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05-16-2014, 07:18 PM - 1 Like   #1
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Pentax F* 300 4.5 disassembly

Pentax F* 300 4.5 disassembly
uttam.hathi
Pentax F* 300 4.5 disassemblyThis disassembly can be seen/achieved in 3 parts A- Front Objective...See more
Pentax F* 300 4.5 disassemblyThis disassembly can be seen/achieved in 3 parts
A- Front Objective Part
B- MID Part
C- last lens assembly part



PART A- FIRST DISASSEMBLE THE FRONT OBJECTIVE PART:
1)the objective part is seperated by reversing half of the rubber as shown in pic '1-c' to expose three holes (these are in the same axis), put the lens in manual mode, rotate as in to focus in manual mode, once one sees one screws, all three will be seen remove the screws.
2) Then unscrew the whole objective assembly to access the aperture assembly see 'pic 2' dis assembled. the front part of the picture is the front objective, keep it aside- this part disassembly will not be discussed.


now we have the mid part and last lens assembly part.
refer 'pic-3'
1) remove the screws
2) remove the bayonet -take care of the contact springs below

PART C- LAST LENS ASSEMBLY PART
3) remove the aperture setting assembly- ring and the lever(refer 'pic-4' aperture ring and lever is in the background)
4)put it in a transperent poly bag remove the aperture ring dont loose the micro ball
5)unscrew the eyepiece assembly
6)remove the 2 screw which hold the electric contactspart remove the top part
7)remove the gear part (copper part) by uncrewing the two screws and removing the same
7)remove the 4 screws hold the shutter aperture lever and slowly remove the top part see 'pic-5' do not remove the two screws which hold the aperture lever before removing the top part
'pic 6' represents alignment part for reassembly

8) this will access the spring remove the spring refer 'pic 7 &7a' picture shown spring removed.

PART B- MID PART
seperating the mid part and last lens assembly part
1)refer 'pic 8'- remove the three screw, then remove the copper ring (more than semicircle), reverse the aperture assembly will come out, else get it in f4.5 position/wide open and remove the aperture assembly.
2)note the trinangular part in 'pic-9'
3)'pic 9a' is the lower part of the aperture

____________________________________________________________________________________________
AUTO FOCUS SERVICING
pic-6 when one rotates the edge part reflects needs good quality lubricant- aviation grade with high tolerance to temperature
in pic-6 below the rubber grip remove the screws and the plates with screws and disassemble, be careful on the bearings


Last edited by uttam.hathi; 05-17-2014 at 06:39 PM.
05-16-2014, 08:24 PM   #2
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Wow, that's something to see!

I hope I never have to do this, but I have an imperfect 2nd copy if I do!
05-17-2014, 02:30 PM   #3
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Very interesting as I just purchased this lens Thursday.
05-17-2014, 06:37 PM   #4
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QuoteOriginally posted by Driline Quote
Very interesting as I just purchased this lens Thursday.
@Driline- Hello if u have purchased presume it has no problems, pls dont attempt such thing unless u have an issue, all that i can say is what a lens.
but its heartening to know that servicing is not at all a issue unless some parts have gone bad, for mine the aperture blades had gone bad so had sent it to service centre for its replacement (i think they do not provide parts) after it came back within a month, the AF jammed, knew it was a minor issue so thaought of cleaning the AF thus the exercise, srry but i forgot to picture the dis assembled af unit, if any one requires i can give detailed instructions as what i did (only on the mid part)

05-17-2014, 06:50 PM - 1 Like   #5
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This solidified my resolve never to attempt disassembling any lens. I broke out in a cold sweat just looking at the photos.
05-18-2014, 09:23 AM   #6
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not when a mission in life is to give a new life to some great lens, this lens was written off was in market for over 2 years from isreal, post stated that this can be nothing other than a paper weight, it still has a scratch on the front glass else glass is good, it affects only on a bright direct sunlight @f11 and above. in lens which i have given a new life, this i am proud of, i brought it just to see what this iconic lens looked opened up.
it had full of glue, the aperture blade had gone bad for which i eventually had sent it to pentax service centre after cleaning and using it for over a year.
see
https://www.flickr.com/photos/34859797@N07/sets/72157644718884482/

---------- Post added 05-18-2014 at 10:07 PM ----------

a photo using this lens before it went to the service centre, after my restoration
https://www.flickr.com/photos/34859797@N07/sets/72157644731796314/

Last edited by uttam.hathi; 02-05-2016 at 10:36 AM.
05-18-2014, 08:11 PM   #7
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QuoteOriginally posted by uttam.hathi Quote
not when a mission in life is to give a new life to some great lens, this lens was written off was in market for over 2 years from isreal, post stated that this can be nothing other than a paper weight, it still has a scratch on the front glass else glass is good, it affects only on a bright direct sunlight @f11 and above. in lens which i have given a new life, this i am proud of, i brought it just to see what this iconic lens looked opened up.
it had full of glue, the aperture blade had gone bad for which i eventually had sent it to pentax service centre after cleaning and using it for over a year.
see
https://www.flickr.com/photos/34859797@N07/sets/72157644718884482/

---------- Post added 05-18-2014 at 10:07 PM ----------

a photo using this lens before it went to the service centre, after my restoration
https://www.flickr.com/photos/34859797@N07/sets/72157644731796314/
Wow, It looks like you pulled that thing from the bottom of the Ganges River.
05-19-2014, 08:09 AM   #8
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thanks but it came from the Holy Land

05-21-2014, 04:27 AM   #9
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food for thought
voigtlander-color-ultron-50mm-1-8-disassembly:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/248134-voig...sassembly.html
https://www.flickr.com/photos/34859797@N07/sets/72157639638310116/

any donors of unwanted quality prime lens
05-21-2014, 04:41 AM   #10
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Much respect to you!
05-24-2014, 10:07 AM   #11
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thanks
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