I think my camera has issues with the shim spacing (or whatever) of the focusing screen, because I can almost never focus accurately via the viewfinder (no matter what lens I use…telephoto, wide angle, fast aperture, etc…and I do have the finder’s focus adjusted for my eye). It’s possible this can only be so accurate, at least with lesser-than-pro series “crop” bodies, but I can only guess. Mine does have the “pentaprism” and not “pentamirror”.

On an unrelated front, have you thought of doing noise test comparisons, like what they did here? http://www.techradar.com/reviews/cameras-and-camcorders/cameras/digital-slrs-hybrids/canon-eos-1dx-1091200/review/page:4#articleContent

I find this particular test even more interesting than what DXOmark has done so far. Especially surprising is that the 5D3 they tested, outperformed all others in a narrow range from ~ISO 25k to 50k…besting even the D4 and 1DX. I’m sure there are logical explanations and counter arguments, but still it’s nice to look at a graphed comparison of noise and dynamic range directly comparing the latest and “best” DSLR’s.

If you’ve already done a similar test, I apologize for not seeing it. I’m less familiar with your new website’s layout.

I don’t think you can make any conclusion just by that. PDAF isn’t going to be as accurate as contrast detection. But if you have a problem with consistent front or back focus then a microadjustment is in order.

Roger

Now i have issues with my camera and AF all lenses behave differently. My short question is: if say Nikon 50 1.4 works perfectly on all distances and all focus points in LV, but has many AF issues in PDAF on the same camera as other lenses works well. Can I conclude that it’s bad lens or problems with camera?

Thank you.

am i wasting my time trying to find a copy of this lens that will autofocus wide open with decent resolution (all of the lenses clean up nicely between f2.8 and f4)- i’m looking for decent (if not great) resolution off center for subject isolation and autofocus wide open for street shooting in low light.

30% of my shoots are out of focus. A third of them (10%) are due to my wrong using the camera ( after checking exif data) but still 20% of my shoots are simply out of focus, even using the new 70-200 f/2.8L IS II

Trying to find an explanation, this site crossed my path. Roger, this is the clearest and most interenting reading I’ve found by far. Thanks a lot

In comparison, a lot more negs and slides taken with a rangefinder (Leica etc) had pin sharp focus.

My critical focus hit rate on the negs / slides taken with a Hasselblad 500-series was abysmal.

I am suspecting that SLR focusing has always been a compromise thanks to mirror box, mirror, and focusing screen alignment tolerances, but that they haven’t really come to prominence until high resolution digital sensors have come to the fore.

It was live view manual focusing on a star chart – just because that’s where I’m most accurate and I wanted a good baseline. I’m not sure how accurate pentaprism would be in comparison: in theory it should be as good, but if the focusing assembly is shimmed improperly it can front focus or back focus.

Roger