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On Sun, 27 Jan 2008 02:35:00 -0600, Ron Hunter <> wrote:

>TIFF has no standard compression, so either lossy, or lossless,
>compression could be applied to the file. Generally TIFF files are
>compressed with LZW compression, which is lossless.

"Baseline TIFF" (which is the standard TIFF which all TIFF implementations are
required to support) files include no compression, CCITT Group 3 compression, or
PackBits compression. All are lossless.

"TIFF Extensions", which may not be supported by all readers, may employ CCITT
T.4 or T.6 compression or LZW compression, both of which are lossless.

The extensions also include an extension for JPEG, which may be either lossy
(Baseline sequential process) or lossless (with Huffman encoding). The type of
JPEG compression used in a particular image file can be determined by looking at
the value of the JPEGProc tag: 1 is lossy, 14 is lossless. There are several
free utilities which display the values of all tags in a JPEG file without you
having to track through the internal linkages.

So the correct answer is: Baseline TIFF files are always lossless. TIFF files
using TIFF extensions or private tags may be lossy.

-- Larry

"John Bean" <> wrote in message
news:...
> On Sun, 27 Jan 2008 13:12:23 +1100, "Pete D" <>
> wrote:
>
>>
>>"John Bean" <> wrote in message
>>news:. ..
>>> On Sun, 27 Jan 2008 09:48:52 +1100, "Pete D" <>
>>> wrote:
>>>>Good to see you back John.
>>>
>>>
>>>
>>>>Have you ordered a K20D yet?
>>>
>>> No fear Pete, I'll see what Samsung has done with their
>>> sensor first. Never buy "MK 1" hardware or run any "V1.0"
>>> software...
>>>
>>> --
>>> John Bean
>>
>>So you don't have a K10D or D or DS or K100D?
>
> Not a D or a K10D. The DS that I have is a second-generation
> design using the same sensor as the D and was was not on
> v1.0 firmware when I bought it, and the K100D is third
> generation using essetially the same hardware; it's the
> sensor more than the body itself that I wouldn't buy in "Mk
> 1" form.
>
> The K10D is a good example - it suffered from some noise
> problems that weren't present in any of the earlier Pentax
> cameras and it wasn't entirely fixed with later firmware.
> Not that it isn't a good performer in its class, just that
> in can't do some of the things I use my DS for because of
> the relatively poor high-ISO performance. None of this was
> discovered until the camera was in the hands of users.
>
> That's what I meant by "never buy Mk 1 hardware or run
> "V1.0" software - I'll let others shake the bugs out before
> I even look at the possibility of buying one.
>
>
> --
> John Bean

I have bothe Ds and K10D and will certainly wait til at least the end of the
year beofre thinking about the K20D unless users convince me otherwise. Mind
you I do not seem to have the noise problems of which you speak but there
you go, different people have different experiences with the same devices.

Still the 14MP sensor looks very good and the rest of the camera is basicly
the same as the K10D.

Pete

In message <Xns9A32B5C89F55Btokeeskildsen@130.225.247.90>, Toke
Eskildsen <> writes
>John Bean wrote:
>> I'd be interested in hearing how you can make it lossy
>> without going to extraordinary effort.
>
>PhotoShop-Windows: "Save as...", select TIFF, set compression to JPEG.
>Gimp: "Save as...", select TIFF, set compression to JPEG.
>PhotoFiltre: No options whatsoever.
>Paint.NET: No options whatsoever.
>IrfanView: "Save as...", select TIFF, set compression to JPEG.
>
>So far, 100% of the programs I checked either provided no way of
>selecting the type of compression at all or provided JPEG among the
>available compressions.

There is also the possibility in some applications to save images as
CMYK rather than RGB and the colour space transformation inevitably
produces losses from rounding errors and out of gamut values.
>
>> For all practical purposes the answer to the original
>> question is "yes, TIFF is lossless".
>
>For all practical purposes, when a beginner asks about a procedure
>where it's easy to make mistakes ("Look! By selecting JPEG and 50%, my
>files get so much smaller!"), it's advisable to make clear how to avoid
>those mistakes.

TIFF will allow you to encapsulate almost anything inside it. Although
the implied meaning is usually RGB with optional lossless compression
there are enough programs that offer JPEG inside TIFF to catch beginners
out and even some who should know what they are doing.

Regards,
--
Martin Brown

--
Posted via a free Usenet account from http://www.teranews.com

Pete D wrote:

<edited for brevity>

> I have bothe Ds and K10D and will certainly wait til at least the end of the
> year beofre thinking about the K20D unless users convince me otherwise. Mind
> you I do not seem to have the noise problems of which you speak but there
> you go, different people have different experiences with the same devices.
>
> Still the 14MP sensor looks very good and the rest of the camera is basicly
> the same as the K10D.
>
> Pete


Hello, Pete:

Did you read Digital Photography Review's take, on the K10D? Here's an
excerpt, from its conclusion:

Pentax K10D Review (December 2006, Phil Askey): Conclusion
http://www.dpreview.com/reviews/pentaxk10d/page25.asp

"When we reviewed the K100D we thought Pentax had got their image
processing just right, however the single element of the entire K10D
equation which left us scratching our heads was just that. Either a
poorly implemented demosaicing algorithm or a strange choice of
sharpening parameters means that while the K10D's JPEG images have
plenty of 'texture' they can lack the edge sharpness we're used to
seeing from semi-pro digital SLR's."

"Pentax may well have been aiming for a smooth film-like appearance
but I at least feel that the inability to tweak this out by increasing
sharpness is a mistake. That said it's unlikely you'll see this
difference in any print up to A3 size, it's a 100% view thing so you
have to decide if that's important to you or not. To get that absolute
crisp appearance you'll need to shoot RAW, and use Adobe Camera RAW or
another third party converter (as the supplied converter produces
similar results to the camera)."

"With the criticism out of the way we return to the K10D as a
'photographic tool', something it does very well. It's a camera you get
used to very quickly and never really leaves you searching for the
correct setting or control. It's also a camera you can grow into, the
unique exposure modes are both creatively interesting and useful, a
range of options such as this encourage you to experiment. At just
under $900 it's a very strong proposition, so despite our reservations
about the slightly soft image processing the K10D just achieves a
Highly Recommended."

So, Phil Askew thinks that the K100D beats the K10D, in image quality.
Further, he gives the former an unqualified "Highly Recommended" rating,
whereas, he states the latter "just achieves a Highly Recommended."

Hmmm...if somebody disguised the K10D as a Canon camera, do you believe
he'd be more impressed with it? <g>


Cordially,
John Turco <>