# 10-20mm vs 4.5mm



## janok (Jan 9, 2012)

Two pictures from the harbor area in Oslo (Aker Brygge). One is taken with a Sigma 10-20mm and the other with the Sigma 4.5mm. 
The fish-eye can create some cool effects, but there are several trade-offs. The 4.5mm use just 1/3 of the CMOS real-estate and it there is somewhat brutal process to unfold the picture from a circle to a square format. This could reduce the sharpness significantly. Below you see the results. Let me know what you think.




Aker Brygge - Sigma 10-20mm by janokiese, on Flickr




Aker Brygge Sigma 4.5mm by janokiese, on Flickr


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## 480sparky (Jan 9, 2012)

I like how you treated the 4.5 in post.  Even losing a lot of data, you can still end up with a great shot.

How about posting the original 4.5mm shot for comparison?


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## Bynx (Jan 9, 2012)

I dont like the curved look of a fisheye. Its about as bad as the bad look of a lensbaby. Both are gimmicky lenses that on very rare occasions might add interest to a photo. But that is rare. The comparison you show here is interesting. To capture the whole shape of the water the fisheye was necessary. I have a 10-20mm Sigma and find it an excellent lens with little distortion that is easily fixed.


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## Compaq (Jan 9, 2012)

Cool! Does that 4.5mm give you a circle formed image with black corners?

The fish eye perspective is something I like in really cramped placed. I remember janok showing the inside of a train compartment or something in a museum - very cool.


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## janok (Jan 9, 2012)

Thank you for the feedback - Compaq, the original pictures looks something like this: http://www.sigmaphoto.com/client/images/productphotos/08142009_img_97451.jpg


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## Compaq (Jan 10, 2012)

I see. Those circle frames could be nice at times, I'd imagine, if the entire thing was cropped to a square format..


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