Odd K20d light meter

<p>I have 1/4 mind to complain to PENTAX, but 3/4 mind to come here first, so:<br>

I have problems with the light meter. First, it would occasionally read that every shot should be 1/4000 of a second. Now it always under-meters (and if I let it have its way, underexposes) by about 3 stops. How can I fix this? Do I need to update the firmware? Clean the reflex mirror (which I did on my film camera to no bad ends) or focusing screen? Or should I make PENTAX take a look? I have used a non-PENTAX battery, but the problem started since I stopped needing to use it (the problem came after one charge worth of use from generic battery (first use) and 2 months with just PENTAX Prop. battery).</p>

<p>Thank you for your help.</p>

Peter,

Considering that the K20D is a three year old and three generation back model, I think your feedback to Pentax may

be somewhat less effective. But I agree with you that the camera underexposes as a baseline behavior. Rather than

three stops for me, I'd say about one stop, though today I was shooting in daylight and had to boost the metering by

two stops. This is quite noticeable after using my Canon 7D which is near perfect for metering.

 

The only time I've had the 1/4000 reading is with the DA Ltd. 15mm. It happens about 15% of the time. Just annoying

enough.

 

To me the underexposure metering is a minor hassle easily fixed by adjusting the compensation. I mostly bracket my

shots anyway so something acceptable is usually there.

 

ME

<p>For me, every lens shows up as 1/4000 in daylight (even with wight overcast and tree canopies). Indoors, it shows up as 1/1500 of a second. I can correct it in post processing, but that that adds an unnecessary 5 minutes to my day (per photo, assuming I don't need noise reduction or sharpening).</p>

<blockquote>

<p>every lens shows up as 1/4000 in daylight</p>

</blockquote>

<p>Well, that sounds like a hardware repair job. I assume you don't have any extended warranty coverage? So, perhaps it will cost at least $200 to get fixed. Time to evaluate whether that cost is worth spending. . .</p>

<p>ME</p>

<p>Any other options as to what it could be? Could I get firmware with, say, adjustable meter to compensate? I paid just a little more than that for the camera.</p>

<p>What lens are you using and in which mode is the body, P? For me this sounds like a problem with the mount contacts, did you try cleaning them?</p>

<p>You can adjust the meter, as I noted above. You should have the latest firmware anyway, but the latest release won't change your problem. I would follow Markus' advice first by gently cleaning the mount contacts with alcohol.<br>

Intuitively I don't think this is the problem, but who knows. I'm guessing that you paid less for a problematic camera--the K20D is probably worth $450 or so.</p>

<p>ME</p>

<p>I am using Av and M, and the body mount contacts are not a factor with anything but my 28mm/2.8. That is Ka mount, and the rest are T, A, M, or K mount (one of each). I will clean my camera though. I've been meaning to do that anyway.</p>

<p>Refurbished by PENTAX-approved retailer</p>

<p>Green-button metering with pre-KA lenses is known to be not particularly accurate with any Pentax DSLR. Exposure errors are the norm, and are different with each lens. Best way for good exposure with pre-KA lenses is chimp the histogram, probably using manual exposure.<br>

Using pre-KA lenses without the green button is ONLY even plausibly accurate at the maximum aperture. The camera has no idea that pre-KA lenses will stop down when you take the picture.</p>

 

<p>Peter,<br>

This might be a dumb question, but since you are using manual lenses with aperture rings have you enabled the feature to allow use of the aperture ring for older lenses? If not, I believe your camera will be metering as if your aperture is always set wide open which would explain the 1/4000 sec. I've had pretty good luck on my K20d with all of my older lenses - but I typically only use the center spot for manual lenses and pick the spots my self. Usually I leave the exposure compensation at +2/3 to +1 stop to just push the histogram a little to the right.<br>

Andre</p>

<p>What Andrew says, although if using an "A" lens, you should be able to just leave the lens set at "A" rather than enabling aperture ring use. What ISO setting are you using? MY K20D meters ok, although tending towards a little underexposure. Somewahat less so after the latest firmware update.</p>

<p>I use ISO 1-400. I do use A on my Ka lens, even on my full manual camera, because it locks it in F22 (in an all manual camera).</p>

<p>I just updated from firmware 1.01 to 1.04. Also, the problem is just with segmented metering. Spot and C/W Spot are "Spot" on.<br /> <br />I can (and would be fine with) live with just those two, but I still want it fixed, So I hope that helps you help me, and thanks for the help thus far.</p>

<p>Correction: only spot works, and it over-exposes by 1/2 stop.</p>

<p>I venture to guess that the camera hardware is alright (because it 'almost' works in spot mode). Is the mirror/focussing screen not completely clean?<br>

EDIT: I saw that you already mentioned about cleaning the focussing screen. Do tell us if that worked.</p>