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07-20-2015, 07:58 AM   #16
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For comparison, I would display a 1:1 (pixel for pixel) image (of a DNG) in Photoshop, next to a 1:1 image from whatever the other thing was.

Anything less than 1:1 is not really fair.

I have been doing a lot of that lately, comparing phone cameras... Nokia 808 (still tops), Samsung S6 (the best camera/phone in current production)... these cameras all have relatively terrible jpeg compression algorithms.

Interesting link on diffraction... Yes a lot of things are possible. I would have thought that diffraction becomes a limit when you are at say F16 or higher, but one rarely needs to do that.

I find that the biggest *practical* factor in poor focus is shooting through plexiglass aircraft windows. The Live View mode works a lot better there. But you never get great quality that way anyway.

07-20-2015, 10:33 AM   #17
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QuoteOriginally posted by peterh337 Quote
For comparison, I would display a 1:1 (pixel for pixel) image (of a DNG) in Photoshop, next to a 1:1 image from whatever the other thing was.

Anything less than 1:1 is not really fair.

I have been doing a lot of that lately, comparing phone cameras... Nokia 808 (still tops), Samsung S6 (the best camera/phone in current production)... these cameras all have relatively terrible jpeg compression algorithms.

Interesting link on diffraction... Yes a lot of things are possible. I would have thought that diffraction becomes a limit when you are at say F16 or higher, but one rarely needs to do that.

I find that the biggest *practical* factor in poor focus is shooting through plexiglass aircraft windows. The Live View mode works a lot better there. But you never get great quality that way anyway.
Pixel on screen for pixel in photo is only fair if you are comparing images having the same number of MP, as frogoutofwater pointed out.
07-23-2015, 12:10 PM   #18
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I am uploading six DNG images here
Index of /images/pentax-17-70-v-16-85/
it's obvious which is which. The first three are the 17-70. The last three are the 16-85.
Camera distance 1.2m, on a tripod and using a timer.
07-23-2015, 02:32 PM   #19
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QuoteOriginally posted by peterh337 Quote
I am uploading six DNG images here
Index of /images/pentax-17-70-v-16-85/
it's obvious which is which. The first three are the 17-70. The last three are the 16-85.
Camera distance 1.2m, on a tripod and using a timer.
Your copy of the DA 17-70 is way out of focus calibration if not downright broken (or just a horrible copy). I have that lens and it's sharpness is nowhere near what your images are unfortunately displaying.

07-23-2015, 02:58 PM   #20
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QuoteOriginally posted by IchabodCrane Quote
Your copy of the DA 17-70 is way out of focus calibration if not downright broken (or just a horrible copy). I have that lens and it's sharpness is nowhere near what your images are unfortunately displaying.
Agreed, at F/8 mine is far better than that, especially at the wide end. I wonder how that test would fare with focus using live view (if that was not done already).
07-24-2015, 03:26 AM   #21
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So this could be taken out by camera calibration?

I tried that, a few months ago. No improvement.
07-24-2015, 01:47 PM   #22
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I should also add that this lens had the SDM fail a year ago and it was fixed and recalibrated by a Pentax repair centre then.

And I checked the focus adjustment on the camera a few months ago.
07-24-2015, 03:08 PM   #23
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It would be interesting to try the two lenses using fine focus on Live View and see if that changes things.

07-25-2015, 01:00 PM - 1 Like   #24
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QuoteOriginally posted by peterh337 Quote
Also I *feel* that the K3 should be a lot sharper than I am getting.
The conventional wisdom on this point is to take greater care with shooting technique. Either that or only review your work at other than full resolution. Even a small amount of missed focus is very evident at full resolution. The same is true for camera motion when shooting hand-held. I think that it is accurate to state that most K-3 users on this forum had a period of adjustment and that once we tightened out technique, most of us could not be happier.*


Steve

* Except, of course, to have the same number of pixels at FF format.
07-25-2015, 01:10 PM   #25
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QuoteOriginally posted by peterh337 Quote
If I want the best result, I use DNG (I shoot jpeg to one SD card and DNG to the other, always) and then convert to 95% quality jpeg in Lightroom, and keep the jpegs which are around 15MB. I would not keep DNG because it isn't future-proof; the format keeps changing in subtle ways.
I would suggest full resolution 16-bit TIFF if you are concerned about both quality and format longevity and are not concerned about having the full flexibility for future work that RAW provides.

As for your question about lenses, I hope you enjoy your DA 16-85. By all accounts it is a fine lens and the WR feature is frosting on the cake.


Steve

Last edited by stevebrot; 07-25-2015 at 01:31 PM.
07-26-2015, 12:19 AM   #26
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Interesting - I didn't know about the TIFF/DNG similarity. I used to think DNG was the way to go, and the teacher on a Lightroom course I went on was very much in favour of that (as was the audience which was nearly all pro photographers, mainly weddings) but then my GF got the Nokia 1020 which saves a low-res jpeg and a full res (40MP) DNG which almost nothing can open. Well, the very latest Adobe stuff can (but Adobe are going the monthly purchase route now - no way!), ACDSEE PRO v7 and PS CS3 and Lightroom 3.4 can't, and I eventually found IRfanView can do it so I batch-convert them. Clearly DNG is not futureproof, in the way even a year-2005 ACDSEE v5 can open any jpeg just fine.

BTW, off topic, would any (cost regardless) micro-4/3 camera achieve this level of quality? In theory no, of course, but if the result is so close one can't tell? Their specs are certainly very good nowadays and they are a lot lighter. If I was doing all this again I would go that route. The reason I am not doing that now is because even a 4/3 is not pocket-sized, so (like a DSLR) it needs a waist pack or a backpack to carry anywhere, a shoulder strap is no good (in many places) because it invites robbery/theft, and the difference between 1kg and 0.6kg is not much once you have a waist pack etc.
07-26-2015, 09:41 AM   #27
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I posted some simple tests here
IT / Website - DSLR v. Micro-4/3
and I will be keeping the K3
07-26-2015, 12:36 PM   #28
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QuoteOriginally posted by peterh337 Quote
Interesting - I didn't know about the TIFF/DNG similarity. I used to think DNG was the way to go, and the teacher on a Lightroom course I went on was very much in favour of that (as was the audience which was nearly all pro photographers, mainly weddings) but then my GF got the Nokia 1020 which saves a low-res jpeg and a full res (40MP) DNG which almost nothing can open. Well, the very latest Adobe stuff can (but Adobe are going the monthly purchase route now - no way!), ACDSEE PRO v7 and PS CS3 and Lightroom 3.4 can't, and I eventually found IRfanView can do it so I batch-convert them. Clearly DNG is not futureproof, in the way even a year-2005 ACDSEE v5 can open any jpeg just fine.
The DNG spec has room to accommodate new features and cameras, and that is its way of staying future proof. There have been some notable fails by manufacturers who natively save to this format. At one time, some of Leica's DNG files would hose a Mac.

You might try Adobe's free DNG converter. I have successfully used it to convert recent DNG files down to work on one of my computers with a very old version of Adobe Camera Raw.
07-26-2015, 12:43 PM   #29
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"The DNG spec has room to accommodate new features and cameras, and that is its way of staying future proof."

That however means having to continually purchase new versions of the display software.

Obviously Adobe likes that

A lot of the time one doesn't want to change the software. If you have something that works, why change?
07-26-2015, 04:41 PM   #30
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QuoteOriginally posted by peterh337 Quote
"The DNG spec has room to accommodate new features and cameras, and that is its way of staying future proof."

That however means having to continually purchase new versions of the display software.
You don't HAVE to do anything.
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