[awscreo]

It wasn't a criticism. All I said is that your example is not concludent for someone interested in af-c. Your camera works for you, then you are a happy shooter and that's all that matters.

I also said camera held focus on an eagle that was flying away from me, shot through the branches. Just not sure if 3-4 frames is a considerable sample size

[Dan Rentea]

I also said camera held focus on an eagle that was flying away from me, shot through the branches. Just not sure if 3-4 frames is a considerable sample size

3-4 frames in which we can see the eagle flying away from you are more concludent than 5-6 images in which the birds are flying perpendicular to the camera, if we talk about af-c performance.

[starbase218]

There are so many variables involved though. I once shot flying pelicans at a lake in Africa. The K-5 and screwdrive 55-300 were up to the task, from a perpendicular view to them flying away from me at an angle relative to the camera. But the background was mainly the sky, so the AF had little choice but to lock on to the birds. I believe I used auto-AF selection and it worked because of that. Also, it was a clear and sunny day, so the AF was quite responsive (e.g. very different from my video).

But I do subscribe to what is also mentioned in the review; in terms of feedback provided by the tracking AF, Nikon is so much nicer to use. The active AF point is always displayed so you know what the camera is tracking. With my K-3, I will find out eventually if tracking is off. But I'd rather know sooner than later. Then at least I know when it's any use to press the shutter, which leads to less "spray and pray" action, less images to go through afterwards and it mitigates the disadvantage of the smaller buffer.

[starbase218]

Anyway, here's one of those pics I took in Africa:



It's a slight crop. This was no problem for the K-5 and DA 55-300 (screw-drive).

I do feel that, somehow, the success rate with birds flying away from the camera is generally higher than with birds flying towards the camera (which may generally yield more interesting photos).

[awscreo]

Here's the sequence with the eagle flying away from me, with branches in the way.
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[starbase218]

In all fairness, my D7100's AF isn't perfect either. I recently found out that the AF points on the left side backfocus slightly. It can apparently be fixed though.

[Nicolas06]

In all fairness, my D7100's AF isn't perfect either. I recently found out that the AF points on the left side backfocus slightly. It can apparently be fixed though.

That why in the end, AF directly on the sensor seems to be a better overall solution:

- Can work at any apperture with proper design
- Can work on the whole sensor area
- No back/front focus by design.

Reflex give a high quality view, but it come at the cost... I don't think the supperior performance of Reflex for sport is related to the mirror box or OVF or the way the phase detect AF is done, this is just it is easier to think about, design, building and doing faster horses than thinking about a car that use gazoline as energy source...

Canon and Nikon don't want mirrorless basically, they want to sell you faster horses...

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Last edited by Nicolas06; 03-29-2017 at 10:00 AM.

[photoptimist]

That why in the end, AF directly on the sensor seems to be a better overall solution:

- Can work at any apperture with proper design
- Can work on the whole sensor area
- No back/front focus by design.

Reflex give a high quality view, but it come at the cost... I don't think the supperior performance of Reflex for sport is related to the mirror box or OVF or the way the phase detect AF is done, this is just it is easier to think about, design, building and doing faster horses than thinking about a car that use gazoline as energy source...

Canon and Nikon don't want mirrorless basically, they want to sell you faster horses...

On-sensor AF is not necessarily better. Disadvantages include:

- suboptimal PDAF design (constrained by the sensor's pixel pitch and semiconductor design)
- slower AF read rates (constrained by the sensor's frame rate)
- higher power requirements to run the sensor and display continuously
- higher sensor temperatures which means higher noise levels in the final image

You are right that Canon, Nikon, and other DSLR makers are selling their preferred solution, but so are the MILC makers. And mirrorless came before SLR in both film and digital worlds so perhaps MILC is the horse and SLR is the car.

P.S. On-sensor AF can suffer from back/front focus if the lens has spherical aberration and the lens is not closed down during AF.

[seagas]

Boxers or Briefs?

I don't recall a time when Pentax was stylish or edgy ever. And I do mean since 1957. Pentax is essentially an optics company that makes competent, conservative cameras on which to mount their lenses. Their statement is the image, not the sexy, polished anodized aluminum body.

My son uses his Canon for his work but he borrows my K-1 and FA77 to take memories of his babies, and that's the absolute truth.

While there is plenty of truth to what you have said. But Pentax at one time was known for their small 35 SLR bodies and light weight, when I got my ME I thought wow, this one good looking camera and it's small size and operation really impressed me. But in the end Pentax always seems to have a niche and never been one of the big boys. Ricoh could really make a difference with lots of marketing, when people see that their lens are equal to anything out there and their camera bodies are almost 90% of Canikon at 50% of the price, they will sell. Most people are sheep and will buy what they are told that is what they need, Ricoh just has to show them the way.

[starbase218]

That why in the end, AF directly on the sensor seems to be a better overall solution:

- Can work at any apperture with proper design
- Can work on the whole sensor area
- No back/front focus by design.

Reflex give a high quality view, but it come at the cost... I don't think the supperior performance of Reflex for sport is related to the mirror box or OVF or the way the phase detect AF is done, this is just it is easier to think about, design, building and doing faster horses than thinking about a car that use gazoline as energy source...

Canon and Nikon don't want mirrorless basically, they want to sell you faster horses...

But if you look at the D500, it also has AF sensors spread throughout the viewfinder area. And I think the applicability of lenses slower than f/5.6 is small anyway.

