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06-16-2019, 08:32 PM   #1
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New K-70 - Metering issues between Live View and OVF

New K-70 check-in on this thread from a 1st usage today... metering issues between Live View and OVF.

Live View meters correctly.
OVF meter underexposes all images by 2 to 3 stops (in my usage today).

Setting exposure settings equally in manual mode, the images appear identical (no aperture block failure).


Last edited by MarkJerling; 06-17-2019 at 02:39 AM.
06-16-2019, 08:46 PM   #2
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QuoteOriginally posted by disasterfilm Quote
New K-70 check-in on this thread from a 1st usage today... metering issues between Live View and OVF.

Live View meters correctly.
OVF meter underexposes all images by 2 to 3 stops (in my usage today).

Setting exposure settings equally in manual mode, the images appear identical (no aperture block failure).
We probably need a separate thread for this issue, since you are not the first to encounter it. Member @RedSky; for example, sent his camera in for repair - they replaced the aperture control mechanism but the problem persisted. When he asked for help here, all he got was advice on dealing with the aperture control mechanism - which just made him mad since that had already been 'fixed'. That is one problem with the aperture control issue - people can't see beyond it and want always to fix it ......even when it isn't the problem.

In your case, is the OVF error sufficiently close that you can get good readings by adjusting the Exposure Control {the +/- EV setting}?
06-17-2019, 02:42 AM   #3
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Moved to thread of it's own.
06-17-2019, 04:34 AM   #4
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QuoteOriginally posted by disasterfilm Quote
New K-70 check-in on this thread from a 1st usage today... metering issues between Live View and OVF.

Live View meters correctly.
OVF meter underexposes all images by 2 to 3 stops (in my usage today).

Setting exposure settings equally in manual mode, the images appear identical (no aperture block failure).
Was it a bright day with the sun behind you ? Camera on a tripod ?

Maybe light entering the viewfinder.

Post a couple of pictures with exif intact demonstrating the problem.

06-17-2019, 07:38 AM   #5
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Definitely didn't mean for this to have its own thread about it, just wanted to log my experience in with the others on the megathread.
The GoogleFu got me to find that one, and I wanted others who also google'd it to have a recent verification that it is, indeed, happening.

Pschlute, thanks for your matrix of questions. I would have included those if I had intended a full expose on the issue.

* Metering mode is Full Matrix metering (full green).
* Problem persisted with native lenses (HD DA 21, D FA 50 macro) and 3rd party lens (Sigma ART 35).
* Issue happened while tripod mounted, so zero changes to the composition.
* Indoors shooting through window. No sun or light sources behind. I covered up the VF with my thumb too while troubleshooting.
* No highlight clipping anywhere across the frame with manual Live View metering. Histogram looked well centered.

Proper metering for even histogram over LV gave one exposure reading. I switched to OVF to save on battery power, and that's when I saw that it spiked to saying the frame was +2 stops over-exposed. About 15 minutes later, the difference was +3 stops.

reh321 - your suggestion is probably what I'll end up doing in the future. Meter the scene in LV, then switch to OVF and adjust the exposure compensation so that it matches. This will be OK as long as I'm not switching back and forth between viewfinder methods, but the notion that it's sometimes +2 and +3 stops' difference is a bit unnerving. Needless to say, I've got a lot more tinkering to do before I fully understand the fix.

I've experienced this phenomenon a whole bunch with every camera I've ever used, particularly when shooting into bright light or hard contrast. It happens with the K-1, KP, K-3, and K-5iis - usually about 2/3 of a stop difference, depending. But it's the other way - in these cases the OVF overexposes just a bit, and Live View metering is more accurate.

I didn't save any of the photos, but if there's any interest in it I'll do an actual work-up of the problem throughout a scene of changing light. I bought this K-70 on a whim, finding a stupidly-good deal on it. So it's not like this is my only camera, or my backup. This one a luxury to have, so I'll just be adjusting its use to particular cases.
06-17-2019, 10:17 AM - 1 Like   #6
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QuoteOriginally posted by disasterfilm Quote
Definitely didn't mean for this to have its own thread about it, just wanted to log my experience in with the others on the megathread.
I will log your report on the other thread as a metering issue and link back to here.

QuoteOriginally posted by disasterfilm Quote
I've experienced this phenomenon a whole bunch with every camera I've ever used, particularly when shooting into bright light or hard contrast. It happens with the K-1, KP, K-3, and K-5iis - usually about 2/3 of a stop difference, depending. But it's the other way - in these cases the OVF overexposes just a bit, and Live View metering is more accurate.
Hmmmmm...so not a K-70 issue? Metering in the optical viewfinder is different than live view, for sure, but which is more accurate is difficult to assess. Is it possible that live view underexposes? I just did a "blank wall" test with my K-3 and that is the result I got in both center-weighted and matrix modes, at least based on histogram evaluation. Moving to the backyard deck + trees + grass, I got the same. Comparing to a hand-held meter showed close agreement with the viewfinder metering.* Whether the same is true for the K-70 is hard to say; the viewfinder metering is quite different than the K-3.



