David Kilpatrick wrote:There is a way of testing this using focus peaking. If the peaking kicks in sooner, and appears stronger, with higher contrast set then CDAF may indeed work better - but the EVF will look horrible.
Here's the actual truth, because I know how CDAF works. Higher contrast if fed to the CDAF detection process will result in LESS ACCURATE focusing but FASTER lock. Lower contrast results in the opposite, more accurate focusing but it will take longer. Extremely low contrast may result in no ability to focus at all.
You can improve CDAF by using a wide aperture, the optimum which Sony apparently think works is f/3.5, because this is the default for video even if you have a faster lens. One of the big hidden issues with the NEX cameras is that you are always focusing at working aperture (my review of the NEX-7 will try to cover this when finished...). So if you want to shoot at f/16, you end up focusing at f/16 too. That works OK with a 200mm lens but with the 16mm for example it almost removes the AF operation entirely. The lens rarely refocuses at all, because at f/16 it believes the image is sharp no matter what you do.
This is where the A77 scores over the NEX-7 - you focus wide open when using very small apertures, and this enables you to pick the exact plane of focus precisely - even if you use focus peaking. The errors in true focus point which result from focusing at small apertures, even regular settings like f/8, are significant with the NEX-7 especially and those who choose to work with manually opened and stopped down classic legacy lenses are bypassing this inherent flaw in the system.
David
Good observation, this is currently my way of focusing properly with the NEX 7, I'm doing manually the SLR process, focusing first wit with the larger aperture and after that going down.
something that is starting to annoying me is the camera don't want to go down more than 1/60 in A mode when you are filming. That makes me decide to almost always film in M mode.
Other stuff about the aperture, the Sony AF to Nex adapter move the Aperture like always returning from the larger to the correct position, it don't do a smooth transition when changing the aperture as if you are using a E-mount lens. This again, make me start shooting movie with a aperture manual adjustment adapter when I want to shoot film with Minolta AF mount.
David, In your review, tried to review the wide angle adapter for the 16mm 2.8. On the Nex 7, I have been able to get very interesting result (when you do some correction in Lightroom).
regards,
Frank