Will the next full-frame A mount camera be mirrorless?

Started Aug 19, 2015 | Discussions
sybersitizen Forum Pro • Posts: 15,592
Re: Will the next full-frame A mount camera be mirrorless?

mick232 wrote:

sybersitizen wrote:

No.

Come back and reprimand me if it turns out that I'm wrong.

How would Sony solve the problem of not having a full-frame PDAF module?

Is it necessary to do that? My understanding is that all full frame cameras that use dedicated PDAF have a similar problem, so the playing field is somewhat level.

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Imagine that you are managing the A99II project and are limited to solving just one problem or the other. Which one matters the most?

VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

mick232 wrote:

sybersitizen wrote:

No.

Come back and reprimand me if it turns out that I'm wrong.

How would Sony solve the problem of not having a full-frame PDAF module?

- release the A99ii with an APS-C PDAF module taken from the A77ii just like they did with the A99? The narrow AF coverage was one of the major issues people had with the A99 and would kill the A99ii in reviews

Mick, if you actually do some digging you would see that if the A77II AF module was used in the next A99 camera the AF coverage would be competitive in the market, equaling or bettering the D810 and 5D Mark III

The black and small squares are the A99, the transparent squares is the A77II overlayed.

A99 and A77II overlaying D800/D810 and 5D Mark III

- develop a full-frame PDAF module? This would be a one-off development effort just for the A99ii that won't exactly reach high sales numbers, and with little chance of ever being re-used in future models

I mostly agree with this, hence it more likely borrowing the A77II's.  It would also give better reason as to why the A77II's AF module has such a large coverage for an APS-C camera, even when compared to the competition.

- re-design the A77ii PDAF module to cover full-frame? If that were possible, why didn't they do it for the A99?

Because the A99 came out a few years before the a77II.  The A99 came out less than a year after the A77, hence why the A99 borrows an updates AF module from the A77.

- buy it, e.g. Nikon Multi-CAM 3500FX-II? It is totally unclear if it can be made compatible

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
eFilm Senior Member • Posts: 1,741
Re: Will the next full-frame A mount camera be mirrorless?

Miclar wrote:

Will the next full-frame A mount camera be mirrorless?

Not likely.

VirtualMirage wrote:

I wouldn't mind seeing a mirrorless A-mount.

Neither would I, but a "mirrorless A-mount" is a contradiction in terms, as the A-mount is a SLR mount with a SLR flange disatance and lens design, whether there is a mirror or not.

There's more to a mount system than just the difference in flange distance. The lenses and their focusing system are different, too.

The extra space from the flange distance could then be used to house internal filters, such as an ND filter, polarizer, or dust screen.

Yes, in theory that would indeed be interesting, and Canon have sort of done it with their Cx00 video camera line and made it work reasonably well. But the Canon lenses are slightly different, too. Albeit maybe not that much. But still...

Then there is Pentax with their K-01 experiment, where the lenses are much like old A-mount lenses. Rather than the pros, the camera combined all the cons of both mirrorless and SLR systems. Again, interesting experiment, anyway.

Nevertheless, I think I would gladly go for such a mirrorless A-mount camera with built-in ND filters if it was closer to C100 II rather than K-01, but I won't be holding my breath for one, for a number of reasons.

KE_DP
KE_DP Veteran Member • Posts: 5,688
Re: Will the next full-frame A mount camera be mirrorless?
1

Yes I believe I heard that argument long ago in that the physical proximity to the mount/lens makes it impossible to make A Mounts mirrorless.

I just don't like the tiny NEX bodies and using an adapter for a top shelf A Mount lens is not something I relish either.

 KE_DP's gear list:KE_DP's gear list
Sony a7R III Sony a7R IV
mick232 Contributing Member • Posts: 976
Re: Will the next full-frame A mount camera be mirrorless?

