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Old May 5, 2008, 9:08 PM   #1
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Join Date: Apr 2007
Location: Sacramento, Ca
Posts: 652

OK .. I thought their might be enough other tight budgeted photographers out there to find this interesting. I wasn't sure where to post this sense it's something of a mixed subject. But there is a question at the bottom, so I put it here.

My biggest disappointment with my switch to digital (I knew this going in) is the crop factor of the DX format. For this reason I still lug around a film camera with my 17mm Tokina lens. I will some day pick up an ultrawide for the DX format but for a year or two that will just not be in my budget.

I recently picked up one of those cheap fisheye attachment lenses that threads to the filter ring of a normal lens. I know, I know, junk right? I thought so too. But I got it for ten dollars so I figured why not? Something to play around with anyway.

My first concern was the extreme barrel distortion. Thou this can be OK even artistic with some subjects I prefer a linier image. I tried using the lens correction filter in Photoshop but it just wasn't good enough. It bent the heck out of the edges but the distortion stayed in the image. I then downloaded a free lens correction plug-in from Photo-Plugins.com and this worked great. But the preview is small and you can't save the settings.

My next worry was the circular image. I was afraid that after cropping to fill the frame I would be left with such a narrow field of view as to defeat the purpose. After some experimenting I found that if used it on a lens with a focal length of 35mm I get just a little of the circle in the corners of the image which is eliminated when the lens correction filter is applied. This leaves me with a field of view roughly the equivalent of a 20mm lens on a 35mm camera. If I zoom in with the lens until the circle is gone and do not correct the distortion it's about the equivalent of a 24mm lens.

Chromatic aberrations? I've seen it in one image around tree branches that were back lit by the sky. Every other image has been fine so far. I see no problem with sharpness either, thou I might if I made a large print.

Now here is my one remaining problem. This lens attachment is about three times as heavy as my 18-55mm Nikkor. Modern AF lenses, even Nikkors, just aren't made all that sturdy. I am concerned that putting the heavy attachment on the front of the lens might throw something out of whack. For this reason I have been using it on an old MF prime lens. But that means more space and weight in my bag. And no in camera metering. Has anyone had any experience with lens damage do to this?
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