Lightroom & Exposure

I've recently started using Lightroom and notice that if I use the 'auto' button in the develop area, it invariably increases the exposure by at least 1/2 as top and often much more.

Is my K30 routinely under-exposing or is there a setting on the camera I'm missing?

Why would they be the same?

The camera is there metering the scene and incidental light etc with whatever method you have set and whatever Pentax software engineering has programmed.

Lightroom is looking at whatever Pentax measured using a different set of criteria.

Why not use the slider and decide yourself.?

This is normal behavior for most photo editors, certainly RAW converters ... first question, are use using a RAW file or a JPEG from the camera?

Camera sensors record data in a way that is optimized for the sensor (ie the best distribution of tones to store the maximum image information). This is not the same as the best way to view a photograph ... an editors job is to redistribute the sensor data in a way that better represents the brightness tones as the eye sees it. Auto functions (as you're using) will use an algorithmic approach to this, producing a tighter histogram with more tones bunched together in the mid to upper region - this produces the small exposure increase for the majority of shots, but it will also usually increase overall contrast (spreading the tones wider).

As dougf8 said, best to take firmer control and ensure your brightness and contrast is ideal for each image - auto functions will not be suitable for many non-'conventional' exposures.

After editing over 300,000 images in lightroom, I've NEVER used the Auto button for exposure

I use the exposure slider and my eyes.

Being a LR newbie, I only tried the auto function to see the effect.

Having done that, I'll certainly just do it by eye in future. Thanks for the comments.

Also adjust the gamma for your monitor....

http://www.photoscientia.co.uk/Gamma.htm

I have mine set to 2.2 as per standard

Theres an auto button? Never realised that...

The exposure point chosen is controlled (in the auto and semi auto modes) by the metering settings of your camera. It's been my experience that Pentax backs itself to be able to capture some detail in the darker shadow regions, and as such opts usually to maintain most of the highlight detail. It does this by exposing a bit 'under' in order to preserve the high light details. Yes you can override this, but it's usually doing it for a reason.

As mentioned above, the camera looks to capture as much detail as possible from a scene and there's a lot of confusion around this. This typically creates an image that's often not that pleasing to the eye straight out of camera, and often doesn't look that much like what the eye saw at the time. There is a fundamental difference between capturing as much dynamic range/detail as possible and 'baking' this into an image the camera thinks is what you want to see.

There is a big (?) discussion to be had around the expectation that you post process all your shots or not etc, but personally that's where I see the difference between a DSLR and an iPhone really. If I'm happy with what comes out of the camera phone then that's great, but I don't expect there to be much of a band for adjustments to this produced image. I've worked with iPhone photos and the depth of information is just not there. The Pentax DSLR however has a very wide range of captured information, and as such is far more adjustable in post production.

The auto button in lightroom applies manipulations as it deems required to adjust the histogram/level of your image into a set shape. If this pre-set guess at what your image 'should' look like matches what you like/want then all good. It shouldn't be taken as anything more than a suggestion. I often press it and then adjust from there, or say 'oh no' and undo that action and proceed myself. The whole aim is to get your image to where you want it, so if it helps then all good, but if it doesn't then you don't need to use it. As others have said, you could and perhaps should adjust the manual exposure slider until you're happy with the results.

Lets not forget that exposure from the camera depends also on the metering mode and where you point the camera before taking a shot. If you shoot outdoors in strong contrasty light then its easy for bright highlights (say clouds, bright reflective surfaces) to be prominent in the scene. Even on matrix mode (which will 'see' these brighter parts and try to compensate for them) this will result in lower exposures.

If you need better exposures at capture then try and identify the 'key tones' - say a face if a portrait, or something that is near to a mid-tone in the subject area. Point the camera at this to get the settings. If needed you can then press the exposure lock * button, recompose and shoot, or for more extended work switch to manual. Don't forget to remeter if the light levels change.

Keep an eye on highlights though, using the histogram or flashing warning on the LCD - if they are getting too high you could activate highlight correction on the camera.