[rickclick]

I'm having some issues with underexposure in manual mode. I hand meter, do a custom WB with an expo disk and adjust my exposure to get the histogram spike to the middle. My meter and the histogram agree but my images (mostly portraits) are about 2/3 stop under exposed. This causes me to have to manually open my lens from about f/10 to f/8. I have tried using the +/- to compensate but it does not have any effect on my exposure. I've been a pro for 46 years so I do have some idea what I'm doing. I've tried finding a number to Ricoh/Pentax to discuss the matter but have been unsuccessful in that effort. Other than that I love the camera.

[Racer X 69]

Hi Rick, welcome to Pentax Forums.


Try posting your question in the K-1 section. Lots of members there who have this great camera, willing to help.

[BigMackCam]

Moved to K-1 forum

[photoptimist]

The +/- function adjusts the camera's interpretation of metered scene brightness.

Changing the +/- setting will automatically change the exposure in P, Av, Tv, Sv, TAv because those modes are designed to use the meter reading to automatically set the exposure.

But +/- does NOT directly change the exposure in M mode because in M mode, the photographer, not the camera is controlling the exposure. Changing the +/- setting in M mode will affect the overexposure/underexposure bar graph which shows the discrepancy between what you have set the exposure to and what the camera thinks is required (including any +/- adjustment). If you use the Green button in M mode after changing the +/- setting, then the camera will reset the exposure to whatever the meter is reading including and +/- adjustments.

[monochrome]

IOW, after you adjust Exposure Comp with +/- you should take another meter reading using either Green Button or DoF Preview Lever.

[Adam]

Are you using an external meter? If so it would be the easiest to dial in the compensation there, or give the camera's meter a shot in a semi automatic mode.

[mattt]

...and adjust my exposure to get the histogram spike to the middle. My meter and the histogram agree but my images (mostly portraits) are about 2/3 stop under exposed...

This part of your question has me scratch my head. If you meter, why are you adjusting exposure to middle the histogram? If the exposure is high Key it (the histogram) should pile up on the right side of the histogram, and if it is low key it should pile up at the left.

[shardulm]

Well isn't the the EV bar become the exposure meter in M mode? So manual changing Aperture, Shutter and ISO changes that reading. It is the thing that looks like |......i..|.........| on the screen where your " i " is the exposure you are going to get and to get it at the middle of the meter you need to bring in more light or less light somehow by adjusting either of the 3 in parameters while in manual mode.
Also your meter setting adds to how this value is indicated by the camera in manual mode as in Spot, Center weighted or entire frame can affect how the camera exposes. Based on the meter setting and the (ISO, aperture and shutter) tells you where your " i " (exposure is.

[rickclick]

The +/- function adjusts the camera's interpretation of metered scene brightness.

Changing the +/- setting will automatically change the exposure in P, Av, Tv, Sv, TAv because those modes are designed to use the meter reading to automatically set the exposure.

But +/- does NOT directly change the exposure in M mode because in M mode, the photographer, not the camera is controlling the exposure. Changing the +/- setting in M mode will affect the overexposure/underexposure bar graph which shows the discrepancy between what you have set the exposure to and what the camera thinks is required (including any +/- adjustment). If you use the Green button in M mode after changing the +/- setting, then the camera will reset the exposure to whatever the meter is reading including and +/- adjustments.

Thanks for the quick reply. I was hoping I could do a setup in a User setting so I wouldn't have to find another work around. The expo disk gives a "spike" in the middle of the histogram when the exposure is correct. I'm using studio flash with soft boxes. If I meter the lights and set the aperture accordingly and then check the exposure with the expo or gray card the histogram indicates a that the exposure is correct. I photograph the subject and load the images on my computer and the supposedly properly exposed images are about 2/3 of a stop underexposed. Sure, I can adjust the meter to a lower ISO, or just always open up the lens but this presents a minor inconvenience. I guess I'm having a hard time understanding why the images are underexposed when the meter and the histogram say they should be properly exposed. Any thoughts? It seems to only be a problem in the studio, outside images seem to be fine. BTW the color of the images beats my Canon 5Ds to pieces!

[pschlute]

Two thoughts...

Are you allowing stray light to enter the viewfinder when you do your "incident" reading ?

How much are you adjusting exposure by to get your histogram spike in the middle ? Why do you need to make this adjustment ?

[leekil]

What type of lights are you using? I have seen underexposure on the K-5 or K-3 when under fluorescent lights, but I'm not sure why. Maybe the flickering and/or color shift of that type of light?

