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10-23-2013, 05:55 PM   #1
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K-3 and low-light shooting

From the specifications and the manual, it's clear the K-3 should be an amazing low-light shooter:
  • -3 to +18 EV brightness range for auto-focus;
  • three extra sensitive f2.8 AF points, compared to the K-5II's one;
  • -3 to +20 exposure metering range coupled to a 86k pixel RGB sensor.
Even compared to an acknowledged excellent low-light cameras like the Nikon D4 or Canon 1Dx, the K-3 looks great:
Nikon D4:
  • -2 to +19 EV brightness range for auto-focus;
  • -1 to +20 EV exposure metering w 90k pixel RGB sensor
Canon 1Dx:
  • -2 to +18 EV brightness range for auto-focus;
  • 0 to +20 EV exposure metering w 100k pixel RGB sensor

Hopefully the K-3 sensor and the Prime III processor will be able to take advantage of all this and deliver great low-noise results.

While I can certainly understand the usefulness of -3 EV sensitivity for the autofocus system, I am somewhat puzzled by the practical value of having such a sensitive exposure metering system capable of metering down to -3 EV.

When you have a scene (or area of a scene) metered at -3 EV, it's going to be very dark and there is unlikely to be any visible detail there at all. It's basically gonna be black there. So while it's wonderful to have a camera that's able to evaluate and set exposure for such a low-light scene, how might -3 EV metering help more than -1 EV?


Last edited by rawr; 10-23-2013 at 10:19 PM. Reason: Added IDx info
10-23-2013, 05:57 PM   #2
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QuoteOriginally posted by rawr Quote
From the specifications and the manual, it's clear the K-3 should be an amazing low-light shooter:
  • -3 to +18 EV brightness range for auto-focus;
  • three extra sensitive f2.8 AF points, compared to the K-5II's one;
  • -3 to +20 exposure metering range coupled to a 86k pixel RGB sensor.
Even compared to an acknowledged excellent low-light camera like the Nikon D4, the K-3 looks great:

D4:
  • -2 to +19 EV brightness range for auto-focus;
  • -1 to +20 EV exposure metering w 90k pixel RGB sensor
Hopefully the K-3 sensor and the Prime III processor will be able to take advantage of all this and deliver great low-noise results.

While I can certainly understand the usefulness of -3 EV sensitivity for the autofocus system, I am somewhat puzzled by the practical value of having such a sensitive exposure metering system which also meters down to -3 EV.

When you have a scene (or area of a scene) metered at -3 EV, it's going to be very dark and there is unlikely to be any visible detail there at all. It's basically gonna be black there. So while it's nice to have a camera that's able to evaluate and set exposure for such a low-light scene, how might -3 EV metering help more than -1 EV?
that is really good to hear, thanks for posting!
10-23-2013, 06:24 PM   #3
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Well I think your thinking of hand held shots only, being able to meter a night shot may save trial and error for exposures up to 30 seconds before bulb is needed.
10-23-2013, 06:31 PM   #4
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QuoteOriginally posted by Dr_who Quote
Well I think your thinking of hand held shots only
True. I don't often do long exposures. What you wrote makes sense.

10-23-2013, 06:47 PM   #5
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QuoteOriginally posted by rawr Quote
how might -3 EV metering help more than -1 EV?
Extra margin...at the far limits, it takes longer to focus. This will let it focus faster in the old dark conditions that would have made the K10D/K20D hunt for a few seconds...
10-23-2013, 06:59 PM   #6
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QuoteOriginally posted by kenyee Quote
Extra margin...at the far limits, it takes longer to focus. This will let it focus faster in the old dark conditions that would have made the K10D/K20D hunt for a few seconds...
Well, the AF sensitivity being -3EV yes, rawr was talking about the metering system being sensitive to -3EV also.

I guess it would make sense to have it sensitive enough to help figure out exposure in night shots without having to shoot trial/error.
10-23-2013, 07:03 PM   #7
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Don't forget that the new metering sensor is helping the AF system as well.
10-23-2013, 07:05 PM   #8
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QuoteOriginally posted by jaad75 Quote
Don't forget that the new metering sensor is helping the AF system as well.
I was thinking that also, but I wasn't sure if it would actually be helping at the -3EV. The RGB sensor is intended to help tracking by recognizing the colours of the tracked object. If it is sensitive to -3EV for colour as well, that'd be awesome.

10-23-2013, 07:13 PM   #9
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QuoteOriginally posted by kenyee Quote
Extra margin...at the far limits, it takes longer to focus.
I guess it is logical that the -3 EV for light-metering will be working alongside the -3 EV for the AF metering, as illustrated below.
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10-23-2013, 07:30 PM   #10
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I expect that the feature below will also help [a bit] with low-light shooting, especially using manual focus lenses (like my Rokinon 85 f1,4), where sometimes it is challenging to see the focus target due to scene dimness:

"Thanks to the application of a new coating to the reflective surfaces, [the pentaprism's] light transmittance is almost 15 percent higher than that of the K-5II’s."
10-23-2013, 08:07 PM   #11
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QuoteOriginally posted by rawr Quote
I expect that the feature below will also help [a bit] with low-light shooting, especially using manual focus lenses (like my Rokinon 85 f1,4), where sometimes it is challenging to see the focus target due to scene dimness:

"Thanks to the application of a new coating to the reflective surfaces, [the pentaprism's] light transmittance is almost 15 percent higher than that of the K-5IIís."
This should also help mitigate the slight dimming effect of the Canon S-screen that some have an issue with. I hardly even notice it. And I already have one ordered for my K-3 so I can install it on day 1. I will always have one until they implement VF focus-peaking.
10-23-2013, 08:24 PM   #12
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QuoteOriginally posted by DogLover Quote
the Canon S-screen
Do they work with the Pentax?
10-23-2013, 08:27 PM   #13
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QuoteOriginally posted by jaad75 Quote
Do they work with the Pentax?
https://www.pentaxforums.com/forums/pentax-k-5/142241-best-screen-ever-manual...anon-ee-s.html

I've got one in my K-5 and it works very well.
10-23-2013, 09:09 PM   #14
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QuoteOriginally posted by jaad75 Quote
Do they work with the Pentax?
Yes, but they have to be cut down to fit. focusingscreen.com sells them with various markings (or none) already cut to fit. Easy peasy. Had one in my K-5 and have one in my K-5IIs now.
10-26-2013, 02:40 PM   #15
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While we are here, is anyone able to explain to me exactly what autofocus to -3EV actually means.

I'm struggling with the concept of how dark this is?
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