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04-15-2018, 08:56 AM   #1
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UWA sample

Hello Folks,
First off, I'm just a novice photographer, and enjoy it as a hobby. I'm just now starting to shoot raw files. And learning how to use UWA lenses, too. So, I just received my DFA 15-30 for my K-1. After reading forum member's posts, I wanted to find out in a hurry if I have a keeper. Would you all please look at my image to see if it has any of the common problems this lens has? I had to get a quick shot this morning before it rained.
Thank you very much,
Terry

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04-15-2018, 09:40 AM   #2
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QuoteOriginally posted by TerryL Quote
Would you all please look at my image to see if it has any of the common problems this lens has?
What problems would that be? I just got one as well.
04-15-2018, 09:49 AM   #3
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QuoteOriginally posted by jatrax Quote
What problems would that be? I just got one as well.
Decentering. Sharper on one side than the other. Just looked at my image, boy my processing is horrible.
Terry
04-15-2018, 10:23 AM - 1 Like   #4
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Common problems ? I have the lens. It has no problems common or uncommon.

If you cannot see an issue with the lens why do you expect anyone else to?

04-15-2018, 10:26 AM   #5
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QuoteOriginally posted by TerryL Quote
Decentering. Sharper on one side than the other.
I know a lot of the Rokinon lenses have had this reported but I have not seen many (any?) comments about the DFA 15-30 being decentered. Is this common?
04-15-2018, 10:37 AM   #6
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QuoteOriginally posted by jatrax Quote
I know a lot of the Rokinon lenses have had this reported but I have not seen many (any?) comments about the DFA 15-30 being decentered. Is this common?
I'm really not sure how common it is, I just happen to see the issue here, last night, when I did a search on DFA 15-30. I'm just hoping that someone with a trained eye will give me an overall opinion.
Terry

---------- Post added 04-15-18 at 10:43 AM ----------

QuoteOriginally posted by pschlute Quote
Common problems ? I have the lens. It has no problems common or uncommon.

If you cannot see an issue with the lens why do you expect anyone else to?
Because I know that experienced users of UWA lenses will see things that I don't.
04-15-2018, 12:35 PM   #7
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QuoteOriginally posted by jatrax Quote
I know a lot of the Rokinon lenses have had this reported but I have not seen many (any?) comments about the DFA 15-30 being decentered. Is this common?
Check out awscreo comment in the following page. awscreo went through 3 copies.
Uneven sharpness in DFA 70-200mm - Page 2 - PentaxForums.com
04-15-2018, 12:58 PM   #8
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QuoteOriginally posted by pentaxfall Quote
awscreo went through 3 copies.
But then he says he had a loose mount screw on the K-1 and thinks that could be the problem???
QuoteQuote:
I did notice however that one of the screws on the K-1 mount could not be tightened fully, and it's on the same side that shows issues. So, I sent the camera in to fix that too. If decentering was caused by the loose mount, then it's possible lenses were not to blame.
He never posted back so it could be the mount or the lens, unknown.



04-15-2018, 01:17 PM   #9
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Can you post a link to a full size original? Really hard to tell with a resized smaller jpeg. Not sure if I think the lower left quadrant is a little off or not. Also, another snap with something a little further away and detail in the top corners would be good.

I have this lens for my K-1, and it's great and sharp. I'm not aware of them being known for decentering issues or anything else, unlike the Rokinon, where it's pretty much accepted you need to check the copy in your hands for decentering as soon as you get it. I think the Pentax/Tamron QA is far beyond that level.
04-15-2018, 01:48 PM   #10
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QuoteOriginally posted by clickclick Quote
Can you post a link to a full size original? Really hard to tell with a resized smaller jpeg. Not sure if I think the lower left quadrant is a little off or not. Also, another snap with something a little further away and detail in the top corners would be good.

I have this lens for my K-1, and it's great and sharp. I'm not aware of them being known for decentering issues or anything else, unlike the Rokinon, where it's pretty much accepted you need to check the copy in your hands for decentering as soon as you get it. I think the Pentax/Tamron QA is far beyond that level.
I've been studying over the image, and I am very happy with the lens. I can see it's potential with the right subject matter. Colors are nice, sharp, and fast focus. Keeping this one.
Terry
04-15-2018, 04:41 PM   #11
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QuoteOriginally posted by TerryL Quote
I've been studying over the image, and I am very happy with the lens. I can see it's potential with the right subject matter. Colors are nice, sharp, and fast focus. Keeping this one.
Terry


That would match what I'd expect. Keep shooting. Have a hunch you're going to like it.
04-16-2018, 12:49 AM - 1 Like   #12
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Hi

I can,t see anything wrong with this image as far as sharpness is concerned.
I have this lens and I cannot find anything wrong with it. It produces stunning IQ.
Oh, wait a moment - I can find a problem with this lens, she is bloody heavy.

Different subject, don't know which of the available RAW converters you use, I use PS and their converter allows to recover highlights of images shot with the K-1 with breathtaking results. The washed out sky could be recovered like you would not believe your eyes. All you have to do is move the highlight slider to the left.

And most if not all RAW converters let you correct pin and barrel distortions, either automatically or manually.

Cheers

Last edited by Schraubstock; 10-27-2018 at 10:43 PM.
04-16-2018, 07:17 AM   #13
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QuoteOriginally posted by Schraubstock Quote
Hi

I can,t see anything wrong with this image as far as sharpness is concerned.
I have this lens and I cannot find anything wrong with it. It produces stunning IQ.
Oh, wait a moment - I can find a problem with this lens, she is bloody heavy.

Different subject, don't know which of the available RAW converters you use, I use PS and their converter allows to recover highlights of images shot with the K-1 with breathtaking results. The washed out sky could be recovered like you would not believe your eyes. All you have to do is move the highlight slider to the left.

And most if not all RAW converters let you correct pin and barrel distortions, either automatically or manually.

Cheers
Thank you for the reply. I am using Lightroom. Just learning to process raw files. And yes, I don't like the washed out sky, either. But, for now, I really don't know what to do about it. My goal is to get everything right in the camera when I shoot, rather than do a lot of processing. I was very slow to move from film to digital cameras. I guess I'm a little "old school". As far as being heavy, I prepared for the weight by getting an extremely nice and heavy duty tripod and Markins ballhead. It's such a pleasure to use this lens on a really nice tripod and bullhead. Now, I just have to learn hyper focal distance and Landscape photography. It's all for fun, and I love it.
Terry
04-16-2018, 07:46 AM   #14
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QuoteOriginally posted by TerryL Quote
And yes, I don't like the washed out sky, either. But, for now, I really don't know what to do about it.
Terry, the only way to really deal with these very high contrast scenes is to use a Neutral Density Graduated filter. That way you get correctly exposed sky and subject. I use the Lee 150 system for the Pentax 15-30. It is not cheap but will do the job. The problem with trying to deal with it in post is that once highlights are blown, they are blown and cannot be rescued. You are correct to try and get it right in camera.

You wont be able to use a screw-in filter on the lens so have a look at the Lee system.
04-16-2018, 10:02 AM   #15
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Images have to be Inspected at 100% resolution to see the problem. Here are examples from decentered DFA* 70-200. I used it for more than 6 months thinking it is fine.


Looks good



Here is the problem
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