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09-21-2016, 06:45 PM   #1
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Lens Distortion?

Took this shot with a Q7 today, using the 02 zoom @ 5mm. f/8, 1/100, 200. It's a DNG, and much smaller than I would have thought (only 1920 x 1440).

Check out the fence and the picnic table at the bottom. Is the 02 zoom supposed to give a fish-eye effect?

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09-21-2016, 07:02 PM   #2
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A DNG image out of the Q 7 is 4000 x 3000 pixels in size, so this image is some how cropped. As for the distortion, I don't see anything that can not be corrected easily, certainly not a "fish-eye" effect.
09-21-2016, 07:04 PM   #3
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its normal, the 02 lens has appox 4.75% barrel distortion at the wide end
when shooting jpeg its corrected by the cameras image processor before its output to a file
when shot in raw no correction is applied.
09-21-2016, 07:16 PM   #4
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Anytime you are shooting on the wide-end of a zoom lens, some distortion is to be expected. It is pretty mild IMO and can be easily corrected with the right software. I use the retail version of Silkypix pro for RAW development, and it can be fixed with lens distortion option enabled.

09-21-2016, 10:58 PM   #5
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Weird distortion to my poor old eyes. It looks to me as though the seat itself may have a curve in in it. I mean the top leading edge of the seat looks pretty straight to me. The back edge has a pronounced curve, The fence left hand panel bottom rail just immediately above the seat looks straight. This section of fence is certainly shaped differently to the wood immediately below. I would get a straight edge and a spirit level before I sent the lens back for repair.
09-22-2016, 12:08 AM   #6
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I should mention, before I fall asleep here, that I got this camera two days ago. These were the first shots I tried.

I don't usually turn on lens correction, but I'll try it now. I also need to learn to hold the bloody thing so that my fat fingers aren't hitting any of the settings!

The manual is in Japanese. I have the PDF in English, but it's on my laptop, so I can't refer to it while I'm outdoors. Reading it on my phone is out of the question. If anyone has the printed manual in English, I would pay good money for it!

Thanks to all and good night.

Rob
09-22-2016, 03:47 AM   #7
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The camera can save image files as raw dng or jpeg. The jpeg is actually a processed raw, with things like CA correction or distortion correction applied. There are numerous options that you can turn on or off for jpeg. If you shoot raw dng, then these corrections will only be applied to the preview, not the actual raw data. The dng has to be opened by a raw processing software, like the supplied SilkyPix, or third party like Lightroom, AfterShot, FastStone, CaptureOne, RawTherapee, Darktable or others. Note that if you are opening a dng without such software, you might be only viewing the preview thumbnail (which would explain the wrong size).
If you are new to photography, take photos in jpeg first. Apply any corrections you want, but keep in mind that applying correction takes a bit of time, up to a couple second after the photo is taken. So if you want to take a lot of photos in fast succession, you might want to turn off these corrections.
If you want to shoot raw, then you need to use a software to apply your own corrections and general Post Processing. This can include lens profiles and distortion correction. With raw, you get more control, but it is all up to you. With jpeg, the camera does pretty much all of this for you, and you can just turn on or off a couple features. You still get some control, but it is not as fine as with raw dng and specialized computer software.
09-22-2016, 05:38 PM   #8
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You sure that wood table was straight to begin with?

09-22-2016, 07:21 PM   #9
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The picnic table is level. So is the fence.
09-22-2016, 07:29 PM   #10
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OK, what's going on here?

Enclosed please find a screenshot which I just made on my laptop.

On top, some pics I shot with a K50 a week ago. The frames are all 4928 x 3264. I used Instant JPEG from RAW to convert one to a JPG.

On the bottom, some shots with the Q7 from yesterday. Please note that they all measure 4000 x 3000 (PhotoME says 4064 x 3000), but when I use IJFR to convert one, it comes out as 1920 x 1440. If I look at the DNG with IrfanView it also shows it as 1920 x 1440.