VirtualMirage wrote:

Mick, if you actually do some digging you would see that if the A77II AF module was used in the next A99 camera the AF coverage would be competitive in the market, equaling or bettering the D810 and 5D Mark III

The A77ii module won't have the same coverage on FF as on APS-C. It seems you are taking the A77ii AF point diagram that is relative to an APS-C sensor and overlay it on top of a FF sensor without taking into account the larger sensor area.

Because the A99 came out a few years before the a77II. The A99 came out less than a year after the A77, hence why the A99 borrows an updates AF module from the A77.

You misunderstood. I didn't indicate Sony should have used the A77ii module in the A99. They used the A77 module in the A99 and may be using the A77ii module in the A99ii (if they release it). My point was: they couldn't "widen" the AF coverage of the APS-C A77 module when used in the A99, hence I doubt they can achieve that when using the A77ii module in a A99ii.

 mick232's gear list:mick232's gear list
Sony Alpha NEX-C3 Sony Alpha a99 Sony 135mm F1.8 ZA Carl Zeiss Sonnar T* Sigma 30mm F2.8 EX DN Tamron SP 24-70mm F2.8 Di VC USD +19 more
mick232 Contributing Member • Posts: 976
Re: Will the next full-frame A mount camera be mirrorless?

sybersitizen wrote:

How would Sony solve the problem of not having a full-frame PDAF module?

Is it necessary to do that? My understanding is that all full frame cameras that use dedicated PDAF have a similar problem, so the playing field is somewhat level.

PDAF modules designed for FF have significantly larger coverage. The competition has such modules, Sony doesn't.

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Imagine that you are managing the A99II project and are limited to solving just one problem or the other. Which one matters the most?

You take it for granted that on-sensor PDAF doesn't work with screw-drive. Just because it didn't work well till now doesn't mean that problem can't be solved. I am yet to hear a convincing argument why an AF motor that can be driven from the signal of an off-sensor module can't be driven from the signal from an on-sensor module.

The difference is: investing R&D there is not a one-off effort, as sooner or later Sony will need this technology in mirrorless A-mount adapters that support screw-drive lenses on E-mount cameras.

 mick232's gear list:mick232's gear list
Sony Alpha NEX-C3 Sony Alpha a99 Sony 135mm F1.8 ZA Carl Zeiss Sonnar T* Sigma 30mm F2.8 EX DN Tamron SP 24-70mm F2.8 Di VC USD +19 more
Briarned New Member • Posts: 3
Re: Will the next full-frame A mount camera be mirrorless?

sybersitizen wrote:

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Is that really a problem for Sony? It's my understanding that the bulk of money is made in lens sales, not bodies. In a few years, mirrorless is likely to at least equal DSLR/SLT in AF performance and surpass it in other areas. They will also flesh out their E mount lens line up. By "encouraging" people to switch to the new mount they are generating a lot of new lens sales. OFC doing this without alienating existing A mount users will be tricky.

VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

mick232 wrote:

VirtualMirage wrote:

Mick, if you actually do some digging you would see that if the A77II AF module was used in the next A99 camera the AF coverage would be competitive in the market, equaling or bettering the D810 and 5D Mark III

The A77ii module won't have the same coverage on FF as on APS-C. It seems you are taking the A77ii AF point diagram that is relative to an APS-C sensor and overlay it on top of a FF sensor without taking into account the larger sensor area.

Wrong!

What AF module do you think is being used in the A99? It is merely an updated A77 AF module. It's not resized. This also explains why the A99 has such a small coverage area.

If you look at an actual APS-C view with the A77II AF module, you would have seen that on the A77II the AF points cover a wider area than what I showed in the images, so it is not a simple overlay. What I did was determined the proper scale by comparing the AF points coverage between an A77 and A77II, which was easy to do. I then took that scale and matched it to the AF points found on the A99 since it is the same AF module.

Here's how the A77II AF module looks on the camera itself, which is APS-C:

Here is an overlay of the A77II and the A77:

And, here again, is my overlay of the A77II scaled to the A99 based on matching the size of the A77 AF points as I did above:

Notice the difference in coverage?

Because the A99 came out a few years before the a77II. The A99 came out less than a year after the A77, hence why the A99 borrows an updates AF module from the A77.

