Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-08-2016, 09:15 PM   #1
Senior Member




Join Date: Jan 2016
Posts: 240
What can cause adapted lens to not focus (all of a sudden)?

Hi,

I just got in one of these Canon FD-to-K-mount adapters (http://www.amazon.com/Fotodiox-Mount-Adapter-Pentax-Camera/dp/B0095OODVO) a little while ago, and when I first tried it with a 50mm Canon FD lens about a week ago, it seemed like it was working ok. Then, I tried it again tonight, with my K-r (the same camera I tried it with before) and it just won't focus at all now.

I'm 100% sure the lens itself is ok, because when I put the lens back on my old Canon Ftb, it focuses fine.

Does anyone have any idea what could cause this?

Sorry if this is a bit off-topic. I've messaged the seller (on Ebay) about this, but I was hoping that someone here might have some idea what could cause this or maybe how to fix it?

Thanks,
Jim

03-08-2016, 09:35 PM   #2
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,756
If it is the same model - note that it has a built in 1.4x teleconverter that is removable. Is there glass in your adapter? FD to K only works with the glass if you want to focus beyond macro. The glass is generally poor quality and ruins the image from the FD lens additionally they take away a stop. So a 35mm f2 becomes a 52mm f2.8 and the crop factor makes that behave like a 78mm on 35mm film in terms of angle of view.
03-08-2016, 09:58 PM   #3
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
QuoteOriginally posted by UncleVanya Quote
If it is the same model - note that it has a built in 1.4x teleconverter that is removable. Is there glass in your adapter? FD to K only works with the glass if you want to focus beyond macro. The glass is generally poor quality and ruins the image from the FD lens additionally they take away a stop. So a 35mm f2 becomes a 52mm f2.8 and the crop factor makes that behave like a 78mm on 35mm film in terms of angle of view.
I was looking at it, and I can see the ring with the notches in it and was wondering if there should be some glass in there, but "No" there isn't any glass lens.

That would explain why it would only focus at about 1" or so !!

I'll message the seller again and find out what is going on !!


Thanks,
Jim
03-08-2016, 10:20 PM   #4
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,133
QuoteOriginally posted by ohaya Quote
I was looking at it, and I can see the ring with the notches in it and was wondering if there should be some glass in there, but "No" there isn't any glass lens.
Next question...where is the glass?

Do a careful inspection of the mirror box in your camera to make sure it is not in there.


Steve

03-08-2016, 10:40 PM   #5
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
QuoteOriginally posted by stevebrot Quote
Next question...where is the glass?

Do a careful inspection of the mirror box in your camera to make sure it is not in there.


Steve
I don't think it's in there. I've written to the seller.

Jim
03-08-2016, 11:47 PM   #6
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,181
There should be a retaining ring that you unscrew to remove the lens (see page 2 in the user documentation).

Kind of scary that the ring and lens should drop out unnoticed. If it's like the version 1 of my "glassless" Minolta adapter the lens and ring would come off on the lens side of the adapter and shouldn't end up in the mirror box. Then again it may not have the same design. And of course, being glassless, my adapter lacks the lens and retaining ring (normally glued in) to begin with.

Last edited by Not a Number; 03-08-2016 at 11:54 PM.
03-09-2016, 02:51 AM   #7
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
QuoteOriginally posted by Not a Number Quote
There should be a retaining ring that you unscrew to remove the lens (see page 2 in the user documentation).

Kind of scary that the ring and lens should drop out unnoticed. If it's like the version 1 of my "glassless" Minolta adapter the lens and ring would come off on the lens side of the adapter and shouldn't end up in the mirror box. Then again it may not have the same design. And of course, being glassless, my adapter lacks the lens and retaining ring (normally glued in) to begin with.
Hi,

Sorry. I may've said something to confuse you all.

The retaining ring is there, still screwed in. There is no lens, but I don't know if there ever was one in there. As far as I remember, there wasn't a lens, at least in the time I've had the adapter.

