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01-02-2019, 07:56 AM   #1
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Pentamirror

Hello, I have a pentax k-r. I have a question. Can you change the pentamirror of the camera. Greetings Michael Siebel

01-02-2019, 08:12 AM - 1 Like   #2
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Welcome to the Forums!

I'm thinking that would be a pretty serious repair.

Why would you want to change out the pentamirror?

Are you sure you're not thinking about the focus screen?
01-02-2019, 09:39 AM - 1 Like   #3
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People have changed pentaprisms in older bodies for years. I'm sure it can be done - but you'd likely need to do it yourself or the cost would be too high. Most models with Pentamirror are pretty old. Current models all use Pentaprisms which are brighter and more durable from what I recall. Your best choice may be to simply replace the camera.
01-02-2019, 10:36 AM - 1 Like   #4
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Is this a terminology issue, are you referring to the focusing screen? If you are asking of the focusing screen is something that can be changed the answer is no on the K-r but yes on later models.

01-02-2019, 10:42 AM - 1 Like   #5
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QuoteOriginally posted by stappenplan Quote
Can you change the pentamirror of the camera.
You will have to find a unit as same size and shape. Otherwise the focusing screen and viewfinder will not be aligned. And be careful about the exposure light sensor.
01-02-2019, 01:26 PM - 2 Likes   #6
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focussing screen (.com) list focussing screens for the K-r, although the price would roughly equal the cost of a used K-r.
01-02-2019, 03:38 PM - 1 Like   #7
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QuoteOriginally posted by grahame Quote
You will have to find a unit as same size and shape. Otherwise the focusing screen and viewfinder will not be aligned. And be careful about the exposure light sensor.
Since it is a Penta-Mirror, I assume that it is made up of five separate mirrors, unlike a Penta-Prism, which is a single block of glass, with five faces precision ground onto it.

I have to believe that the positioning, as well as the size, of the five individual mirrors is critical and that factory has special jigs to hold them in place, while it is being assembled. These jigs would not be available to the public, and would probably be difficult to fabricate, especially without knowing the exact angles and dimensions of the mirror assembly.

So, my not-so-educated guess would be that, no, a pentamirror is NOT replaceable, at least not by anyone lower in the parts chain that an authorized repair facility. Like many other repairs to these cameras, I strongly suspect that it would be cheaper to buy a good, used camera.
01-03-2019, 01:40 PM - 1 Like   #8
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It would make better sense for the PentaMirror to be a monolithic assembly and installed as one piece. The individual mirrors would be aligned, assembled bonded together and quality test on as separate assembly process. To have an adjustable frame on the chassis to hold each individual mirror which has to be aligned and calibrated for each individual chassis would not be cost efficient in labor or time, even if automated.

01-03-2019, 02:51 PM   #9
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QuoteOriginally posted by noblepa Quote
Since it is a Penta-Mirror, I assume that it is made up of five separate mirrors, unlike a Penta-Prism, which is a single block of glass, with five faces precision ground onto it.

I have to believe that the positioning, as well as the size, of the five individual mirrors is critical and that factory has special jigs to hold them in place, while it is being assembled. These jigs would not be available to the public, and would probably be difficult to fabricate, especially without knowing the exact angles and dimensions of the mirror assembly.

So, my not-so-educated guess would be that, no, a pentamirror is NOT replaceable, at least not by anyone lower in the parts chain that an authorized repair facility. Like many other repairs to these cameras, I strongly suspect that it would be cheaper to buy a good, used camera.
QuoteOriginally posted by Not a Number Quote
It would make better sense for the PentaMirror to be a monolithic assembly and installed as one piece. The individual mirrors would be aligned, assembled bonded together and quality test on as separate assembly process. To have an adjustable frame on the chassis to hold each individual mirror which has to be aligned and calibrated for each individual chassis would not be cost efficient in labor or time, even if automated.
I'm pretty sure the pentamirror is preassembled and held together with tape if I recall correctly. Then the assembly is placed into the camera. The tricky bits are all done before the main assembly.
01-03-2019, 03:28 PM   #10
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Welcome to the forum Michael! DSLR cameras, especially those with pentamirror viewfinders, have more then one mirror- so responses might not pertain to the problem you might be having. Since this is a K-r, a nice camera, but at the somewhat low end of Pentax DSLR models, expenses that would be necessary to return it to normalcy might be better put towards an upgraded model. The K-r was an upgrade over the previous K-x, but much better camera bodies have since emerged.
01-04-2019, 08:35 AM   #11
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QuoteOriginally posted by mikesbike Quote
Welcome to the forum Michael! DSLR cameras, especially those with pentamirror viewfinders, have more then one mirror- so responses might not pertain to the problem you might be having. Since this is a K-r, a nice camera, but at the somewhat low end of Pentax DSLR models, expenses that would be necessary to return it to normalcy might be better put towards an upgraded model. The K-r was an upgrade over the previous K-x, but much better camera bodies have since emerged.
Not to quibble but, I agree with all that you say here except that the K-r was an upgrade. After falling for that line I replaced my K-x with a K-r and regretted it. On the up side, that pushed me to get the K-5 which was definitely an upgrade.....
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