You misunderstood. I didn't indicate Sony should have used the A77ii module in the A99. They used the A77 module in the A99 and may be using the A77ii module in the A99ii (if they release it). My point was: they couldn't "widen" the AF coverage of the APS-C A77 module when used in the A99, hence I doubt they can achieve that when using the A77ii module in a A99ii.

But why would they even need to enlarge/widen it if they used the A77II module? As my diagrams show, the A77II module when fitted on a full frame is already competitive with some of the best DSLRs out there right now in terms of frame coverage. Unless Sony wants to expand further than that, there is no need to modify the A77II module for wider coverage. Of course, the A7R II's OSPDAF will still have superior coverage.  Now if they want, they could do some sort of OSPDAF assist similar to what the A99 has but improved.  That should help with tracking and maybe AF final lock on accuracy.

What I also don't understand is here you just admitted that you agree that A77 AF module was used in the A99 yet didn't want to believe my overlay diagrams of how much more coverage the A77II module would have over the A77 module.

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

eFilm wrote:

Miclar wrote:

Will the next full-frame A mount camera be mirrorless?

Not likely.

VirtualMirage wrote:

I wouldn't mind seeing a mirrorless A-mount.

Neither would I, but a "mirrorless A-mount" is a contradiction in terms, as the A-mount is a SLR mount with a SLR flange disatance and lens design, whether there is a mirror or not.

There's more to a mount system than just the difference in flange distance. The lenses and their focusing system are different, too.

It's not a contradiction and it could work just fine as mirrorless.  The flange distance wouldn't change, so that has no impact on the functionality of the lens.  As for the focusing system, if the system was purely PDAF it shouldn't be a problem.  The problem was when CDAF was used.  But as evidenced with the A7R II, SSM type lenses appear to be working fine in the latest hybrid AF system.  It's older screw drive lenses is where its performance and capability is still in question.

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
sybersitizen Forum Pro • Posts: 15,592
Re: Will the next full-frame A mount camera be mirrorless?

mick232 wrote:

sybersitizen wrote:

How would Sony solve the problem of not having a full-frame PDAF module?

Is it necessary to do that? My understanding is that all full frame cameras that use dedicated PDAF have a similar problem, so the playing field is somewhat level.

PDAF modules designed for FF have significantly larger coverage. The competition has such modules, Sony doesn't.

Do you consider 'somewhat level' vs. 'significantly larger' worth debating? That's okay, but I don't.

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Imagine that you are managing the A99II project and are limited to solving just one problem or the other. Which one matters the most?

You take it for granted that on-sensor PDAF doesn't work with screw-drive.

I certainly do. It's an existing 'problem', unless you can point to a camera in which it works.

Just because it didn't work well till now doesn't mean that problem can't be solved.

It doesn't work at all - and the possibility exists that it might never be solved and it might never work well. That's why I asked you to imagine which one matters the most (which you didn't answer).

I am yet to hear a convincing argument why an AF motor that can be driven from the signal of an off-sensor module can't be driven from the signal from an on-sensor module.

I am yet to see a camera in which that capability is implemented. Why is that?

The difference is: investing R&D there is not a one-off effort, as sooner or later Sony will need this technology in mirrorless A-mount adapters that support screw-drive lenses on E-mount cameras.

If they can accomplish that, and if they choose to do it.

sybersitizen Forum Pro • Posts: 15,592
Re: Will the next full-frame A mount camera be mirrorless?

Briarned wrote:

sybersitizen wrote:

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Is that really a problem for Sony?

It certainly must be a problem of some kind because it is not implemented in any camera without a mirror.

It's my understanding that the bulk of money is made in lens sales, not bodies.

Well, now you're talking marketing. And in today's market, I have doubts that you're even right about that. Lots of A7xxx buyers don't even bother with Sony lenses at all. They can put just about any lens on their cameras. Moreover, those little cameras are expensive - until they're superseded by a new model - so Sony is probably making a nice profit just cranking them out.

