ALLSTAR
REDuser Sponsor
Hi Everyone,
on our lens production line, besides 105mm micro F2.8 and 135mm F1.8 are in production, we are going to start producing 18-35mm F1.8 zoom lens.
Recently, we tested and disassembled sigma 18-35. This lens has well optical quality, excellent CA control, almost no breathing. However, the shortcomings is, loose light in 4 corners when the iris is wild open. And when focusing, the image will distort in 4 corners.
In the mechanical phase, fortunately it has lots space to be modified to PL mount easily. But unfortunately, it's zoom direction is opposite to common usage. About this, I did some research and found out that there is nothing I can do with it. Because when turning zoom, there are several glasses groups moving at the same time. And I don't have accurate data about the glass, therefore I cannot rebuild it.
About the focus, the original lens's rotation angle is about 120 degree. IMO, it is
absolutely not enough for cinema, espacialy the rotation from infinite to 2ft only about 35 degree! Please see the marks in the picture:
This is a F1.8 lens, precise focusing is a must-have condition. So we will rebuild it's focus parts to let it has over 300 degree rotation angle. This part is really complicate, so it won't be cheap.
But some people ask me if they can get this lens with low price. If I don't change the focus part, the rehousing will be mouh easy. The rehousing level will be like our 80-200 lens. So the price will be about the same.
I don't want to make two versions for one lens. So I want to do some survey about this for reference. Please let me know which one you perfer:
A. The lens has rebuilding focus, with over 300 degree rotation angle. Pirce is about 5000 USD.
B. Just rehousing the lens, without changing focus parts. Price is about 3000 USD.
Or if you have any suggestions, please let me know.
Thank you very much.
Tom
Allstar.cine
Update:
We decided to make both types of 18-35mm:
1. 18-35mm Lite
Front diameter: 95mm / 72mm thread
Focus turning angle: 120 degrees
0.8 pitch gears on focus, zoom and iris
changeable stainless steel mount system with PL, Canon and Nikon mount
Price hasn`t be 100% decided, the modification will be similar to our 80-200 lens, so maybe it will be priced at $2900-2700USD
2. 18-35mm Cinema
Front diameter: 95mm / 72mm thread
truly "new re-designed" focus structure ,focus turning angle is over 300 degrees
0.8 pitch gears on focus, zoom and iris
changeable stainless steel mount system with PL, Canon and Nikon mount
Price will be around $5000USD
Lite version will be first. We will divided our lens products into two line: Lite and Cinema. The main difference between them is focus structure, lite version will keep the original focus structure like other rehousing lens in the market. Cinema version will re-build focus structure to get precise focus.
on our lens production line, besides 105mm micro F2.8 and 135mm F1.8 are in production, we are going to start producing 18-35mm F1.8 zoom lens.
Recently, we tested and disassembled sigma 18-35. This lens has well optical quality, excellent CA control, almost no breathing. However, the shortcomings is, loose light in 4 corners when the iris is wild open. And when focusing, the image will distort in 4 corners.
In the mechanical phase, fortunately it has lots space to be modified to PL mount easily. But unfortunately, it's zoom direction is opposite to common usage. About this, I did some research and found out that there is nothing I can do with it. Because when turning zoom, there are several glasses groups moving at the same time. And I don't have accurate data about the glass, therefore I cannot rebuild it.
About the focus, the original lens's rotation angle is about 120 degree. IMO, it is
absolutely not enough for cinema, espacialy the rotation from infinite to 2ft only about 35 degree! Please see the marks in the picture:
This is a F1.8 lens, precise focusing is a must-have condition. So we will rebuild it's focus parts to let it has over 300 degree rotation angle. This part is really complicate, so it won't be cheap.
But some people ask me if they can get this lens with low price. If I don't change the focus part, the rehousing will be mouh easy. The rehousing level will be like our 80-200 lens. So the price will be about the same.
I don't want to make two versions for one lens. So I want to do some survey about this for reference. Please let me know which one you perfer:
A. The lens has rebuilding focus, with over 300 degree rotation angle. Pirce is about 5000 USD.
B. Just rehousing the lens, without changing focus parts. Price is about 3000 USD.
Or if you have any suggestions, please let me know.
Thank you very much.
Tom
Allstar.cine
Update:
We decided to make both types of 18-35mm:
1. 18-35mm Lite
Front diameter: 95mm / 72mm thread
Focus turning angle: 120 degrees
0.8 pitch gears on focus, zoom and iris
changeable stainless steel mount system with PL, Canon and Nikon mount
Price hasn`t be 100% decided, the modification will be similar to our 80-200 lens, so maybe it will be priced at $2900-2700USD
2. 18-35mm Cinema
Front diameter: 95mm / 72mm thread
truly "new re-designed" focus structure ,focus turning angle is over 300 degrees
0.8 pitch gears on focus, zoom and iris
changeable stainless steel mount system with PL, Canon and Nikon mount
Price will be around $5000USD
Lite version will be first. We will divided our lens products into two line: Lite and Cinema. The main difference between them is focus structure, lite version will keep the original focus structure like other rehousing lens in the market. Cinema version will re-build focus structure to get precise focus.
