Opposite of Reverse adapter ring or extension tube


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etegration

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Oct 14, 2003
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#1
We use a Reverse adapter ring or extension tube to get close or closer macro with existing lens and couple it between the lens and the camera.

Is there such a thing as an opposite to a extension tube? Where you'll couple it in between the lens and camera body to produce a further looking image aka wider? A wider angle converter of sorts in point and shoot cameras term but for DSLR?
 

Octarine

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Pasir Ris
#2
If an extension tube achieves an effect of magnification than the opposite is necessary for wide angle - can you push any lens further into the camera? It would hit the mirror.
There are such wide angle adapters, they consists of a glass element put in front of the lens. Optical quality is rather mediocre. Be prepared for Chromatic Aberrations and distortions. 'denniskee' has started a thread gathering information and example picture, more to see here: http://www.clubsnap.com/forums/showthread.php?t=477934&highlight=wide+angle+converter
 

giantcanopy

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#3
There are some stratospherically priced cine wide angle adapters by companies such as schneider. Might not have the exact size thread mount but if u r keen to get something that might be actually more expensive than a dedicated wide angle lens. ..

Ryan
 

etegration

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#4
If an extension tube achieves an effect of magnification than the opposite is necessary for wide angle - can you push any lens further into the camera? It would hit the mirror.
There are such wide angle adapters, they consists of a glass element put in front of the lens. Optical quality is rather mediocre. Be prepared for Chromatic Aberrations and distortions. 'denniskee' has started a thread gathering information and example picture, more to see here: http://www.clubsnap.com/forums/showthread.php?t=477934&highlight=wide+angle+converter
i was thinking about this itself but was wondering if there's any adaptors that instead of being pushed (instead of pushing lens away from camera body) into the camera, uses some optics like mirrors? thanks for replying.
 

Octarine

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#5
i was thinking about this itself but was wondering if there's any adaptors that instead of being pushed (instead of pushing lens away from camera body) into the camera, uses some optics like mirrors? thanks for replying.
Think about the optics. What the front element doesn't cover / capture won't appear at the rear element. So for wide angle you must put something in front of the front element to change the optical specifications and the resulting field of view. That's what those adapters are doing - with the known side effects. There are mirror lenses .. but these are telephoto lenses (e.g. 300mm or 500mm, various brands).
 

Dec 28, 2007
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#6
First, reverse adapter ring or extension tube doesn't change focal length. They just make your lens focus closer. By moving your camera closer, you get more detail with the same view angle. Note this is different from zoom-in (i.e. useing longer focal length), although you get more detail in both cases.

Second, even if you can push the lens "into" the camera a bit, you don't get any wider picture. What you get is a lens which can focus beyond infinity. Unlike focusing closer, focusing beyond infinity is totally useless.
 

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