In a few years, mirrorless is likely to at least equal DSLR/SLT in AF performance and surpass it in other areas.

People keep saying that. We'll see.

They will also flesh out their E mount lens line up. By "encouraging" people to switch to the new mount they are generating a lot of new lens sales.

"Encouraging" sounds much more palatable than "forcing", doesn't it?

OFC doing this without alienating existing A mount users will be tricky.

Yep.

seans1969 Forum Member • Posts: 71
Re: Will the next full-frame A mount camera be mirrorless?

alpha1984 wrote:

I'd love if they got the auto focus system stable and fast enough to eliminate the translucent mirror. I think Sony is pretty close to getting it as near perfect as it'll get. My hope is that Sony will give 2 full frame models one lower cost to compete with the nikon d750 and a higher end to compete with the d810. Sony now has 5 full frame mirrorless cameras so I think 2 and maybe even 3 full frame models with a model just above the a77ii would be even better. Either way sony really needs to say something and say it soon otherwise they're going to lose even more A mount shooters.

Here's what I think Sony should do for A mount full frame at the very least:

A99ii:
36 megapixels
Same autofocus system as a77ii just stretched for full frame.
No GPS a waste of battery with every cell phone having geo tagging now, just use that, however keep NFC and Wi-Fi for remote controlling of shutter.
Higher resolution EVF

A99r:
42 megapixels from a7rii
Most up to date autofocus system
Better/higher quality build quality/weather sealing
NFC and Wi-Fi as above
Better battery life by at least a factor of 2 (double a99 life)
Upgraded EVF

I could go on for days about upgrades to these cameras but to keep it short and sweet make an a99ii with more resolution and the a99r as having even more resolution but at a premium. Have the a99ii @$2500 and a99r @ $3500, hell toss an a88 in there for $1400 without weather sealing and made of plastic with the a99 sensor but make it backlit and update the autofocus system and call it good. Just my worthless $0.02

Jordan

I totally disagree with dropping the GPS feature having tried using the geotagging from phone feature on other cameras I found it to be the most unreliable and painful experience, the only thing it did well was kill my cell phone and camera batteries.

 seans1969's gear list:seans1969's gear list
Panasonic LX100 Fujifilm X100F Sony Alpha DSLR-A900 Panasonic Lumix DMC-GF1 Leica M9 +32 more
mick232 Contributing Member • Posts: 976
Re: Will the next full-frame A mount camera be mirrorless?

sybersitizen wrote:

mick232 wrote:

sybersitizen wrote:

How would Sony solve the problem of not having a full-frame PDAF module?

Is it necessary to do that? My understanding is that all full frame cameras that use dedicated PDAF have a similar problem, so the playing field is somewhat level.

PDAF modules designed for FF have significantly larger coverage. The competition has such modules, Sony doesn't.

Do you consider 'somewhat level' vs. 'significantly larger' worth debating? That's okay, but I don't.

A corollary question: If the camera is mirrorless, how would Sony solve the problem of not supporting AF with millions of screw-drive lenses?

Imagine that you are managing the A99II project and are limited to solving just one problem or the other. Which one matters the most?

You take it for granted that on-sensor PDAF doesn't work with screw-drive.

I certainly do. It's an existing 'problem', unless you can point to a camera in which it works.

Just because it didn't work well till now doesn't mean that problem can't be solved.

It doesn't work at all - and the possibility exists that it might never be solved and it might never work well. That's why I asked you to imagine which one matters the most (which you didn't answer).

I am yet to hear a convincing argument why an AF motor that can be driven from the signal of an off-sensor module can't be driven from the signal from an on-sensor module.

I am yet to see a camera in which that capability is implemented. Why is that?

The difference is: investing R&D there is not a one-off effort, as sooner or later Sony will need this technology in mirrorless A-mount adapters that support screw-drive lenses on E-mount cameras.

If they can accomplish that, and if they choose to do it.

