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02-11-2007, 03:35 PM   #1
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K10D Viewfinder Question.

I never mentioned this, earlier on, as I figured the condition to be par for the course. But, what I have been noticing (since the very start) is a fine, uniform graininess of the viewfinder. I remember that the very same condition applied to our Olympus C-740UZ, and (after querying about it) I learned that it (the graininess) was characteristic of its "Electronic Viewfinder". I just automatically assumed that my K10 utilized an electronic viewfinder also and, therefore, was the reason behind what I was seeing.

The reason that I question it now, is that I just recently read over something which stated that the K10D did not incorporate an electronic viewfinder. If this is the case, then what could be the reason for the grainy appearance in my viewfinder? I wonder if it could be the lens, itself. I just have the one - which is the Tamron 18-200mm AF DII XR, and (as it is the only lens that I have had on this camera) I wonder if the nature of this particular lens would be causative (and normal) for that uniform grain.

Maybe someone who also has the above lens, in their stable, could let me know if they are seeing the same - and whether the graininess disappears whenever a different type of lens is attached to their K10.


Last edited by NLAlston; 02-11-2007 at 04:53 PM. Reason: grammatical error.
02-11-2007, 04:16 PM   #2
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it's the focusing screen. it's not smooth, but has a sort of texture. it's the same w/ my film bodies.
02-11-2007, 04:16 PM   #3
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The viewfinder becomes dark and grainly only when slow lenses are used, and I think this is happening in your case. I highly doubt there would be something wrong with the camera...

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02-11-2007, 04:36 PM   #4
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An Answer

QuoteOriginally posted by NLAlston Quote
I never mentioned questioned this, earlier on, as I figured the condition to be par for the course. But, what I have been noticing (since the very start) is a fine, uniform graininess of the viewfinder. I remember that the very same condition applied to our Olympus C-740UZ, and (after querying about it) I learned that it (the graininess) was characteristic of its "Electronic Viewfinder". I just automatically assumed that my K10 utilized an electronic viewfinder also and, therefore, was the reason behind what I was seeing.

The reason that I question it now, is that I just recently read over something which stated that the K10D did not incorporate an electronic viewfinder. If this is the case, then what could be the reason for the grainy appearance in my viewfinder? I wonder if it could be the lens, itself. I just have the one - which is the Tamron 18-200mm AF DII XR, and (as it is the only lens that I have had on this camera) I wonder if the nature of this particular lens would be causative (and normal) for that uniform grain.

Maybe someone who also has the above lens, in their stable, could let me know if they are seeing the same - and whether the graininess disappears whenever a different type of lens is attached to their K10.
If you have ever used classic film camera's they all are grainy. In fact all penta prism camera's have this "Grain". What you are seeing is the plastic focusing screen. It is an opaque plastic that reflects the image coming of off the penta prism..Totally Normal. What the K10D has that they all don't is interchangeable focussing screens. Pentax also gave me the "Landscape" screen with a horizontal and vertical grid to keep your horizon plumb.

Ben

02-11-2007, 04:55 PM   #5
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Mo & Jon ~ Thanks for your responses. They served to provide a GREAT deal of relief .
02-11-2007, 04:55 PM   #6
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I tried taking a close up of the stock focus screen (the one that comes with the body) did not really show much off.

you did give me reason to finally change it from the stock to the LI-80 screen AF scale (has scale in the center going vertically and horizontally)
also got to test out the 540 in manual mode (lens was a reverse mount Pentax SMC-F 35-80mm)

02-11-2007, 04:57 PM   #7
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Thanks Ben.
02-11-2007, 05:04 PM   #8
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Jon,

You know, (as much perusing of the manual, that was done) I don't remember coming across anything about 'Interchangeable Focusing Screens'. I guess I felt that nearly all things about a camera (excluding the add-ons, such as flash units, lenses, etc.) fell under the "It is as it is" category. the 'IFS' capability sounds as if it is a very desired, and important part of this camera's makeup, and I am going to look into it.

