Wide Angle Info

[Neil Corbett]

Looking for some info on wide angle lenses for the Z1. They always have a figure included, ie '0.8x' or '0.7x'? What does that mean and should i be looking for a higher number as the best option?

Also, a friend lent me a wide angle manufactured by Zunow which, when at its widest, had a lot of picture out of focus at the edges. Zunow is not a name that comes up a lot in my searches and was wondering if it might be a poor lens choice?

Neil

[Duncan Craig]

Hiya, well your questioned have been answered many times before on here.

Basically a .7 is wider than a .8 - the lower the number the wider the adaptor will be.

Seems to me the Zunow lens has already proved itself as a POS, buy something that actually works. Search this forum for recommendations.

Personally I have the Sony .8, the Optex gave too much flare.

[Oliver Smith]

It depends on how wide you want your image.

0.7, 0.8 refers to scales of wideness. ( I have no idea how it relates to camera lenses)
anything below .66 will end up distorting straight lines.

0.3 gives you a 180 degree field of view, probably around 8-10mm in photography terms.

Depending on your budget, have a look at Raynox lenses. They're reasonably affordable and have excellent clarity if used at full wide. Zoom through isnt too spectacular so it depends on your context. If you want a really wide lens, a Century Optics 0.3 would be the go, but its only for very specific purposes that you would even consider owning one.

[Boyd Ostroff]

Originally Posted by Oliver Smith

0.7, 0.8 refers to scales of wideness. ( I have no idea how it relates to camera lenses) anything below .66 will end up distorting straight lines.

As a practical matter that may be true based on the lenses which are available, but I don't think it has to be like that. I have a 14mm wide angle lens for my Nikon which gives a really wide field of view with almost no distortion. These are sometimes called "PC" (perspective corrected) or "rectilinear" lenses. It has to do with the design of the lens, not anything inherent in the focal length itself. Of course, you get what you pay for too... that Nikon lens wasn't cheap!

The numbers like 0.7x and 0.8x are actually very easy to understand and relate to focal lengths if you have the specs on your camera's built-in lens. They mean exactly what they say; with a 0.7x adaptor you would multiply the focal length of your camera's built-in lens times 0.7. Camcorders have zoom lenses, so obviously the zoom setting affects the focal length.

On your Z1 if you zoom full wide the actual focal length will be 4.5mm which is the equivalent of a 32.5mm lens on a 35mm SLR camera (you will find this info in the specifications section at the back of your Z1 manual). So if you add a .7x wide adaptor then the 35mm SLR equivalent would be:

.7 x 32.5 = 22.75mm

You can do the math yourself to compare the effects of other adaptor lenses. We've discussed adaptor lenses for the Z1 here in the past - see the following:

http://www.dvinfo.net/conf/showthread.php?t=77240
http://www.dvinfo.net/conf/showthread.php?t=67014
http://www.dvinfo.net/conf/showthread.php?t=58525

[Ryan Avery]

Originally Posted by Oliver Smith

It depends on how wide you want your image.

0.7, 0.8 refers to scales of wideness. ( I have no idea how it relates to camera lenses)
anything below .66 will end up distorting straight lines.

0.3 gives you a 180 degree field of view, probably around 8-10mm in photography terms.

Depending on your budget, have a look at Raynox lenses. They're reasonably affordable and have excellent clarity if used at full wide. Zoom through isnt too spectacular so it depends on your context. If you want a really wide lens, a Century Optics 0.3 would be the go, but its only for very specific purposes that you would even consider owning one.

The magnification of a lens does not necessarily give you the degrees of field of view. A .3x lens can have anywhere from 130 to 180 degrees of view. The Century Extreme Fisheye for the Sony Z1 for example is the only lens on the market with 180 degrees field of view but is still only a .3x. Our .3x Ultra Fisheye is 130 degrees field of view even though it is the same magnification. The amount of barrel distortion allowed in the optical design enables the field of view.

http://www.schneideroptics.com/centu...x1/hdr-fx1.htm

A .7x is 30% wider and a .8x is 20% wider than you existing lens. The formula for 35mm equivalents is dependent on the size of the CCDs used in the camera.

Ryan Avery
Regional Sales Representative
Schneider Optics