I've written to the seller, to ask him/her if there was a lens there before I got it.
03-09-2016, 07:04 AM   #8
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,181
If there was no optical element the only way it could focus is close-up or "macro" - you must not have tried to focus on anything past say 4-6 inches.

03-09-2016, 07:53 AM   #9
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
QuoteOriginally posted by Not a Number Quote
If there was no optical element the only way it could focus is close-up or "macro" - you must not have tried to focus on anything past say 4-6 inches.

I know that this sounds dumb, but I don't know if I did try it earlier or not, other than mounting it on a camera with the FD lens. And yes, now, it only focuses like a couple of inches.
03-09-2016, 04:00 PM   #10
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
All's well!!

Hi,

You all will think I'm going crazy (possible), but I had vaguely recalled POSSIBLY removing the lens when I first got the adapter, to see how it worked for macros.

So I just got home and ran around trying to figure out (a) IF I did remove the lens and (b) where I might have put the lens, and VOILA, I just found it !!!

Later,
Jim
03-09-2016, 04:02 PM   #11
Pentaxian
bertwert's Avatar

Join Date: Jun 2015
Location: Golden, BC
Photos: Albums
Posts: 5,377
QuoteOriginally posted by ohaya Quote
Hi,

You all will think I'm going crazy (possible), but I had vaguely recalled POSSIBLY removing the lens when I first got the adapter, to see how it worked for macros.

So I just got home and ran around trying to figure out (a) IF I did remove the lens and (b) where I might have put the lens, and VOILA, I just found it !!!

Later,
Jim
*slow clap*
03-09-2016, 04:28 PM - 1 Like   #12
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 8,664
QuoteOriginally posted by ohaya Quote
Hi,

You all will think I'm going crazy (possible), but I had vaguely recalled POSSIBLY removing the lens when I first got the adapter, to see how it worked for macros.

So I just got home and ran around trying to figure out (a) IF I did remove the lens and (b) where I might have put the lens, and VOILA, I just found it !!!

Later,
Jim

Quite a saga, Jim.


I have a (likeable) accountant who, um, operates like you.


Very stressful for the two of us!
03-09-2016, 08:17 PM   #13
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,181
Ha ha! I guess a "senior member" is allowed his/her "senior moments".

Of course when you get to be a plain old senior like myself those moments happen with alarming frequency - at least the times you can remember them.
03-10-2016, 10:35 AM   #14
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,756
Good, now you can try to use the lens. I'm afraid it will disappoint you with that glass added in the light path. It is the only way to use it - but you may be better off buying the pentax equivalent and selling the FD to a mirrorless user.
03-10-2016, 07:32 PM   #15
Senior Member




Join Date: Jan 2016
Posts: 240
Original Poster
QuoteOriginally posted by UncleVanya Quote
Good, now you can try to use the lens. I'm afraid it will disappoint you with that glass added in the light path. It is the only way to use it - but you may be better off buying the pentax equivalent and selling the FD to a mirrorless user.
Now that you mention it, I think that was why I removed the lens: I think I tried it originally and focus was really "soft" so I took the lens out to see how the FD lens would work for macro, and then... I forgot about all of that ...

Jim
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!
camera, canon, cause, cause adapted lens, focus, idea, lens, pentax help, photography, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-30 photos dark all of a sudden HedoGunner Troubleshooting and Beginner Help 16 12-18-2015 04:02 AM
Lens all of the sudden needs focus adjustment? stillshot2 Pentax SLR Lens Discussion 7 07-09-2015 06:46 AM
What degree of wetness can a non-WR lens be exposed to? ravenorxs Troubleshooting and Beginner Help 17 03-30-2015 07:31 PM
Sudden death of a ZX-7 - what to do now? 1L6E6VHF Pentax Film SLR Discussion 10 09-20-2013 04:56 PM
Some part of my image does not appear on focus, How can i get it all in focus? rustynail925 Photographic Technique 11 09-08-2010 07:24 AM



All times are GMT -7. The time now is 03:28 PM. | 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