most scenarios, I understand what to use or else at least figure it by trial and error.

In many online discussions, I read that "P-Mode" (or, program mode) is something very useful. But, so far I can't understand its purpose or use.

So, my question is basically two.

  • what is fundamental difference between "Auto-mode" and "P-mode" ?
  • What are some use-case scenarios for "P-mode" ?
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    \$\begingroup\$ +1 Good question. I just realized there is differences in P exposure mode between camera makes and perhaps models even. Though this question does not work for me, as I have a Sony A37. \$\endgroup\$ Commented Oct 25, 2013 at 14:42
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    \$\begingroup\$ This distinction is common to most DSLRs that I know, not just this model or brand. \$\endgroup\$
    – mattdm
    Commented Oct 26, 2013 at 19:41
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    \$\begingroup\$ @mattdm - yes, P-mode nearly the same really. My first comment to this question was a request to drop the "Nikon D5100" from the question title. But I deleted it then - for example Sony has two slightly different "Auto"-modes, so asking what difference is between P-mode and Auto, one would first need to know which Auto-mode it was. \$\endgroup\$ Commented Oct 26, 2013 at 20:11
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    \$\begingroup\$ @kmonsoor - RTFM was intended as a lighthearted suggestion which anyone with a software engineering background knows. I can revise my answer to include a selection of the page numbers you didn't read if that would be valuable to you. \$\endgroup\$ Commented Oct 28, 2013 at 11:14

4 Answers 4


The main difference is that many options are 'locked out' and set to their defaults in Full Auto (Auto) mode. The manual has all the info you'll need on what is available and when. In decreasing order of automation the modes are...

Full Auto

Do everything - leave only the most basic functions open to the photographer.

Scene modes

Like Full-Auto with preset values for the chosen conditions.

Programmed modes

Unlike the auto/scene mode many settings are user controlled in the P/S/A modes such as...

  • Metering mode
  • Auto Focus mode
  • Exposure lock/compensation
  • Flash settings
  • White balance
  • ISO Sensitivity

Also, advanced options (i.e. bracketing, HDR, Active D-Lighting, multiple exposures) are also available. In P-mode where shutter/aperture is calculated for you, the dials allow you to shift the balance between shutter/aperture.

These modes offer a good balance of automation and user control. So, any situation where you want more control of the camera than that is offered by Auto mode, but don't want to have to do everything yourself would be a good use case for the program modes (P/S/A).

P Flexible Program - Do most things but allow plenty of scope for overrides

A Aperture Priority - Use the photographers chosen aperture and balance the shutter speed up to get a good result.

S Shutter Priority - Use the photographers chosen shutter speed and balance aperture settings up to get a good result.


Automate as little as possible.


Probably, the best way to summarise the differences is that P is the 'photographer's auto', see it as an equal to the A/S modes. It's intended for someone who knows what they're doing but is happy to let the camera do the work and will step in to enhance or inform the camera's decisions. Adding fill-in flash or over/under-exposing would be some good examples.

The scenario when you dial in Auto is when you're giving a camera to someone who knows nothing about photography, usually with the only instruction "Look through the hole, press the button!"

  • \$\begingroup\$ can you plz add some scenario, when it would be better to shoot in P-mode ? i think, that would make your answer more "complete". Thanks ! \$\endgroup\$
    – kmonsoor
    Commented Oct 28, 2013 at 15:10
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    \$\begingroup\$ Edited - hope that clears up what scenario is right for which of the two modes. \$\endgroup\$ Commented Oct 28, 2013 at 16:24

The fundamental difference between Auto mode and P mode is the ability to control other parameters beyond aperture (Av) and shutter speed (Tv) when in Program mode. Things such as ISO, metering mode, exposure compensation, focus mode, etc. are not user selectable in Auto mode as the camera selects them for you.

As far as use cases goes I can think of a few:

  • Situations that have a great variation in brightness from shot to shot. If you are struggling with a dark scene that needs both a wide aperture and fairly slow shutter speed one second, and bright light that calls for a fast shutter and small aperture the next, using P mode allows the camera to adjust both without you needing to change a value you would have locked in using Tv or Av mode.
  • In situations that you are going to shoot manually, you can begin by taking a few test shots in P mode to get a middle of the road starting point to base your settings on in M mode. This might be especially helpful for newer photographers who are still learning how to shoot manually.
  • In more casual shooting situations when you are in 'snapshot' mode but want a little more control than allowed with Auto mode.
  • When you hand your DSLR to a non-photographer to snap a quick picture of you and Aunt Bernice at the local Cracker Barrel restaurant.
  • As a learning experience, using the program shift in P mode is a great way to illustrate the effect different Tv/Av combinations with the same overall exposure value will have on the image.

Assuming that it is similar to Canon models, the Auto mode generally locks down most camera functionality to a very basic set of features. P mode uses the auto functionality for setting exposure, but otherwise leaves the rest of the camera open to the photographer.

Generally Auto is designed for people that don't know how to use the features of the camera where as P mode is for people that simply don't want to be bothered with having to make decisions about exposure other than setting the exposure compensation value, but otherwise want to control the camera.


Difference between Auto mode and P-mode

  • Auto mode won't let you set anything. All settings are computed by camera.

  • In P-mode, camera computes exposure and let you change the ratio between aperture and shutter speed. You can find more in manual.

  • So fundamental difference is that in P-mode you have some control over the final image.

Real question is difference between P-mode and A/S-mode

P-mode looks like A-mode and S-mode combined. The differences:

  • In P, you can't select values that underexpose / overexpose image
  • In P, the values are somehow limited (its given by graph in manual), e.g. now I can't select f/22 at ISO100 in my room, because shutter speed will be more than 8". So I am stuck at f/16, 8".
  • In P, you can't use auto-ISO. If you do, you won't be able to change values at all (at least on my D600)

Use-case scenario of "P-mode"

Don't know. As I remember, I also had started using P-mode. But due to the confusion of how the algorithm works, I moved to A-mode. I had to tune auto-ISO settings, which was frustrating and sometimes I forget to re-set it properly next day...

Now, I shoot manual and everything is much much simpler. You just rouhly choose your aperture and shutter speed. Then you fine tune it using metering in viewfinder, sometimes you pump up ISO if you want to keep current values.

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    \$\begingroup\$ In P-mode exposure compensation (under/over exposure) can easily be dialled in using the +/- button on the top panel + a dial. ISO control is the same in all the P/S/A modes in that it expects you to tell it when you want to control iso (using the iso button + front dial to toggle auto-iso and rear to set the value when auto-iso is off.) \$\endgroup\$ Commented Oct 26, 2013 at 21:30

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