EM1 or D600, for Weddings?

turbsy wrote:

thxbb12 wrote:

I mostly agree . However, there is another advantage to MFT which is autofocus reliability. Indeed pdaf in dslrs is not nearly as accurate as cdaf. To me this is even more important than all other reasons combined. With MFT one can use lenses wide open with no problems which is not the case with a 1.4 FF lens for instance.

I have never had a problem with AF on my Nikon ff with f1.4 lenses. I only have extended experience with one though and the Sigma 35mm has been great.

It might be fine most of the time, but it's inherently less reliable. There are so many parts involved in the focusing process that any little inaccuracy may lead to not perfectly sharp pictures which is something one sees very well on a 36MP image. The alignment between the sensor and AF sensor must be perfect (or close to it). If there is a slight misalignment, the image you see in the VF doesn't match what the AF sensor sees. So you might very well think it's properly focused when it's not. This is why manufacturers provide micro-adjustments to "fix" AF inaccuracies. And it's really a body + lens combination that's why one usually needs different micro-adjustments for different lenses. When it comes to zoom lenses, it's actually not enough to compensate for different inaccuracies at various focal lengths. For example, with my D800 and 70-200 VR, I had to use different adjustments depending whether I was shooting at 70mm, 135 or 200mm!! What a pain in the butt! Moreover, light type can affect the AF module, making shooting with different light sources unreliable too. Shooting mirrorless is so liberating in this regards. Long gone are my AF frustrations.

Even dpreview aknowledges the general AF accuracy issue in their review of the Fuji X-T1. This is what they say as to why mirrorless is much more desirable when shooting at wide aperture (page 10):

“One huge advantage of mirrorless cameras like the X-T1 over SLRs is autofocus accuracy with fast primes. Almost all SLRs struggle to focus fast primes sufficiently accurately to make the most of high resolution sensors, because the autofocus system is entirely separate from the image sensor itself. But mirrorless cameras determine focus by looking at the actual image projected by the lens onto the sensor, which is an inherently more accurate way of doing things. Enthusiast SLRs offer focus microadjustment settings as a workaround, but even this isn’t always sufficient to overcome their limitations.”

and:

“For example it can focus the 56mm F1.2 lens sufficiently accurately to get consistently sharp images wide open every single shot, regardless of subject distance or the position of the AF area within the frame. This contrasts very favorably with our recent experiences trying to persuade the Nikon D7100 to work with the AF-S Nikkor 58mm f/1.4G properly; even with AF microadjustment set, the camera simply couldn’t focus the lens accurately at all subject distances.”

More here: http://photographylife.com/fuji-x-t1-preview-and-image-samples#ixzz316mmYNTi

When I first started shooting with MFT, I was very impressed by the IQ of most lenses wide-open. DSLRs lens might be fairly sharp too, but a slight AF inaccuracy nullifies this which leads to the following question I pondered myself: what's the point of having higher resolution sensors and high quality lenses wide-open if what you get is a 1/3 of the resolution because of AF inaccuracy? I know it's a gross exageration in many cases, but I find MFT to be flawless and extremely reliable in focusing.  I feel I'm really using the most of the 16MP my E-M1 offers.