What's Going On at 12mm?


GSiGuy

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Sep 14, 2010
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#1
I hope someone can point me in the right direction here as i'm getting some serious "vignetting" at 12mm on my DA 12-24...

Here are 2 sample pics of the problem...





Both pics were not processed except for conversion into JPEG and re-sized.

It looks like the lens hood is the culprit here but i have never read about this problem anywhere on the net. I do have a rodenstock HR MC super uv filter on but the pattern of the shadow seems to indicate that the culprit is the lens hood... Am i right?

I have checked all my pics and noticed almost all have the problem at 12mm. I therefore do not think it's cos i didn't attach it properly on the lens cos i can't have wrongly attach it all the time. It's fine when you tele in; only at 12mm got this. I have also checked the lens hood to see if it is bent but it doesn't look like it is.

Is this normal?
 

ranchy

Senior Member
Jan 11, 2010
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#2
Hmm.. I don't own the lens but I can't comment much. I felt it could be the Filter which is causing the vignetting. Did you try remove your UV filter and try taking with it?
Just a suggestion..

Cheers.
 

GSiGuy

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Sep 14, 2010
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#3
Hmm.. I don't own the lens but I can't comment much. I felt it could be the Filter which is causing the vignetting. Did you try remove your UV filter and try taking with it?
Just a suggestion..

Cheers.
i'm afraid not cos i only noticed it when i got back and looked at the pics in more detail
 

creampuff

Senior Member
Jul 11, 2006
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#4
Don't have this problem with my 12-24mm. Is your filter ring thick by any chance? Are you stacking filters? I did get a little vignetting once when I slapped on a thick filter without the hood on. I only use filters that have a thin filter ring for this lens.
 

GSiGuy

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Sep 14, 2010
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#5
Don't have this problem with my 12-24mm. Is your filter ring thick by any chance? Are you stacking filters? I did get a little vignetting once when I slapped on a thick filter without the hood on. I only use filters that have a thin filter ring for this lens.
Well i think it's the thin type. It certainly is less thick than the UV filter i have on most of my other lenses. I also switched UV filters with the thinner one i have on another lens and i still get that vignetting. It really seems like the lens hood cos i just tried taking pics with and without it on and the difference is apparent.

Any ideas what can i do now?
 

GSiGuy

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Sep 14, 2010
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#6
I've also taken shots with the UV filter off and it's still there...
 

gtl1987

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Oct 28, 2008
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#7
Don't look like vignetting to me judging from the pics you posted. Think the lens might have a problem. Time to send it in?
 

sunnycamera

Senior Member
Dec 8, 2010
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#8
try stop down to f8, will it improve
 

hjbyeo

Senior Member
May 5, 2006
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#9
Take out the hood, and it's still like that?

I never had problems with the 12-24 except when using with Square Filters. This also doesn't look like the usual vignetting ...

Was it like this when you first bought it? Have you left your bag in the car (and possibly under the hot sun)?
 

GSiGuy

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Sep 14, 2010
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#10
Take out the hood, and it's still like that?

I never had problems with the 12-24 except when using with Square Filters. This also doesn't look like the usual vignetting ...

Was it like this when you first bought it? Have you left your bag in the car (and possibly under the hot sun)?
Someone in Pentaxforums asked me to check the lens hood designation and it seems that the one i have is for the DA*16-50. I think that could be the problem. So now i am trying to contact seller to see if a switch to the proper one can be done. If not, then at least my worst problem is trying to buy a new lens hood...
 

gtl1987

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Oct 28, 2008
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#11
Someone in Pentaxforums asked me to check the lens hood designation and it seems that the one i have is for the DA*16-50. I think that could be the problem. So now i am trying to contact seller to see if a switch to the proper one can be done. If not, then at least my worst problem is trying to buy a new lens hood...
That's probably it then. Good thing it's not the lens. Why not try some pics with nothing on? No filters, no hood.
 

fengwei

Moderator
Staff member
Aug 25, 2004
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#12
Someone in Pentaxforums asked me to check the lens hood designation and it seems that the one i have is for the DA*16-50. I think that could be the problem. So now i am trying to contact seller to see if a switch to the proper one can be done. If not, then at least my worst problem is trying to buy a new lens hood...
Please show us a photo of the lens w/ hood on, so we can tell if the hood is the matching one. The surface finishing of DA*1650 hood is quite different from the one for DA12-24, and you can see the difference between your (DA*1650) hood and the (DA12-24) lens surface finishing.
 

SyncGuy

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Sep 14, 2011
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#13
Uh oh... Sounds like a hoodie fanatic at work.. Haha! I am using metal tele hood for my lenses for 28mm, 35mm and 50mm with no problems..

I think the guy fail in hood calculation including crop factor.. :p

Including crop factor:

@ 12mm - Max hood length (1.5x12) = 18mm/1.8cm

@ 24mm - Max hood length (1.5x24) = 36mm/3.6cm

So if your current hood measures >2cm, definitely wrong hood.. :(
 

Last edited:

edutilos-

Senior Member
Dec 28, 2010
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#14
Definitely looks like a hood problem, based on the black parts in the picture.

Take off the hood and see if you still get the problem. :)
 

GSiGuy

New Member
Sep 14, 2010
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#15
Definitely looks like a hood problem, based on the black parts in the picture.

Take off the hood and see if you still get the problem. :)
edutilos, stuck my camera out the window today with the hood reversed and took this quick and dirty shot...



only coverted to JPEG and resized. no PP.

Seems like the shadows aint there. Though at F16, i can see i need to clean my sensor :bsmilie:
 

edutilos-

Senior Member
Dec 28, 2010
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#16
Definitely the hood problem and not the lens problem, right.

Now that you've identified the issue, just correct it! Good luck!

P.S. You do not really need a hood unless there is flare. But of course it's good to carry it around in case there is, and better to use it all the time to avoid flare that may not be immediately visible. :)
 

GSiGuy

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Sep 14, 2010
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#17
Please show us a photo of the lens w/ hood on, so we can tell if the hood is the matching one. The surface finishing of DA*1650 hood is quite different from the one for DA12-24, and you can see the difference between your (DA*1650) hood and the (DA12-24) lens surface finishing.
Here are the pics of the lens, FW...







The last one shows the hood designation, which is "PH-RBJ 77" whilst i am told is the designation for the replacement hood for the DA 12-24 is "PH-RBI 77" The former is apparently a replacement hood for a DA*16-50.

So it must be the hood's fault. Unfortunately, i have left 2 friendly sms to the seller to tell him of the problem and offered to meet him to do the exchange, or if DA*16-50 sold, then give me contact of buyer so i can do exhange with him, but not response from him since this morning...:cry:
 

Yamakasi

New Member
Jan 26, 2008
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#18
took a look at my 12-24 hood..it is PH-RBI so you got the wrong hood on it
 

GSiGuy

New Member
Sep 14, 2010
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#19
took a look at my 12-24 hood..it is PH-RBI so you got the wrong hood on it
Thanks! I know have 100% confirmation its cos of the hood... pity i didnt notice when i bought lens. i am now worried seller is ignoring my pleas... anyone know if the replacement hood can be bought locally? If not, where is the next best place?
 

Yamakasi

New Member
Jan 26, 2008
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#20
if u wan the original pentax then u hv to try emjay and ask them to bring in for you..otherwise ebay will be a gd source
 

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