6 ms·

why it would be "extremely difficult with m4/3 and other small-sized equivalents" ?

lb1lf 10y ago
Short answer - focus performance tends to leave a bit to be desired as cameras go smaller. (Though this can -for some subjects - be compensated for by focusing on the place the action is going to be in advance.) Also, long - as in really long - lenses are hard to come by in MFT. Most useful for wildlife.
- iwintermute 10y ago
  There's also APS-C sensors, and even mirrorless full-frame
- slantyyz 10y ago
  The often mocked Nikon 1 series is generally considered to have the best all-around PDAF of mirrorless cameras. It can track about the same as a DSLR (definitely faster than a 5D1, possibly faster than a 5D2). It has a weaker native lens selection than M43 but it has a 70-300mm lens that translates to 190-810mm (factoring 2.7 crop factor) that birders love. It can also use adapted F mount lenses with decently fast AF (center point only). On the other hand, the N1 series has so many other weaknesses (like being massively overpriced for what you're getting) that it's not a great system for most people.
jfindley 10y ago
Two key reasons: 1) m4/3 and similar cameras use EVFs (electronic viewfinders) instead of optical ones - these have inherent and percievable lag. It's getting better, but still present (and due to the way they work, it's unlikely to be eliminated in the near future). This means that what you see through the viewfinder is a bit behind what's really happening, making precise timing hard. 2) Focussing on fast-moving targets - espcially if the background is "busy" (i.e. has lots of contrast) is very hard for the camera (and user!) to get right. Most non-DSLR cameras use contrast-based autofocus, which is more accurate for still scenes, but slower and worse at dealing with demanding situations like the one I illustrated. DSLRs use phase detection sensors, which are much better at highly demanding situations like these (although slightly less accurate with still subjects). Neither of these means that it's impossible - but it does mean that in situations like the one I described your success rate - shots that are in focus, and where the timing is correct - tends to be significantly lower than with a highend DSLR. When you're trying to capture a rare event (again like the one I described) that you only have one attempt at per day/week/whatever, a significantly reduced success rate is a really big problem.
- 3chelon 10y ago
  The EVF lag is the primary reason I've stuck with DSLR over micro-4/3 until now. Every one I've tried, no matter how fast it's purported to be, has just enough lag to make me feel slightly queasy. Another reason is that the EVF is a screen with all its inherent issues. A screen is its own light source, compared to a DSLR finder which is the sunlight bouncing off the scene via the mirror directly into your eye. Your eye via a mirror can see a much larger dynamic range than the EVF screen, and you can make a call on exposure based on that. That said, if the EVF was truly representative of what the sensor was picking up, it may actually be useful, but the EVF is almost certainly showing a quantized version of what the sensor is seeing, and when you get the image in Lightroom or whatever it'll be different to what you saw on the EVF.
- iwintermute 10y ago
  RE 2) mirror-less cameras now use hybrid focus - both contrast and phase detection, also they have much more focus points to work with. Plus shooting speed should also be quicker in mirror-less (not sure if super high-end DSLR is still close) - sony a6000 gives you 11 fps of continuous shooting rate
  - jfindley 10y ago
    Some of them have started doing this - tech is always marching forward. However no mirrorless system in the world comes close to a highend DSLR. The Sony a6000 is probably the best mirrorless system I'm aware of right now for autofocus, but it still can't come close to what a skilled (for example) Nikon D5 user can do. There are a number of reasons for this, some of which are: 1) One dimensional phase detect sensors, rather than the (more expensive) cross-hatch ones used in DSLRs, which don't perform as well with movement or low light conditions. 2) Reduced processing power, lack of dedicated autofocus processing silicon, and less sophisicated data pipeline in general. 3) Greatly reduced user control. DSLRs, pro ones especially, have enormously sophisiticated control systems, and the ability to completely switch setup very quickly. There are a huge number of ways I can influence what descions the autofocus system makes on my cameras, and I use them to make sure the camera corretly interprets what part of what object it should be focussing on. I probably want the camera to be focussing on the head of the bird (rather than the wingtip, which is typically what a m4/3 system will go for), but that's unlikely to be in the exact centre of the frame, and definitely isn't the closest or most distinct object in the scene, so I need to tell the camera (very quickly and accurately) what it should do. Small mirrorless cameras with limited physical buttons and less tightly controllable focus systems make this very hard. Highend DSLRs can also beat that continuous shooting rate - a Nikon D5, for example, will do 12fps (or 14fps with the mirror locked up). However frames per second isn't always relevent - you're going to be at 1/2000s minimum for this sort of shot, which means that even at 12fps you're capturing only ~ 0.6% of the time. If there's one specific moment you're targetting, even at very high fps, holding the shutter down is a bad strategy. It's useful in some situations (fps is important for pro sports photography for example), but it's often less important than a lot of people seem to believe.

