Archived posting to the Leica Users Group, 2011/01/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]As I understand it, the CoC is also related to how large the expected final print is, and most people don't expect you blow up a 35mm to mural sized print... On Tue, Jan 4, 2011 at 5:14 PM, Ken Carney <kcarney1 at cox.net> wrote: > It might conceivably still have some use in the digital age. I calculated > the DOF for 35mm full-frame with a 50mm f/1.0 lens and the subject at five > feet, and it came out to a near limit of 4.91 feet and a far limit of 5.09 > feet. I guess there you just go for the eyes and hope they're not too big. > That was with a circle of confusion of .03mm. Don't know how these > calculations relate to those marked on the lens. For 35mm the COC used is > .03mm and I remember it being considerably smaller for LF. This is > probably > because the 35mm lenses are sharper than the LF lenses. I think. > http://www.dofmaster.com/dofjs.html > > Ken > > > On 1/4/2011 6:24 PM, Mark Rabiner wrote: > >> For years I thought the CIRCLE OF CONFUSION was an insider joke >> photographers played on people trying to learn photography. And that it >> really didn't exist at all. Then I tried to place into an advanced photo >> class in a community college (color printing) and had to take a placement >> test and got in trouble. >> >> >> -------------------- >> Mark William Rabiner >> Photography >> http://gallery.leica-users.org/v/lugalrabs/ >> mark at rabinergroup.com >> Cars: http://tinyurl.com/2f7ptxb >> >> >> >> >> From: Ken Carney<kcarney1 at cox.net> >>> Reply-To: Leica Users Group<lug at leica-users.org> >>> Date: Tue, 04 Jan 2011 18:12:27 -0600 >>> To: Leica Users Group<lug at leica-users.org> >>> Subject: Re: [Leica] What are the most important aspects of a >>> photographic >>> image ? >>> >>> I have willed that part out of my mind. I did make a spreadsheet with >>> the formulas for front and back focus (Lotus 123 in those days instead >>> of Excel). Here are the calculations: >>> http://www.dofmaster.com/equations.html >>> I like autofocus better. >>> >>> Ken >>> >>> On 1/3/2011 8:58 PM, Mark Rabiner wrote: >>> >>>> Which circle of confusion did you pick? >>>> >>>> >>>> -------------------- >>>> Mark William Rabiner >>>> Photography >>>> http://gallery.leica-users.org/v/lugalrabs/ >>>> mark at rabinergroup.com >>>> Cars: http://tinyurl.com/2f7ptxb >>>> >>>> >>>> >>>> >>>> From: leo wesson<leowesson at gmail.com> >>>>> Reply-To: Leica Users Group<lug at leica-users.org> >>>>> Date: Mon, 3 Jan 2011 20:41:38 -0600 >>>>> To: Leica Users Group<lug at leica-users.org> >>>>> Subject: Re: [Leica] What are the most important aspects of a >>>>> photographic >>>>> image ? >>>>> >>>>> Who? >>>>> >>>>> Thanks! >>>>> Leo Wesson >>>>> 817.733.9157 >>>>> www.leowesson.com >>>>> >>>>> >>>>> On Jan 3, 2011, at 19:30, Ken Carney<kcarney1 at cox.net> wrote: >>>>> >>>>> My first photo seminar was with a Famous West Coast Photographer. His >>>>>> advice >>>>>> was ditch the 35mm and get a real camera (I think I brought an M3 and >>>>>> a >>>>>> couple of Summicrons, or maybe a Contax to the class, but definitely >>>>>> TriX). >>>>>> So I bought a nice 4x5 field outfit, a Linhof Technica and lenses, and >>>>>> for >>>>>> good measure an 8x10 rig also. The focus part was a little tedious. >>>>>> Once >>>>>> you knew the distance to the target, you pulled out a little chart for >>>>>> each >>>>>> lens that showed the range of focus for each stop, based on your >>>>>> desired >>>>>> circle of confusion. Then you measured the various zones, which gave >>>>>> you >>>>>> the >>>>>> key to the ISO for that shot and thus the development time for that >>>>>> particular sheet, based on your densitometer tests. After, of course, >>>>>> you >>>>>> had consulted your reciprocity failure chart. Sometimes it happened >>>>>> that >>>>>> by >>>>>> the time I made the exposure everything of interest, including the >>>>>> light, >>>>>> had >>>>>> vanished. Then the light bulb began to flicker on that something >>>>>> more...immediate...m >>>>>> >>>>> ight be appropriate. Then, Gracia Dios, along came digital and the >>>>> exposure >>>>> comp dial. >>>>> >>>>>> Ken >>>>>> >>>>>> >>>>>> >>>>>> On 1/3/2011 6:33 PM, Mark Rabiner wrote: >>>>>> >>>>>>> I think its nice to get the thing in focus most the time. >>>>>>> >>>>>>> >>>>>>> -------------------- >>>>>>> Mark William Rabiner >>>>>>> Photography >>>>>>> http://gallery.leica-users.org/v/lugalrabs/ >>>>>>> mark at rabinergroup.com >>>>>>> Cars: http://tinyurl.com/2f7ptxb >>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>> Leica Users Group. >>>>>> See http://leica-users.org/mailman/listinfo/lug for more information >>>>>> >>>>> _______________________________________________ >>>>> Leica Users Group. >>>>> See http://leica-users.org/mailman/listinfo/lug for more information >>>>> >>>> >>>> _______________________________________________ >>>> Leica Users Group. >>>> See http://leica-users.org/mailman/listinfo/lug for more information >>>> >>>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > -- // richard <http://www.imagecraft.com/> // icc blog: <http://imagecraft.com/blog/> // photo blog: <http://www.5pmlight.com> [ For technical support on ImageCraft products, please include all previous replies in your msgs. ]