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| p.1 #9 · Focus with a UWA lens |
(EDIT: To clarify, I do my live view focusing almost exclusively at the 10x setting.)
On the off chance that this could be useful... some thoughts about how to use live view focusing.
I've seen people run into problem with live view by looking too closely at the LCD, or even by using a loupe-like device to see it more closely. While some find this effective, I know I'm not the only one who has found that it is possible to end up looking at individual "pixels" on the LCD and be distracted from seeing how those pixels display - or not - an accurately focused image. I know that is counter-intuitive - it seems the you would need to look more closely at this display in order to accurately gauge focus.
But that's not what I've found.
Instead, I pull back a bit from the LDC live view display so that I can get a more generalized view of things and not be distracted by individual pixels. I rotate the focus ring until things are in the right general area. Then I gently rock back and forth across that zone of focus a few times, generally trying to get a sense of the physical feeling of the location of the focus ring as the focus hits the sweet spot. If I look too closely and too analytically, it is possible to get stuck in that loop where it never seems "perfect" - but if I step back a bit, I can find that spot that seems optimal. I also keep in mind that the LCD - at least on the 5D2 - does not have enough resolution to perfectly display the image resolution that the camera/lens system is producing. It is more of an indicator of what is going on than it is a perfect, real display of it.
I generally make an educated guess about which particular object within the frame to focus on. I don't deal with the hypothetical hyperfocal distance stuff - frankly that is obsessive overkill in virtually all cases, and it carries the danger of over-thinking things. So I begin with focusing on something within the frame that seems roughly in the middle of the range of subject elements that I want to see in focus. Once that is accomplished, if the scene contains elements whose distance from the camera varies enough that I think I might be pushing the DOF, I press the DOF preview button and use the 10X magnification to "zoom" around the frame and check focus on both near and far elements to ensure that they will be sufficiently focused for my critical intent. (You must have exposure simulation enabled on the 5D2 in order for this to work correctly.)
There is a notion that one should always pick the "sharpest" aperture in order to maximize potential image sharpness, and this leads some to lean towards, say, f/8 and shy away from, say, f/16. In the real world of big prints, this is unnecessary and may even be counterproductive. Sharpness is always a relative thing. Nothing is ever "perfectly" sharp - even in prints that have excellent sharpness. Depending upon the lens, while the center may be sharpest at f/8, the corners might be sharper at f/11. Or the maximized sharpness at f/8 isn't worth much if you give up sharpness for elements that are further out of the plane of optimum focus by eschewing f/16. Photographically speaking, sharpness is not a purely objective thing - there is an important subjective element to the perception of sharpness and it is not as simple as picking the supposedly "sharpest aperture."
And after making a lot (many tens of thousands) of photographs with full frame DSLRs, I can report that the occasional obsession over avoiding f/16 is unwarranted. Yes, if I don't need larger DOF I may shoot by default at f/8 or f/11. However, I frequently - perhaps most often, with certain subjects - shoot at f/16 and there is no discernible sharpness loss in prints at very large sizes - and there is a gain in sharpness overall in many cases when near and far objects are sharper than they might have been at a larger aperture.
This is true whether one uses live view to focus manually - as I almost always to when shooting landscape and similar subjects - or uses AF.
Edited on Nov 03, 2012 at 04:04 PM · View previous versions