Size of K100D focus screeen question


Transit

Link Posted 26/06/2009 - 06:22
Hi Guys,
I am about to cut down a Pentax MG focusing screen to fit my K100D.

I could whip out its screen and check with calipers but trying to minimize handling it
has anyone got the K100D screen dimensions please ?
cheers
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

Transit

Link Posted 27/06/2009 - 00:41
The quivering hand picks up the tweezers and approaches the K100
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

hefty1

Link Posted 27/06/2009 - 00:45
Good luck! When you do find the size don't forget to report back so we'll know if anyone asks in future
Joining the Q

gartmore

Link Posted 27/06/2009 - 09:19
Are they the same thickness? Might be important too.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

Malo1961

Link Posted 27/06/2009 - 09:35
gartmore wrote:
Are they the same thickness? Might be important too.

I have read some articles on that other forum (PentaxForums),stating they have the same thickness.
There are some guys who use the screens of the MX and MG to adjust for use in the Pentax KxxxD's.
Apparently it also solves the exposure problems that occur when using non A lenses.

Martin.
Best regards,

Martin.


Curious about my photography?? Just Follow the Light.

rlebleu

Link Posted 27/06/2009 - 15:58
Also there is small metal shim that separates the focus screen from the pentaprism/mirror. I have a k20d, and bought a Katzeye focus screen. The Katzeye was a tiny bit thicker than the original Pentax focus screen. Accurate focus is so easy to detect with the split prism, and it was disconcerting to see a tiny variation when using autofocus.

Rachael at Katz Eye advised me about the availability of different size shims from Pentax - I bought three and the middle one was perfect. The Pentax invoice called the shim a "focus adjusting washer".

Note that this does not affect the autofocus performance. But it is encouraging to see the image in the viewfinder is sharp when using autofocus...

Dick

Transit

Link Posted 30/06/2009 - 10:13
Flushed with focusing success I come with good news

Decided the tweezers needed boots.
Looks crude but held on to the wee tab with no marking. Used lens tissue if fingers needed.




The k100d screen was easily released with this finely honed tool
The numbers are in that gift to good measurement, the millimeter.




Encased in wide tape with enclosed air bubbles the MG screen contemplates its fate...the 4 inch sander, 100 grit.




Incredibly, despite failing eyes, light and grip, there is progress...
amazed that there was no dust under the tape and no damage to the screen !




Forewarned about the 'collapse onto mirror issue' I fashioned the custom screen catcher.




Had a few issues with adhesive left behind on the screen but it pulled off cleanly with sticky tape dabbing.

Couldn't get the wee tray shut with the shim in so left it out .

Results ?
Well I am just so happy with the results. have the SMC M 50/1.4 @ 1.4 onboard and she is achieving focus every time. In dim light inside, the split collar shift is a piece of cake to spot .

Well worth the effort and $ saved
cheers
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River
Last Edited by Transit on 30/06/2009 - 10:17

fatspider

Link Posted 30/06/2009 - 10:34
I cant believe you used a BELT SANDER
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link

hefty1

Link Posted 30/06/2009 - 11:04
Excellent stuff! I like a bit of DIY ingenuity
Joining the Q

Clarky

Link Posted 30/06/2009 - 11:16
I'm not sure if I am waffling here but wouldn't it be important to have the split screen (centre part of the focus screen) dead centre in the view finder for it to work properly. If you have ground away one edge it would be off centre.

As I said, i'm not sure if it matters but thought I would ask the question.
Camera:|K-7|
Pentax Lenses:|DA12-24/f4 ED AL|DA35Ltd Macro|FA31Ltd|FA77Ltd|FA50/1.4|F70-210|FA20-35 f4/AL|A*200/f4 Macro ED|A50/1.7|A50 Macro f2.8|1.7xAF adapter|
Voigtlander|125/f2.5SL Macro APO Lanthar|
Sigma Lenses:|EX DG 100-300 f4|2X & 1.4X TC|
Flashes:|AF540FGZx2|RingFlash AF160FC|

Transit

Link Posted 30/06/2009 - 11:24
impotentspider wrote:
I cant believe you used a BELT SANDER

hehe i have a very light touch
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

Transit

Link Posted 30/06/2009 - 11:25
Clarky wrote:
I'm not sure if I am waffling here but wouldn't it be important to have the split screen (centre part of the focus screen) dead centre in the view finder for it to work properly. If you have ground away one edge it would be off centre.

As I said, i'm not sure if it matters but thought I would ask the question.

Yes you are correct.I took the same amount off opposite sides so the circle is in the center.
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

Class_A

Link Posted 30/06/2009 - 11:57
Awesome job, Pete.
It looks as if you didn't turn the split-prism by 45 degrees. I think I'd like that. Makes the grinding more interesting as well.

greyhoundman

Link Posted 30/06/2009 - 12:59
I always use my 1" X 30" belt sander to make new screens. Frosted scotch tape is a breeze to draw pencil lines on.
http://greyhoundman.blogspot.com/2006_10_01_archive.html

Very good DIY, Transit.

Malo1961

Link Posted 30/06/2009 - 13:02
I wonder, How is your light meter behaving with this screen and using NON A lenses.
Any compensation needed, or is exposure spot on ?

Martin.
Best regards,

Martin.


Curious about my photography?? Just Follow the Light.
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