On 7/11/2015 8:35 AM, Chuck Norcutt wrote:
I wish my results with the 75-300 were as good. I don't think it's the lens. Either vibration (me) or focus or
both. Actually, maybe insufficient DoF if I'm wavering back and forth.
This is a regular problem for me hand held, although I notice it much more with CU/macro. My body has a tendency to move
slightly forward and backward, moving the plane of focus. I try to bracket, try to catch the moment when my movement is
at the right place or discipline myself to get focus close, but then press through AF to shutter release in one quick
motion.
I'm much more prone to the last with long tele shots, which may be part of why I have less trouble with them. I can see
where your technique of AF on a separate button could make it even more difficult.
I just checked a shot that was almost good enough and see the the aperture at 300mm was f/6.7 at about 30 feet. f/9
as you're using would have given me about a foot DoF rather then the 6" or so that I got a f/6.7.
I know what the calculations will tell me. I'm aware of the great specter of diffraction blur. And yet shot after shot
after shot tells me, peeping at 100%, that diffraction is less of a problem than inadequate DoF and misplaced focal
plane for macro and long tele, where DoF tends to be shallow relative to the depth of the subjects.
These shots would have been at f11 if there were more light.
Part of the reason I was thinking the IBIS on the GX7 was more effective at 300 mm than the E-M5, or the lens just got
along better with the GX7, turned out to be plane of focus differences. When I suspected one was working better than the
other, and took a few moments to take careful shots of a close-ish (3 m) subject with tripod and both cameras, I was in
the field and only looked quickly at enlarged images on the camera LCDs (before running to catch up with Carol, Bob and
Joan, who were wondering what had happened to me.) I operated on that assumption for the rest of that trip.
But when I got home and could really look, it turned out that the two cameras had focused slightly differently, focal
planes an inch or two different. Because of the 3D depth of the subject, in one shot, some parts were in perfect focus,
others softer; in the other shot, different parts were in perfect focus. Since I was using a tripod and the same lens, I
conclude that the AF of the two cameras works slightly differently with a complex subject. I guess this shouldn't have
surprises me. I already knew that Oly mirrorless CD AF behaved differently with deep, complex subjects than Canon DSLR
PD AF.
Had I shot at f11 or f13, instead of f8, I suspect my results would have been better. When I dare to use it, f16 always
seems to be good with 3D subjects. Moderate softness from diffraction that can be partially corrected with
deconvolution* is often better than greater softness from inadequate DoF and/or slightly misplaced focal plane.
Another reason my posted results may be better than yours is that I use deconvolution The generic deconvolution in
FocusMagic seems to work pretty well with the slightly soft images not uncommon with E-M5 and 75-300 at the long end.
Moderate amount early in post, more after downsampling for print or web.
With the E-M5 II, I'm getting much cleaner pixel level results right out of the box, that need less care to reveal all
the detail. How much is the definitely better IBIS and how much the lack of shutter shock, I don't know. I know all the
published stuff about shutter shock shows it disappearing by about 1/320 sec. I think that's because they didn't
look/test at really long focal lengths. My first year in New England with the E-M5, I got some really strong
double/multiple looking images at 300 mm, even at faster shutter speeds. Once I found about the 1/8 sec. delay for
shutter shock, all that disappeared.
Focused Moose
* Yes, I know, Mike, but this is practice, not theory. It may be doing the right things for the wrong reasons, or I may
be misinterpreting what's happening. But as long as what happens is good ...
--
What if the Hokey Pokey *IS* what it's all about?
--
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