lb1lf 10y ago

Short answer - focus performance tends to leave a bit to be desired as cameras go smaller. (Though this can -for some subjects - be compensated for by focusing on the place the action is going to be in advance.) Also, long - as in really long - lenses are hard to come by in MFT. Most useful for wildlife.

iwintermute 10y ago
There's also APS-C sensors, and even mirrorless full-frame
slantyyz 10y ago
The often mocked Nikon 1 series is generally considered to have the best all-around PDAF of mirrorless cameras. It can track about the same as a DSLR (definitely faster than a 5D1, possibly faster than a 5D2). It has a weaker native lens selection than M43 but it has a 70-300mm lens that translates to 190-810mm (factoring 2.7 crop factor) that birders love. It can also use adapted F mount lenses with decently fast AF (center point only). On the other hand, the N1 series has so many other weaknesses (like being massively overpriced for what you're getting) that it's not a great system for most people.

jfindley 10y ago

Two key reasons: 1) m4/3 and similar cameras use EVFs (electronic viewfinders) instead of optical ones - these have inherent and percievable lag. It's getting better, but still present (and due to the way they work, it's unlikely to be eliminated in the near future). This means that what you see through the viewfinder is a bit behind what's really happening, making precise timing hard. 2) Focussing on fast-moving targets - espcially if the background is "busy" (i.e. has lots of contrast) is very hard for the camera (and user!) to get right. Most non-DSLR cameras use contrast-based autofocus, which is more accurate for still scenes, but slower and worse at dealing with demanding situations like the one I illustrated. DSLRs use phase detection sensors, which are much better at highly demanding situations like these (although slightly less accurate with still subjects). Neither of these means that it's impossible - but it does mean that in situations like the one I described your success rate - shots that are in focus, and where the timing is correct - tends to be significantly lower than with a highend DSLR. When you're trying to capture a rare event (again like the one I described) that you only have one attempt at per day/week/whatever, a significantly reduced success rate is a really big problem.

3chelon 10y ago
The EVF lag is the primary reason I've stuck with DSLR over micro-4/3 until now. Every one I've tried, no matter how fast it's purported to be, has just enough lag to make me feel slightly queasy. Another reason is that the EVF is a screen with all its inherent issues. A screen is its own light source, compared to a DSLR finder which is the sunlight bouncing off the scene via the mirror directly into your eye. Your eye via a mirror can see a much larger dynamic range than the EVF screen, and you can make a call on exposure based on that. That said, if the EVF was truly representative of what the sensor was picking up, it may actually be useful, but the EVF is almost certainly showing a quantized version of what the sensor is seeing, and when you get the image in Lightroom or whatever it'll be different to what you saw on the EVF.
iwintermute 10y ago
RE 2) mirror-less cameras now use hybrid focus - both contrast and phase detection, also they have much more focus points to work with. Plus shooting speed should also be quicker in mirror-less (not sure if super high-end DSLR is still close) - sony a6000 gives you 11 fps of continuous shooting rate
- jfindley 10y ago
  Some of them have started doing this - tech is always marching forward. However no mirrorless system in the world comes close to a highend DSLR. The Sony a6000 is probably the best mirrorless system I'm aware of right now for autofocus, but it still can't come close to what a skilled (for example) Nikon D5 user can do. There are a number of reasons for this, some of which are: 1) One dimensional phase detect sensors, rather than the (more expensive) cross-hatch ones used in DSLRs, which don't perform as well with movement or low light conditions. 2) Reduced processing power, lack of dedicated autofocus processing silicon, and less sophisicated data pipeline in general. 3) Greatly reduced user control. DSLRs, pro ones especially, have enormously sophisiticated control systems, and the ability to completely switch setup very quickly. There are a huge number of ways I can influence what descions the autofocus system makes on my cameras, and I use them to make sure the camera corretly interprets what part of what object it should be focussing on. I probably want the camera to be focussing on the head of the bird (rather than the wingtip, which is typically what a m4/3 system will go for), but that's unlikely to be in the exact centre of the frame, and definitely isn't the closest or most distinct object in the scene, so I need to tell the camera (very quickly and accurately) what it should do. Small mirrorless cameras with limited physical buttons and less tightly controllable focus systems make this very hard. Highend DSLRs can also beat that continuous shooting rate - a Nikon D5, for example, will do 12fps (or 14fps with the mirror locked up). However frames per second isn't always relevent - you're going to be at 1/2000s minimum for this sort of shot, which means that even at 12fps you're capturing only ~ 0.6% of the time. If there's one specific moment you're targetting, even at very high fps, holding the shutter down is a bad strategy. It's useful in some situations (fps is important for pro sports photography for example), but it's often less important than a lot of people seem to believe.