[stevebrot]

Interesting - I didn't know about the TIFF/DNG similarity.

I apparently edited out the section of my comment relating to TIFF and DNG because it contained an inaccuracy. Here goes another try.

All DNG are compliant to the TIFF/EP standard specification*. What that means is that a fully compliant TIFF/EP reader should be able to handle any well-formed DNG file. Pentax PEF files are also TIFF/EP compliant. It is because of that similarity that it is often stated that Pentax PEF and Pentax-generated DNG are the same except for a few details.

Playing a little rename game using files from my K-3, Lightroom 5.6 and Picasa 3:

Pentax-generated DNG ==> <filename>. PEF

Readable by both Picasa and Lightroom

Pentax-generated DNG ==> <filename>.TIF

Readable by both Picasa and Lightroom, though Picasa will display the smallest of three embedded jpegs.

Pentax PEF ==> <filename>.DNG

Readable by Lightroom, but Picasa will barf

Pentax PEF ==> <filename>.TIF

Readable by Lightroom, but Picasa says bad file

But wait! It gets more interesting!

Export to TIFF from Lightroom for any of the renamed files appears to be equivalent to an export from the original camera-generated RAW.

The truth is out there somewhere!


Steve

* The relationship between TIFF/EP (ISO 12234-2) and the Adobe-controlled TIFF image format standard is a little complicated. There is a significant intersection between the two standards, but no direct compatibility. The Wikipedia article on TIFF/EP is a good place to start. Let me know if you can make full sense of it...I can't

https://en.wikipedia.org/wiki/TIFF/EP

---

Last edited by stevebrot; 07-26-2015 at 09:54 PM.

[peterh337]

Stevebrot - try this DNG
http://peter-ftp.co.uk/images/WP_20141225_09_51_33_Raw__highres.dng
(my own site - safe)

This is ex Nokia 1020. Only IRfanview can read it. CS3, LR, ACDSEE PRO v7 can't.

The colour are over-saturated but that could be the lack of a camera profile... the phone displays it correctly.

[GeneV]

"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?

Did you try the free DNG converter from Adobe to go downversion? You do not have to change display software if the file can be converted to be compatible with older versions of ACR.

Whether it is Adobe or any other company you are often fighting a losing battle keeping old versions working with new hardware, but I kept my CS3 alive way past its prime with the converter.

[peterh337]

Yes; the free Adobe converter does open that DNG and is able to convert it to a lower version which CS3 can open.

Many thanks for the tip.

[redcat]

Best prime : Sigma Art 35mm 1.4
Best zoom : Sigma 17-50 f2.8
Best prime lenses for the Pentax K-3 - DxOMark
Best zoom lenses for the Pentax K-3 - DxOMark

[GeneV]

To the original topic, for me it is the 16-50, followed by the 17-70, but I haven't shot a lot of newsprint with the 18-135. I don't have the 16-85, and with FF on the horizon, I'm not sure I will. I will probably be looking for a range like 28-105 that I don't already have covered multiple times. At F/8, and in the approximate range we are discussing, everything from my Kit 18-55 to the 17-70, to the 18-135, to the 16-50 will do an excellent job which meets my needs in a walk around. My copy of the DA*16-50/2.8 is stellar at F/5.6.

[ChristianRock]

Best prime : Sigma Art 35mm 1.4
Best zoom : Sigma 17-50 f2.8
Best prime lenses for the Pentax K-3 - DxOMark
Best zoom lenses for the Pentax K-3 - DxOMark

Every review I've ever seen says the Tamron 17-50mm (non-VC) is better than the Sigma 17-50mm optically. Of course the Sigma has a silent motor, so that is an advantage. But the Tamron doesn't even make it to that list, so I wouldn't consider it seriously. Nor does the DA 17-70, or the 16-85. Also, from that list we are supposed to believe that the kit lens is better optically than the Sigma 8-16. Ahahaha. And it says the DA 16-45mm is the best Pentax zoom...

Then there's other issues - it says that the Sigma 17-50mm's best performance is at 50mm f/2.8... that the 16-45mm is best at 28mm and f4. They have this tendency to say that lenses are at their best wide open. So either they're wrong, or everybody else that does tests is wrong. You decide.

So take dxomark's recommendations at your own risk...

[peterh337]

Well, a current 17-50 is going to be better on IQ than a current 17-70, obviously, price for price, etc.

The lesson for me is that lenses do improve over time and I am not surprised that today's 16-85 is very visibly better than a ~2007 17-70 (both Pentax and both similar launch price).

[CFWhitman]

Stevebrot - try this DNG
http://peter-ftp.co.uk/images/WP_20141225_09_51_33_Raw__highres.dng
(my own site - safe)

This is ex Nokia 1020. Only IRfanview can read it. CS3, LR, ACDSEE PRO v7 can't.

The colour are over-saturated but that could be the lack of a camera profile... the phone displays it correctly.

My results:

Raw developers:
RawTherapee 4.0.12.0 opens this file with no problems.
Darktable 1.6.7 opens it with no problems (only works on Unix-like operating systems, like Mac OS X or Linux).
Lightzone 4.1.2 opens the file with no problems.

Image editors:
Gimp 2.8.10 opens the file with no problems.
Krita 2.8.1 opens the file with no problems.

