Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-23-2009, 07:08 AM   #1
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
DOF 6.5mm Opteka vs 10-17mm Pentax

Here is a comparison between the two 180 Fisheye lenses @F8 focused @12in. Since I have a great Sigma 15mm F2.8 full frame 180 fisheye that works great as a 15mm super wide angle on Pentax DSLRs I chose the 6.5mm Opteka.






08-23-2009, 07:20 AM   #2
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
Cool, now show us some of the 6.5mm captures it produces...
08-23-2009, 08:02 AM   #3
wll
Veteran Member




Join Date: Nov 2006
Location: Mission Hills, CA
Posts: 773
Very Cool !

That lens looks great on that camera.

Do you know, will Rokinon be marketing it ?


wll
08-23-2009, 08:38 AM   #4
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
A test shot with it.
6.5mm Opteka @F8 HDR strong 1/30 sec 100iso



08-23-2009, 08:54 AM   #5
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
QuoteOriginally posted by wll Quote
That lens looks great on that camera.

Do you know, will Rokinon be marketing it ?


wll
B&H also sells the 7mm Vivitar version.
Vivitar | 7mm f/3.5 Series 1 Fisheye Manual Focus Lens | 7MMC
08-23-2009, 09:56 AM   #6
Veteran Member




Join Date: Sep 2007
Location: La Crescenta, CA
Posts: 7,452
The Rokinon version is available on eBay.
08-23-2009, 10:47 AM   #7
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
QuoteOriginally posted by deadwolfbones Quote
The Rokinon version is available on eBay.
Rokinon 8mm Fisheye Lens for Pentax K-7 K2000 K200 K20D - eBay (item 350241599423 end time Sep-17-09 07:46:11 PDT)
08-23-2009, 12:09 PM   #8
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
Is that the same lens as marketed by Samyang as 8mm? If so, how can it be, that different sellers give such a widely different focal length value? 6.5mm versus 7mm versus 8mm doesn't sound much, but in the ultra-wide world it is very different.

Does anybody know, what's true or whether these are different lenses?

Thanks for any insight.
Ben

08-23-2009, 01:36 PM   #9
Veteran Member
WheresWaldo's Avatar

Join Date: Sep 2006
Location: North Carolina
Photos: Gallery
Posts: 498
Ben, because the projection Samyang used only allows an approximation of the focal length. Lenstip.pl went into an explanation of this in their review of the 8mm Samyang variety.

Samyang 8 mm f/3.5 Aspherical IF MC Fish-eye review - Introduction - Lenstip.com

That means Samyang can call it 8mm while Vivitar calls it 7mm and Opteka calls it 6.5mm. In the end it is still exactly the same lens.
08-23-2009, 01:49 PM   #10
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by WheresWaldo Quote
Ben, because the projection Samyang used only allows an approximation of the focal length. Lenstip.pl went into an explanation of this in their review of the 8mm Samyang variety.

Samyang 8 mm f/3.5 Aspherical IF MC Fish-eye review - Introduction - Lenstip.com

That means Samyang can call it 8mm while Vivitar calls it 7mm and Opteka calls it 6.5mm. In the end it is still exactly the same lens.
Thanks for the info. Sounds like the effective fl varies with distance from the image center - so everybody can state a correct fl... (I have to read-up more on the different projections)

Ben
08-23-2009, 01:55 PM   #11
Veteran Member




Join Date: Apr 2009
Photos: Gallery
Posts: 489
QuoteOriginally posted by jogiba Quote
A test shot with it.
6.5mm Opteka @F8 HDR strong 1/30 sec 100iso

Is this a crop?
08-23-2009, 02:02 PM   #12
Loyal Site Supporter




Join Date: Sep 2006
Location: Bronx NY
Photos: Gallery | Albums
Posts: 5,611
The Vivitar at B&H is only available in Canon, Nikon and Sony/Minolta mounts.

NaCl(surprise surprise)H2O
08-23-2009, 03:08 PM   #13
Veteran Member
WheresWaldo's Avatar

Join Date: Sep 2006
Location: North Carolina
Photos: Gallery
Posts: 498
Since the Opteka and Rokinon are exactly the same lens, does it matter that B&H doesn't carry the Vivitar in a KA mount , besides you pay a premium for the Vivitar name when buying any of the Samyang made optics.
08-23-2009, 03:59 PM   #14
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
QuoteOriginally posted by Cosmo Quote
Is this a crop?
That is the full image.
1600x1063px image
08-23-2009, 04:35 PM   #15
Veteran Member




Join Date: Apr 2009
Photos: Gallery
Posts: 489
How isn't it a circular image?
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
15mm, fisheye, k-mount, opteka, pentax, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Opteka Fisheye Adapter vs. Opteka 6.5mm fisheye goldenarrow Ask B&H Photo! 2 08-11-2010 04:04 PM
Pentax Micro-Four-Thirds 17mm F2.8 17mm F2.0 14mm F2.8 ianchen Pentax News and Rumors 167 07-15-2010 11:52 PM
Got my Opteka 85mm 1.4! tcdk Pentax SLR Lens Discussion 14 09-15-2009 01:06 PM
Opteka 6.5mm f/3.5 Manual Focus Aspherical Fisheye Lens for Pentax Russell-Evans Pentax SLR Lens Discussion 4 08-19-2009 02:01 PM
Pentax SMC-FA 5mm f1.4 at Photozone Kim Pentax SLR Lens Discussion 1 04-19-2007 11:23 AM



All times are GMT -7. The time now is 04:02 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top