Sony Alpha Rumors has announced a new patent that's been filed by Sony, regarding a new type of zoom lens. The new lens, referred to as a "fusion," should offer the brightness of a "high grade" 3x zoom, and the magnification of a "popular type" 4-5x zoom. How does it do it? Well, ask DK (in fact, he is quoted in the Sony Alpha Rumors article.) The intention is to offer a zoom lens that performs like two different constant aperture zoom lenses in one; instead of taking lots of intermediate steps in the maximum aperture throughout its zoom range, it takes only one, in the middle, after serving as a faithful 3x f/2.8 zoom. Imagine a Tamron 17-50/2.8 that kept zooming past 50mm as if by a 1.4x teleconverter.

The example given in the article is of a 16-80/2.8-3.5, but I can't find these specifications exactly in the patent, and they do seem a little ambitious. Anyone having more experience with patents and technical writing is welcome to pry further and see what you can gather. I have provided a link to the patent in PDF format below.


Patent US 20100020410 A1

Sony Alpha Rumors - New Sony patent shows a new lens

Another patent has surfaced, regarding a means by which to employ a tilting mechanism in a camera lens. The novel interface which it proposes is that of a ring-type control. Instead of tilting the barrel of the lens, a ring on the outside uses a cam cylinder and reference pins to tilt a group of elements within it.

http://sonyalpharumors.com/new-sony-alpha-tilt-shift-lens-patents/

http://www.freepatentsonline.com/20090201595.pdf

That looks as the VFC principal -a smart solution for a tilt mechanism.

Regards

It's most likely they would actually link this to a shift mechanism. If you just tilt either the lens itself (traditional method) or a group (only possible with some very careful optical design along the same lines as used by IS lenses) the optical axis doesn't line up with the image plane centre, which means you don't get the best part of the image circle.

The traditional way to overcome this is to shift the lens as you tilt (drop front used with downward tilt) to keep the image circle centred on the film/sensor.

If you can get hold of a Sigma 18-250mm OS, you will find that the IS group would be capable of acting as a shift lens. Thing it, you can't take a shot at all with the group at 'rest' position, which is equal to a fair amount of rising front on a landscape view. Switch the camera on, and the image immediately 'sinks' to centre up. But it looks sharp enough in its de-centered form.

Maybe Sony has spotted this, and realises that if you add a tilt to the same group (and get the design right) you can have a tilt lens which keeps the image axis centered. In fact, all tilt and shift could be internal. No need for any movement of the complete mount.

David

On more, this time about macro lenses:
http://www.google.com/patents?id=i5zIAA ... q=&f=false

For a while, I thought Sony was mostly towards licensing designs from Zeiss & Tamron.
It seems that Sony actually also does R&D on their own about lenses, it's just that it takes time to do so.

That's the 30mm f/2.8 SAM macro lens - retrofocus macro design with moving front group only. A conventional 30mm macro is impossible with a back focus around 40mm (the practical limit of placing a rear element in the Alpha system). So they designed one built like a wide angle, but not actually wide in angle.

Since I do not have a 30mm here, I can't confirm that the focusing method used is exactly as shown in the patent, but it looks as if that's what this is.

David

I'm wondering why the Sony DSLR division does not communicate more about this one.
If this is really an innovative design, they should have organised a press conference, show some nice slides, and distribute press kits. Journalists love to hear about new tech stuff that they can show to the readers and Sony get some "free" advertisement as well as establish itself as a technology leader.

OK, this design has got me curious. A lens is now ordered and on the way. Unlike the 50mm f/1.8, this is something new and I had not really understood how new. There has never been a macro lens for an SLR which is as short as 30mm yet can focus to infinity. Also, Sony state 2cm close focus - meaning 2cm from the lens front, not their usual way of measuring.

