woodman411 said:
Mikehit said:
woodman411 said:
Take a few minutes to read through this thread and ask yourself if specs are everything: https://www.dpreview.com/forums/post/59526785
Did I read that right? The Sony does not AF wide open?
That is correct, even with Sony GM lenses. Just so that this doesn't get taken out of context, the full description of the issue would be "the Sony does not AF wide open when using higher f-stops, like f7.1. Quoting Sung Park:
The only lens I (used to) own that opens up the aperture for focusing is the zeiss distagon 35 f1.4, which unfortunately is a lens that I never use in a studio environment. The G 70-200 f4, GM 70-200 f2.8, GM 24-70 f2.8, Zeiss Planar 50 f1.4, GM 85 f1.4, Zeiss 16-35 f4 all focus stopped down so experience the issues I've described.
Well, I always thought, "of course not".
Put a Canon onto LiveView One Shot, and crank the aperture to f/14 in a dim room, til almost everything is barely visible. Tap somewhere on the screen or hit the AF button, and the screen will suddenly light up for a second or so while it focuses -- that's the camera going to max aperture when it needs more light to electronically AF. Then it returns to being dark.
Now put it into LiveView AI Servo. Now, when you press the AF button, it doesn't light up anymore. If you tap the screen, I think it lights up ONCE. Then, it tries (usually unsuccessfully) to track it in the dark.
On a Sony A7RII, the screen or EVF does not change brightness as you AF. I always assumed this meant that the aperture did not open up to AF. Makes sense, right? Otherwise, the screen would need to be artificially and gradually darkened while the diaphragm opened, and lightened as it closed, at exactly the same rate, and since they can't make the EVF look better than jello pudding, I always assumed that this was not possible.
I also assumed that this was by design because electronic viewfinder/live view is all you've got, and the screen is supposed to show you what you're going to shoot (not what you'd shoot at the widest aperture). So if it constantly went between light and dark (even between f/2.8 and f/4), it would drive you bonkers on the screen, and if it were a big jump, like f/1.4 to f/11, it probably give someone a seizure through the EVF if it was constantly tracking and taking pictures. Remember, it MUST darken (aperture blades close) in order to take the shot, so if it were to shoot at wide open aperture, or they'd have to black out the screen, and neither is really desirable.
So they pick the least offensive option, which is to assume that the electronic focusing is good enough to focus any time you have enough light that you can see what you're shooting on the screen. And, they bank on their electronic AF being so excellent (all that DR in the sensor!) that it can handle the job. Now, I admit, I kind of assumed that there was some menu option to give you the Canon situation where the screen toggles back and forth between light and dark, but I guess not. I also never found such a thing (or something that keeps the aperture always wide open until the moment you're recording), but I blamed it on myself, rather than the camera. Either way, both feel infinitely inferior to an optical viewfinder in that situation.
And, yes, yes, I know, anyone who actually takes photographs in poor lighting situations or with strobes or flashes or whatever, will scream a laundry list of reasons why this whole scheme of not opening up the aperture to focus sounds like a terrible idea. I'm just not sure how else you'd do it and not have it look ridiculous on the screens. Anyways, in the current scenario, even if the AF system and sensor are super duper amazing, I cannot be convinced that AF can't do a better job with more light than with less light.
