Open Photography Forums  
HOME FORUMS NEWS FAQ SEARCH

Go Back   Open Photography Forums > Digital Camera Discussion > Imaging Technology: Theory, Alternatives, Practice and Advances.

Imaging Technology: Theory, Alternatives, Practice and Advances. This is a brand independent discussion of theory, process or device. Ignore this forum unless this matters to you!

Reply
 
Thread Tools Display Modes
  #1  
Old October 13th, 2007, 05:42 PM
John_Schwaller John_Schwaller is offline
Member
 
Join Date: May 2006
Location: Cary (Raleigh), NC, USA
Posts: 41
Default Mirror Lock Up....or not?

A few months ago, EOS Magazine published an article which leads one to question the use of mirror lock's value on very fast or long shutter speeds.

EOS Magazine is a UK publication, which I though many in other geographies might not have access to. I requested the ability to copy and post this article and yesterday received the following reply:

Hi John

Further to your e-mail, we intend to put the Mirror Lock article on our site, but in the meantime here is a pdf version for you to use. Please credit EOS magazine and our website.

Kind regards

Angela August
Editor



The EOS magazine web site is: http://www.eos-magazine.com/ They also have a forum at: http://www.eos-forums.com/

I have placed the article on 'Free File Hosting'. This is my first use of FFH, so I hpope it works OK.

http://www.freefilehosting.org/publi...ror%20lock.pdf

Anyway....I thought this might make for an interesting discussion.

John
Reply With Quote
  #2  
Old October 14th, 2007, 03:59 AM
Bart_van_der_Wolf Bart_van_der_Wolf is offline
pro member
 
Join Date: Jun 2006
Location: Netherlands
Posts: 4,054
Default

Quote:
Originally Posted by John_Schwaller View Post
I have placed the article on 'Free File Hosting'. This is my first use of FFH, so I hpope it works OK.
I works fine.

Regarding the article, I agree with the general findings. Exposure times of approx. 1/15th of a second are most sensitive for mirror slap induced vibrations, larger mirrors requiring more dampening of the vibrations. It may be helpful to remind that Carbon fiber (and wooden) tripods also exhibit better vibration dampening.

Bart
Reply With Quote
  #3  
Old October 22nd, 2007, 02:09 PM
Walter Ash Walter Ash is offline
New Member
 
Join Date: Oct 2007
Posts: 8
Default

Quote:
Originally Posted by Bart_van_der_Wolf View Post
I works fine.

Regarding the article, I agree with the general findings. Exposure times of approx. 1/15th of a second are most sensitive for mirror slap induced vibrations, larger mirrors requiring more dampening of the vibrations. It may be helpful to remind that Carbon fiber (and wooden) tripods also exhibit better vibration dampening.

Bart
I would agree, although for safety I'll use it for up to 1/60th second exposures, or even shorter ones at focal lengths above 100mm. I've noticed a difference in the critical, 100% magnification sharpness of shots taken at 200mm and up to 1/1000th of a second. In practice this difference is minor as I'm normally not printing that big, but it illustrates the point that this isn't a "step function" where it's only needed in a certain range and irrelevant in other ranges. It's a gradual drop-off in effects.

For long exposures without point light sources you almost don't even need a cable release as long as you can press the shutter button once to open the shutter and a second time to close it (most if not all digital SLRs don't have this function, but some film cameras do). The exception is with point light sources like street lights - any minor vibration can show up even in a long exposure as these point sources are usually very intense and will leave minor trails or squigglies if the camera shakes. If it's a moonlit landscape or something and a 30 second + exposure - not necessary to worry about mirror lockup or cable release. The vibrations will dampen out before any significant exposure is made on the film or sensor.
Reply With Quote
  #4  
Old October 24th, 2007, 04:02 AM
Aidan Weatherill Aidan Weatherill is offline
New Member
 
Join Date: Sep 2007
Posts: 3
Default

The main reason I use mirror lockup on my 400D is that it reduces the auto timer from 10 seconds to 2 seconds :)
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are Off
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 06:08 AM.


Posting images or text grants license to OPF, yet of such remain with its creator. Still, all assembled discussion 2006-2017 Asher Kelman (all rights reserved) Posts with new theme or unusual image might be moved/copied to a new thread!