Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-19-2011, 12:01 PM   #1
Senior Member




Join Date: Jun 2010
Location: Saarbrucken
Photos: Gallery
Posts: 332
FA 77 limited aperture question

Dear Pentax Forum community,
Just a brief question. It might sound stupid but I need your opinion.
So I got FA77 limited few weeks ago and yesterday noticed that the blades are not precisely aligned that is obvious when the aperture ring is closed. Two blades looks bigger then the other. It is not like a big problem – coz lens woks great but it just bother me.
Would you consider this as a problem?
Thanks in advance.
Best regards,
Yuriy

04-19-2011, 12:07 PM   #2
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 17,892
you might want to ask pentax service in an e-mail whether the aperture shape is typical of the lens or not.

I have seen many times that at extreme small apertures the blades don't always close to form a perfect geometric shape, but the lens still works and the overall exposure is good, so unless you have a warranty issue, it is probably OK, but you need to establish when the issue was noticed and when pentax (or the seller if not bought new) was notified so that you can easily establish the date when the defect is noticed, if the lens fails some time soon.
04-19-2011, 12:18 PM   #3
Senior Member




Join Date: Jun 2010
Location: Saarbrucken
Photos: Gallery
Posts: 332
Original Poster
Thanks a lot. I got it new from B&H. I will follow your recommendation and will contact Pentax. I saw similar things in the case of some of my older lenses but have not expected that it will be the case with brand new FA77
Thanks again.
04-19-2011, 02:43 PM   #4
Veteran Member




Join Date: Mar 2009
Location: Ohio, USA/ India
Photos: Gallery
Posts: 478
All of my FA limiteds have assymetrical shape when the aperture is closed. I found some threads that discussed this - seems to be quite common. I would not worry about it. Interestingly the FA 50 1.4 I had was perfect in terms of symmetry.

04-19-2011, 02:53 PM   #5
Forum Member




Join Date: Jun 2010
Location: slovenia
Posts: 57
looks like many has this (my 31 and 15 do). i saw pictures of perfect aperture on limiteds. but you did not buy limited to shoot it at closed aperture anyway...
04-19-2011, 03:02 PM   #6
Senior Member




Join Date: Jun 2010
Location: Saarbrucken
Photos: Gallery
Posts: 332
Original Poster
Yes, my FA50/1.4 did have well matched blades, as well as DA15. I found mismatched blades on FA77 and SMC Takumar 55/1.8.
And yes, limited lenses are definitely not for closed aperture use, but stopped down to f4 or further it might affect the bokeh in certain conditions? Am I wrong?
04-19-2011, 03:21 PM   #7
jac
Loyal Site Supporter
Loyal Site Supporter




Join Date: Dec 2010
Location: Clyde River, Nunavut, Canada
Posts: 2,364
I just checked my 43, 77 & 31. All three seem to be symmetrical when closed, near as I can see, for what it's worth.

04-19-2011, 04:38 PM   #8
Veteran Member
wlachan's Avatar

Join Date: Sep 2006
Location: Canada
Photos: Albums
Posts: 2,625
Pretty much all my Pentax lenses have asymmetrical aperture shape when fully stopped down. So long as the widest few stops are good, there is nothing to worry. The chance of getting a perfect sample is pretty slim imho, if existed at all.
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!
aperture, blades, k-mount, pentax lens, question, slr lens

Similar Threads
Thread Thread Starter Forum Replies Last Post
K-r's aperture question jangole Pentax K-r 5 01-21-2011 05:40 PM
Aperture 3 topaz dNoise question Tony3d Digital Processing, Software, and Printing 4 11-04-2010 11:44 PM
Aperture 3 topaz dNoise question Tony3d Digital Processing, Software, and Printing 3 10-20-2010 09:16 AM
Making a slideshow w/ Aperture question..... UpNorth Digital Processing, Software, and Printing 4 05-06-2010 08:23 AM
Aperture for Portraits question MSM Photographic Technique 14 08-30-2009 01:55 AM



All times are GMT -7. The time now is 12:26 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