Thanks much.

02-11-2007, 05:04 PM   #9
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Guessing that you never had the pleasure of using a view camera (something in say 4 by 5 or 8 by 10 inches for the film size)? They use a 'ground glass' focusing screen; something like a Gilbeys Gin bottle circa 1960 or so. The light comes through the lens and projects against that screen; you hide your head under a cloth and sometimes use a magnifying glass right on the back surface to get extremely sharp focus.

While you can focus on a piece of clear glass, how do you see the image? It 'passes' straight through!

You frost the glass, grind it, give it a very fine, very shallow rough surface that's still about 85% transparent and presto, a focusing screen; the view camera ground glass is about 50% transparent (both give or take a few % pts).

In your K10, It's not reflected, it's in the light path above the mirror before the penta-prism. Remove your lens, hold the camera upside down and look, there it is, focusing lines and all. The penta-prism and eye piece flip it top to bottom and left to right so it's normally oriented to the scene and make it's focal point right for the normal eye relief typical to SLRs--a few millimeters-a viewcamera presents the image fliped up to down and right to left. and it's large enough to need no further correction to be seen correctly.

It takes a funny pair of tweezers and a steady hand to pop the K10 focusing screen out and change it for another with different etched focusing aids.

It's glass. It's expensive.
02-11-2007, 06:24 PM   #10
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Also, do NOT touch the focusing screen when you have it out. It is easy to ruin it. They are very delicate!
02-11-2007, 06:48 PM   #11
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when you buy the pentax replacement, it comes with tweezers and a nice case. it's 50 dollars a pop, so yeah, better be carefull. i have to clean the stock one now, thats why i replaced it in the first place
02-11-2007, 07:23 PM   #12
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QuoteOriginally posted by -=JoN=- Quote
when you buy the pentax replacement, it comes with tweezers and a nice case. it's 50 dollars a pop, so yeah, better be carefull. i have to clean the stock one now, thats why i replaced it in the first place
Jon, just out of curiosity, what does one use to clean the focusing screen? Methanol (eclipse fluid) and pec pads like the sensor? Or is there another method?

NaCl(color me curious)H2O
02-11-2007, 07:53 PM   #13
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QuoteOriginally posted by NaClH2O Quote
Jon, just out of curiosity, what does one use to clean the focusing screen? Methanol (eclipse fluid) and pec pads like the sensor? Or is there another method?

NaCl(color me curious)H2O

i posted a thread here before, asking the same question, someone suggested, soap and water.

(searched for the thread it was actually I.gislin, here was his post)

QuoteOriginally posted by i.glisin Quote
Believe it or not: wash it! (If it is really dirty and if you can not clean it with compressed air.)

This is how: rinse the screen first (to get rid of larger particles that could scratch the screen), have some soap on your thumb and index finger, rub gently both surfaces between your fingers. Then rinse thoroughly (avoid touching the screen, not critical but may help) and let it dry on air. Compressed air or hair dryer at low setting and not to close helps to dry it within seconds. Do not wipe with anything! Don't use any abrasive cleaner of course. Be careful not to drop the screen on anything hard or sharp and make sure you'll not wash it down the sewer by chance. That's all. (Tested and it works.)

The physics behind it: focusing screen is just a piece of plastic with matte surface. Touching it with any paper towel or cloth will just push dust deeper into the micro structure or help larger particles grip it and stay there. Cleaning with the brush blower does the same, pushes dust in. Cleaning it with soap and water will free surface from anything sticky that may be holding dust and will let water molecules carry dust away (they are much finer than any brush!).

and here is the original thread

https://www.pentaxforums.com/forums/pentax-dslr-discussion/1386-cleaning-focusing-screen.html

also I found a nice artilce in pop photo (this was about 8 years ago) on how to clean slr systems..

How To Clean SLR Finder Systems - - PopPhotoOctober 1998
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