That's how the photo above came out small... the camera is set to 4x3; RAW; L with 3 stars as I thought.

Addendum: PhotoME is also showing something called "reduced-resolution image data" which shows - you guessed it - 1920 x 1440. When I look at the same item for the K50 shot, the dimensions are not reduced.

Is there anything I can do to stop making these Q7 shots "shrink"?
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09-23-2016, 03:53 AM   #11
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QuoteOriginally posted by rlg118 Quote
I used Instant JPEG from RAW
does a window will appear where you can choose "Native size only" as one of the options
09-23-2016, 04:00 AM   #12
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I don't know about that software. I would just download RawTherapee and try with that software. Its free, its powerful, but its not necessarily easy to master. Or Lightroom from Adobe, that one is easy to use, but not free. You can get free trial, I think.
Other free options include FastStone and Darktable.
I think most of these have lens profiles or at least manual distortion correction.
09-23-2016, 07:08 AM   #13
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QuoteOriginally posted by Ratcheteer Quote
does a window will appear where you can choose "Native size only" as one of the options
Yes. You can choose "Native size only", or "Native and smaller sizes". With the second option, you choose maximum height & width, and it will return two copies.

I can only guess that it's reading that reduced-size field.

---------- Post added 2016-09-23 at 10:30 ----------

QuoteOriginally posted by Na Horuk Quote
I don't know about that software. I would just download RawTherapee and try with that software. Its free, its powerful, but its not necessarily easy to master. Or Lightroom from Adobe, that one is easy to use, but not free. You can get free trial, I think.
Other free options include FastStone and Darktable.
I think most of these have lens profiles or at least manual distortion correction.
I have RawTherapee onboard. I haven't used it much, but I created both an 8-bit JPEG and a 16-bit PNG (at a whopping 57 megabytes!), both at 3992 x 2992, using the DNG in question, with it. That's close enough for jazz.

Also downloaded FastStone. Will check it out later.

IJFR is so easy to use, and fast, as well - it just seems an awful shame that I would have to process the Q7 photos totally differently than those from the K50. Perhaps a note to the developer is in order...
09-23-2016, 07:54 AM - 1 Like   #14
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Raw file always contains a full resolution raw data, of course, but it often has a reduced jpeg embedded. This is done so that programs doesn't have to e.g. "develop" the raw data on the fly every time you need to quickly preview the picture.

Anyway, for some cameras "reduced" resolution jpegs aren't reduced at all, they're full resolution jpegs tagged as "reduced", but your Q7 embeds reduced resolution jpegs in 1920x1280 size as PhotoME points out. If PhotoME writes 1920x1280 files, it's not converting the raw data to jpeg, it's grabbing the embedded reduced size jpeg.

But that doesn't mean that Q7's file is recorded in reduced size, the file still has full resolution raw data. I don't know if PhotoME cannot process raw data, but if that's the case, you need a program that can do that kind of stuff as Na Horuk suggested. If you have silkypix that originally came with Q7, you could try that.

There's a thread that talked about this:
https://www.pentaxforums.com/forums/136-pentax-q/289822-q7-dng-files-being-lo...-size-why.html
09-23-2016, 09:20 AM - 1 Like   #15
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Yeah, 8bit jpeg is the standard for photo sharing. Tiff is if you want to do heavy editing. Png is not really useful with photos, it is more for graphics design
So, yeah, it seems that other software was pulling the preview jpeg instead of reading the actual raw data. Maybe you can google for the question, as other users may have experienced the same problem. Usually this problem happens with some freeware codecs designed just for fast previews.

Regarding user friendliness, yea, that's why I chose Lightroom. Easiest, fastest to use, but still good for all kinds of stuff. My main issue with RawTherapee is that it has so many functions and icons and buttons that I waste time looking for things

Last edited by Na Horuk; 09-23-2016 at 12:05 PM.
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