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-   -   What's the difference between a $30 and $180 Wide Angle Lens? (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/146254-whats-difference-between-30-180-wide-angle-lens.html)

Brian Boyko March 20th, 2009 12:24 PM

What's the difference between a $30 and $180 Wide Angle Lens?
 
Okay, I gotta know: What's the difference between an Opteka $30 Wide Angle 37mm .5x lens, and the $180 Canon Wide Angle 37mm .5x lens?

Mark Ganglfinger March 20th, 2009 01:19 PM

most likely the $30 lens is going to have significant distortion around the outer edges, where the $180 lens will still have it, but not as bad.

Dave Blackhurst March 20th, 2009 08:12 PM

Number and quality of elements, coatings, and glass, as well as the "shell". Compare the size and weight and think about that as well...

As noted this will affect the amount of distortion, the level of detail, and other elements of the final result... lens flare, barrelling, blurring (edge AND middle if the lens is cheap enough!), CA, etc. etc.

Cheap WA's are OK for casual use (maybe), but you're getting what you pay for (again, maybe...).

Particularly with a truly high grade lens (not the repackaged SD lenses with "high definition" boldly proclaimed on the pretty boxes for the unawares...), it will make a big difference when shooting HD.

Chris Swanberg March 21st, 2009 12:07 AM

Dave has pretty well summed it up. The cheap lens will likely suffer from image distortion and or lack of sharpness at the edges, and almost assuredly will demonstrate significant chromatic abberration (light of different colors not coming to a focus on the same plane - the appearance is a color fringe or halo). The way to fix these issues is as Dave said, use better glass (ED or Flourite) add more elements to the lens, and possibly even increase the diameter.

Most of it is really just optical physics.

Boyd Ostroff March 21st, 2009 09:39 AM

.5x is a pretty wide convertor to start with. At those prices, even the $180 one, I'd be surprised if you didn't see significant barrel distortion (makes the horizon look like a smile). I don't know what you're trying to accomplish, but you may have better luck finding a reasonably priced .7x lens without distortion. In case you don't know, you multiply your camera's nominal focal length by that number to get the effective focal length. So if the wide setting on your camera is equivalent to 40mm (for example), a .5x convertor would make it like a 20mm lens and a .7x convertor would make it like a 28mm lens. The wider you go, the more expensive it gets to make a lens without barrel distortion.

If you buy a $30 lens you will just waste $30. I learned this myself several years ago. There was a clearance table at a store with a Sony 37mm wide adaptor for $30. I figured, what do I have to lose for $30? The answer was $30. The lens would not focus and was full of distortion. I threw it away. Often those lenses are intended for older, cheap 8mm analog cameras where you wouldn't notice the problems as much.

Brian Boyko March 23rd, 2009 10:46 AM

What lens would you recommend for a Canon HG20 with a 37mm thread?

Shane Gerrish March 24th, 2009 05:23 PM

anyone heard of the brand "GroBartig" in wide angle lenses? [it seems well made and is a german lens]

edit: did a bit of a quick test and it looks more like a fisheye lens.

Ronald Lee August 12th, 2009 11:35 PM

Quote:

Originally Posted by Brian Boyko (Post 1032034)
What lens would you recommend for a Canon HG20 with a 37mm thread?

I have the Sony high grade wide angle converter. It seems to work nicely.

Guy McLoughlin August 13th, 2009 02:05 PM

Century Precision Optics | DS-55WA-37 0.55x Wide | 0DS-55WA-37

Dave Blackhurst August 13th, 2009 04:51 PM

I'll second the Sony HG series lenses (.7x). Pretty decent quality to price ratio, although I've always picked mine up second hand. Current model is HGA07 I believe, departing from their earlier numbering scheme of "HG0737*", meaning "high grade", .7x, 37mm thread, *= whatever alphabetical designation, none, X, Y, C that I know of - the Y was a beastly heavy lens, but with commensurate quality.


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