[MrPetkus]

Folks,
I'm having big exposure issues spot metering on the K5 - 1-2 stops on average. The only lens that will properly expose using spot meter is the DA* 50-135/2.8. This lens is also SDM and the only lens that doesn't have FF issues in low light. I don't own any other SDM lenses. I'm not claiming there is a connection between problematic metering and SDM/non-SDM drive lenses - just noting what I've observed. Note: I don't want this to become yet another FF problem thread.

I'll just focus on the DA 15/4 as an example. The 15 is my favorite out-with-the-family lens. Center weighted and segment metering is OK. Spot is *always* over-exposed. Does anyone else have this issue? How about when using the K5 - 15/4 combo? I suspect this isn't issue isn't pandemic otherwise there would be other threads about it. Ideas?

[Cannikin]

Spot metering isn't actually a "spot". Just like the AF "points", it covers an extended area in the center of the frame. The wider the lens, the more likely it is to have extra stuff included in the "spot", throwing it off.

In any case, spot metering works fine with my K-5 + 15 ltd, as long as I make sure the thing I'm trying to meter off takes up most of the center "( )" area in the viewfinder.

[MrPetkus]

I know what spot metering is - it doesn't matter what I'm shooting. Every single image is overexposed. Again, never had this issue on the K7, same lens. If yours is working then something must be wrong with my camera.

[Cannikin]

I know what spot metering is - it doesn't matter what I'm shooting. Every single image is overexposed. Again, never had this issue on the K7, same lens. If yours is working then something must be wrong with my camera.

Sorry, didn't mean to imply that you don't know what you're talking about. Just thought I'd just check one of the more obvious solutions considering it happens with a wide angle lens but not the telephoto.

Should probably check with Pentax then.

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Last edited by Cannikin; 02-06-2011 at 09:35 PM.

[MrPetkus]

No, I'm sorry. Just irritated. Here are 3 pics that I *just* took - straight from the camera, just converted to JPEG. Focus on clock face. Same results if I focus on anything else inside or outside, distance or close.

All 3 aperture priority, f/4, Auto WB.
Pic 1 Center weighted, ISO 5000, 1/30s
Pic 2 Segment, ISO 6400, 1/30s
Pic 3 Spot, ISO 6400, 1/8s -- there is no guesswork on my part, I simply see that the shutter speed is plain wrong at this point.

Sorry, didn't mean to imply that you don't know what you're talking about. Just thought I'd just check one of the more obvious solutions considering it happens with a wide angle lens but not the telephoto.

Should probably check with Pentax then.

[philbaum]

Do you have a split lens viewfinder screen installed on your K5. Split lens after market screens are known to mess up the spot metering capability. At least they did on my K20 till i remembered reading about the problem

[MrPetkus]

Yes I do - the KatzEye! So that's what the problem is - I'll be damned. Lemme google that. Thanks for pointing me in that direction!

Edit: So what was your solution - get rid of the split screen viewfinder?

Do you have a split lens viewfinder screen installed on your K5. Split lens after market screens are known to mess up the spot metering capability. At least they did on my K20 till i remembered reading about the problem

[MrPetkus]

So I went to the KatzEye site and read this information. Looks like this is another "case closed". Thanks philbaum.

The KatzEye™ focusing screen for the Pentax K-5 and K-7 shows only a very slight effect on light metering. In our testing, the KatzEye™ screen tested within factory tolerance in nearly all situations. The only exception is when using spot metering with lenses having apertures of f2.8 or smaller. This combination may produce overexposure, so it is advisable to use either center-weighted average metering or multi-segment metering to preserve accurate meter response when using small aperture lenses. In the event that spot metering mode must be used with a small aperture lens, it is advisable to set an appropriate exposure compensation by reading the histogram of a test shot. Approximate exposure compensation values are as follows*:


Note: These exposure compensation suggestions are a recommended starting point only and actual results may vary depending on conditions. Users are advised to take a test photo and check the histogram before beginning any critical work. Apertures indicated in the above chart are the lens maximum aperture as indicated on the lens body and are not affected by the actual aperture chosen for a given photo.

* Metering test results presented are based on testing of the K-7 model. While results are expected to be similar for the K-5, users of this model are strongly encouraged to take a test shot and check the histogram before beginning any critical shooting.

[philbaum]

Yes I do - the KatzEye! So that's what the problem is - I'll be damned. Lemme google that. Thanks for pointing me in that direction!

Edit: So what was your solution - get rid of the split screen viewfinder?

Thanks for the rep point! I kept the katzeye screen and just stopped using spot metering. when i upgrade to the K5 I'll keep the K20 and its screen. It was especially useful for long tele's, manual in particular.

I'm shooting more indoors stuff now, including live theatre, where the spot metering would be useful. so my plan for the K5 is to just stay with the stock screen so i can use spot metering. I'm not implyin that one can't use other metering indoors, but i get in situations trying to shoot actors faces on a dark stage with spotlights on them, and spot metering is something i'd like to try for that.

best wishes,