Image Previewers:
Ristretto 0.6.3 will not preview the file (it just ignores it).
Geeqie 1.1 previews the file with what seems to be a negative preview.
Shotwell 0.18.0 previews the file with no problems.

ImageMagick 6.7.7 (display) opened the file with no problems (ImageMagick is a set of image processing utilities).

I did notice that RawTherapee and Darktable both displayed the image with more vivid colors (particularly the clay pot), and I'm guessing that this is the over-saturation that you were talking about in IRfanview. All the other programs that opened it correctly seemed to open it with what I'm guessing are more accurate colors. As you may have guessed, I'm generally on Linux and so don't have that much use for programs that won't run on Linux. However, several of these programs are available for Windows and/or OS X as well. So at least you have some more options.

[ScooterMaxi Jim]

If you open yourself up to primes and a few more mm of focal range then the FA 77mm will probably reign supreme. Any of Pentax's other primes won't be far behind. They are all ridiculously sharp.

Why comment when the original post made it clear what works best for his/her situation?

Most of us here understand and appreciate the differences between zooms and primes; and we use both based on how circumstances demand. Frankly with the modern sensors and better zoom lenses, the difference has little to do with sharpness - which for purposes of normal viewing (not pixel peeping which essentially is a disease) - our eyes are not capable of discerning the difference between a sharp zoom and a prime. However, a good prime will most often render the scene more naturally and impressively - and that's what really counts.

Bottom line, sharpness really isn't the only issue - image quality has far more to do with bokeh, depth, saturation, none of which has anything to do with the resolution chart.

---------- Post added 07-29-2015 at 10:31 PM ----------

Every review I've ever seen says the Tamron 17-50mm (non-VC) is better than the Sigma 17-50mm optically. Of course the Sigma has a silent motor, so that is an advantage. But the Tamron doesn't even make it to that list, so I wouldn't consider it seriously. So take dxomark's recommendations at your own risk...

The last sentence is my view. As for the Tamron - Sigma comparison, it just isn't taking all IQ aspects into account. The Tamron can be sharper at point of focus but has terrible field curvature at wider apertures - making it a poor landscape lens. The Sigma is much more solidly built, and far sharper in the corners - but is relatively large by comparison. Both lenses can produce stunningly lovely images, but overall the Sigma will outperform corner-to-corner by a fairly wide margin. Its a complicated comparison.

[clackers]

. Both lenses can produce stunningly lovely images, but overall the Sigma will outperform corner-to-corner by a fairly wide margin.

Hope so, Jim, I'm buying one! :-)

[ChristianRock]

The last sentence is my view. As for the Tamron - Sigma comparison, it just isn't taking all IQ aspects into account. The Tamron can be sharper at point of focus but has terrible field curvature at wider apertures - making it a poor landscape lens. The Sigma is much more solidly built, and far sharper in the corners - but is relatively large by comparison. Both lenses can produce stunningly lovely images, but overall the Sigma will outperform corner-to-corner by a fairly wide margin. Its a complicated comparison.

I'm going to get, I think, one of the two at some point. So from what you're saying, the Sigma is better for landscapes and the Tamron is better for taking pictures of people and things? That has been my observation from looking at sample pictures... the Tamron would be the obvious choice for me, but there's 3 things that make me consider the Sigma:
1. Silent motor. I might start doing some small events and the silent AF might be a big bonus.
2. 77mm filters. I have good filters for my Tokina 19-35 (Tiffen ND, Tiffen Circular Polarizer, Nikon 81A). I'd have to get new filters for the Tamron (67mm).
3. Focus issues with the Tamron are so common. Quality control and build quality in general seem better with the Sigma (at least this particular Sigma, as well as the new 17-70 seem very consistently good).

The Tamron, to me, is sharper (in-focus as you said), renders better especially where people are involved, and has better colors to my eyes. Especially color transition which can't really be fixed in PP - the Sigma seems to smudge the edge of the colors (is that what bad micro contrast does?). So it might be a while before I decide. In the meantime I'll see if the Tokina 19-35 and a flash fulfill my needs (that plus my DA 35 2.4 and F 50 1.7 should be all I need for event/people shooting, honestly). The Tokina is great at f5.6 but suffers at wider apertures. The primes are fantastic even 1/3 of a stop down from full aperture, so my normal and short tele needs are covered.

Hope so, Jim, I'm buying one! :-)

I'll be paying attention to see what you think of it.

[ScooterMaxi Jim]

I think you've nailed it, overall. I got a chance to handle the Tamron - on my brother's Nikon. It seemed nice and the color saturation is great. He isn't rough on equipment, but his fell apart and should have been covered by warranty - they refused.

I think the two Sigma lenses 17-50 and new version of 17-70 are very comparable; I'm not sure they are quite as good as Tamron or various Pentax lenses for color rendition. If you want to do portraits with a zoom - the longer lens seems to be the better option. I generally don't like portraits with 50mm lenses. I use my 85mm often - and feel that the 70-85 range is optimal on the crop sensor cameras.

[peterh337]

Just an update: I am really pleased with the 16-85 lens. Very sharp.

[kh1234567890]

This is ex Nokia 1020. Only IRfanview can read it. CS3, LR, ACDSEE PRO v7 can't.

Adobe Camera Raw 9.1.1 (PS, LR etc) reads it without any problem ...