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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Introducing new wide zoom!!!!

chuck colburn said:
All zooms have focus shift as they vary their focale length. The best have very little. But all of them have some. You can get it spot on at the long end (front focus) and the wide end (back focus) and at a spot about 1/3 to 1/2 way done the focale length range. The mechanisim that contols focus shift is called the compensator. It is the group of moveable elements behind the variator group which is the one that varys the focale length of the lens. As lens mechanical design, optical formula and glass types have improved over time the focus shift has become less and less. But it does exist.
And it can be measured.
Click to expand...

I must be mixing up your words..
What you're describing is what we call zoom curve. Similar to your description, theoretically, say at 6' focus comes up right on the mark, then you zoom to mid zoom and focus is no longer coming up on the 6' mark but at the other end of zoom it does come up on the mark. That is typical zoom curve. Which is easily corrected in most modern cine zoom lenses.
I disagree that "All zooms have focus shift (zoom curve)".
Sorry if I'm just splitting hairs here. I think we are both talking about the same thing, just different words. Cheers!
 
Evin Grant said:
I just did a critical back focus test on Ruby and if there is any "zoom curve" it's hidden by the DOF of such a wide lens. I can't detect any significant shift in focus distance at any of the marked focal lengths.
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Hi Evin,

I was not asking about the Depth of Field which is what I take it you mean by not seeing any shift in focus distance. I was asking about depth of FOCUS shift which is very shallow on a wide angle lens.
 
chuck colburn said:
Hi Evin,

I was not asking about the Depth of Field which is what I take it you mean by not seeing any shift in focus distance. I was asking about depth of FOCUS shift which is very shallow on a wide angle lens.
Click to expand...
Chuck,
There is no focus shift on this lens,
Optically and mechanically Depth of focus does not change on this lens. no image shift
Stuart
 
Expanded Focus Ruby 14-24mm T2.8

Expanded Focus Ruby 14-24mm T2.8

I want everybody to know about our focus expansion change.

Ruby 14-24mm T2.8, has 50 degree of focus rotation. The final product has been re design so that the focus travel will be approximately 95-120 degree.
We will be able to get many focus marks in this focus range. Engraving marks that we should be able to engraved will be as follow:
1 foot 2 inches, 1 foot 4 inches, 1 foot 6 inches, 1 foot 8 inches, 2 feet, 2 1/2 feet, 3 feet, 4 feet, 5 feet, 6 feet, 8 feet 10 feet 15 feet 25 feet and infinity, with complete accuracy with our anti back lash design.

Here is a couple of pictures at 14mm 4K.

http://www.e3media.com/client/ruby4k1.zip

http://www.e3media.com/client/ruby4k2.zip

If you have any questions or concerns, feel free to contact us.

Stuart
 
Excerpt from a recent Thom Hogan article, I thought this was interesting :

"As my eventual review of the 14-24mm will reveal: it's a 5 out of 5, a 10 out of 10, a 100 out of 100, an n out of n. It doesn't matter what scale you rate it on, it's just a near flawless lens. Too bad about the "no filters" bit. The funny thing is that the 14-24mm Nikkor is a better lens than the Zeiss 18mm or Zeiss 21mm. Yep. A zoom outshoots the high-end primes. Really."

He refers of course to the original, not Ruby.
 
Stuart, you said something about doing a longer zoom. Do you have anything that will go past 70mm, like to 80 or 85? I'm not up on all of the still lenses out there and if there is something of high quality like that.
 
Lee Saxon said:
Excerpt from a recent Thom Hogan article, I thought this was interesting :

"As my eventual review of the 14-24mm will reveal: it's a 5 out of 5, a 10 out of 10, a 100 out of 100, an n out of n. It doesn't matter what scale you rate it on, it's just a near flawless lens. Too bad about the "no filters" bit. The funny thing is that the 14-24mm Nikkor is a better lens than the Zeiss 18mm or Zeiss 21mm. Yep. A zoom outshoots the high-end primes. Really."

He refers of course to the original, not Ruby.
Click to expand...

And this is exactly why I choose to rehouse the 14-24 T2.8 to Cine!!

Thanx Lee for the Info!

Stuart
 
Sorry, this info must be somewhere, or I could figure it out if I weren't so lazy not to do the math, but what is the horizontal field of vision of the lens on RED at 14mm?
 
FocusOptics said:
Rudi,
this lens covers ff35 horizontal is 36mm across.
Stuart
Click to expand...

Sorry Stuart (and thanks!) but I meant coverage in degrees, as in 75, 80, 90 degrees, whatever it yields on a S35 sensor. I know that this should be slightly over 110 degrees on a FF35 frame, but I don't know exactly what it is on the smaller S35 frame...
 
My guess is around 80 degrees horizontal angle of view with the Ruby 14mm on the Red.
That's somewhat equivalent to an HD wide video lens at 5.4mm for wide or handheld work.
 
RedCrosser said:
My guess is around 80 degrees horizontal angle of view with the Ruby 14mm on the Red.
That's somewhat equivalent to an HD wide video lens at 5.4mm for wide or handheld work.
Click to expand...

Ok, that's wide enough for what I need, not optimal but surely enough. Now I just need to wait until enough people buy the lens so I can rent it and test it before buying it. And yes, which lens is next? The 24-70 sure sounds like a logical step.
 
Rudi Herbert said:
Sorry Stuart (and thanks!) but I meant coverage in degrees, as in 75, 80, 90 degrees, whatever it yields on a S35 sensor. I know that this should be slightly over 110 degrees on a FF35 frame, but I don't know exactly what it is on the smaller S35 frame...
Click to expand...

Should be about 90° - 61° on a RED One. 114° - 84° on FF35
 
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