Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-31-2010, 10:12 AM - 1 Like   #1
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Sigma 4.5mm. The good and the bad.



This lens really has some incredible properties.

Here's a few of my fav shots so far. These are all right off the camera (and uploaded to FB).











So, there's the good. The lens is really pretty amazing. The lens obviously distorts everything so it's hard to decide how sharp it truly is. I think sharp enough for the type of pictures you'll be taking with it. As for DoF, at 4.5mm it's almost impossible to tell the difference between f2.8 and f8.

My partner says it's like being in the glass globes from the movie Labyrinth, and if she's shooting, this is the second most likely for her to use.

Here's the bad:

Your feet will be in the picture. Having the full 180 field of view is fun and bizarre, but it means that you have to be super aware of where everyone, including yourself are. I've gotten my fingers in the picture just from holding onto the lens, and as for your feet, it's almost guaranteed to capture them.

This lens isn't reporting focal length to the K-7 body, or the K-7 body isn't accepting the focal length, and you cannot choose the focal length like you can with an A lens. This means that the SR on the k-7 goes absolutely NUTTY. It looks and feels like it's trying to correct an 800mm lens rather than a 4.5mm lens. If you turn on live view and wobble the camera, you can actually feel the SR jerk the camera about and watch the image move all over the screen.

If you do not use the work around of turning off SR, you simply cannot take a sharp or useful picture with this lens, even at 1/2000th you'll get double images.

Sigma support has been a little underwhelming on this issue, saying their k-7 with the lens attached does similar things, but that it shouldn't affect quality. When I sent them samples, they suggested I send in the lens to them for repair or have Amazon send me another one. Amazon has sent me another one, and it's got the same issues.

I'm still waiting to hear back from Pentax support. I'll ping them again on Monday about it.

If we have any Sigma or Pentax reps on the forums, I'd be happy to send you a link to the full res sample images demonstrating this problem.

05-31-2010, 11:14 AM   #2
Inactive Account




Join Date: Jul 2008
Location: Vancouver, Canada
Posts: 1,104
Thats pretty wide ...the 360 horizon view on #3 is crazy. I've seen the lens locally but, never seen photos until now. It's not something I'd buy, cool results none the less.
07-25-2010, 09:49 AM   #3
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Original Poster
I'm also a little slow sharing from Pentax support on this issue:

QuoteOriginally posted by Pentax:
This is the first time this issue has been reported, and you are correct, we do not test with 3rd party lenses. The range of focal lengths that can be entered manually in the K-7 “Input Focal Length” menu is 8mm to 800mm and it is quite possible that the range of focal lengths that the camera can recognize automatically is also from 8mm to 800mm. This lens lies outside this range. (There were no 4.5mm lenses for DSLRs available when the K-7 was in development). The Shake Reduction system should work with PENTAX lenses within the 8mm to 800mm range but may not work with lenses outside this range or with 3rd party lenses.
I suspect this will be of moderate interest to those that have bought the 8-16mm
07-25-2010, 09:19 PM   #4
Pentaxian
Steinback's Avatar

Join Date: Jan 2008
Location: GTA, ON, Canada
Photos: Gallery | Albums
Posts: 1,672
Interesting that the upper limit of shake reduction on the K-7 is 800mm. I have actually reached that hand held with my 400mm and a teleconverter (and got useable images with it) but only used the combination a few times.

I suppose you get to wait to see if the next generation of bodies get shake reduction for wider lenses.

07-26-2010, 12:02 AM   #5
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,679
Thanks for sharing this experience with this FE, Clinton.

I found it hard enough keeping my feet out of the FOV using the DA 10-17, so well done with all those results there...
07-26-2010, 02:19 AM - 1 Like   #6
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,314
you say the shake reduction feels like it is trying to correct for 800mm?

the question is, what shows up in the EXIF data?

as for feet in view, I get this also with my 8mm fisheye, it's pretty hard to have a 180 degree FOV without some body parts in it.
07-26-2010, 02:44 AM   #7
Inactive Account




Join Date: Nov 2008
Location: Stavanger, Norway
Posts: 150
Is it your feet I see in the last pic? :P

Awesome photos. Tried this lens in a store once, the FOV is wild!
07-26-2010, 04:48 AM   #8
Pentaxian
MRRiley's Avatar

Join Date: Feb 2007
Location: Sterling, VA, USA
Photos: Gallery | Albums
Posts: 6,276
Wish Sigma had sent one of these along with the other 10 lenses they let us try out at the East Coast Pentaxians gathering this past weekend. Would have been a fun lens to play with.

Beggers can't be choosers though can we. Pentax didn't send doodley...

Mike

07-26-2010, 09:04 AM   #9
Pentaxian
reeftool's Avatar

Join Date: Dec 2007
Location: Upstate New York
Photos: Gallery | Albums
Posts: 8,011
I often have to be careful of where my feet are with my DA 10-17 also and it's almost impossible to take a picture from my kayak without getting some part of the boat in the frame.
07-26-2010, 10:41 AM   #10
Site Supporter
Clinton's Avatar

Join Date: Feb 2010
Location: Salt Lake City, UT
Photos: Gallery | Albums
Posts: 1,800
Original Poster
@nimrad yup, those are my feet. i stood up on a chair to get a angled downward shot. Unless I could have hung from a wire, having my feet in the pic was unavoidable, but acceptable in this case.

@Lowell the exif shows as 0mm. On body it shows as ---mm, and the menu on the k7 for picking the focal length is grayed out and disabled. The reason I say 800mm is because the sr is wild. It will shake the circular image from almost the top of the frame to the bottom in live view.
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!
amazon, camera, k-7, k-mount, length, lens, pentax, pentax lens, picture, sigma, slr lens, sr
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone bought the Sigma 4.5mm fisheye yet? Clinton Pentax SLR Lens Discussion 10 01-15-2013 10:43 AM
Sigma 4.5mm and 10mm f:2.8 Substitute Pentax SLR Lens Discussion 5 09-06-2009 04:37 AM
Sigma 4.5mm Substitute Pentax SLR Lens Discussion 28 09-30-2008 03:25 PM
any news on the Sigma 4.5mm fisheye? Gooshin Pentax SLR Lens Discussion 0 03-31-2008 11:36 AM
any news on the 4.5mm and 10mm Sigma fisheyes? Gooshin Pentax SLR Lens Discussion 0 01-18-2008 05:21 AM



All times are GMT -7. The time now is 10:17 AM. | See also: NikonForums.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