[recklessdiffraction]

I was wondering about the spot meter in the KP. I generally prefer spot metering because I so dislike what I've previously experienced of digital cameras auto matrix metering.

With a one degree spot meter we can properly use the Zone system. This is to my understanding pretty much a black and white thing, and film oriented too. However , or whatever ... I was wondering if the spot meter in the KP is anything like the one degree meters that Sekonic and the like produce. I'm obviously going to go and play with this idea and see what I observe. But I'm interested to hear if anyone else is into spot metering and applying zone metering techniques?

For example the1 degree spot meter would meter the choosen area to middle grey (zone 5). If that were a dark area where we wanted to retain some detail we could then under expose to bring it down to zone 3. Obviously in the digital realm we tend to be less fussy about this type of thing. The medium encourages snappy shooting, chimping, shooting - all in a continuous and immediate feedback loop.

Still I'm thinking, is the spot meter like a 1 degree meter.

Daft as it sounds Im contemplating a project where I limit myself to 12 exposures as that would equate to 120 roll at 6x6. So a bit of discipline to slow down and learn to get the right exposure in camera in one shot. Which is very old style but kind of how it was and possibly one of the attractions of photography in the film days. I mean it wasn't all photojournalism dashing off a dozen rolls.

[UncleVanya]

This older thread may help:
Light meter vs DSLR - PentaxForums.com

One bit of info it gave me was that unless you use a long lens the spot meter in the camera isn’t 1 degree it’s larger.

[c.a.m]

is the spot meter like a 1 degree meter.

The extent of the spot area in degrees depends on the focal length of the attached lens.

On the Pentax K-7, K-5, K-3, and KP APS-C format cameras, the spot metering frame corresponds to the center mark in the viewfinder*: ( )

The centre spot width occupies 10.6% of the horizontal frame width (proportional to the sensor width in mm or the lens horizontal angle of view in degrees).The spot angles for various focal lengths are shown below.



*Reference:e.g., K-3 II Operating Manual, English, p. 16

- Craig

[photoptimist]

On the K-5 (and probably the KP), the central circle of the viewfinder that shows the boundaries of the spot meter is a bit more than 1% of the frame area. To turn the camera into a 1° spot meter, you'll need roughly a 135mm lens. A longer lens will give a narrower spot meter

You'll find that M mode and the over/under exposure bar graph on the back panel display can really help with Zone system measurements.

As far as limiting yourself to 12 exposures, just limit yourself to tiny SD cards. A 512 MB card will probably only hold 10-15 images (depending on the scene details, focus, and ISO of the image). And if you only have larger cards, then fill them with a folder of crap until there's only 512 MB or so of space left.

Have fun!

P.S. I see @c.a.m beat me to it on the focal length issue. Note that the "centre spot width occupies 10.6% of the horizontal frame" implies the spot occupies about 16% of the vertical frame which implies it occupies a bit more than 1% of the total frame area.

[recklessdiffraction]

This older thread may help:
Light meter vs DSLR - PentaxForums.com

One bit of info it gave me was that unless you use a long lens the spot meter in the camera isn’t 1 degree it’s larger.

Thanks yes. Took a while to read it but as always lots of good info around here.

---------- Post added 01-19-21 at 02:59 AM ----------

The extent of the spot area in degrees depends on the focal length of the attached lens.

On the Pentax K-7, K-5, K-3, and KP APS-C format cameras, the spot metering frame corresponds to the center mark in the viewfinder*: ( )

The centre spot width occupies 10.6% of the horizontal frame width (proportional to the sensor width in mm or the lens horizontal angle of view in degrees).The spot angles for various focal lengths are shown below.



*Reference:e.g., K-3 II Operating Manual, English, p. 16

- Craig

That is the kind of detail that I was hoping for. Amazed that you had this to hand. Really useful. Thanks for your help.

---------- Post added 01-19-21 at 03:32 AM ----------

On the K-5 (and probably the KP), the central circle of the viewfinder that shows the boundaries of the spot meter is a bit more than 1% of the frame area. To turn the camera into a 1° spot meter, you'll need roughly a 135mm lens. A longer lens will give a narrower spot meter

You'll find that M mode and the over/under exposure bar graph on the back panel display can really help with Zone system measurements.

As far as limiting yourself to 12 exposures, just limit yourself to tiny SD cards. A 512 MB card will probably only hold 10-15 images (depending on the scene details, focus, and ISO of the image). And if you only have larger cards, then fill them with a folder of crap until there's only 512 MB or so of space left.

Have fun!

P.S. I see @c.a.m beat me to it on the focal length issue. Note that the "centre spot width occupies 10.6% of the horizontal frame" implies the spot occupies about 16% of the vertical frame which implies it occupies a bit more than 1% of the total frame area.

Yes I figured it had to be M mode, tho I find that graph display less helpful. It flickers and moves about a bit much. How would you apply it? I was figuring I'd just set the shutter that I wanted and then adjust the aperture to find a good exposure reading for the spot area. Assuming that then being middle grey, I'd then over or under expose to place the selected spot on zone 3 or zone 7 or 8 (depending on what texture and detail I want to retain and whether or not I'm metering shadows or highlights).

Good idea about using small cards. I'll have to search around the house given that you can hardly buy these things anymore. It's cheaper to buy a 16gb card than a 512mb class 4! Anyway its a great idea and either way I'm going to do it.

thanks again, cheers

[UncleVanya]

You can format your larger cards and set the partition smaller than the actual size.

[recklessdiffraction]

You can format your larger cards and set the partition smaller than the actual size.

Cheers. I'll try that. Yesterday I tried an old 1gb card I found buried in a pocket in a bag. I ran off about 4 pictures in the living room and the camera led card access lamp was flickering away for minutes trying to catch up. I thought it was crashing!

[UncleVanya]

Cheers. I'll try that. Yesterday I tried an old 1gb card I found buried in a pocket in a bag. I ran off about 4 pictures in the living room and the camera led card access lamp was flickering away for minutes trying to catch up. I thought it was crashing!

LOL - yes, some of those old cards are quite slow.

[pacerr]

. . . the spot area in degrees . . .

I find it most useful to think of the 'spot meter', not in degrees of projected area, but rather what it ignores . . . that it does not integrate exposure readings outside of the 'spot' defined by the lens in use whatever that spot may be at any given time.

Other metering methods do involve some sort of algorithm for incorporating readings for all of the areas in the scene.

Center weighted mode biases for the center of the scene but accounts for edges with some degree of lessor weight.

Various auto modes divide the scene into a matrix and assign weight to each sector in a 'logical' manner based upon an OEM-driven algorithm; useful only if you know what that assigned pattern is. I.e., many auto metering schemes presume that readings from the extreme corners should have less value than from center and horizon sectors. Other choices may bias for landscape patterns, sports-centric shots, etc. (RTFM and experiment)

ALL metering systems require knowledge of what is specifically being metered and when and how that information should be used wisely. Calibration against a standard is useful if not a necessity.

Or . . . ya can just chimp it 'til ya get your blinkies right then PP it into submission!

[steephill]

Or . . . ya can just chimp it 'til ya get your blinkies right then PP it into submission!

Exactly, ETTR then PP until it looks like you meant it. But then people want RAW histograms, Uni-balance WB and all sorts of other complications.