07-20-2010, 11:03 AM
[quote name='larsrc' date='20 July 2010 - 11:15 AM' timestamp='1279617327' post='1150']
I believe my own eyes over those calculations. If the viewfinder showed f/5.6 regardless of aperture, you wouldn't see any DOF effect of using the DOF preview button. I see a very clear effect. I'm guessing those calculations talked about using an f/2.8 lens.
-Lars
[/quote]
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
I believe my own eyes over those calculations. If the viewfinder showed f/5.6 regardless of aperture, you wouldn't see any DOF effect of using the DOF preview button. I see a very clear effect. I'm guessing those calculations talked about using an f/2.8 lens.
-Lars
[/quote]
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