[Ian Stuart Forsyth]

I'm having some issues with underexposure in manual mode. I hand meter, do a custom WB with an expo disk and adjust my exposure to get the histogram spike to the middle. My meter and the histogram agree but my images (mostly portraits) are about 2/3 stop under exposed. This causes me to have to manually open my lens from about f/10 to f/8. I have tried using the +/- to compensate but it does not have any effect on my exposure. I've been a pro for 46 years so I do have some idea what I'm doing. I've tried finding a number to Ricoh/Pentax to discuss the matter but have been unsuccessful in that effort. Other than that I love the camera.

If you are going through all of this trouble I would first ignore the histogram on the back of the camera and jump straight in finding out where the camera clips data, the reason why I say ignore the camera histogram is it only shows you the jpeg processed data and not the raw.

Most cameras will underexpose the raw data 1-2 stops below the maximum exposure the sensor can store. The best way to see this is to find a raw viewer that allow you to see the clipping point. Instead of going into great detail and not reinventing the wheel here is some very useful information.
Why Bother Shooting RAW If You Are Culling JPEGs?

and another
How to Use the Full Photographical Dynamic Range of Your Camera | FastRawViewer

Here I done a little test



So here what I had done is use the cameras meter and metered on middle grey and using the cameras histogram showed this to be the best exposure, I have a nice range with no clipping happening in my data. Now is this the best exposure ? and have I captured as much DR the raw file would allow

So what data did the raw file capture


So here is what data was collected in the raw file and where the highlights sit in that file, as you can see I am rather far from clipping any data with this exposure and if you look close I am over 1 stop from clipping the white patch. So do you think this was the best exposure for this scene?

Now I can see that for the very scene I can increase my exposure by 1 stop correction ( 1 and 1/3 stops) without clipping any data.

So here I increased the exposure time by 1 stop correction ( 1 and 1/3 stops)and this is what the image would look like on the histogram of the camera

Doesn't look very good as I have clipped a lot of the data one would need for this scene or have we ?


Here is what the raw file captured with that 1 stop increase in the exposure, I have very little clipping in the data with less that 5% in the green channel.

So here is a side by side comparison, one using the cameras meter that produced a very nice looking histogram to that of capturing as much DR the sensor can store

So you may ask why go through all of this trouble


Here is a close up of the shadows and you can see a decrease in the shot noise, this was done utilising as much of the scenes DR with that of what the raw file from the camera can store.
Just by optimising this we can see a 1 stop decrease in the noise found throughout the image.

So the question arises how are you going to implement this into your exposure management? I have run out of time as I should be getting other things done tonight but will continue this another day.
I hope this was helpful

ISF

[eccs19]

This is not an answer to your question but more just a comment on your situation. I have found the same situation with my K-1, but that being said, any of my Pentax camera's have always seemed to exhibit this "problem". I personally like a photo that is slightly underexposed, so when I expose how I think I'd like the photo, it ends up being even more underexposed then I've planned. Through experience with the camera, I now make sure I expose to the right to get more what I actually want. I find darker scenes tend to be worse, but again with the experience with the camera, I know to watch for this. I shoot RAW, but have set the JPG to a neutral profile and this seems to help with the rendering of the preview to be a little more true to what the files are when imported into the computer, but I still do make sure my exposure is a little higher then what I want, just so there is less adjusting after the fact in the computer.

[Ian Stuart Forsyth]

Now to continue you must first decide on how you are going to implement this knowledge, rather than telling what to do I would rather tell you what I have done and let you decided if you would use it or devise your own method.


So this only works with my D800 you will have to find where your camera clips in relation to what the camera meters.

(there was an error in my earlier post, I stated I raised the exposure by 1 stop but it was 1 and a 1/3) My exposure management I have given a buffer in my highlight data of 1/3 stop, I have done this by increasing my EC by +1 in camera. So to check things out and make sure that I have no flubs I meter on M grey and then after checking with a raw viewer to see if I have clipped any data on white using that override of 1 stop.

For future reference Without changing any settings in the camera I would move the cameras spot meter point over to the white and see what the cameras meter reads and remember this. This will give a reference point for ETTR and if you feel that you are getting close to clipping white in any of your scenes take a reading on that portion of the scene that comes close to clipping and see where it falls on the cameras meter and this will give you a clue to how much wiggle room you have left.

Hopefully you still have your scene setup that you have determined the setup of your cameras metering I would just adjust the handheld meter EC+ or – until it the HHM reads the same for that scene. I would then go through and fire off some test to see that the HHM reads that M grey and also making sure that you have whatever buffer you have allotted to keep some white data.

[Tan68]

Which software are you using ?
Does it support the K-1 files ?

I ask because I use a not-supported 4/3 camera, EP-L6, with my raw editor by changing the camera ID in EXIF to a subsequent model, EP-L7, and, while the software will then recognize the files, they are all viewed in software 2/3 stop underexposed. The exposure is otherwise fine but whatever default ..stuff the software does to imported files just aint quite right.