Archived posting to the Leica Users Group, 1999/11/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]- --=====================_15042149==_.ALT Content-Type: text/plain; charset="us-ascii" Sorry, Elisardo Louzan, I am not wrong. A 50mm lens 10 feet away from the subject has the EXACT SAME DOF as a 100mm lens 20 feet away from the subject. A 50mm lens at f/1.4 focused at 10 feet has from 9'7" to 10'5" in focus. A 100mm lens at f/1.4 focused at 20 feet (exact same image size on the film as the 50mm example), the DOF is from 19'7" to 20'5". The depth of field is EXACTLY the same. EXACTLY 10 INCHES IN BOTH CASES. DOF has EVERYTHING to do with IMAGE SIZE, which is a combination of the focal length you are using AND how far away you are from the subject. If the image size on the film is the same, the DOF is the same for a given f/stop, REGARDLESS OF FOCAL LENGTH. This is a simple fact. Jim At 06:07 AM 12/1/99 -0500, elisardo louzan wrote: > > Jim, > > Sorry, you are wrong! DOF is affected by the focal length of the lens you > use. > > "Everything you know is wrong" by CTEIN > PhotoPro September/October 1994 pp50-51 - --=====================_15042149==_.ALT Content-Type: text/html; charset="us-ascii" <html> <font face="Courier, Courier"><b>Sorry, Elisardo Louzan, I am not wrong.<br> <br> </b>A 50mm lens 10 feet away from the subject has the EXACT SAME DOF as a 100mm lens 20 feet away from the subject. A 50mm lens at f/1.4 focused at 10 feet has from 9'7" to 10'5" in focus. A 100mm lens at f/1.4 focused at 20 feet (exact same image size on the film as the 50mm example), the DOF is from 19'7" to 20'5". The depth of field is EXACTLY the same. EXACTLY 10 INCHES IN BOTH CASES.<br> <br> DOF has EVERYTHING to do with IMAGE SIZE, which is a combination of the focal length you are using AND how far away you are from the subject.<br> <br> If the image size on the film is the same, the DOF is the same for a given f/stop, REGARDLESS OF FOCAL LENGTH.<br> <br> This is a simple fact.<br> <br> Jim<br> <br> <br> <br> <br> </font>At 06:07 AM 12/1/99 -0500, elisardo louzan wrote: <br> <font size=2><blockquote type=cite cite>Jim,</font><br> <br> <font size=2>Sorry, you are wrong! DOF is affected by the focal length of the lens you use.</font><br> <br> <font size=2>"Everything you know is wrong" by CTEIN</font><br> PhotoPro September/October 1994 pp50-51</blockquote><br> </html> - --=====================_15042149==_.ALT--