Steve Spencer
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 Re: Nokishita - Sigma 35mm 1.4 DG DN Art priced at $899 | |
bjornthun wrote:
Steve Spencer wrote:
bjornthun wrote:
Steve Spencer wrote:
vdo1 wrote:
bjornthun wrote:
Steve Spencer wrote:
bjornthun wrote:
Steve Spencer wrote:
bjornthun wrote:
Steve Spencer wrote:
bjornthun wrote:
j4nu wrote:
Hmm I also thought so but I think the best focusing DN lens I tried is using HSM:
https://www.sigma-global.com/en/lenses/a019_35_12/
Maybe Sigma doesn’t have Sony’s linear XD motors to provide the required torque in Sigma’s case or in Sony’s case just force.
The new 35/1.4 DG DN has a focus group consisting of only one light lens element, according to the press text on SAR. That may explain how Sigma gets away with a stepper motor in this case. I see that Sony uses dual XD motors even on the new small 24/2.8, 40/2.5 and 50/2.5 G lenses.
So, stepper motors appear a bit dated to me, and HSM-motors are stone age D(inosaur)SLR tech. 
I see no evidence from any reputable site (only gushing by Sony fans) that linear motors are better than stepper motors. Sony has extensively used linear motors most other manufacturer have used stepper motors for their mirrorless lenses. Both technologies are relatively old and borrowed from existing tech (linear motors from speakers and stepper motors from clocks). They are competing technologies without either clearly being better than the other.
This article from Dpreview may be of interest.
https://www.dpreview.com/articles/6776198643/first-impressions-of-the-sony-50mm-f1-2-gm?slide=11
Two quotes from the linked text.
« Two independent floating focus groups allow for close focusing distances, and are driven by four 'extreme dynamic' linear motors (two per focus group). We're told by Sony that these linear motors are very efficient at generating linear motion, as they don't require any translation of rotational motion to linear motion, as ring-type and stepper motors do.»
and
« In comparison, the tiny FE 35mm F1.8 optic takes 0.3s to rack from its minimum focus distance to infinity, while the Nikkor 35mm F1.8 S takes around 1s to do so. That makes the 0.5 - 0.6s figure for the 50mm F1.2 GM nothing short of impressive.»
Yes, Sony claims the technology they use is better than competing technology, yawn. Manufacturer claims of superiority should be separated from actual evidence of said superiority. DPR is simply quoting what Sony claims. And the comparison of just two lenses establishes nothing. Of course manufacturers build individual lenses with different speeds. Did Nikon ever say anything about their 35 f/1.8S as being their fastest AF lens? Of course not. What we know is that the FE 35 f/1.8 is faster than the 35 f/1.8s, but this one test tells us nothing about whether stepper motors or linear motors as a category are faster.
The Nikon 35/1.8 Z is larger, heavier and more expensive than the Sony 35/1.8 FE, yet it focuses more slowly. From Dpreview’svreview of the Sony 35/1.8, « At F1.8 it is sharper and has more contrast than the Sony Distagon T* FE 35mm F1.4 ZA and the Nikon 35mm F1.8 S, almost approaching the benchmark Canon 35mm F1.4L II lens.», link https://www.dpreview.com/reviews/sony-fe-35mm-f1-8-review/3 . The Sony lens not only focuses faster than its Nikon counterpart, it’s optically superior too, according to Dpreview. The Sony 35/1.8 FE is $698 and the Nikon 35/1.8 S is $846.
The Sony 50/1.2 GM is smaller and lighter than the Nikon 50/1.2 S
Do linear (XD) motors have a size advantage, allowing a lens to be constructed smaller than lenses with HSM/USM/SWM motors and stepper motors?
Who knows if linear motors have a size advantage? Sony just may be more interested in building smaller lenses than Nikon. Nikon clearly didn't build their 50 f/1.2S to be small, and they clearly had a moderate size (around a pound) in mind for all their f/1.8S lenses. The Sigma 85 f/1.4 Art DG DN is an example of a fairly small 85 f/1.4 lens with a stepper motor and the Canon 35 f/1.8RF with 1:2 magnification is quite small at 305g for a lens with that short of an MFD and it too has a stepper motor, so perhaps lenses can be built small with stepper motors as well, but Nikon just hasn't tried to minimize size as much as Sony, Sigma, and Canon.
Well, we don’t know why Nikon hasn’t tried more to shrink their lenses as much as their competitors have.
I suggest we leave it here and return to disussing the upcoming Sigma 35/1.4 DG DN. 
We also don't know why Nikon would be using superior technology yet obtain poorer results than Sony.
Anyone knows when the first reviews of the Sigma will hit the wires?
I think we need to understand that performance is more than AF speed and sharpness. If all you care about is AF speed and sharpness the FE 35 f/1.8 would be hard to beat. That lens is very sharp and focusses very fast. If you care about aberrations (especially axial CA) or about the bokeh a lens produces, then you may not like the FE 35 f/1.8. It will be interesting to see what this Sigma 35 f/1.4 does with regard to balance between characteristics. I think the Sigma 35 f/2i is a very balanced lens with very good performance in AF, sharpness, aberration control, and bokeh while it doesn't maximize any of these while leaving poor performance in others (as I believe the FE 35 f/1.8 does). Will the Sigma 35 f/1.4 take the same approach balancing size, AF, sharpness, aberration control, and bokeh? We will have to wait to see.
Dpreview, Chris and Jordan in their video, say the Sigma 35/1.4 DG DN with stepper motor focuses much slower than the Sony 35/1.4 GM with linear motors.
is that their words or do they just say the Sigma focusses slower than the Sony? Sony clearly made fast focussing a priority, perhaps Sigma did not. Can you link to the DPR video?
You can easily find it on Dpreview. It’s new today.
I don't go on Dpreview as a general rule. I do like Chris' and Jordan's review, however, and have appreciated them since they started making them for the Camera Store in Calgary. I had hope since you mentioned it you might be able to link to it or at least answer question about it.
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