Steve

* Sekonic handheld indicated 1/3 stop more than viewfinder meter.
06-17-2019, 11:23 AM   #7
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QuoteOriginally posted by disasterfilm Quote
reh321 - your suggestion is probably what I'll end up doing in the future. Meter the scene in LV, then switch to OVF and adjust the exposure compensation so that it matches. This will be OK as long as I'm not switching back and forth between viewfinder methods, but the notion that it's sometimes +2 and +3 stops' difference is a bit unnerving. Needless to say, I've got a lot more tinkering to do before I fully understand the fix.
The best solution would be to get the metering fixed.

One alternative solution would be to program a 'User Mode' to set EC to something like +2.5 if that is generally correct.
06-17-2019, 01:23 PM   #8
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QuoteOriginally posted by disasterfilm Quote
I bought this K-70 on a whim, finding a stupidly-good deal on it.
Is your K-70 new? If so, perhaps you might want to negotiate a replacement from the seller as defective?


Steve

06-17-2019, 08:46 PM   #9
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QuoteOriginally posted by disasterfilm Quote
Definitely didn't mean for this to have its own thread about it, just wanted to log my experience in with the others on the megathread.
The GoogleFu got me to find that one, and I wanted others who also google'd it to have a recent verification that it is, indeed, happening.

Pschlute, thanks for your matrix of questions. I would have included those if I had intended a full expose on the issue.

* Metering mode is Full Matrix metering (full green).
* Problem persisted with native lenses (HD DA 21, D FA 50 macro) and 3rd party lens (Sigma ART 35).
* Issue happened while tripod mounted, so zero changes to the composition.
* Indoors shooting through window. No sun or light sources behind. I covered up the VF with my thumb too while troubleshooting.
* No highlight clipping anywhere across the frame with manual Live View metering. Histogram looked well centered.

Proper metering for even histogram over LV gave one exposure reading. I switched to OVF to save on battery power, and that's when I saw that it spiked to saying the frame was +2 stops over-exposed. About 15 minutes later, the difference was +3 stops.

reh321 - your suggestion is probably what I'll end up doing in the future. Meter the scene in LV, then switch to OVF and adjust the exposure compensation so that it matches. This will be OK as long as I'm not switching back and forth between viewfinder methods, but the notion that it's sometimes +2 and +3 stops' difference is a bit unnerving. Needless to say, I've got a lot more tinkering to do before I fully understand the fix.

I've experienced this phenomenon a whole bunch with every camera I've ever used, particularly when shooting into bright light or hard contrast. It happens with the K-1, KP, K-3, and K-5iis - usually about 2/3 of a stop difference, depending. But it's the other way - in these cases the OVF overexposes just a bit, and Live View metering is more accurate.

I didn't save any of the photos, but if there's any interest in it I'll do an actual work-up of the problem throughout a scene of changing light. I bought this K-70 on a whim, finding a stupidly-good deal on it. So it's not like this is my only camera, or my backup. This one a luxury to have, so I'll just be adjusting its use to particular cases.
QuoteOriginally posted by disasterfilm Quote
I've experienced this phenomenon a whole bunch with every camera I've ever used, particularly when shooting into bright light or hard contrast. It happens with the K-1, KP, K-3, and K-5iis - usually about 2/3 of a stop difference, depending. But it's the other way - in these cases the OVF overexposes just a bit, and Live View metering is more accurate.

I think, as what you are describing with your cameras is an entirely different issue than the aperture solenoid issue, it's certainly appropriate in it's own thread. Especially as you say you've had this problem with near every Pentax DSLR you've owned. Certainly, the K-1, KP, K-3 and K-5iis do not have the part that causes the issues others have had with their K30, K50 and, in limited cases, K70 cameras.
06-18-2019, 06:00 AM   #10
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QuoteOriginally posted by disasterfilm Quote
I've experienced this phenomenon a whole bunch with every camera I've ever used, particularly when shooting into bright light or hard contrast. It happens with the K-1, KP, K-3, and K-5iis - usually about 2/3 of a stop difference, depending. But it's the other way - in these cases the OVF overexposes just a bit, and Live View metering is more accurate.