I don't disagree with any of that. It is only Sony who could be expected to come up with technology like that, as others simply don't need it as they have not switched to mirrorless and/or have no screw-drive legacy - so far Sony didn't, and it may be for technical or commercial reasons. Personally, as said, I doubt technically the problem can't be solved, that doesn't mean that Sony will do it.

 mick232's gear list:mick232's gear list
Sony Alpha NEX-C3 Sony Alpha a99 Sony 135mm F1.8 ZA Carl Zeiss Sonnar T* Sigma 30mm F2.8 EX DN Tamron SP 24-70mm F2.8 Di VC USD +19 more
eFilm Senior Member • Posts: 1,741
Re: Will the next full-frame A mount camera be mirrorless?

VirtualMirage wrote:

eFilm wrote:

Miclar wrote:

Will the next full-frame A mount camera be mirrorless?

Not likely.

VirtualMirage wrote:

I wouldn't mind seeing a mirrorless A-mount.

Neither would I, but a "mirrorless A-mount" is a contradiction in terms, as the A-mount is a SLR mount with a SLR flange disatance and lens design, whether there is a mirror or not.

There's more to a mount system than just the difference in flange distance. The lenses and their focusing system are different, too.

It's not a contradiction and it could work just fine as mirrorless. The flange distance wouldn't change, so that has no impact on the functionality of the lens.

But the functionality of the lens would still remain that of a standard SLR lens. The lenses would still be SLR lenses, designed for a SLR system with a separate AF module off-axis. Take away the mirror and add PDAF sensors in the sensor, and it would still be a SLR system without a mirror. Yes, technically a 'mirrorless' camera, but it would still behave like a dSLR. A native mirrorless system like the E-mount is still significantly different, from sensor to lens cap. The glass stack on the sensor, the focusing system, the lenses, the focusing lens array, the focusing motors, they're all different.

Again, I wouldn't mind one, either, and such a camera would be interesting indeed, along the lines of Canon C100 Mk2. However, it wouldn't be an E-mount camera using an A-mount. Neither would the A-mount lenses become modern mirrorless lenses. Which is why the future is more likely to be in E-mount or something similar rather than in A-mount, with or without the mirror.

Nevertheless, that would be an interesting way to prolong the lifespan of the A-mount for yet another decade or so. Or maybe even to repurpose it as a new cine system, along with new set of fully manual cine lenses. But I think that's just my daydreaming.

Emacs23 Regular Member • Posts: 454
Re: Will the next full-frame A mount camera be mirrorless?

so no MFA is needed.

I doubt a bit about this. Many users of A7 r II suffer from front-back focus, so this can be a PDAF specific issue, not just AF sensor alignment.

 Emacs23's gear list:Emacs23's gear list
Sony Alpha NEX-5N Sony E 18-55mm F3.5-5.6 OSS Leica Super-Elmar-M 18mm f/3.8 ASPH Leica Summilux-M 35mm f/1.4 ASPH Leica Summilux-M 50mm f/1.4 ASPH +3 more
VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

eFilm wrote:

But the functionality of the lens would still remain that of a standard SLR lens. The lenses would still be SLR lenses, designed for a SLR system with a separate AF module off-axis. Take away the mirror and add PDAF sensors in the sensor, and it would still be a SLR system without a mirror. Yes, technically a 'mirrorless' camera, but it would still behave like a dSLR. A native mirrorless system like the E-mount is still significantly different, from sensor to lens cap.

What makes you think the lenses and won't work with an OSPDAF?

The lenses couldn't care less where the AF system is located. It could be located on the top, bottom, or directly on the sensor, it wouldn't matter. It is ultimately the camera telling the lens where to focus. The catch is the type of focusing being used (PDAF only, CDAF only, or hybrid) which can cause an impact and potentially the focusing mechanism used on the lens (SSM, SAM, or screw drive). Screw drive, so far seems to be the main one in question as to whether it works properly or not.

But again, the flange distance and lens don't care where the AF sensors are at.

The glass stack on the sensor, the focusing system, the lenses, the focusing lens array, the focusing motors, they're all different.

