Yeah, I have the same lens, good old Vivitar Series 1 (with macro setting), OM mount of course.

Amazon just sent me a note saying they still don't have stock, so it looks like this lens is delayed. Maybe some heavy demand?

Interview with one of lens constructor

Q: Does an access to low dispersion glass of different kind (SLD, FLD) or high refraction index glass make the work of an optics specialist noticeably easier?

A: Although low dispersion glasses are essential optics for the development for high performance lenses, using them does not explain the whole story of the success. Adequate experiences and flexible ideas are essential for lens design as it enables us to grasp the features of each optic and optimize them in the product.

Q: Why the Sigma 18-35 mm filter is 72 mm in diameter while its moderately convex front element is only 49 mm in diameter? Was it impossible to use a smaller filter?

A: Although it may not be possible to attach the 49 mm filter, attaching a frame close to that size is possible. However, the frame of the filter will cause vignetting in the edges thus it's not realistic.

Q: How the optical stabilization influences the resolution of an image? After all in such a construction there are movable elements. Is designing stabilized lenses more difficult than designing ordinary lenses?

A: We think that the optical stabilization system reduces camera shake which affects resolution. Because the optical stabilization system needs to move some of the lens groups, the lens design with OS function will be more difficult from both optical and mechanical points of view.

Q: More and more cameras, launched on the market, are mirrorless constructions, characterized by short flange focal distances. Of course such a situation demands a quite different approach to the lens construction, especially when it comes to telephoto lenses. Do you still look for new technical solutions in an active way when it comes to the optics or are the coatings the only innovation here? Or maybe the construction process is just like playing with Lego blocks, modifying slightly the same proven constructions over and over again?

A: Concerning telephoto lenses for mirrorless cameras, it's important to take the design of AF system into consideration. Rather than flange focal distance, to function the lens groups and the optimized mechanical design is more substantial element for a lens development. There are many ways to improve lens performance apart from optical technology. Thus, we are always working on any type of development for our technical innovation. Conventional designing methods have also some room for improvement, so our engineers are refining their skills by studying it thoroughly.

http://www.lenstip.com/136.1-article-Interview_with_constructor_of_Sigma_lenses_Interview_with_constructor_of_Sigma_1.4_35_and_18-35_mm_f_1.8_lenses.html

Comparison with Rokinon 35/1.4 and Canon 24-70 f2.8L

Most 16, 17 or 18mm-to-something-mm lenses show very noticeable barrel distortion at their widest focal length. This lens has barrel distortion at 18mm, but it performs better than many similar lenses by showing only a modest amount. As usual, the barrel distortion is corrected as the focal length increases until essentially being gone at around 22mm. Pincushion distortion then creeps into the picture and becomes mild from 28 through 35mm.

Overall, I am very pleased with the image quality from this first-ever lens design. It has a green light for my own needs.

Featuring Sigma's HSM (Hypersonic Motor) driven AF, the Sigma 18-35mm f/1.8 DC HSM A Lens focuses with very good speed.

At short distances, this lens is practically parfocal (focus distance settings remains the same throughout the zoom range). Longer distance focusing likes more focus adjustment through the available focal length range.

The Sigma 18-35mm f/1.8 DC HSM A Lens has very smooth, perfectly-damped and ideally-sized zoom and focus rings that have no play in them

http://www.the-digital-picture.com/Reviews/Sigma-18-35mm-f-1.8-DC-HSM-Lens.aspx

Is there the possibility to add this lenses directly to a GH3? or do I have to use a ring adapter and lose the autofocus?

As far as I know they do not plan to make m43 version. So best idea is to get Nikon version + Nikon G to m43 adapter, plus later get Nikon G to m43 lens turbo.

I went to local camera store and they told me Sigma hasn't any Nikon version of this lens yet, is that true? Also is there any particular reason Sigma don't wanna make a m43 version of the lens. You will think they should seeing now that they have BMCC MFT, and BMPCC and all the various m43 cameras.

@HillTop1

http://www.bhphotovideo.com/c/product/967345-REG/sigma_18_35mm_f1_8_dc_hsm.html

And Blunty has posted a fresh review of the Sigma 18-35, on the Canon 70D. He really likes this lens.

B&H has shifted the expected delivery date from August 22nd to September 25th.

All these videos of review nerds ejaculating all over it start to get a little boring ;)

.-. Finally got my Sigma 18-35 EF mount. So far, on 2.5K Blackmagic, it's amazing. Every focal length I want for the camera primarily in one fast, sharp piece of glass. Will still get a 50, and I kept my 85/1.8 Canon, along with the 12/1.6 SLR and 25/0.95 SLR (for anything hyperFast).

I also got to test the GL Optics PL rehouse of this lens on Pocket Camera and it's equally sick. It'll feel right at home with a VIewfactor'd out Pocket Cam. Really looking forward to it.