However, on-sensor AF does make it easier for a manufacturer to create a reliable phase-detect AF system. And with mirrorless, there are less moving parts in the camera which should make it easier to develop and more reliable. I think IBIS is also more "at home" in a mirrorless camera, as it stabilizes the viewfinder, AF and light metering sensor as well.

From a purely technological point of view, I think DSLR versus mirrorless is like CD player versus media player. And err... I don't have a CD player anymore. Even though I'm Dutch and it was at least partially a Dutch invention.

But the upside is that CD players are cheap. The same goes for DSLRs and their lenses. And for some applications, mirrorless is just not as good as DSLR (yet).

[photoptimist]

On-sensor PDAF requires compromises that affect both AF performance and image quality. Adding the little half-lenses on the main image sensor to create the phase information for AF isn't as good as having separate aperture masks used by a dedicated module. Moreover, these micro-lenses degrade image quality and mean that the micro-prism black-out effect occurs on the main sensor if the lens has a narrow aperture or has an unusual exit pupil geometry. Either the camera or the RAW developer must correct or fudge-in the values for any pixels involved in on-sensor PDAF.

The advantage of a separate PDAF module is that the module optics, PDAF sensor chip, analog electronics, and processing elements can be totally optimized for that one function (and the main sensor can be optimized for image quality). Sure, that design comes with the significant complication of all the mechanical systems of the DSLR design but camera makers have had decades to optimize those systems.

[starbase218]

On-sensor PDAF requires compromises that affect both AF performance and image quality. Adding the little half-lenses on the main image sensor to create the phase information for AF isn't as good as having separate aperture masks used by a dedicated module. Moreover, these micro-lenses degrade image quality and mean that the micro-prism black-out effect occurs on the main sensor if the lens has a narrow aperture or has an unusual exit pupil geometry. Either the camera or the RAW developer must correct or fudge-in the values for any pixels involved in on-sensor PDAF.

The advantage of a separate PDAF module is that the module optics, PDAF sensor chip, analog electronics, and processing elements can be totally optimized for that one function (and the main sensor can be optimized for image quality). Sure, that design comes with the significant complication of all the mechanical systems of the DSLR design but camera makers have had decades to optimize those systems.

Ok, you seem to know more about this stuff than I do. Thanks for the information.

[Nicolas06]

On-sensor PDAF requires compromises that affect both AF performance and image quality. Adding the little half-lenses on the main image sensor to create the phase information for AF isn't as good as having separate aperture masks used by a dedicated module. Moreover, these micro-lenses degrade image quality and mean that the micro-prism black-out effect occurs on the main sensor if the lens has a narrow aperture or has an unusual exit pupil geometry. Either the camera or the RAW developer must correct or fudge-in the values for any pixels involved in on-sensor PDAF.

The advantage of a separate PDAF module is that the module optics, PDAF sensor chip, analog electronics, and processing elements can be totally optimized for that one function (and the main sensor can be optimized for image quality). Sure, that design comes with the significant complication of all the mechanical systems of the DSLR design but camera makers have had decades to optimize those systems.

source? Because for example Cannon try to catch up with their sensor and the new one have millions of PDAF points and still offer much better performance than the previous generation...

KP is a sensor with PDAF bundled in it and the quality is said to be much better than APSC Pentax camera had before it.

The read speed limitation is nonsense because in most sensor (except Nikon dual AF) only a few place have the PDAF sensor and nothing prevent some dedicated circuitry to read from it at fast as you want.

Overall we see what Panasonic can do with GH5, bust rate of 30-40fps, AF at the level of D5 that also work in video, Extremely efficiant and reactive.

Reflex are not anymore where innovation appear. Reflex are horse. Sorry.

[starbase218]

KP is a sensor with PDAF bundled in it and the quality is said to be much better than APSC Pentax camera had before it.

The KP does not have on-sensor PDAF: Pentax KP Review: First Shots

[photoptimist]

source? Because for example Cannon try to catch up with their sensor and the new one have millions of PDAF points and still offer much better performance than the previous generation...

KP is a sensor with PDAF bundled in it and the quality is said to be much better than APSC Pentax camera had before it.

The read speed limitation is nonsense because in most sensor (except Nikon dual AF) only a few place have the PDAF sensor and nothing prevent some dedicated circuitry to read from it at fast as you want.

Overall we see what Panasonic can do with GH5, bust rate of 30-40fps, AF at the level of D5 that also work in video, Extremely efficiant and reactive.

Reflex are not anymore where innovation appear. Reflex are horse. Sorry.

How well does that Canon sensor AF work in low light? The dedicated sensor in DSLR PDAF can have large, very sensitive pixels coupled to dedicated signal amplifiers.

Also, it will be interesting to analyze the artifacts in the RAW image created by all those PDAF-attenuated pixels. PDAF pixels lose at least 1 EV of DR. They'll be especially an issue in the bokeh parts of the image where all the left-hand PDAF pixels will be blind to the right half of the bokeh light. No doubt, the camera (or RAW developer) will just fill in the data as if it's a stuck pixel and most people won't care.

There's still innovation occurring in DSLRs such as K-1's advanced mirror mechanism and OVF overlay. And DSLR makers continue to increase the number of AF points, accelerate the processing of AF data, and extend the optical design of dedicated PDAF to handle both f/2.8 and f/8 optics.


I'm not saying SLR is superior only that both technologies have respective advantages and disadvantages.