Originally posted by stevebrot I am not sure that I am reading your comment above accurately. This is my interpretation:
Very thorough answer, thank you ahead for that.
You interpretation sounds pretty correct. Worry-some are last 2 points. I used to be 70-90 % accurate with K-30 (my previous main camera). Now with k-3 i am barely at 25-30% accuracy. (I try to avoid K-3 s¤%& words)
Originally posted by stevebrot The stock focus screen is not particularly good for manual focus. The focus sensitivity is only about f/4. Likewise the apparent DOF is more than what is really present. Due to limitations of the stock screen (see above), I have an aftermarket screen with split-image focus aid
How big is this - aftermarket screen? What is it, some 8-10" tablet? How you carry or connect it? while it can be OK for macro shooting and maybe even for tripod-landscape - waiting for moment - this style is absolutely nonsense for guy like me bicycling to places and walking 5-15 km in rampant or bog area. How can one use such thing for birding? My point is - decent on-camera focus system alone should be sufficient to make picture, without any aids.
Originally posted by stevebrot Focus confirm will often light when the split image is clearly not matched. In those cases, there would be missed focus if I took the camera's advice.
Sometimes this phenomenon happens to me too - but what camera advice here?? I shoot almost all pictures via optical viewfinder. Not using live view -because this one was more inaccurate for me as focus confirm. Focus confirm method did work very well with K-30 and K-50. Simple caught focus sound and red dot on focus point were reliably sufficient with them. Didn't matter which focus point you used.
Originally posted by stevebrot Focus confirm uses exactly the same sensor as the AF system. The difference is that it uses the center focus point only. That center point is cross-point and has f/2.8 sensitivity.
This one really confuses me. let's say, i am taking landscape in park, and there is close object in left lower area of frame and i want to keep focus lock on that object By reading you statement, that means while i set focus via appropriate lower left point on focus area, - focus confirmation is still done via central 3 points only? Sounds mad.
In reality, in situation above i often get what i want - meaning that point is in focus and sharpest. This is when usually K-3 does not fail.
But it fails very often, if there is no such strong object in focus area and you do not want to move angle so much to have one. Lets say, hayfield with forest far on horizon. Hay-field in evening fog. Or bird sitting on hay, reed-beds and etc. Here you miss often. Or shooting over plants level under the trees - with F6,3 -11 it may fail. or it misses when focus point is far away.
Problem is actually focus locking. I use manual regime with shutter releases anytime - is locked or not setting. That because hayfield tend not to stand still. Nature is not still most time at all.
and yes, shots may be quite long - i can handheld 1/13 1/15 with ease and it was enough with K-30. With K-3 even tripod with remote shutter does not help and it's better to shoot near 1/30-1/60 at least. If you ask why so slow times, then - forest bog and such areas before and after dawn. You do not want to have High ISO here, and even with 640-1000 you still fall quickly to this time frame - if not using tripod.
But i am not complaining inability to hold, but failure to focus outdoors: against bright light, in good light, on meadow barely moving and etc.
(while i can make very good results at night-time)
Originally posted by stevebrot With a high resolution sensor and pixel peeping, missed focus is more evident than with a lower resolution sensor. The same is true for softness due to poor quality optics and camera/subject motion.
As much i understand - to have anything meaningful on frame after - focus MUST lock before/at shot moment. If you press shutter without camera "caught focus", there is just muted or blur image, no focus anywhere. And here is point of K-3 failure. It says it is focused, but is not. And it happens in good conditions too. (And i am not speaking pre- or back focus issues here.)
Originally posted by stevebrot I almost always use AF-S, center point only for AF
Hmm, i tend to use AF-C in manual. Should try out AF-S in manual.
But i still refuse only central point usage, otherwise all this AF system is just plain junk.
Originally posted by stevebrot Program line should not affect the AF or focus confirm performance directly, though use of wider apertures may make mild missed focus more obvious.
i mostly do not have "unexpected" focus issues with narrow DOF - as wide apertures give. But with auto program line it happens sometimes. So i use Normal or Macro regimes only.
Originally posted by stevebrot With a high resolution sensor and pixel peeping, missed focus is more evident than with a lower resolution sensor. The same is true for softness due to poor quality optics and camera/subject motion
What some call pixel peeping, i call hi-quality printout ability. For family or travel album 30-50 % magnification is sufficient. For 100% size printout - not.
And here we are more at particular lens and sensor complex separation limits, than focusing. With current DA lens-line and 24 Mpixel APS-c pentax is not exactly there yet (and nikon D810, D750 and even D610) are km-s ahead on landscape. Canon 6D separates also far better on its 20 MP than K-3... (having only one meaningful cross-focus point at center).
Overall i try out this AF-S thing and lets see.
---------- Post added 07-27-15 at 12:17 PM ----------
Originally posted by bm75 You want him to jump ship ?!!!!
No way Nikon d750 would be more performant than a7r II for landscape and , as a plus, if he wants, he can put EVERY KIND of lens into Sony mirrorless cameras via adapters. I say twice: want more for landscapes and don't trust in Pentax?Go to SONY !!!
I'll wait for the new Pentax FF !!!!!
about sony:
Camera Database - DxOMark
What sony- were is that sony???
D750 is one of the best landscape cameras for not too high price. (if you think dixo is just pixel-peeping with no real world contact - look flickr user tizziano results with D610 and D750 or do your own search on web).
And if there is no pentaprism viewfinder - there is NO camera.