It took a long time ...

[bfitzgerald]

I think there are a few reasons but pretty much none of them have anything to do with cost. The only advantage over screw driven lenses is quietness of AF and Sony dropped the ball badly there making SAM noisier than screw drive ones!

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.

[pakodominguez]

Thanks Barry for taking care of business, I’d probably add.
Focus accuracy depends mainly on the body not the lens so much, although there is the question of how well the gear train is designed, how much slack in a given lens there is, or how much wear etc. the main thing to remember is we didn’t NEED SAM lenses in the first place, all Sony had to do was build the existing design to a better quality standard.
Greg

the photo review site photozone dispute that claim and says the AF accuracy with SAM lenses is superior to old screw-driven lenses. Given he knows a lot more about this topic than you do, I will take his words.

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.

[bfitzgerald]

My 28-80mm D feels better built that an "easy choice" lens Sony seriously cheaped out build wise here. Shame as the optics look good on most of them.

[agorabasta]

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.

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?
No offence, OK ?

[OneGuyKs]

I think there are a few reasons but pretty much none of them have anything to do with cost. The only advantage over screw driven lenses is quietness of AF and Sony dropped the ball badly there making SAM noisier than screw drive ones!
.

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.

[OneGuyKs]

the photo review site photozone dispute that claim and says the AF accuracy with SAM lenses is superior to old screw-driven lenses. Given he knows a lot more about this topic than you do, I will take his words.

Also, Sony engineers know much more than you do whether they needed SAM lenses or not, so why don't you leave that to them? Screw-driven lenses still don't AF with A580's CDAF system. SAM ones do.

The whole reason why Sony is wasting time inventing SAM lenses and fooling around with CDAF is because of video, most people who do STILL photography didn’t need either of them, but I bet they wouldn’t say no to more SSM lenses. The glass in the SAM lenses is fine, but they could have made them a standard screw drive lens without the extra weight and size instead. And having to NOT add the motor into the design would have made them even cheaper.
Greg

Ps. Ha ha you might have a long silence there on the usefulness of the EVF in the studio Barry….

Nonsense. CDAF is crappy with video and DSLR lenses. That's why we have E-mount (with CDAF lessen) and SLT for A-mount.

CDAF is more accurate than PDAF (no back and front focus issues) and it can be used (in future) to auto calibrate PDAF lenses (for micro focus adjustments as an example). Only SAM AF with CDAF and the AF is more accurate in general too on SAM.

As for EVF in studio, EVF is superior anywhere, studio or not, A55's bugs not withstanding.

[OneGuyKs]

Nope. Electric coupling with an in-lens motor is simply much cheaper than some precision mechanical gear could be.
In fact, given the modern tech, producing a screw-driven lens would be cheaper to do with the cam's screwdriver coupling to a position sensor in the lens and then again feeding the control signal into the in-lens motor

Nope yourself agorabasta, are you saying that the basic reason was that Sony was suddenly overwhelmed with ultraism and wanted to give us cheap lenses and it was by pure accident that they discovered they could focus with CDAF at some point after they made them?
Greg

Why don't you offer your services to Sony engineering department, Beetham? Obviously, you sitting at your home know all about screw-driven and SAM lenses and why SAM were not needed?

SAM lenses in general have better AF accuracy. They are still better than screw-driven lenses even if noise is similar.

I don't believe Sony will ever release the old screw-driven lenses again.

[bfitzgerald]

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.

I'm not sure you've grasped the point being made here. So I'll repeat it for you.
The only reason the A580 cannot contrast AF with screw drive lenses is because Sony decided to make it that way. It's a "Sony crippled" implementation for contrast AF as said other makers CAN contrast AF with screw drive lenses.

Let's talk about EVF's WYSIWYG? Really raw shooter and you think you'll get an accurate display in the VF of the image? Think again jpeg processed image in the EVF.
Option to calibrate the EVF?? I doubt it somehow even on the new A77. Remember the A700 "My lcd isn't right" debate..I do!
EVF gains up in low light WYSIWYG flies out the window there
Bad DR blocked shadows and blown highlights
Colour tearing when panning or movement
Much heavier battery use
SLT mirror remains in place during shooting compromising image quality
EVF is entirely useless for flash photography you can't predict that with it!

Of course I completely understand that some newbies coming from a point and shoot superzoom might want an EVF..however on this board I suspect we're all experienced enough to have done a little bit of work on "WB and Exposure"

Controversial? Maybe the backlash starts here...
SLT isn't around because folks are on the streets demanding it..it's around because makers see a longer term chance to cut costs and production manufacturing time.

[OneGuyKs]

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.

I'm not sure you've grasped the point being made here. So I'll repeat it for you.
The only reason the A580 cannot contrast AF with screw drive lenses is because Sony decided to make it that way. It's a "Sony crippled" implementation for contrast AF as said other makers CAN contrast AF with screw drive lenses..

That doesn't make any sense since their is no "higher" end camera that does AF with screw-driven lenses. They would "cripple" it if they wanted to up-sell a higher end model, but as we know, A580 is the last of the breed.

The "other" makers have different driven screw-driven lenses We here have Minolta heritage. These lenses can't -- or at least so far Sony was unable to make them work with CDAF.

SAM lenses do (probably due to smaller increments on SAM compared to screw-driven lenses).

[OneGuyKs]

Let's talk about EVF's WYSIWYG? Really raw shooter and you think you'll get an accurate display in the VF of the image? Think again jpeg processed image in the EVF.

Even partial WYSIWYG is better than zero WYSIWYG from crappy OVF.

[OneGuyKs]

EVF is entirely useless for flash photography you can't predict that with it!

Thanks for agreeing that my WYSIWYG argument is valid, since OVF is 100% useless with AND without flash photography, BOTH.

[OneGuyKs]

.
SLT isn't around because folks are on the streets demanding it..it's around because makers see a longer term chance to cut costs and production manufacturing time.

That's another great argument in favor of SLT. Cost cutting is always good. Cheaper is better than expensive one

.
Of course I completely understand that some newbies coming from a point and shoot superzoom might want an EVF..however on this board I suspect we're all experienced enough to have done a little bit of work on "WB and Exposure"

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.

[bakubo]

These lenses can't -- or at least so far Sony was unable to make them work with CDAF.

Sony has been unable to make reliable control wheels too so we are seeing a pattern of things Sony can't figure out how to do that other companies can. Time to hire some better engineers? Even if it means luring them away from Nikon, Canon, and Pentax?

[OneGuyKs]

These lenses can't -- or at least so far Sony was unable to make them work with CDAF.

Sony has been unable to make reliable control wheels too so we are seeing a pattern of things Sony can't figure out how to do that other companies can. :

No, just switch to SAM/SSM that has better AF accuracy too. So as it turns out, SAM/SSM is better system after all.

[bakubo]

No, just switch to SAM/SSM that has better AF accuracy too. So as it turns out, SAM/SSM is better system after all.

Hey, you are the one that said Sony was unable make them work. I think I get your drift though. Users should just drop some crazy glue into their control wheels and not use them. Voila! Problem solved, well, at least, solved in the Sony way. Seriously though, I think the Sony solution will be that they will get rid of the control wheels that they are unable to make work and replace them with a touch screen.