K5 Metering?

Started Dec 22, 2010 | Discussions
barony2396 New Member • Posts: 2
K5 Metering?

Hi,

First time poster, first time Pentax owner. Please be nice!
Sold Nikon gear. Everything getting too big and heavy.
Now have K5 + FA & DA primes. Love the setup.

Question for Pentax experts. Compared to Nikon the metering seems to be very different.

Consistently I need to add 1-1.5 stops of positive exposure comp indoors at F1.8-F2.8 to get a decent exposure (but it is quite predictable, which is good)

Outdoors seems closer, but still finding a lot of exposure comp needed due to what seems to be super conservative metering for highlights. Again, often a full stop or more.

Have also had some issues with on camera flash creating massively overexposed images, but this has been inconsistent and may be my own fault. (I didn't have any exposure comp dialed in at the time.)

Does this sound like the normal parameters of the Pentax meter to you, or do I potentially have a problem? Other than this, love the camera and the lenses.

Would especially love to hear from anyone else who's used both Nikon D90 and K5 for their comparison.

Thanks in advance.

Lee Davis Regular Member • Posts: 344
Re: K5 Metering?

I have a K20D (am hoping to buy a K5 in the new year) and I have found issues with the metering. I thought the K5 was supposed to be 'better', though I suppose what is termed as 'better' is subjective.

Traditionally Pentax does tend to 'underexpose' to preserve the highlights.

What I could never understand though was why my K20 also underexposes on dull cloudy days - anyone know why they do that?

Lee

Brad99 Veteran Member • Posts: 3,145
Re: K5 Metering?

With regard to the flash issue, I've seen a few people say they have found a workaround until Pentax fix the firmware, the answer seems to be turning on highlight expansion - thread over on the other forum.........

pentaxforums.com/forums/pentax-k-5-forum/126224-k-5-bounce-flash-overexposure-fix.html

richardplondon
richardplondon Forum Pro • Posts: 11,006
Re: K5 Metering?

Two things to separate here: exposure, and processing.

EXPOSURE

It is widely stated that Pentax matrix metering tends to conservatively expose to protect the highlights (I don't believe they are the only ones doing that, myself). If you are prepared to accept blown highlights, or to partly recover them in Raw development, then some positive EC will give that. But blown highlights are not recoverable in JPG, so if this standard behaviour is a fault, it's a least a "good" one.

If the image does not contain any bright highlight areas, and seems underexposed overall (rather than merely low-key), then highlight protection is not the explanation. There may be some other kind of metering issue. The tone of the subject may have tricked the meter (especially a problem in spot metering, but also an issue in centre-weighted) or the matrix metering may have made the wrong call - and it can only ever make a basic guess, btw, it cannot be expected to truly "understand" as we do.

Our absolute exposure is whatever it needs to be in order to maximise shadow detail without blowing highlights. The reality much of the time, on full auto, is a camera that effectively performs "expose to the right" - not a camera that meters average reflectance in the classic way. So we can expect our midtones to wander around a bit, not to follow some ideal of accuracy. The interrelationship of tones in between black and white, in this sense, is determined by the subject not the camera.

PROCESSING

Given a certain highlight protection, we then have the question of how many stops of exposure darker than the whitepoint, are to be considered a midtone or whatever (gamma, contrast curve). On the K-5 this can be adjusted quite well using the "key" adjustment for JPG (I don't recall its exact name, sorry). I have increased it substantially from the default, and am happy with the "brighter exposed" look for the same absolute exposure - in other words, when the exact same aperture and shutter and ISO are used. There are also general contrastiness, highlight and shadow contrast settings. These JPG settings can be adjusted against a background preview image that demonstrates the live effect.

So the camera can be set to generate JPGs in a "brighter" way. This is done directly from the captured Raw image, AFAICT, and correspondingly preferable over lightening up a saved JPG, later, in the computer.

If we are processing a Raw instead, then the only absolute restrictions are the exposure itself, and the amount of highlight recovery achievable. The black clipping, tone curve, contrast and brightness etc, and colour calibration that we first see are just someone else's notion . Adobe, or whoever, has made a guess at what we may want to see as a starting default for our Raw conversion. If we don't like that, for a particular image, we change it.

Or if we want different overall behaviour we can change the software closer to our liking ( set Raw default ), perhaps so that all future images we open will be already set to a brighter "look", ready for finetuning, or darkening again where that is appropriate.

This is not greatly different, in principle, to when a JPG shooter sets up the camera to his or her preference.

RP

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awaldram
awaldram Forum Pro • Posts: 13,271
Re: K5 Metering?

Brad99 wrote:

With regard to the flash issue, I've seen a few people say they have found a workaround until Pentax fix the firmware, the answer seems to be turning on highlight expansion - thread over on the other forum.........

And switch off auto iso

pentaxforums.com/forums/pentax-k-5-forum/126224-k-5-bounce-flash-overexposure-fix.html

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ozdean
ozdean Forum Pro • Posts: 26,307
Re: K5 Metering?

Andrew I'm wondering if having auto iso on with flash might be a lot of the problem?
--
Regards Dean - Capturing Creation

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Barry Fitzgerald Forum Pro • Posts: 29,888
Re: K5 Metering?

Can't comment on the K-5 but I've seen the K-x need a bit more help in low light than it should do on this front.

In comparison my Km5d can meter quite accurately even with very very low light and exposures of many seconds long. My Pentax seems to struggle a bit here again this is low light levels maybe lower than many would shoot in.

