04-01-2014, 04:30 PM
(This post was last modified: 04-01-2014, 05:54 PM by Brightcolours.)
Quote:AF or not AF depends on one's photography. Personally, I never use MF unless I'm doing macro work.
Because it takes time to MF the moment is either gone or blurry. Another issue is that the subject may become impatient, waiting for you to properly MF...
I can understand the need for MF when using a SLR/DSLR wide-open since the AF might not be accurate enough or not accurate often enough. With mirrorless, AF accuracy is almost spot on so it's a non issue.
For portraits, I actually find the feature detection of MFT absolutely invaluable. It's able to pick the closest eye at a surprising high hit rate. Amazing! Quite a game changer. No more fiddling with focus points or worrying about the subject being outside the array of focus points. I can't imagine going back to a DSLR, let alone MF. We've gone such a long way, it's now so much easier to capture candid moments.
It's quite funny to see how much people nit pick about the tiniest IQ difference between lenses when any AF inaccuracy will offset any of the supposedly sharpness advantage of one lens versus another. It's become even more an issue with super high pixel counts. Great, one has 36MP, but in the end 16MP would have done the same job if not better because AF was spot on.
36mp is not that high at all, a 16mp MFT like the EM-1 has a higher pixel pitch so would be equally affected (more so actually, as the pixels get more magnified at equal image size). That the current 36mp cameras appear to have some issues is not related to 36mp (D800 some AF issues and left AF point issues, A7r shutter shake issues). But some Olympus MFT models have shutter/IBIS issues too.
I don't seem to have such AF issues as your past DLSRs seem to have been plagued with... My Canon EOS 350D had some AF inconsistencies, but I can't say the same of my 6D.
Actually, AF spot on or not has nothing to do with pixelcount - and if it's missed on 36 MP, it's not better on 16MP if it's missed there, too 
Also, there's no guarantee that a shot missed by wrong AF operation wouldn't have been missed by manual focussing. All lenses can be switched to manual focus, but manual focus only lenses can't be switched to AF mode.
It all depends on the subject I'm photographing, if it's moving, I will never have a big chance to get a well focussed, well composed shot in that moment with MF. All earlier well composed, well focussed MF shots were just: well prepared, but rarely spontaneously. Relying on DoF is no alternative to me. Even with big enough DoF it's a difference between the sharpest zone in a picture and the DoF area - it's just not true, that within the DoF area all things are equally sharp - they are just less blurred than they would be with a more shallow DoF.
But I understand well the need of a nice, smooth and not too easy going focus ring when it comes to LV. It's one of the things I like very much on the latest Sigmas, they have a transmission and are well damped. It's a pleasure to manual focus them.
On the other side, I really like the touchscreen of a Lumix µ4/3, it's "point and shoot" at it's best and it's a shame, Nikon doesn't have this feature in their DSLRs.
Quote:36mp is not that high at all, a 16mp MFT like the EM-1 has a higher pixel pitch so would be equally affected (more so actually, as the pixels get more magnified at equal image size). That the current 36mp cameras appear to have some issues is not related to 36mp (D800 some AF issues and left AF point issues, A7r shutter shake issues). But some Olympus MFT models have shutter/IBIS issues too.
Agree, FF would require ~64mp to have a similar pixel density to 16mp in MFT land. However, the big issue with PDAF is that it requires a perfect alignment between the AF sensor and the imaging sensor. Plus, body and lenses need to be calibrated in order to have accurate AF. It's very possible a lens would require different adjustments at different focal length. On my D800, my 70-200 required different micro adjustments whether at 70mm, 135 or 200mm. What a pain in the butt!
I used the D800 as an example, because a relatively small AF inaccuracy would show up while it wouldn't be the case with a D700 for instance. Because the density is less, the AF inaccuracy is masked by the larger pixel pitch.
Shutter shock is a different matter entirely and a rare occurrence with the E-M1. The A7R seems to have a major issue as far as shutter shock is concerned though.
All these issues will be gone with the advent of electronic shutters. We are not there yet, but it's just a matter of time until we do.
Quote:I don't seem to have such AF issues as your past DLSRs seem to have been plagued with... My Canon EOS 350D had some AF inconsistencies, but I can't say the same of my 6D.
I've never used Canon equipment. However, Pentax was pretty bad, especially the K5. The D800 had issue too, but it was never really acknowledged nor addressed by Nikon (how surprising). The fact remains that the technology is flawed. CDAF + on sensor PDAF is the way to go. Again, it's just a matter of time until mirrorless tracking catches up with the current state of the art in the DSLR world. Nikon CX seems to be already fairly close...
Quote:Actually, AF spot on or not has nothing to do with pixelcount - and if it's missed on 36 MP, it's not better on 16MP if it's missed there, too
It has to do with pixel pitch. The smaller the pixel pitch, the more visible it will be. However, CDAF is miles and bounds more accurate and consistent than PDAF in DSLRs (no calibration required - read my post above).
Ah, you're talking about 16MP on µ4/3 - well, in that case you're right, as the lenses have shorter focal lengths and usuallly are not very fast. So they are therefore less critical to focus with no big movements of the mechanics.
But even if CDAF might be more accurate and less needy to adjust, adapted on a FF it would be a pretty slow thing.
I agree basically with the advantages of on-sensor-focussing and also the problems with differerent adjustments on different distances (for primes) and FLs (for zooms). It's just, the PDAF is still more convincing to me on a D800 than the comparatively slow CDAF of the typical DSLR. But the bigger the sensor, the bigger the problems of AF and alignment of sensor, lens and AF module. I think, if we had sensors with high pixel counts in some cameras, we would easily see that those "low pixel" count cams would also have AF issues - not only the D800. And I also think, we are with those high MPs already very close to the limits of manufacturing in extremely tight tolerances.
I'm still wondering - as I wrote in the V3 thread - why no camera manufacturer came out with the idea of using the CDAF for adjusting the PDAF. That could be done with various distances and focal lengths. Camera on tripod, target (printed in the manual), LiveView - set the distance of the lens. Go to PDAF and check for the difference, the set the AF finetune values. This could be done automatically and without endless test series.
Quote:t
I agree basically with the advantages of on-sensor-focussing and also the problems with differerent adjustments on different distances (for primes) and FLs (for zooms). It's just, the PDAF is still more convincing to me on a D8ng the CDAF for adjusting the PDAF. That could be done with various distances and focal lengths. Camera on tripod, target (printed in the manual), LiveView - set the distance of the lens. Go to PDAF and check for the difference, the set the AF finetune values. This could be done automatically and without endless test series.
Let have more wishful thinking: machine learning, when camera learns AF adjust transparently to user
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