Yes, indeed Sony was unable to make A-mount screw driven lenses work with CDAF on A580. SAM lenses AF with CDAF no problem. I don't care what other brands are doing (they don't have A-mount lenses).bakubo wrote:Hey, you are the one that said Sony was unable make them work.OneGuyKs wrote:No, just switch to SAM/SSM that has better AF accuracy too. So as it turns out, SAM/SSM is better system after all.
you are talking Pro - Video, right?OneGuyKs wrote: The only reason that DSLRs were stuck with optical viewfinder is because PDAF AF did not work with EVF. It was never a "plus" but a byproduct of PDAF AF system that needs to direct light to AF sensor. The "pro" camcorders used by real pros who actually do real pro work (unlike you) never needed OVFs.
That's because EVF is superior, for real pros, period.
OneGuyKs wrote:bakubo wrote: Yes, indeed Sony was unable to make A-mount screw driven lenses work with CDAF on A580. SAM lenses AF with CDAF no problem. I don't care what other brands are doing (they don't have A-mount lenses).
Plus, AF accuracy is better on SAM/SSM
So there.
well iirc Olympus gave up too so maybe it isn't that easy?bfitzgerald wrote:
I can't actually believe I'm reading this!
Denial in the extreme..unable should be replace with "unwilling" Now I can't call this a deal breaker it's not but it is odd and it's not a technical problem either they just decided not to do it.
I have a virtually brand new KM28-75 (purchased new from B&H) and I've never noticed any focussing problems with it on any of my bodies, I haven't used it a lot though as I seem to end up using the KM24-105 more.pakodominguez wrote:I had the chance to use for a month, side by side, the KM 28-75 f2.8 and the SAM 28-75 f2.8 -optically the very same lens. The SAM focused faster AND more accurate than the KM version -the build quality on this lens is much better than what we can find on the "easy choice" lenses, I don't know if the SAM on it is also "much better" or not.
agorabasta I took the liberty of checking the specific gravityagorabasta wrote:Well, Barry, isn't it about the time for you to provide some data supporting your idea that Sony SAM lenses are any heavier than their comparables?bfitzgerald wrote:It does add weight and size to a lens which is probably one reason Pentax have stuck with screw drive for all their limited lenses.
No offence, OK?
of the KM28-75 versus the SAM28-75, it is as follows: who said the KM version have a focusing problem?Greg Beetham wrote:I have a virtually brand new KM28-75 (purchased new from B&H) and I've never noticed any focussing problems with it on any of my bodies, I haven't used it a lot though as I seem to end up using the KM24-105 more.pakodominguez wrote:I had the chance to use for a month, side by side, the KM 28-75 f2.8 and the SAM 28-75 f2.8 -optically the very same lens. The SAM focused faster AND more accurate than the KM version -the build quality on this lens is much better than what we can find on the "easy choice" lenses, I don't know if the SAM on it is also "much better" or not.
Greg
Greg, I deduce you'd never see - use the Sony version of this lens. The KM is more plastic, while the Sony is more metal and better build.Greg Beetham wrote:agorabasta I took the liberty of checking the specific gravityagorabasta wrote:Well, Barry, isn't it about the time for you to provide some data supporting your idea that Sony SAM lenses are any heavier than their comparables?bfitzgerald wrote:It does add weight and size to a lens which is probably one reason Pentax have stuck with screw drive for all their limited lenses.
No offence, OK
SAM28-75 565g (dimensions=77.5x94mm)
KM28-75 508g (dimensions=73x94mm)
http://kurtmunger.com/konica_minolta_af ... id255.html
Greg
Just to be clear to everyone. I did not write what is above that appears to be a quote from me. Barry, something got messed up when you quoted the above.bfitzgerald wrote:OneGuyKs wrote:bakubo wrote: Yes, indeed Sony was unable to make A-mount screw driven lenses work with CDAF on A580. SAM lenses AF with CDAF no problem. I don't care what other brands are doing (they don't have A-mount lenses).
Plus, AF accuracy is better on SAM/SSM
So there.
I can't actually believe I'm reading this!
Denial in the extreme..unable should be replace with "unwilling" Now I can't call this a deal breaker it's not but it is odd and it's not a technical problem either they just decided not to do it.
I guess Sony couldn't work out how to do DMF or put the ISO in the VF on any of their Alpha models nope it was impossible to do it..sigh, thump! SLT is part down to cost cutting and as suggested there for video.
SAM is just better with consistently (on average) better AF accuracy. That's all.Greg Beetham wrote:I have a virtually brand new KM28-75 (purchased new from B&H) and I've never noticed any focussing problems with it on any of my bodies, I haven't used it a lot though as I seem to end up using the KM24-105 more.pakodominguez wrote:I had the chance to use for a month, side by side, the KM 28-75 f2.8 and the SAM 28-75 f2.8 -optically the very same lens. The SAM focused faster AND more accurate than the KM version -the build quality on this lens is much better than what we can find on the "easy choice" lenses, I don't know if the SAM on it is also "much better" or not.
Greg
This is not consistent with my experience with both SAM and screw-driven AF lenses. My screw-driven lenses hunt less and are quicker to follow objects moving toward or away from the camera.OneGuyKs wrote:SAM is just better with consistently (on average) better AF accuracy. That's all.
What lenses are you comparing? List them.KevinBarrett wrote:This is not consistent with my experience with both SAM and screw-driven AF lenses. My screw-driven lenses hunt less and are quicker to follow objects moving toward or away from the camera.OneGuyKs wrote:SAM is just better with consistently (on average) better AF accuracy. That's all.
The build quality of the KM28-75 looks to be of a very high standard to me, the fits and tolerances are very neat and smooth, and even if it is plastic as you say one would be hard pressed to realize it. In any case the question was, is a SAM version of a lens bigger and heavier than the screw drive version, and I believe that I've shown that it is, in any case I still say we didn't need SAM lenses in the first place, SSM yes SAM no.pakodominguez wrote:I had the chance to use for a month, side by side, the KM 28-75 f2.8 and the SAM 28-75 f2.8 -optically the very same lens. The SAM focused faster AND more accurate than the KM version -the build quality on this lens is much better than what we can find on the "easy choice" lenses, I don't know if the SAM on it is also "much better" or not.
Like I said before we didn't need CDAF, we didn't need video (that's why the A580 has CDAF) and we didn't need SAM lenses.OneGuyKs wrote:
That's not the only advantage, as we know SAM can AF with A580's CDAF but screw driven lenses can't. And SAM can AF more accurately more often (photozone).
It's still superior.
Why would Minolta have designed their AF system to work with CDAF? The Minolta AF system is superior to the other brands of AF because it can focus through glass at an object on the other side, the other two struggle to do this, also you don't need to use a circular polarizer with the Minolta AF you can use a linear one and they work twice as good as a circular one.OneGuyKs wrote:
The "other" makers have different driven screw-driven lenses
SAM lenses do (probably due to smaller increments on SAM compared to screw-driven lenses).
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