07-19-2010, 09:28 PM
Rainer and popo are both right.
There is one caveat with modern cameras however, although this was also valid to some degree in the film age. Unless you use an -S type focusing screen (for Canon anyway), an Eg-S for the 5D Mark II, which is also called a high precision matte, or something similar on any other camera, you will perceive a DoF through the view finder as if the lens is stopped down to approximately F/5.6.
This is caused by the fact that standard focusing screens for dslrs are relatively coarse grained mattes, to let through as much light as possible, making the VF image appear brighter. Because coarser screens have a greater thickness for capturing the image, DoF appears different than what the camera will record, unless you take a picture at F/5.6. The DoF preview button therefore only really helps from F/5.6 on into the smaller apertures, which is probably why popo suggested F/11 and F/16.
A high precision focusing screen has a much finer structure, hence is much thinner in the image capture area, and therefore displays more accurately how the actual DoF looks like.
Kind regards, Wim
There is one caveat with modern cameras however, although this was also valid to some degree in the film age. Unless you use an -S type focusing screen (for Canon anyway), an Eg-S for the 5D Mark II, which is also called a high precision matte, or something similar on any other camera, you will perceive a DoF through the view finder as if the lens is stopped down to approximately F/5.6.
This is caused by the fact that standard focusing screens for dslrs are relatively coarse grained mattes, to let through as much light as possible, making the VF image appear brighter. Because coarser screens have a greater thickness for capturing the image, DoF appears different than what the camera will record, unless you take a picture at F/5.6. The DoF preview button therefore only really helps from F/5.6 on into the smaller apertures, which is probably why popo suggested F/11 and F/16.
A high precision focusing screen has a much finer structure, hence is much thinner in the image capture area, and therefore displays more accurately how the actual DoF looks like.
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....