Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-30-2007, 08:55 PM   #16
Veteran Member
stewart_photo's Avatar

Join Date: Apr 2007
Location: Heidelberg, Germany
Posts: 1,864
QuoteOriginally posted by noblepa Quote
It seems to me that the distance from the nodal point of the lens to the sensor and the distance from the nodal point to the focusing screen MUST be identical. Otherwise, the focus would not be the same. (snip) For that reason, moving the screen one way or the other is simply not an option.

The "cropping" of the image to 95%, therefore, must be happening between the screen and the eye; that is, somewhere in the pentaprism/pentamirror assembly. Either that, or the screen is not the same size as the sensor. (snip)

Well, "moving the screen one way or the other is simply not an option" unless one changes the lens design, thereby changing the nodal point. Pentax is obviously now restrained somewhat, due to a number of factors, to a specific lens design, but remember we're using theory to explain reality here.

And your assumptions about where the percentage loss is occurring is likely correct, except that it might also be in both (a bit in the prism and a bit in the focusing screen).


QuoteQuote:
I, too, don't understand why the camera makers do this. (snip)

It's not really all that mysterious, Paul. Big, bright, viewfinders with nice magnification sell cameras. Therefore, manufacturers seek to offer that and are obviously willing to sacrifice a small area along the edges of the viewfinder image in the process.

By the way, this discussion is now complex enough to suspect we're losing some along the way. For those individuals, here (Wikipedia) is a decent general description of the overall design of a modern digital SLR camera, complete with a diagram and a picture of the Pentax K10D as an example of that modern DSLR camera.

stewart

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, dslr, image, photography, viewfinders
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
People This picture is full of life guillermovilas Post Your Photos! 2 10-29-2010 08:42 PM
Full Frame Viewfinder Magnification tropiciel Pentax Film SLR Discussion 1 09-19-2010 05:54 PM
Can camera show a picture after post-processing? KxBlaze Digital Processing, Software, and Printing 13 06-18-2010 10:04 AM
Show me a K-7 picture better than K20D's cbaytan Pentax DSLR Discussion 43 07-14-2009 09:33 PM
Coffee house show - Fun Picture Gaelen Post Your Photos! 2 10-21-2007 10:14 AM



All times are GMT -7. The time now is 03:51 AM. | See also: NikonForums.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