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10-11-2014, 08:51 AM   #1
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why do pentax bodies always underexpose

Every pentax I've owned has had this issue. They all naturally want to underexpose the shot. Does anyone know why they're set up this way?

10-11-2014, 08:55 AM   #2
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QuoteOriginally posted by shaolen Quote
Every pentax I've owned has had this issue. They all naturally want to underexpose the shot. Does anyone know why they're set up this way?
To help preserve highlights.
10-11-2014, 08:55 AM   #3
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In artificial light, using AWB my k50 likes to underexpose, but outdoors it likes to overexpose. Solution, manual white balance. As to why they're set up like that.... I'd say just poor metering.
10-11-2014, 08:57 AM   #4
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For whatever reason, Pentax has decided to be conservative with their exposure algorithms. Since their cameras have excellent dynamic range and since digital is a "positive process" (like film slides and unlike film negatives), the big danger is blowing out highlights because they can never be recovered. So shooting a bit to the left on the histogram is being on the safe side...

10-11-2014, 08:59 AM   #5
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QuoteOriginally posted by luftfluss Quote
To help preserve highlights.
+1 that's always been my understanding too about 2/3 of stop.
10-11-2014, 09:53 AM   #6
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But how do you determine the consistent underexposure? I mean, compared to what?
10-11-2014, 09:56 AM   #7
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QuoteOriginally posted by Na Horuk Quote
But how do you determine the consistent underexposure? I mean, compared to what?
Compared to a Canon which want to over?
10-11-2014, 09:57 AM - 1 Like   #8
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QuoteOriginally posted by Na Horuk Quote
But how do you determine the consistent underexposure? I mean, compared to what?
Various light meters and other camera manufacturers products.

10-11-2014, 09:59 AM   #9
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QuoteOriginally posted by Kerrowdown Quote
Various light meters and other camera manufacturers products.
Pentax might be considered the dark side then while Canon is the Bright..Nikon neutral /close the thread please
10-11-2014, 10:04 AM   #10
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The slight under exposure (-1/3 to -2/3) stop has been consistent over enough camera bodies that I think it is intentional. Pentax sets the meter to preserve the highlights feeling that you can either bring it up in post or use EV comp to adjust depending on the conditions. This way anyone can get an OK image without losing the highlights and if you are knowledgeable enough to want to risk bumping into blown highlights you can use the EV comp.

On k-x, k-5 and k-5IIs I always ran at +2/3 EV. On the k-3 however I find it is very nearly right on and usually do not bump the EV comp.
10-11-2014, 10:20 AM   #11
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QuoteOriginally posted by shaolen Quote
why do pentax bodies always underexpose
This is an historic complaint.* The practical aspects are covered above and the intent is to avoid highlight clipping. This is commonly referred to as ETTR (Expose To The Right). The resultant photos usually look somewhat dull and grim, but you can recover from the mild underexposure in PP. This is preferable to losing the highlight detail to clipping. The situation is not as simple as a consistent 2/3 stop downward bias in that there looks to be a more complicated algorithm at work.** After all, they don't call it multi-point matrix metering for nothing. Jatrax is quite correct that the K-3 seems to do a better job than earlier bodies.


Steve

* IIRC, underexposure was the subject of RiceHigh's initial series of anti-Pentax rants back in the ancient past.

** Gray card readings are generally comparable between the camera and hand-held meters.

Last edited by stevebrot; 10-11-2014 at 10:25 AM.
10-11-2014, 11:30 AM   #12
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QuoteOriginally posted by shaolen Quote
Every pentax I've owned has had this issue. They all naturally want to underexpose the shot. Does anyone know why they're set up this way?
I suppose the question on other cameras also applies - "why do other cameras default to overexpose?" I have seen too many photos from Canikon users that tend to over expose and clipping high lights.
In general and especially in film days... we are taught to expose to the right (ETTR) a bit to get some shadow details that otherwise you would not get. Technology has changed and with high dynamic range sensor, it is more preferable to err on the under-expose side than over since shadow details can be recovered while clipped highlights are lost for good.
10-11-2014, 11:32 AM   #13
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I use the exposure compensation button for all images I take. It's a quick way to adjust the exposure without changing any of the settings.
10-11-2014, 11:58 AM   #14
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QuoteOriginally posted by shaolen Quote
Every pentax I've owned has had this issue. They all naturally want to underexpose the shot. Does anyone know why they're set up this way?
My K-5 overexposes.
10-11-2014, 12:26 PM   #15
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QuoteOriginally posted by ElJamoquio Quote
My K-5 overexposes.
My k30, with the matix metering and the sun in the frame can also overdo it.
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