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05-31-2010, 10:12 AM - 1 Like   #1
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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
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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
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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
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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
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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
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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
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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
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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...


07-26-2010, 09:04 AM   #9
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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
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@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.

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