Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-01-2010, 11:33 PM   #1
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Opening the front element on a Pentax-A 28-80

I picked up this lens at a pawn shop for next to nothing, but I noticed it has a spot on the element just behind the front element. It looks like a condensation spot, and I expect it'll be easy to clean with a lens cleaner.

I tried removing the front element by unscrewing it, however, when it reached the end of it's threads, it spins freely but wont slide out, as though the focus ring is holding it in place.

Is there any quick and easy way behind the front element to clean the glass?

The lens in question is the one pictured here:

Pentax-A 28-80/3.5-4.5

Thanks!

05-02-2010, 02:14 AM - 1 Like   #2
Pentaxian
Arjay Bee's Avatar

Join Date: Sep 2006
Location: Bamaga, QLD
Photos: Gallery | Albums
Posts: 2,882
I have a very fungus ridden copy of that lens and took it apart just to see how it was built -
If you take the rubber/vinyl grip off the focus ring there are three small screws under it - take those out and the front lens assembly should just screw off.
But then that is perhaps what you have done already and the last bit doesn't release... more explanation necessary.
05-02-2010, 08:18 AM   #3
Veteran Member




Join Date: Feb 2010
Location: NYC
Photos: Gallery
Posts: 1,071
Cgoudie, I'm no lens technician but I'm fairly certain that to get to the back of the front element, you will need a spanner wrench, which is available here:

S.K. Grimes - New Design Optical Spanner Wrench.
05-02-2010, 05:47 PM   #4
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Original Poster
Thanks Arjay, that was exactly what I needed. Unscrewed the 3 screws (one of which was jammed and had to be worked carefully) and the focus ring and element came off with ease.

At that point, I cleaned the spot with lens cleaner, blew if off with some canned air, blew out the inside of the lens while I was at it, and reassembled. Looks good as new.

Hangu: You'll probably be appalled, but I opened it very gently with some needle nose pliers, not squeezing them together, but using them wide open to apply down-pressure. I wouldn't advise it to anyone repairing a super nice lens, but this lens just didn't seem worth a $45 repair tool. At that point, I may as well have taken it to our local repair shop.

In any event, the lens is clean now and works like a champ.

Thank yee kindly for the info.

05-02-2010, 05:52 PM   #5
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Original Poster
In retrospect, had I known I could have removed the focus ring this easily, I would have used something else entirely to loosen the front element. I would have used a tool I have that is like an o clamp with a slowly tightening twist handle and wrapped the lens with a lens cloth so that I didn't tighten it directly on the lens.

I have no doubt the tool above would be a far better option for me, but again a lens worth the cost of the tool I'm just going to take to a shop.
05-02-2010, 06:27 PM   #6
Veteran Member




Join Date: Feb 2010
Location: NYC
Photos: Gallery
Posts: 1,071
QuoteOriginally posted by cgoudie Quote
Thanks Arjay, that was exactly what I needed. Unscrewed the 3 screws (one of which was jammed and had to be worked carefully) and the focus ring and element came off with ease.

At that point, I cleaned the spot with lens cleaner, blew if off with some canned air, blew out the inside of the lens while I was at it, and reassembled. Looks good as new.

Hangu: You'll probably be appalled, but I opened it very gently with some needle nose pliers, not squeezing them together, but using them wide open to apply down-pressure. I wouldn't advise it to anyone repairing a super nice lens, but this lens just didn't seem worth a $45 repair tool. At that point, I may as well have taken it to our local repair shop.

In any event, the lens is clean now and works like a champ.

Thank yee kindly for the info.
I'm not appalled at all. I've done the same thing as you on far nicer lenses. That tool is quite pricey for such a simple instrument.

Congrats on getting it cleaned, that lens is very underrated. There's something special about the A zooms imo, the colors are generally very nice. I hope you put it to good use.
05-02-2010, 06:40 PM   #7
Senior Member




Join Date: Nov 2009
Location: adelaide
Photos: Albums
Posts: 211
QuoteOriginally posted by hangu Quote
I'm not appalled at all. I've done the same thing as you on far nicer lenses. That tool is quite pricey for such a simple instrument.

Congrats on getting it cleaned, that lens is very underrated. There's something special about the A zooms imo, the colors are generally very nice. I hope you put it to good use.
Those tools are expensive if you buy a cheep vernier caliper non digital and are handy with a file you can make your self a great micro adjustable lens tool for less than $20.00.
Cheers Mark
05-02-2010, 08:43 PM   #8
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,817
I always use improvised tools and recommend real ones to others. On some lenses, you have to work very close to the lens surfaces or apply lots of force. That's when the real tools can pay off.

05-02-2010, 08:46 PM   #9
Veteran Member




Join Date: Feb 2010
Location: NYC
Photos: Gallery
Posts: 1,071
QuoteOriginally posted by Just1MoreDave Quote
I always use improvised tools and recommend real ones to others. On some lenses, you have to work very close to the lens surfaces or apply lots of force. That's when the real tools can pay off.
Same here.

I've come to realize that you shouldn't skimp on tools. You can save 20 bucks but it's rarely worth it.
05-04-2010, 06:27 AM   #10
Pentaxian
Arjay Bee's Avatar

Join Date: Sep 2006
Location: Bamaga, QLD
Photos: Gallery | Albums
Posts: 2,882
Once you get a taste for opening lenses you suddenly notice dust under all the front lens elements and that starts to average out the cost of those dedicated lens spanners .
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!
element, front, front element, k-mount, lens, pentax lens, pentax-a, slr lens, spot
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Can dust go under front element? DA. NecroticSoldier Troubleshooting and Beginner Help 11 04-21-2010 01:40 PM
spots inside front element Taff Pentax SLR Lens Discussion 14 09-08-2009 07:46 PM
Pentax SMC-A 70-210/F4: Front Element Removal NeverSatisfied Pentax SLR Lens Discussion 4 12-28-2008 01:59 AM
Front element spots Ash Pentax SLR Lens Discussion 9 05-02-2007 12:58 PM



All times are GMT -7. The time now is 02:53 PM. | See also: NikonForums.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