Steve Spencer
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 Re: Samyang 35-150mm f/2.0-2.8 | |
JVan_02 wrote:
Steve Spencer wrote:
JVan_02 wrote:
Steve Spencer wrote:
Jerky_san wrote:
I was wondering if any of you could shed any light on Samyang and their steppers? They claim they have "Linear STM" but I've seen some people on comments sections say they don't really have Linears in the sense that Tamron and Sony have but instead are just using marketing. Does anyone have any experience with Samyang on that front? I know the lens isn't out so I guess no one would really know about this particular lens. The youtube video seemed to indicate a very slight AF noise but it seemed very tolerable.
Btw I ask because I'm seriously debating buying this over the Tamron to save a bit on another piece of glass I want.(Sony 200-600mm)
Linear and stepper motors are mutually exclusive categories. Stepper motors move the elements in a circular motion around a central axis and were often used in clocks before they were used in cameras if that helps understand how they move. Linear motors as the name implies moves the elements back and forth in a straight line. So saying you have a linear stepper motor is an oxymoron--it is like saying you have a square circle. It is a claim that isn't possible.
That said the crazy idea often propagated on these forums that one time of motor (usually linear) is better than the other type of motor is equally silly. What matters is the details of how the motor works (e.g., how much power it has, how fast it works, how quiet it work, etc) not the type of motor. Sony has in recent years built some really great linear motors, but that doesn't mean stepper motors are necessarily worse motors. It is people who argue for such non-sense that leads to the ridiculous and obviously untrue marketing claims of linear stepper motors. What we need is better specification of the motors in our lenses regardless of what type they are.
Whether or not the motors are actually at the point where the marketing hype meets reality is one question. However, from a mechanical standpoint there are three real advantages of linear (electromagnetic motors) over stepper motors.
Less moving parts means less points of failure which should mean higher average durability. No idea how things have progressed since this post, but in general we're already at or near the point where linear motors are mechanically simpler than stepper motors. At some point, failure of electromagnetic motors should approach the point of jamming/derailing of helicoids.
The simpler design allows for easier insertion of linear motors inside of other mechanisms. Again, this is covered by the blog post but even beyond that I wouldn't be surprised if linear motors was how things like the 16-35 pz ended up being so compact. I'm not an optical engineer so it's hard to say specifically what would be impossible using steppers, but in general the same expertise applied to simpler problems allows for better results.
While it's hard to say if acceleration/top speed will ever be an advantage due to that also relying on power delivery and power efficiency (and not just mechanical capability of the motor design), linear motors can absolutely be more precise than steppers due to the precision of stepper motors being mostly gear limited. This advantage will mostly manifest in applications like macro or wide aperture lenses where stepper motors traditionally took a speed hit for greater accuracy. Linear motors need no such sacrifices—compare focusing speeds of the 50 1.2 S, 50 1.2 RF, and 50 1.2 GM. Speedy macro lenses should also be possible here.
So yes, in many ways I'd say Linear motors are a technological leap.
There is no evidence whatsoever that linear motors are simpler than stepper motors. Stepper motors can be super simply and they were as built into clocks for decades. No evidence linear motors are a technological leap either. They have been built into speakers for decades.
There is zero evidence that linear motors are more precise either. Keep in mind stepper motors have kept time precisely for decades in clocks. They have been used for decades and after decades of use they still precisely keep time.
You are again parroting points about linear motors being better than stepper motors with zero evidence. Not a single link comparing the two technologies. There is a name for those sorts of claims: misinformation.
Sure, no evidence that most stepper motors, even those utilizing electromagnetism, are geared. Exceptions always exist, and of course you can say Wikipedia isn't accurate but scientific articles on Wikipedia have long held up under scruitiny.
However if you wanted a more photo-centric look at the motors, in this post A Look at Electromagnetic Focusing which you clearly didn't read the first time, we see the author introduce linear motors with:
[Linear motors] have some nice advantages over other types of motors: they are simple, silent, and very fast.
Furthermore, we get pictures! Of linear motors!
Wow, just elements driven along a rail via magnetism. No moving parts. Very, how shall we say it... simple. Durable. Reliable. This position is reaffirmed years later starting at 23:00 of this podcast by people who take apart and repair cameras all day, and people who design cameras.
But maybe you know more than the fine people at Lensrentals. You did say I was parroting misinformation after all.
However, I'd refer you to your own confident assertion that the mechanics of wrist and pocket watches can be compared at all in terms of precision to the mechanisms that shape soundwaves.
Somehow, Steevo, you seem more confidently ignorant every time I happen to come across you.
Confidently ignorant? I think that is a personal attack. Don't you? I made arguments about your argument. You make attacks about me as a person. Not cool and in fact, a clearly inappropriate action. Duly reported.
Oh, and I did read the lens rental blog post (and I have read it several times before). It talks about linear motors being reliable. It does not present any information about them being more reliable than stepper motors. It just doesn't say what you report it saying and that is misinformation. When you post a link and say it says something it doesn't that is misinformation. When someone calls you on it and you call them "Steve," and personally attack them that is bullying someone when they call you on presenting misinformation. You seem to have that routine down.
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