There is some room for improvement on this..granted it's not that rare a lot of cameras will need help in metering for low light. I would have expected the K-5 to be better in this area. Not the end of the world but something to add to the "have a look at this Pentax" list.

Younes Senior Member • Posts: 1,597
Re: K5 Metering?

Well, I just posted in another thread going on ( pictures in Holland), that the metering of the K5 seemed incredibly spot on given the amount of snow in the pics and the fact that the OP didn't dial in any exposure comp.
Check the thread.

Otherwise, you also use cW metering and use AE Lock button to properly expose the portion of the pic you really want well exposed. It's there for this purpose....

On the K10, I often dial in some positive exp comp (( 0,7 ) when using matrix metering since it's so conservative!

Cheers

-- hide signature --

Younes ( Paris, FR)
K100D,K10D,D40 + lenses

pentaxnut Regular Member • Posts: 332
Re: K5 Metering?

Hi there,

Can't say I've had much exposure to Nikon gear, but for my K10D, K7 and K5, here is what I generally do:

1) Set metering to center weighted

2) Set AF point to the center ('m used to manual focus systems, so it is easier for me to get AF lock and then re-compose)
3) slave AE to AF point (in the menus)
4) watch the histogram

Keep in mind, the histogram is based on the preview JPEG, not the raw data. ACR may tell you something different. When shooting in manual mode, I find the camera tends to under expose a little, quite consistently. Usually, I hit the green button to get a reading and then adjust from there using the front and back dials.

The above settings get me closest to what I experienced with my MF Pentax film gear.

Other than that, all I can tell you is it is an incredibly versatile piece of gear, and more than a little experimentation is likely to be needed before you feel really comfortable. Don't be afraid to bracket, and use the results of that as a guide. I think you can bracket up to 5 shots, which is a bit extreme for day to day shooting, but quite reasonable for 'experimentation'.....

Jarda_Houdek Contributing Member • Posts: 812
Re: K5 Metering?

Matter of taste I believe. I like the exposure as metered by my K-5 (but K10D did underexpose), only indoors I put in place +0.5 correction. I'd have to dial -1 compensation on Nikon to achieve image I like.
--

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djezraj Contributing Member • Posts: 749
Re: K5 Metering?

Hi. I think Pentaxnut may be right about the K10D settings as mine works well this way as well.

I have on Occation used My K10D and A D90 side by side. Indeed in Program mode the D90 needed some - exposure compensation to preserver the highlights and the K10d some positive compensation when metering off of the bright sky. Afterward both images were surprisingly comparable each having their own strengths likely related to CCD/CMOS and other specifics....etc

The D90 metering even in Matrix seemed to bias itself for mid tones especially faces, This was advantageous when trying to expose to the right for a portrait but would often wash out details and blow highlights if not careful, It was easy enough to fix of course.

Pentax seems to be as said here more conservative when it comes to exposure and can underexpose but when you get used to that it gives you more wiggle room to decide whats best. DPR made it pretty clear they liked this as the K5 has lots of room in shadows and highlight in this respect.
I do recommend to play around with the metering modes and exposure compensation.

As far as Flash goes Auto ISO may be the issue and perhaps firmware. The rest I will leave for the experts here
Good luck. Im sure you will feel at home in no time

Cheers
Roger

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tdwesbo
tdwesbo Senior Member • Posts: 2,138
Re: K5 Metering?

Perhaps post some examples?

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photogerald Senior Member • Posts: 1,798
18% grey

Lee Davis wrote:

What I could never understand though was why my K20 also underexposes on dull cloudy days - anyone know why they do that?

If your underexposed photos also include those clouds, that is why - the camera is trying to meter the clouds as 18% grey (or 12% according to http://www.bythom.com/graycards.htm ), which causes the photo to be underexposed. Matrix metering is supposed to be "smarter" and recognize these types of scenes, but I find it to be a bit unpredictable in my K20D so I just user center-weighted now and make the appropriate adjustments when I recognize lighting conditions that could fool the meter.

awaldram
awaldram Forum Pro • Posts: 13,271
Re: K5 Metering?

ozdean wrote:

Andrew I'm wondering if having auto iso on with flash might be a lot of the problem?

Outside 'X' I'm pretty confident it is, In low light the camera does its best to capture ambient light and is quite happy up @ iso3200

With this much sensitivity from the sensor I don't think the current flash range can be quenched fast enough to avoid blow out.

Selecting iso400 seems to cure a lot of ills, Which I guess would have been the upper limits when the flashes were designed

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Regards Dean - Capturing Creation

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OP barony2396 New Member • Posts: 2
Re: K5 Metering?

Hi,

Thank you all for all of your advice. The auto ISO+Flash was definitely responsible for my flash overexposure problem.

As for the metering generally, I'm rapidly getting used to it. The digital preview function helps a lot. I suspect the meter is smarter than I am...

Anyways, can't say I'm unhappy with the purchase. The K5 and FA31 Limited together are dynamite.

Paul.

pentaxnut Regular Member • Posts: 332
Re: K5 Metering?

Wait until you put a 40mm pancake on it.....then it feels like a point and shoot....

photogerald Senior Member • Posts: 1,798
Re: K5 Metering?

barony2396 wrote:

Thank you all for all of your advice. The auto ISO+Flash was definitely responsible for my flash overexposure problem.

Glad you found the cause of the problem. It sounds like something that can be easily fixed by Pentax in a firmware update.

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