. . . I bought this K-70 on a whim, finding a stupidly-good deal on it. So it's not like this is my only camera, or my backup. This one a luxury to have, so I'll just be adjusting its use to particular cases.
Interesting topic. I just did a quick test on my K-S2 and KP. The K-S2 underexposes in LV, but by only ~1/4 stop. The KP showed no difference. I'd get it fixed under warranty if that option is available to you.
06-18-2019, 12:25 PM - 1 Like   #11
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QuoteOriginally posted by stevebrot Quote
Is your K-70 new? If so, perhaps you might want to negotiate a replacement from the seller as defective?


Steve
Hi Steve,

Thanks for all of your comments and suggestions.

It's definitely a metering issue and it's unlike what I've seen with my other K-mount cameras. I'm willing to bet it's not a K-70 issue; it's likely it's a "this individual camera" issue.

I was short-thoughted to call this similar to the other metering inconsistencies I've experienced on the other cameras. Those won't manifest in brick wall tests or evenly-lit scenes. It happens for me when shooting into bright lights and into hard contrast - like shooting straight into the sun in a scene. The OVF exposes brighter than the LV in that case a whole bunch. OVF is quicker at clipping highlights, and LV metering seems to avoid it better. And 0.6 stops (at the worst) is definitely an acceptable variance to me; no complaints at all.

The scene I first shot with this camera wasn't that same scene-lighting case. I had a K-1 on hand, and IIRC it metered evenly in both modes.

I think I'll dig around inside the open body cavity and see if I can find something that looks strange. I can't explain it otherwise - the metering sensor is thinking there is more light than there is, so it's not like there's a neutral-density film covering the sensor (since that would err the other way).

QuoteOriginally posted by stevebrot:
Is your K-70 new? If so, perhaps you might want to negotiate a replacement from the seller as defective?
This was a repackaged model + 18-135 lens from Amazon Warehouse, listed in very good condition, reporting a cosmetic issue on the front of the body and none of the boxes for the body or lens. I also took delivery 10 weeks ago, so I'm far outside the return period. I guess this is reverse karma, because in the Deals forum I've been quick to speak well of Amazon Warehouse in the past. Now I get to tap the brakes on that.

Any repair is going to be more costly than I paid for the body itself, so I think I'll maybe convert it to an IR camera instead, where I wouldn't meter off the OVF anyway. Change of plans for how I intended to use the body, but this could be my lemons-to-lemonade solution.

---------- Post added 06-18-19 at 02:43 PM ----------

QuoteOriginally posted by MarkJerling Quote
I think, as what you are describing with your cameras is an entirely different issue than the aperture solenoid issue, it's certainly appropriate in it's own thread. Especially as you say you've had this problem with near every Pentax DSLR you've owned.
Thanks Mark, and I agree. Definitely not the aperture block solenoid issue.

I cringed a bit re-reading my past post, since it's definitely not the same phenomenon I've seen with the other cameras. I don't think it's a K-70 model issue, I think this one is a "this specific device" issue.

Last edited by disasterfilm; 06-18-2019 at 12:40 PM.
06-21-2019, 05:59 AM   #12
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Hello,

K70 User, since Q4 2017. Shutter Count 9000+. I had the same Problem yesterday, ( 20.06.2019 ) Viewfinder and Liveview exposure doesnt equally match ( Highest delta met ~ 5 Stops ) . Right adjusted Metering through Viewfinder results in underexposure. Adjusting other Parameters to Overexposure (by Metering reading) result to normal exposed Images. Using Live View seems to be the healthy option, nothing strange there. Using Auto Mode makes the camera usable only in LV. The Viewfinder is usable only on other fully or partial manually adjusted Modes but some "calibration shooting" is required, metering has to be ignored.


1 Hour Test made ( today - 21.06.2019 ) using 2 AL Limited 21mm 3.2F , 35mm 2.8F. Using different Lenses does not influence the problem. Same Problem countered as the last day. After some shooting the device randomly metered equally again ( Delta ~1/4 stop )

All other settings were left on stock Adjustments.

The camera is still within Warranty but the random "fix" confuses me, so, i will keep testing the following days before contacting my Distributor.
06-21-2019, 10:01 AM - 1 Like   #13
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Before this "issue" becomes an example of "Internet Truth"*, it might be good to mention that the two metering systems evaluate from very different inputs using different algorithms. Neither system is immune to being "fooled" and for many subjects, a truly acceptable exposure may be impossible from a single exposure regardless of meter sophistication. In terms of actual metered LV, neither is intrinsically more "accurate" except, perhaps, as response to a calibrated light source. A camera repair shop can do that comparison and might even do so for free.


Steve

* ...the combination of reported observations, conventional wisdom, bias, and wishful thinking as interpreted from the Web and republished by bloggers, in social media, and by forum users.
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