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Forum: Lens Clubs
10-26-2011, 09:00 PM
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Stefan, these are fantastic: the lens looks great and is is an excellent invesment indeed! Congratulations. Now, if you'll be so kind as to spoil us with more of your work. Yeah, I know I can go to the blog, but get out and shoot with this gem and post here for us.
Ernest
BTW, the Pumpkin shot is exceptional, and amazingly sharp.
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Forum: Lens Clubs
10-15-2011, 08:53 PM
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Stefan:
I wouldn't take the numerical variations seriously. There was a poster in our Lens Club once who tried to argue the Sigma 10-20mm is not really a 10mm lens. They based this conclusion on an AOV equation and on the published AOV from the Sigma web site: here, for example, 10-20mm F4-5.6 EX DC HSM - Wide Angle Zoom Lenses - SigmaPhoto.com
The poster did not realize that Sigma reports AOV @ their site based on their sensor which, when the math is done, returns an AOV of 102.4 degrees. When the poster read the reported AOV for the Tamron 10-24 as 110.5 degrees, they falsely concluded the Sigma 10-20mm was not really a 10mm lens @ the wide end, and even used this mentality to trash the Sigma brand.
The AOV calculation, as you know, is dependent upon the dimensions of the sensor, which vary slighty from brand to brand. Read here: Samyang offers 14mm F/2.8 IF ED MC Aspherical lens: Digital Photography Review where DPReview reports AOV for the 14mm Samyang as 92.5 degrees.
In the case of the Canon APS-c sensor, which actually has a 1.6 crop factor, the numbers vary even more. Even though a 300mm lens acts like a 450mm lens on Pentax APS-c & 480mm on a Canon APS-c, the lens is still a 300mm lens. Or as some like to say around here: "300mm is 300mm."
Also, the equation you posted assumes an aspect ratio of exactly 3:2, which can throw more confusion into things.
Clear as mud?
:)
JT
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Forum: Lens Clubs
03-22-2011, 11:27 PM
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I usually have no interest in fisheye scenes, but like this one.
The flower is great--the street shot has certain poignancy. This is a great club you have begun---I look forward to stopping in now and then.
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