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PeteAtkinson

Member Since 25 Nov 2008
Offline Last Active Today, 06:36 PM
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Posts I've Made

In Topic: Rectilinear wide angle for Nikon DX

Today, 06:36 PM

Adam, the 8-16 Sigma is rectilinear - there's no full circle.


In Topic: Rectilinear wide angle for Nikon DX

Yesterday, 06:11 PM

Sigma 8-16. It seemed to me to be "better" than the Nikon 12-24, but that's a subjective view.


In Topic: Full Frame SLR wide angle corrector port tests

14 April 2016 - 12:31 AM

I am amazed! Concave side towards the dome!! I will try to find one at ADEX to look at it! Thanks.


In Topic: Full Frame SLR wide angle corrector port tests

10 April 2016 - 06:55 AM

Perhaps someone with this corrector lens could measure the curvature of both surfaces, to determine whether one or both are aspheric. The way I would do this is to scribe approx. curvature on a piece of thin card, cut it out, and see if it fits flush to the surface of the lens. Then do another, making adjustments till it's a perfect fit.

In New Zealand 20 years ago I had coated plano-convex dioptres made which were said to flatten the curvature of field, but B&W diopters always seemed to give better results.


In Topic: Sigma 15 fisheye, least parallax point anyone?

24 March 2016 - 01:55 AM

This helps a lot! And it shows why I need to ask, as my measurements are so bad, and yours, and Simon K's are virtually the same!

Many thanks to both of you. If you have NPP measurements for other lenses used underwater Randall it would be great if you could post them on Wetpixel where they should be pinned. Thanks again!

 

www.peteatkinson.com