Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-20-2013, 03:12 PM   #1
Site Supporter
Site Supporter
gsrokmix's Avatar

Join Date: Oct 2009
Location: CT
Photos: Albums
Posts: 515
Aperture ring on 645 45mm A lens?

Hi,

I have kind of a silly question. i just received a 645 SMC-A 45mm lens to use with a Mirex T/S adapter. While I was checking the lens out I was changing the aperture manually (without the lens being mounted to anything) and the aperture wasn't changing. This is the first 645 lens I've ever held in my hand. Do I need to actuate any of the levers on the lens to see the aperture open & close? On any 35mm A lenses I have owned the aperture moved as I changed the ring without doing anything else. I do not have an adapter to use this lens on my K20 & I do not have the Mirex yet. I wanted to make sure the lens arrived safely & the mechanics were operating properly.

Any thoughts or help would be appreciated.

Thanks,

George

02-20-2013, 03:59 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 51,593
QuoteOriginally posted by gsrokmix Quote
Hi,

I have kind of a silly question. i just received a 645 SMC-A 45mm lens to use with a Mirex T/S adapter. While I was checking the lens out I was changing the aperture manually (without the lens being mounted to anything) and the aperture wasn't changing. This is the first 645 lens I've ever held in my hand. Do I need to actuate any of the levers on the lens to see the aperture open & close? On any 35mm A lenses I have owned the aperture moved as I changed the ring without doing anything else. I do not have an adapter to use this lens on my K20 & I do not have the Mirex yet. I wanted to make sure the lens arrived safely & the mechanics were operating properly.

Any thoughts or help would be appreciated.

Thanks,

George
Without the adapter mounted, it should stop down as you turn the aperture ring as long as it's not mounted on a camera.

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



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:
02-20-2013, 04:29 PM   #3
Site Supporter
Site Supporter
gsrokmix's Avatar

Join Date: Oct 2009
Location: CT
Photos: Albums
Posts: 515
Original Poster
Hi Adam,

Thanks for the reply. The lens only stops down to the selected aperture if I slide one of the levers. One of the levers moves pretty easily, and the other doesn't seem to move at all no matter where the aperture ring is set. I'm assuming it's something I'm doing (or not) because the lens is in pristine shape.

Thanks again,

George
02-20-2013, 04:37 PM   #4
New Member




Join Date: Mar 2012
Posts: 4
If I recall correctly what you are facing is completely normal with a 645 lens. The adapter should have a small peg on it that puts tension on the aperture lever as you stop it down. I can remember asking myself the same question while waiting for my cheap ebay adapter to arrive in the post. Unfortunately I have sold my 645 kit now, so I can't be 100% sure.
Either way, you have an excellent lens there. I was always impressed by the quality and sharpness of my 645 lenses.

02-20-2013, 04:50 PM   #5
Site Supporter
Site Supporter
gsrokmix's Avatar

Join Date: Oct 2009
Location: CT
Photos: Albums
Posts: 515
Original Poster
Thanks Joe, that's reassuring. Hopefully the Mirex will arrive shortly & I can verify that the lens functions as it should. I'm excited to try this combo. I think I may look for a 75mm to use with the Mirex next if I like the setup. I agonized over this setup as it was kind of pricey so I hope it provides good results.

George
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!
45mm, adapter, aperture, k-mount, lens, mirex, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Stubborn aperture ring on SMC-A 50 f/1.7 Sluggo Pentax SLR Lens Discussion 10 01-07-2015 11:07 PM
Aperture ring, Green Mode, K lens AndreyS Troubleshooting and Beginner Help 15 08-19-2012 02:17 PM
Stuck aperture ring on A 50 1.7 petergottlieb Pentax SLR Lens Discussion 9 10-22-2010 07:17 AM
Sears lens with PK on aperture ring (K mount??) jqjones Pentax SLR Lens Discussion 3 02-16-2010 10:20 PM
using an aperture ring lens on the K100D Super burntsienna Pentax DSLR Discussion 3 02-25-2009 02:10 PM



All times are GMT -7. The time now is 04:37 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