Archived posting to the Leica Users Group, 2003/04/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Well could look it up but i think the magnification factor is the key.same magnification same dof.So a wide angle close up would give the same dof as a lele lens further out as long as the mag.stays the same.Therefore the format has to do something with it for the same reason. simon - ----- Original Message ----- From: "Red Dawn" <reddawn@singnet.com.sg> To: <leica-users@mejac.palo-alto.ca.us> Sent: Thursday, April 24, 2003 1:22 PM Subject: Re: [Leica] Digital Aesthetic > ----- Original Message ----- > From: "Jim Laurel" <jplaurel@nwlink.com> > Subject: [Leica] Digital Aesthetic > > > > > Correct me if I'm wrong, but I believe depth of field is related to focal > > length and aperture size alone. The depth of field of a 25mm lens is the > > same regardless of the size of the film or digital sensor. Consider the > > example above and let's assume that the film shooter is using a 50mm set > to > > f1.4. To acheive the same FOV, the DSLR user will need a 31mm lens. But > > lenses around this focal length with maximum apertures of f1.4 are few and > > far between, not to mention that a 31mm lens at f1.4 will still have more > > DOF than a 50mm at 1.4. The DSLR shooter could use the same 50mm f1.4 > lens, > > and back off from the subject, but then again, the increased distance to > > subject will result in increased DOF. > > Hi Jim, > > i do believe u're wrong. > > Let's take the EOS 10D with a 50mm f1.4 lens (a combo which i happen to own > as well) and shoot a subject at f1.4. The equivalent focal length is 50 x > 1.6 = 80mm. > > Now let's then take a 80mm R Summilux and mount it on a EOS 1v film body > (again i also own this body), frame the SAME subject and keep the > composition and subject size EXACTLY THE SAME. > > The 2 pictures will look identical because we have kept the subject size / > magnification and framing the SAME. If u compare the 2 shots, they will have > the SAME DOF. This is because the subject distance is constant, and so is > the aperture. > > Remember, DOF is also affected by subject distance! Don't take my word for > it though - do your own visual tests and find out for yourself :) > > The only thing u're right is the difficult of finding lenses to simulate > your favourite focal lengths. U're right in the sense if u want a TRUE 50mm > on a DSLR, and nothing but a 50mm, it is impossible to find a 31mm lens that > will fit the bill. However, you can use a 35mm lens on the 10D to simulate > 56mm. > > Can you really tell the difference between 56mm and 50mm in actual real life > shooting? I don't think so :) > > Boon Hwee > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html