Free Shipping on ALL Products
camera reviewsbest cameraslens reviewsphotography tipscamera forumvideo toursphotography bookssupport me
It is currently Fri Oct 31, 2014 5:38 am

All times are UTC




Post new topic Reply to topic  [ 8 posts ] 
Author Message
PostPosted: Thu Oct 28, 2010 6:08 pm 
Offline

Joined: Mon Jan 18, 2010 3:52 pm
Posts: 2177
Location: The Netherlands
Hi all,
I got a question to those who use/have used MF lenses with aperture rings, or to those who have knowlegde about them.

When I use, for instance, my 35-70 zoom lens, at 35mm f/2,8 the exposure is 1/200. When I zoom in to 70 mm, and use the max. aperture too (that's f/4) the shutterspeed is 1/100, of course, BUT the aperture ring is set at f/2,8. Should that make diffrence if I set it to f/4? Of course not...
But it is! When I zoom in, and set the aperture at f/4 the exposuretime is 1/80, instead of 1/100.
Same applies to all my MF lenses, could anybody explain this?

My conclusion is that the max. aperture is slightly larger than written.

cheers

_________________
Ruben

Panasonic DMC-FZ18, Panasonic DMC-FZ28, Canon G5, Canon 350D, Canon 50D + BG-E2N
Tamron 17-50 2.8, Canon EF 70-200mm f/4L USM,
Canon 18-55 II plus lots of Minolta MD/M42 lenses and bodies


Top
 Profile  
 
 Post subject:
PostPosted: Thu Oct 28, 2010 8:12 pm 
no,it won't make a difference.

the aperture won't change but the distance light has to travel to hit your sensor(or film) will.

the size of the glass in the camera is generally the factor.


Top
  
 
 Post subject:
PostPosted: Fri Oct 29, 2010 1:26 am 
Offline
User avatar

Joined: Tue Jul 27, 2010 8:57 am
Posts: 1551
Location: Winterpeg, Manisnowba, Canada
That's odd, there should be no difference!

Palak makes a good point, it's the amount of glass on the lens.

_________________
-Evan

Gear: 7 Nikon Nikkor AI-S and AF-S lenses, SB-700 flash, Nikon D7000, Nikon FM, variety of accessories

"There are no rules for good photographs, there are only good photographs."
- Ansel Adams


Top
 Profile  
 
 Post subject:
PostPosted: Fri Oct 29, 2010 6:21 am 
Offline

Joined: Mon Jan 18, 2010 3:52 pm
Posts: 2177
Location: The Netherlands
That could be the case...

Thanks guys. :wink:

_________________
Ruben

Panasonic DMC-FZ18, Panasonic DMC-FZ28, Canon G5, Canon 350D, Canon 50D + BG-E2N
Tamron 17-50 2.8, Canon EF 70-200mm f/4L USM,
Canon 18-55 II plus lots of Minolta MD/M42 lenses and bodies


Top
 Profile  
 
 Post subject:
PostPosted: Fri Oct 29, 2010 7:40 am 
Offline

Joined: Mon Jan 18, 2010 3:52 pm
Posts: 2177
Location: The Netherlands
But, guys, how could it be possible that the max. diaframga on 70 mm is f/4, and when I set the diafragma-ring to f/2,8 that I get a shorter exposure?

I mean, the 35-70 has a max. F of 2,8-4,0; so when @70mm the diafragma should be f/4, but I set the ring to 2,8 I get a shorter exposure.

Strange, isnt it?

_________________
Ruben

Panasonic DMC-FZ18, Panasonic DMC-FZ28, Canon G5, Canon 350D, Canon 50D + BG-E2N
Tamron 17-50 2.8, Canon EF 70-200mm f/4L USM,
Canon 18-55 II plus lots of Minolta MD/M42 lenses and bodies


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 01, 2010 3:00 pm 
Offline

Joined: Mon Jan 18, 2010 3:52 pm
Posts: 2177
Location: The Netherlands
Could anybody help?

_________________
Ruben

Panasonic DMC-FZ18, Panasonic DMC-FZ28, Canon G5, Canon 350D, Canon 50D + BG-E2N
Tamron 17-50 2.8, Canon EF 70-200mm f/4L USM,
Canon 18-55 II plus lots of Minolta MD/M42 lenses and bodies


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 01, 2010 4:20 pm 
Offline
User avatar

Joined: Sun Feb 15, 2009 12:59 pm
Posts: 6009
Location: The Netherlands
decouple the lens, zoom to 70mm, look through it and twist the aperture ring?

_________________
I take pictures so quickly, my highschool was "Continuous High".


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 01, 2010 4:34 pm 
Offline

Joined: Mon Jan 18, 2010 3:52 pm
Posts: 2177
Location: The Netherlands
And even then, the aperture closes!

@70mm it should be f/4, but when I turn the aperture dial to f/4 it closes slightly. That's confusing me :?

_________________
Ruben

Panasonic DMC-FZ18, Panasonic DMC-FZ28, Canon G5, Canon 350D, Canon 50D + BG-E2N
Tamron 17-50 2.8, Canon EF 70-200mm f/4L USM,
Canon 18-55 II plus lots of Minolta MD/M42 lenses and bodies


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  

All words, images, videos and layout, copyright 2005-2012 Gordon Laing. May not be used without permission.
/ How we test / Best Cameras / Advertising / Camera reviews / Supporting Camera Labs

Webdesign by Alphabase IT
Powered by phpBB® Forum Software © phpBB Group