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next PZ Lens Test Report: Voigtlander Ultra-Wide Heliar 12mm f/5.6 Aspherical II
#1
[url="http://www.opticallimits.com/sony-alpha-aps-c-lens-tests/544-voigtlander12f56nex"]http://www.opticallimits.com/sony-alpha-aps-c-lens-tests/544-voigtlander12f56nex[/url]



Not stellar but still quite good
#2
Interesting lens but it looks to me that size (i.e. pocketability) is its biggest asset.



BTW, if you click on "All tests" and scroll down you don't see both of the new heliar tests. Only of you click on "Sony Alpha APS-C" you see them.
#3
[quote name='Klaus' timestamp='1284445527' post='2734']Not stellar but still quite good[/quote]



And a waste of time one is tempted to add.
#4
[quote name='Klaus' timestamp='1284445527' post='2734']

[url="http://www.opticallimits.com/sony-alpha-aps-c-lens-tests/544-voigtlander12f56nex"]http://www.opticallimits.com/sony-alpha-aps-c-lens-tests/544-voigtlander12f56nex[/url]



Not stellar but still quite good

[/quote]

It does look good on that black NEX. And its performance is not half bad for such a wide range finder lens...



Isn't it harder to build such wide lenses for range finders as the lens sits so close to the film (sensor) that you will get more light fall off towards the corners?



The sample images actually look quite attractive.
#5
[quote name='Brightcolours' timestamp='1284479382' post='2746']

It does look good on that black NEX. And its performance is not half bad for such a wide range finder lens...



Isn't it harder to build such wide lenses for range finders as the lens sits so close to the film (sensor) that you will get more light fall off towards the corners?



The sample images actually look quite attractive.

[/quote]

It doesn't so much depend on the distance to the film or sensor, as on optical vignetting caused by the AoV and the resulting stretching of the image towards the edge of the image circle, which is an unavoidable phenomenon in rectilienar lenses. One could design a lens with an even wider AoV and much larger image circle, and essentially use only the centre part of the image, so that vignetting is less in the "cropped" part of the image, but that would make such a lens rather large. An example of such a lens actually is the TS-E 17 mm when not tilted or shifted, which only has a 1 EV vignetting figure wide open, where it really should have something in the order of 3 to 4 EV if not more, if it had a 43 mm image circle.



Since RF lenses often were designed to be as small as posisble, they don't normally cater for extended image circles.



You can actually compare this a little to the effect of the sun on the earth, where the light intensity is much higher in the tropics compared to the temperate or pole latitudes, due to the larger surface the same quantity of light now has to illuminate (and heat up) off the tropics.



BTW, in principle it is easier to design a WA or UWA lens for an RF camera than it is for an slr or dslr, due to the extra complications caused by the retrofus design required for a (d)slr. In principle, an RF design can be totally distortionless, with realtively few elements, while that is impossible with an (U)WA (d)slr lens which requires the use of a retrofocus design to clear the mirror, generally adding several extra elements, plus barrel distortion (due to asymmetrical placement, out of necessity, of the aperture mechanism). Before someone asks: moustache distortion is caused by trying to optically correct barrel distortion in an UWA lens, and this is never 100 % successful, hence the wavy result.



Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#6
I'm really prefer small lenses and so this lens would be really nice except the price. So maybe there should be a portability ranking? ;-)
#7
[quote name='Marco' timestamp='1284630698' post='2831']

So maybe there should be a portability ranking? ;-)

[/quote]



Yup... it's calculated like this:



Portability value of a lens = Height x Width x Depth = Volume <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='Big Grin' />
#8
[quote name='genotypewriter' timestamp='1284633392' post='2834']

Yup... it's calculated like this:



Portability value of a lens = Height x Width x Depth = Volume <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='Big Grin' />

[/quote]

I think you forgot another important aspect, Geno: weight <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='Smile' />.



Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#9
[quote name='wim' timestamp='1284676893' post='2867']

I think you forgot another important aspect, Geno: weight <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='Big Grin' />.



Kind regards, Wim

[/quote]

So something like this?

volume^2 + weight^2 = portability^2



Lets call it the Photogorean theorem.
#10
[quote name='Brightcolours' timestamp='1284678497' post='2869']

So something like this?

volume^2 + weight^2 = portability^2



Lets call it the Photogorean theorem.

[/quote]



But what about praxis. ;-) It is more a ranking like: Very small(pancake), small(small primes), medium(kit zooms), big(something like a 85/1.4), very big. So I could get a list of small lenses which is maybe helpful. ;-)
  


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