07-20-2010, 11:25 AM
[quote name='larsrc' date='20 July 2010 - 01:03 PM' timestamp='1279623798' post='1156']
I think I see what you're talking about. [url="http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/"]A comment here[/url] talks about how the viewfinder as such has an aperture (sorta), which they claim is about f/4 for APS-C. Indeed, if I take my f/1.8 and do DOF preview to f/2.8, I see virtually no change, but on an f/5.6 lens DOF preview to f/8 gives about a stop of darkening and shows a difference in DOF. It's a gradual effect, no surprise. Stopping the f/1.8 down to f/4, I can barely see any change in DOF (letters appear slightly sharper), but the viewfinder does dim somewhat. Stopping down to f/5.6 clearly shows a difference in DOF. This matches well with what that thread said.
So a more precise description is that the viewfinder doesn't show apertures larger than about f/4, but the effect of smaller apertures can be seen. I might have misconstrued what you said, I understood it as if the viewfinder always showed f/5.6, even at smaller apertures.
Yet another advantage to FF and Live View.
-Lars
[/quote]
Yes, I didn't mean it is always F/5.6. It is slightly different. The DoF will increase with closing down the aperture and using the preview button,, just that you will see a noticeable effect until upwards of F/4 - F/5.6.
I actually did a test once, with macro, and a few lenses with extension tubes mounted, with different focusing screens, and MF, i.e., moving the camera to an area so that a specific part of the subject looked sharp in the VF. With the standard focusing sceen I was off by more than half of the shots, with de precision matte only by about 10 %. This I attribute to DoF perception (especially when checked against LiveView).
For ultimate precision, LiveView and 10X magnification is best, however <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. An Angle Finder at 2.5X magnification is second best <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.
Kind regards, Wim
I think I see what you're talking about. [url="http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/"]A comment here[/url] talks about how the viewfinder as such has an aperture (sorta), which they claim is about f/4 for APS-C. Indeed, if I take my f/1.8 and do DOF preview to f/2.8, I see virtually no change, but on an f/5.6 lens DOF preview to f/8 gives about a stop of darkening and shows a difference in DOF. It's a gradual effect, no surprise. Stopping the f/1.8 down to f/4, I can barely see any change in DOF (letters appear slightly sharper), but the viewfinder does dim somewhat. Stopping down to f/5.6 clearly shows a difference in DOF. This matches well with what that thread said.
So a more precise description is that the viewfinder doesn't show apertures larger than about f/4, but the effect of smaller apertures can be seen. I might have misconstrued what you said, I understood it as if the viewfinder always showed f/5.6, even at smaller apertures.
Yet another advantage to FF and Live View.
-Lars
[/quote]
Yes, I didn't mean it is always F/5.6. It is slightly different. The DoF will increase with closing down the aperture and using the preview button,, just that you will see a noticeable effect until upwards of F/4 - F/5.6.
I actually did a test once, with macro, and a few lenses with extension tubes mounted, with different focusing screens, and MF, i.e., moving the camera to an area so that a specific part of the subject looked sharp in the VF. With the standard focusing sceen I was off by more than half of the shots, with de precision matte only by about 10 %. This I attribute to DoF perception (especially when checked against LiveView).
For ultimate precision, LiveView and 10X magnification is best, however <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. An Angle Finder at 2.5X magnification is second best <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.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 ....