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03-07-2009, 05:14 AM   #1
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For people who understand the K mount, is it possible to make NX mount work w it?

(edit: sorry about the thread title, there isn't enough room...)

OK, so we know the m4/3 mount works with limited number of 4/3 lenses but they AF slowly (I am guessing the power current is not as stronge?)

And its alot harder for KFA mount to implement due to mechanical screw drive and mechanical aperture lever. How hard is it to make decently backward competible NX mount on the Samsung camera?

Let's forget about what Samsung is actually doing and pretend they do want to work with the KFA mount and esepcially the DA lenses. How can this work? I think people who have alot of teleconverters can answer this question easier.

Aperture:

for lenses that have aperture ring, if we have to press "meter" button before we shoot, doesn't seem like that big a problem. So basically its like what pre-A lenses work on the Pentax bodies now. With NX at lease you get to use old lenses from other mount. (BTW, does Nikon AI/AIS work the same way. You can use the aperture ring to control the aperture? What modern Nikon lenses has aperture control on the lens?)

Aperture lever:

well we need these in order to use the DA lenses. I don't see why shouldn't the NX mount use the same lever. It's a simple enough mechanic to implemet on the converter.

They probably can make the lever travel shorter and still be able to make a coonverter that works properly on the K mount. Is this possible?

AF USM contacts:

I think this is the most obvious option. They should use the same signal and pin number as the USM contacts. That way we get to AF "slowly". The question is has Samsung repackage any USM lens. We have 16-50 DA*, 50-135 DA*, DA17-70 and 55 DA* (both of the last two have no screw drives.) I don't know the situation of the new 200mm DA* and 300mm. I think it would be nice of Samsung to make the pins competible w K mount USM lenses.

I remember somebody said they will make the pins competible with the Canon EF mount. While is not a bad idea and I wouldn't mind being able to AF with all modern Canon lense. My question is, is it legal? IIRC, isn't the Sigma mount pin competible w Canon mount, but you have to physically hack the camera in order to make it AF the Canon lense. In order words, only a handful of Sigma bodies in the world can do it. OTOH, I remember Sigma's 3rd party lense are all reverse engineered. So can Samsung make a NX->EF adopter without being sued to oblivion? (Since I don't see any 3rd party is doing that for the m4/3 body its probably too much patent and copyright mine field to over come?)


AF Screw pins.
OK, first of all, is there a converter out there that can carry ovr the screw drive to the lens? If its doable then we know it can be done. Very important if you want to use the DA pancake lenses. But if Samsung is taking over the AF pin space with their own crap then I will hate them for it. Even if they are not offering a screw pin at least Pentax can make a version that can, in the future.

To be honest this is the least important thing of the 4 things I listed above. If there is decent 10X manual focus aid, I can live without the AF on most of the FA/DA lenses. The upside is you get to use lense from other mounts.


Last edited by whatever7; 03-07-2009 at 06:45 AM.
03-07-2009, 08:23 AM   #2
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QuoteOriginally posted by whatever7 Quote
is it possible to make NX mount work w it?
Despite your lengthy introduction, all problems you mentioned can easily be solved. The engineering effort is middle. It wouldn't be cheap and I fear that if Samsung isn't doing one, nobody will.

I here assume that the mount's power supply wouldn't be weak.

But be aware that Samsung may have decided to use an encrypted electronic protocol which would force any third party to license it. The K mount electronic protocol is not encrypted.

Slow focussing with µFT is more a problem with contrast AF algorithms rather than mechanics. Of course, the availbale algorithms are poor (speaking as somebody who has written one).
03-07-2009, 05:25 PM   #3
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Moved to SLR lens section.
03-07-2009, 05:58 PM   #4
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for AF i doubt that they would use screw drive. secondly, i also doubt that they would be able to put a motor with enough torque inside any adapter.

aperture lever, again, i am totally skeptical why they would do that. it's a new concept, time to start fresh and electronic.

03-07-2009, 06:05 PM   #5
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QuoteOriginally posted by falconeye Quote
Despite your lengthy introduction, all problems you mentioned can easily be solved. The engineering effort is middle. It wouldn't be cheap and I fear that if Samsung isn't doing one, nobody will.

I here assume that the mount's power supply wouldn't be weak.
Are you saying the slow AF on the m4/3 system is due to different AF mechanic, not the power of the AF pins? So the m4/3 lenses focuse so fast because it has different construction, not becasue its lighter than the 4/3 lenses?

