Archived posting to the Leica Users Group, 2001/04/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> Austin sez: > > > Enough said, I understand where you are going with > this...simply circle of confusion issue...and I understand > why you said what you said. Note that you still get the > same physical amount of blur, it is just less significant > > simply because of the larger negative. An interesting > point. > > SonC rejoins the picking of nits: > > I don't think it's a "Circle of Confusion Issue," unless I'm > confused. <snip> > See Warren Young's excellent discussion of Circle of > Confusion: > http://www.cyberport.com/~tangent/photo/fcalc/help/CoC.htm Exactly. As it says, you are enlarging the MF film less than the 35mm film to make the 'equivalent' 8x12 print...and therefore increasing the COC. Which also means objects the same 'size' (WRT the film format) will appear to be less blurred with larger film formats. To quote from that URL: "The film size is important because you don't have to enlarge large negatives as much to get a particular sized print. So, a 6 × 4.5 cm frame, being roughly twice the size of a 35mm frame, will have a CoC that's roughly twice the size of that for a 35mm frame. In other words, if a fuzzy disc 0.025 mm wide looks like a point when printed from 35mm film, you can have an 0.043 mm disc on 6 × 4.5 cm film and still have the same apparent degree of sharpness if you enlarge it to the same size print as you made from the 35mm frame."