Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-06-2013, 12:24 PM   #1
Senior Member




Join Date: Jun 2011
Posts: 120
Pentax A 50 F1.7, focus o infinity

Tried last night the lens on stars, using live view and 10x loupe find out that the focus is almost there but not quite, it need few mm focus travel to reach pinpoint stars. Anybody have some idea, is a problem of the lens, all are the same?
Thanks.

06-06-2013, 12:39 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 41,361
If it goes past infinity, try turning it the other way. Variations in temperature can oftentimes shift the true point of infinity focus.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

06-06-2013, 12:41 PM   #3
Senior Member




Join Date: Jun 2011
Posts: 120
Original Poster
No, no past. Tried and there goes to infinity but no reaching the infinity. Hope I made a mistake but... Usually other lenses goes beyond infinity but this stops close to it.
06-06-2013, 12:55 PM   #4
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,492
I guess the lens was probably disassembled at some point. Does the mount have a normal thickness? There are some lens disassembly guides out there, you can try to get to the focus ring and adjust it. Or send it to some repair store, but it will probably cost around.. 50 euro or so.

06-06-2013, 01:20 PM   #5
Inactive Account




Join Date: Dec 2008
Location: North Carolina
Photos: Albums
Posts: 1,720
The Pentax lenses are a little trickier to adjust than many, since the name ring must be removed. It is still a very straight forward process though.
06-06-2013, 02:07 PM   #6
Site Supporter
boriscleto's Avatar

Join Date: Dec 2009
Location: Liverpool, NY
Photos: Gallery
Posts: 12,469
QuoteOriginally posted by elliott Quote
The Pentax lenses are a little trickier to adjust than many, since the name ring must be removed. It is still a very straight forward process though.
That is true up to the M series. The A series is different.

Here is a good place to start.

https://www.pentaxforums.com/forums/do-yourself/153858-how-remove-fungus-50mm-f1-7-lens.html

https://www.pentaxforums.com/forums/maintenance-repair-articles/179884-pentax...-database.html

Last edited by boriscleto; 06-06-2013 at 02:20 PM.
06-06-2013, 02:18 PM   #7
Inactive Account




Join Date: Dec 2008
Location: North Carolina
Photos: Albums
Posts: 1,720
QuoteOriginally posted by boriscleto Quote
That is true up to the M series. The A series is different.
Well that is true, the same ring needs to be removed, it just doesn't have any writing on it on the A series.
06-06-2013, 03:03 PM   #8
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,113
QuoteOriginally posted by valy Quote
Hope I made a mistake but...
Nope. One of my A-50 1.7`s does the same thing, the other one I have is fine. As far as how to fix it, no idea.

p.s. The problem lens has been owned by me since mid 80`s and never been messed with by anyone.

06-06-2013, 03:33 PM   #9
Senior Member




Join Date: Jun 2011
Posts: 120
Original Poster
Ok, disassemble, but then what to do?
06-07-2013, 01:11 PM   #10
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,113
QuoteOriginally posted by valy Quote
Ok, disassemble, but then what to do?
This link might help in figuring out how to tweak the focus, mainly step 3 and 11.
Pentax 50mm repair 1
06-07-2013, 03:37 PM   #11
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,492
Ok, but if you disassemble it! Make sure you have enough space. Clean space. No dust, no hair, nothing should enter your lens. Have plenty of space and remember what you took apart in what order. And make sure you have the right tools, if you try to force things with bad tools, you might damage things. Good luck
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
focus, k-mount, lens, pentax lens, slr lens, stars
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax F50mm f1.7 infinity focus. David&karen Pentax SLR Lens Discussion 5 07-16-2012 05:42 AM
M 50 f1.7 vs. A 50 f1.7 Gareth.Ig Pentax SLR Lens Discussion 4 06-05-2012 08:17 PM
Vivitar 50mm f1.7 won't focus to infinity ChopperCharles Pentax SLR Lens Discussion 2 05-21-2012 12:47 PM
Pentax DA 50-300mm wont focus to infinity??? TopherTheME Pentax SLR Lens Discussion 5 12-04-2011 07:02 AM
For Sale - Sold: Price reduced: Pentax K200D, FA 50/f1.4, DA 55-300 ED, M 50/f1.7, A 35-70/f4 zj4c Sold Items 5 11-21-2011 11:05 AM



All times are GMT -7. The time now is 12:13 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top