Can you confirm the glass stack is different?  What impact does that have to AF? I know it can have an impact on image quality.  Also, the glass stack doesn't necessarily have to be different to allow OSPDAF, just look at the A99.

The focusing motors are different because the E-mount initially started off as a CDAF system, which requires a motor that is optimized a little differently.  A OSPDAF only system, I don't see why SSM won't work.  Even the newest hybrid system appears to be working fine with them.  But screw drive lenses are still in question.

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

Emacs23 wrote:

so no MFA is needed.

I doubt a bit about this. Many users of A7 r II suffer from front-back focus, so this can be a PDAF specific issue, not just AF sensor alignment.

Evidence?  Are you sure it is specific to the lens and not a user error,camera picking a different focus target, or AF/Shutter priority?

Ever thought that it could be due to a bad lens?

The problem with AF issues on current SLR type cameras is usually a misalignment of sensor distance and AF module distance from the lens.  If the AF module is ever so slightly at a different distance from the lens than the sensor is or if it is tweaked off-angle, you focus becomes off.Once in a while it can be a bad lens, such as one that was dropped.

I had an issue with an RX100.  Technically, it should lock on focus pretty accurately and doesn't offer any kind of lens alignment.  The camera was dropped, shifting or loosening the optics.  The accuracy of AF lock-on became more hit or miss.  The problem wasn't the focusing system, but the lens itself.  Some warranty work later, this was resolved.

If the AF system resides directly on the sensor, then the AF is being confirmed directly from the sensor plane.  Providing the lens isn't damaged and barring any user/configuration error, the camera should have a much higher focus success rate without the need for MFA than an SLR does with it, especially with zooms.

Also keep in mind that you can change the priority to shutter over AF, meaning that your risk of out of focus shots increase as it might then try to take a shot before focus confirmation has been confirmed.  Setting to AF priority will increase your hit rate of in focus shots, but you might "miss" the shot because the camera won't release the shutter until it confirms focus.  There is also a balanced mode which tries to sit between the two, but it isn't perfect.

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
sybersitizen Forum Pro • Posts: 15,592
Re: Will the next full-frame A mount camera be mirrorless?

VirtualMirage wrote:

Emacs23 wrote:

so no MFA is needed.

I doubt a bit about this. Many users of A7 r II suffer from front-back focus, so this can be a PDAF specific issue, not just AF sensor alignment.

Evidence? Are you sure it is specific to the lens and not a user error,camera picking a different focus target, or AF/Shutter priority?

Ever thought that it could be due to a bad lens?

What constitutes a bad lens in such a case? Whatever that is, it would behoove the camera manufacturer to provide a method to address the badness through AF micro adjustment.

The problem with AF issues on current SLR type cameras is usually a misalignment of sensor distance and AF module distance from the lens.

This has been discussed before, and here is the evidence you seek:

If the only reason for AF micro adjustment was to compensate for a discrepancy between the imaging sensor distance and the PDAF sensor distance, we would expect that the micro adjustment for every lens would be the same with any specific camera. But we know that is not the case, and individual lenses almost always need individual adjustment values for optimum performance... so there must be more than one reason. That's why I, like Emacs23, don't assume that MFA will never be needed.

VirtualMirage
VirtualMirage Veteran Member • Posts: 3,956
Re: Will the next full-frame A mount camera be mirrorless?

sybersitizen wrote:

VirtualMirage wrote:

Emacs23 wrote:

so no MFA is needed.

I doubt a bit about this. Many users of A7 r II suffer from front-back focus, so this can be a PDAF specific issue, not just AF sensor alignment.

Evidence? Are you sure it is specific to the lens and not a user error,camera picking a different focus target, or AF/Shutter priority?

Ever thought that it could be due to a bad lens?

What constitutes a bad lens in such a case? Whatever that is, it would behoove the camera manufacturer to provide a method to address the badness through AF micro adjustment.

Misaligned/skewed optics, loose optics, bum AF motor are typically what I see.

Some things MFA can't fix, especially if the variance of accuracy isn't consistent (loos optics or bad motor for instance)

The problem with AF issues on current SLR type cameras is usually a misalignment of sensor distance and AF module distance from the lens.