What this means is that the lens will have a true focal length closer to 15mm when focused at 1:1. With a 15mm lens, there should be 30mm from the lens front nodal point to the subject at 1:1. The front nodal point may be 10mm into the lens, but it could be deeper due to the design - maybe 20mm, in which case the lens will have a true focal length of 20mm at 1:1.

These focal lengths are shorter than my 25mm micro lens. Also, if this starts as a 30mm f/2.8 and uses the focus method shown by the patent, then it will maintain f/2.8 as it focuses - at 1:1, it could be equal to using a 20mm f/2 plain lens. Olaf may have some views on this, or a definitive way of determining the front and rear nodal points - I can do that with an optical bench but I don't have an optical bench!.

Pity the M-AF automatic Novoflex bellows is prohibitive in price.

David

Can one patent a lens design? So no lenses with the same design can be made? If so, there'll be soon a lens patent war between Canon, Nikon, Sony etc. You can make much more profit with these wars rather than selling your product

I'd say SoCaNikon could also sue Sigma for reverse-engineering their SSM/HSM protocols. This is a violation of IP. But probably they think it's wiser to allow them to continue.

I remember cases where 3rd parties had to withdraw ink cartridges because they were able to communicate with the printers electronics, which was considered violation of IP. I am talking here of mere ink cartridges that communicated back how much drops are left or so, not about full print heads.

My view is that Sony's patent is for the exact design - the configuration of elements. Many lens designs of the past were patent for long periods. Minolta had an amazing line-up of patent lens ideas. I don't think it would need much alteration to the design to make a similar lens to all appearances, which just happened to work slightly differently inside.

David

Tokina has a 35/2.8 Macro. Is it with a similar design?

I would guess Tokina's is a simple retrofocus, as it reaches 1:1 at 14cm from the sensor plane which equals exactly the correct distance for a simple 35mm lens. Although the mount register of the Alpha system is under 45mm, if you measure one of the deepest intruding lenses like the 50mm f/1.4 you will find it sticks 9mm into the lens throat - meaning that that actual clearance required for the mirror is more like 35mm. So it would need a very powerful retrofocus design to achieve that at 35mm.

In fact, I have a 35mm Prinz f/5.6 lens unit in my studio for 42mm thread. It will focus to infinity directly mounted on a camera body, and if it's retrofocus at all, it is only by having a very small degree of asymmetry in the design.

But 30mm is another matter, than extra 5mm shorter would make a conventional design focusing at infinity impossible. The closest focal length match you can get in past history would be the 30mm f/3.5 Meyer Lydith, which is of course a true retrofocus.

David

It's nice to remain F/2.8 at close focus but with a 35mm, the camera need to be so close that you probably block a lot of light.
I think an APS-C 60mm or 100mm macro would make a lot more sense.

I have the lens now. This is one STRANGE lens. The SAM is ultra noisy - worse than the earliest Canon micromotor lenses - and quite slow. It weighs nothing and is built to withstand, er, nothing. The 2cm close focus is scary, apart from the shadow issue and the flash not illuminating a single part of the subject (even the ringflash would miss). But having said that, it is an extremely sharp lens over about 85% of the frame even when wide open. The corners honestly don't improve much, they are affected more by curvature of field at f/2.8 than by aberrations. I have to do some proper tests, but it appears free from CA and distortion when used at normal distances and very sharp when used for macro. Also, at 1:1 it is near perfect in geometry and field flatness.

Everything about this lens says: I am really made for 4/3rds format.

And, it loses very little speed as you focus close. At 1:1 it should be an f/5.6 lens, but it works as f/4.5 - a plain illuminated field which needs 1/500th at f/2.8 at infinity, needs 1/200th at f/2.8 at 1:1. The loss of aperture is 1.3 stops instead of 2 stops. This means that at 1:1, the unusual focus mechanism is reducing the actual focal length to just 24mm.

This lens is definitely the design shown in the patent, same concave rear element larger than the front, etc.

David

Hi David,

Do you think that you can live with the plastic mount? Otherwise, it is a nice lens, I wish they made it FF!
Regards