Wny do manual pictures come out dark, but OK in AUTO with same Shutter / Aperture?

[serialteg]

Hi there!

First post ever here! I have a Nikon D5100 DSLR (my first DSLR) and a question:

I'm taking a picture in Manual (because I do have some experience mainly in 35mm and darkroom print developing) and it comes out dark.

I take the same picture, without flash, in Auto Program (fully automatic) and it comes out nice and balanced.

The question is why is this, if I'm using the same aperture and shutter speed in Manual that the Auto Program chose, both without flash?

Thank you!

 

[hirejn]

You can't take the exact same photo in the exact same conditions at the exact same settings and get two different exposures. At least one variable is somehow changing. Take a closer look.

 

[serialteg]

Thank you for your answer, hirejn! That's precisely what bothers me, but it is probably due to my ignorance in the fact that I'm a beginner with this camera and it has a lot of settings. What would you consider to be a factor in the big change between the two?

I'll upload an AUTO pic and a manual pic, at exactly the same ISO / Aperture settings.

 

[480sparky]

Having a couple of examples (with intact EXIF) too look at would certainly help.

One possibility: Exposure Compensation is set way to far on Manual, but doesn't affect the Auto shot.

 

[hirejn]

Post examples.

 

[zombiemann]

If I had to guess, all else being equal, auto mode is changing your ISO

 

[paigew]

Yes check your ISO. You do not want it on AUTO ISO.

 

[serialteg]

This is an AUTO shot at 1/80, f4.5



Manual shot at 1/80, f4.5

 

[JacaRanda]

View attachment 52653

This is an AUTO shot at 1/80, f4.5

View attachment 52654

Manual shot at 1/80, f4.5

What was ISO on each?

 

[hirejn]

The ISO must be changing. There's no EXIF information with the image so it doesn't show ISO. It's possible that your auto mode is using auto ISO and the manual mode is not.

 

[serialteg]

What was ISO on each?

ISO was 80 on the viewfinder, 1/80 as the camera presents it on the back LCD.

 

[serialteg]

The ISO must be changing. There's no EXIF information with the image so it doesn't show ISO. It's possible that your auto mode is using auto ISO and the manual mode is not.

Using EXIF, the AUTO shot has a EXP. MODE, ISO: (AUTO), 400

Whereas in Manual, EXP. MODE, ISO: M, 100

 

[Patrice]

What was ISO on each?

ISO was 80 on the viewfinder, 1/80 as the camera presents it on the back LCD.

The base iso of your camera is 100, are you sure the iso was 80? That seems to be the shutter speed your looking at.

 

[Gavjenks]

1/80 is your shutter speed, not your ISO. As in, the shutter is open for 1/80th of a second.

Your ISO is how much the signal on your sensor is boosted. It takes the form of multiples of 100 in most digital cameras, by multiples of 2, so 100, 200, 400, 800, 1600, etc.

There are THREE exposure variables (Shutter, Aperture, ISO), and you're only showing us two of them. The one you're not showing us is probably changing, which is ISO.

 

[Patrice]

The ISO must be changing. There's no EXIF information with the image so it doesn't show ISO. It's possible that your auto mode is using auto ISO and the manual mode is not.

Using EXIF, the AUTO shot has a EXP. MODE, ISO: (AUTO), 400

Whereas in Manual, EXP. MODE, ISO: M, 100

There is your answer. There is a two stop difference iso100 and iso 400 which accounts for the difference in the image you posted.