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03-17-2012, 08:26 AM   #1
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tunneling effect with my 45mm wide angle

Hi all,

Is there a way to remove the tunneling effect when I use 45mm wide angle. So far i did not found anything maybe the lense it's cheap. Just want to make sure I am not missing anything before returning the lense.


here is my setting:
k5 with tamron 18-200 with a 45mm wide angle with macro

thank you

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03-17-2012, 08:48 AM   #2
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It's called "vingetting".

I'm not really understanding this: "tamron 18-200 with a 45mm wide angle with macro"... are you using a wide-angle and a macro adapter on the end of your Tamron 18-200? Either one could cause vignetting.
03-17-2012, 09:05 AM   #3
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yes,

when i use the tamron 18-200 I have no vignetting, all is good

thank for the help sorry for my poor englsh
03-17-2012, 09:49 AM   #4
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It looks like vignetting from a lens hood that is too narrow, or possibly from a filter with a thick rim. Are you using either on this lens? if so, try a shot with just hte bare lens.

03-17-2012, 10:16 AM   #5
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I take a guess that the OP uses one of those add-on macro lens adapter on the Tamron 18-200. I have used once before, but found that it degrades the quality of the lens, so I never use it again. I can see not only vignetting but the accentuated barrel effect as well, which of course is undesirable.
03-17-2012, 10:18 AM   #6
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QuoteOriginally posted by zardan Quote
yes,

when i use the tamron 18-200 I have no vignetting, all is good

thank for the help sorry for my poor englsh
OK, it's the "wide angle" adapter that is causing the vignetting. Many of the wide-angle adapters cause this problem to a greater or lesser degree, I would avoid using it. If you have a smaller lens, like the Pentax 18-55, it might work better.
03-17-2012, 11:39 AM   #7
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Yes aleonx3, the wide angle have a macro add on,

Any suggestion of wide angle that i can use with my 18-200mm tamron
03-17-2012, 11:57 AM   #8
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I am not in favor of any add-on adapter to put in front or back of the lens. If you need something wider than 18mm, you can look into DA12-24/f4 which is excellent IMO, but you can also get the equivalent Tamron 10-24mm or Sigma 10-20mm which are less costly. As for macro lens, you can get one of the Tamron SP AF90/f2.8 Di version or one of DFA 50 or 100 macro lens. You can also try with M-50/f4 version which is slightly less costly. Note also that anything else than 1:1 ratio is not "true" macro; also note that "close focusiing distance" does not always mean "macro". There are other options you can consider such as using a "reverse ring adapter" to turn a normal lens into a "macro" lens.

03-19-2012, 11:55 AM   #9
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I have used various screw-on wide and tele and close-up adapters. Most of the wide adapters I have used, suck. They give poor resolution and bad distortion around the image edges. I have not yet tried a Sony VCL wide adapter; the Sony VCL tele adapter I have is good. An Australian member here is selling a set of 58mm-thread 0.7x (wide) and 1.7x (tele) adapters in the Marketplace.

I use one special ultra adapter. It is the PRECISION DESIGN SUPER AF FISHEYE LENS 0.25X with a 58mm rear thread. I got it new on eBay a few months ago for US$20, including shipping from China to California. It comes with a set of step rings so it can be used on lenses with front threads of 52-55-58-62mm. I use it on my DA18-250 or DA18-55 to get a full-circle fisheye image at 18mm; it gives a frame-filling image with no vignetting at around 55mm, equivalent to a lens of around 14mm. The image edges aren't great, but they also aren't as terrible as with the other adapters I've tried.

But if you want your wide images to look good, you need a good wide lens. The Pentax DA12-24 is rather expensive; the Sigma 10-20s are well loved by people who finally get good copies -- these lenses have known quality-control problems. I recommend the Tamron 10-24, which is not too costly, and good optics and a good warranty.

Good luck!
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