This has been discussed before, and here is the evidence you seek:

If the only reason for AF micro adjustment was to compensate for a discrepancy between the imaging sensor distance and the PDAF sensor distance, we would expect that the micro adjustment for every lens would be the same with any specific camera. But we know that is not the case, and individual lenses almost always need individual adjustment values for optimum performance... so there must be more than one reason. That's why I, like Emacs23, don't assume that MFA will never be needed.

No, you are not seeing it correctly. The lens can and does play a factor in the distance and accuracy of the AF, hence why MFA changes from lens to lens or camera to camera. But the difference is that when the AF sensors are directly on the sensor, the sensor is seeing and measuring the final image output. It is able to adjust for those changes from lens to lens, camera to camera. You can't do that with a dedicated PDAF module that is on a different plane of the sensor. It's that direct feedback and interaction with the sensor itself with no middle man that makes it possible. That's the difference between a dedicated AF module off plane versus OSPDAF in plane. I think you might be oversimplifying how AF works.

If it didn't work, then even native E-mounts lenses would be needing MFA.

 VirtualMirage's gear list:VirtualMirage's gear list
Sony RX100 Sony a77 II Tokina AT-X Pro 11-16mm f/2.8 DX Tamron SP AF 90mm F/2.8 Di Macro Tamron SP 70-200mm F/2.8 Di VC USD +18 more
sybersitizen Forum Pro • Posts: 15,592
Re: Will the next full-frame A mount camera be mirrorless?

VirtualMirage wrote:

sybersitizen wrote:

VirtualMirage wrote:

Emacs23 wrote:

so no MFA is needed.

I doubt a bit about this. Many users of A7 r II suffer from front-back focus, so this can be a PDAF specific issue, not just AF sensor alignment.

Evidence? Are you sure it is specific to the lens and not a user error,camera picking a different focus target, or AF/Shutter priority?

Ever thought that it could be due to a bad lens?

What constitutes a bad lens in such a case? Whatever that is, it would behoove the camera manufacturer to provide a method to address the badness through AF micro adjustment.

Misaligned/skewed optics, loose optics, bum AF motor are typically what I see.

Some things MFA can't fix, especially if the variance of accuracy isn't consistent (loos optics or bad motor for instance)

I doubt that either of knows nearly enough about the science to say with certainty what MFA could not be used to fix.

The problem with AF issues on current SLR type cameras is usually a misalignment of sensor distance and AF module distance from the lens.

This has been discussed before, and here is the evidence you seek:

If the only reason for AF micro adjustment was to compensate for a discrepancy between the imaging sensor distance and the PDAF sensor distance, we would expect that the micro adjustment for every lens would be the same with any specific camera. But we know that is not the case, and individual lenses almost always need individual adjustment values for optimum performance... so there must be more than one reason. That's why I, like Emacs23, don't assume that MFA will never be needed.

No, you are not seeing it correctly. The lens can and does play a factor in the distance and accuracy of the AF, hence why MFA changes from lens to lens or camera to camera. But the difference is that when the AF sensors are directly on the sensor, the sensor is seeing and measuring the final image output. It is able to adjust for those changes from lens to lens, camera to camera.

I don't happen to believe that. I suspect that some lens anomalies that could cause less than perfect AF will go uncorrected in the absence of MFA - anomalies that perhaps could otherwise be corrected with MFA. Where's your evidence to the contrary?

You can't do that with a dedicated PDAF module that is on a different plane of the sensor. It's that direct feedback and interaction with the sensor itself with no middle man that makes it possible.

Again, I don't think either of us knows enough to confidently make such a statement.

That's the difference between a dedicated AF module off plane versus OSPDAF in plane. I think you might be oversimplifying how AF works.

And I think you might be oversimplifying it.

If it didn't work, then even native E-mounts lenses would be needing MFA.

That is exactly what some of us are talking about because apparently it doesn't always work.

Keyboard shortcuts:
FForum MMy threads