QuoteQuote:
But be aware that Samsung may have decided to use an encrypted electronic protocol which would force any third party to license it. The K mount electronic protocol is not encrypted.

Slow focussing with µFT is more a problem with contrast AF algorithms rather than mechanics. Of course, the availbale algorithms are poor (speaking as somebody who has written one).
That's not what we are talking about though. What we want is to use older A/F/FA/DA lense on the NX body, not the other way around.
03-07-2009, 06:58 PM   #6
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I agree with K100d on this. Samsung will mostly probably be starting fresh. Its much too troublesome and costly for them to ensure some compatibility with Pentax lenses.

For using Pentax Lenses on Samsung.

Assumptions
-NX mount ~ to m4/3.

Aperture Control - Pentax is I believe the only mount that embedded their contacts onto the mount plate. All other mounts have created a contact strip inside the body cavity. The contacts for KA and later generations of lenses (w/ respect to aperture control) function primarily to tell the body the range of apertures the lens is capable of. When the photo is taken, the aperture lever is released only enough for the lens to close down to the desired aperture for the shot before opening it back up. Assuming NX contact pins are of the same function and operation, they'd still need to run the wires from the contact strip on the rim of the back opening into the wall of the converter tube and then up to the surface of the mount plate. That alone will cost you more then your average electronically connected extension tube. Adding the mechanisms to control the aperture level will compromise the small size of the NX body.

Autofocus - With the screw drive becoming obsolete, it seems only logical that Samsung will follow suit. Object of NX system is to be simple and compact. To install an AF motor on the camera body will also compromise its small size. If a motor where to be installed into the converter housing, it will have to be bigger and very expensive.

I don't think we should expect any compatibility with Samsung's NX system beyond what we can do with 4/3rds (and micro 4/3rds). Hang on to those old lenses and wait for cameraquest and those ebay wholesalers to come up with an adapter.
03-08-2009, 08:01 AM   #7
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QuoteOriginally posted by FotoPete Quote
Hang on to those old lenses and wait for cameraquest and those ebay wholesalers to come up with an adapter.
That's not going to happen. A manual adapter: maybe. An automatic adapter, as I wrote: the effort is middle, not low. Only Pentax, Samsung or Sigma are candidates to make one. And only Samsung would have an interest to do so. Its price would be ~500$ and it would bring the size of the NX up to that of a K-m at least.

whatever7, "What we want is to use older A/F/FA/DA lense on the NX body, not the other way around."... I perfectly understood this. You didn't understand my response. So, let me explain...

An NX would have to use a contrast-based AF system (like µFT). Current algorithms (which are all poor) need many repositionings to aquire focus. Unlike phase-based AF which typically only need 1 repositioning. Older/current FA/DA lenses would be slow with the current generation of contrast-based AF algorithms. This may improve over time. But not with a first generation NX firmware.
03-08-2009, 09:44 PM   #8
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QuoteOriginally posted by falconeye Quote
...
whatever7, "What we want is to use older A/F/FA/DA lense on the NX body, not the other way around."... I perfectly understood this. You didn't understand my response. So, let me explain...

An NX would have to use a contrast-based AF system (like µFT). Current algorithms (which are all poor) need many repositionings to aquire focus. Unlike phase-based AF which typically only need 1 repositioning. Older/current FA/DA lenses would be slow with the current generation of contrast-based AF algorithms. This may improve over time. But not with a first generation NX firmware.
But how do the two m4/3 lenses focus so fast on the Panasonic G1?

Frankly I don't want to talk about the speed of AF. Does it matter that much compare to no AF at all. Too bad they move the thread to this subforum, which has alot less traffic than the other one.

03-08-2009, 09:53 PM   #9
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Technically, there is nothing about an adapter that could not be overcome, but that doesn't mean it will happen. A completely manual adapter is quite possible, perhaps even likely, but an autofocus, auto aperture adapter would most likely have to come from Samsung themselves.

Doing an adapter that would handle SDM lenses would be easier than one that could handle screw drive (which would require a significant motor in the adapter), but as falconeye pointed out, cameras with only electronic viewfinders depend on a different type of autofocus system that is not as robust as those found on reflex cameras.

Then there is the complication of the mechanical aperture lever on K mount lenses. This would require some kind of electronic to mechanical conversion coupler on the adapter. This could also be tricky.

Again, it could be done, but I have significant doubt that it will be done.

Last edited by CFWhitman; 06-11-2010 at 08:12 AM.
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