[Leica] Image circle

[hopsternew at gmail.com (Geoff Hopkinson)]

Yes! It is just a better corrected circle. ;-)
FWIW all of the M lenses produce an image circle sufficient to cover all of
the 24x36 mm rectangle and Peter Karbe (Optics department head at Solms)
recently said that the S system lenses provide an image circle sufficient
for that camera's 30x45 mm sensor (but no larger)

Cheers
Geoff
http://www.pbase.com/hoppyman


On 20 March 2010 08:40, philippe.amard <philippe.amard at sfr.fr> wrote:

> Is the circle really a circle when using ASPH lenses?
>
> Sure?
>
> Phx
>
>
>
> Le 19 mars 10 ? 23:34, Mark Rabiner a ?crit :
>
>
>> Richard,
>>>
>>> The size of a lens image circle is not absolute but depends on your
>>> criteria. Most lenses are sharp and relatively distortionless in the
>>> center of the image. Quality and illumination fall off as you move
>>> away from the axis. You have reached the edge of the lens image circle
>>> when the image quality no longer meets your photographic requirements.
>>> That being said, the easiest way to determine the approximate size of
>>> the image circle is to hold the lens in front of a ground glass. Adjust
>>> it so that it focuses a distant scene and simply measure the
>>> illuminated circle on the ground glass. Most normal lenses have a
>>> reasonable quality of image in a circle with a diameter approximating
>>> their focal
>>> length. Symmetrical lens designs tend to have a bigger image circle and
>>> are frequently used for wide angle lenses.
>>> Larry Z
>>>
>>>
>>
>> And your image circle gets better when you work closer.
>> That you learn from view camera work.
>>
>> [Rabs]
>> Mark William Rabiner
>>
>>
>>
>>
>>
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>>
>>
>
>
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