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05-27-2009, 09:44 PM   #16
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QuoteOriginally posted by panoguy Quote
- Accessing AEB *is* a bit trickier, and takes a bit more time than the dedicated button on the K20D (maybe 1 or 2 seconds). The difference is that you are looking at the big back screen and all 5 brackets can be seen on the larger scale, but at least the wheels work the same way. I hope another physical button can be remapped for this feature for those of us who want it.


Pentax, please let assign different function to RAW button!

Also delete button in picture taking mode could be used as bracketing button...

05-27-2009, 10:02 PM   #17
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QuoteOriginally posted by Edvinas Quote


Pentax, please let assign different function to RAW button!

Also delete button in picture taking mode could be used as bracketing button...
The RAW button does have another function...press it once for Raw and press it twice for Jpeg
05-28-2009, 12:54 AM   #18
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QuoteOriginally posted by panoguy Quote
What Pentax has put in (which is actually image fusion, not 32-bit then tonemapping)
How do you know?
05-28-2009, 02:03 AM   #19
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Enfusing three exposures is generally much faster than creating a HDRI and then doing tonemapping. Would require less resources to do and is faster. Would be kind of stupid to offer just few tonemapping settings (HDR modes seen by user) which would work with some scenes and not with others.


Last edited by Maffer; 05-28-2009 at 02:01 PM.
05-28-2009, 08:59 AM   #20
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QuoteOriginally posted by blende8 Quote
How do you know?
Well, consider it "speculation with possible proof" for now! I've spent many, many years in the computer vision and imaging end of the software industry working on HDR processing along with the researchers in this field, and I just finished comparing tonemapping algorithms for my employer's 3D rendering software (again!). The differences of the "lighter" method to a particular fusion method are too minimal to be a fluke. It also makes the most technical sense for limited hardware like a camera, as fusion minimizes the memory overhead and doesn't require increased processing precision (which is expensive in every sense of the word, and would yield benefits well beyond this one feature). It also falls in line with much of the filtering and convolutions almost all modern DSLRs do, and the sad "market truth" that floating point output (exr, etc.) would cause huge confusion among consumers.

Last edited by panoguy; 05-28-2009 at 09:38 AM. Reason: simplification
05-28-2009, 04:03 PM   #21
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To add to the evidence, the advance K-7 brochure copy says "HDR 
capture 
quickly
 snaps
 3 
images [...] 
then blends 
the 
best 
parts 
of 
each 
into 
a 
single 
output 
image." Tonemapping isn't usually described that way.
05-29-2009, 05:25 AM   #22
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Whatever it does, HDR is a toy/gimick - I don't see it as any real practical use. Create a 32 bit Radiance file, then you have a winner, or even create a new file format that incorporates the three (or 5 please) raw images with data to link them together for easier post processing.

Or open source the firmware and let us do the coding ;}
05-29-2009, 06:48 AM   #23
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found this

http://www.adorama.com/alc/blogartic...mid=80238&jb=0

Even before factoring in the dedicated first of its kind in-camera High Dynamic Range capture mode, the Pentax K-7 is a winner for HDRI shooters. Many other manufacturers would be wise to take a look at the creative controls and feature set that Pentax put into the K-7 for HDR-minded photographers, particularly at this $1,299 US List price point:
One-touch Auto Exposure Bracketing burst setting options.
+/-2 EV spacing for 3 or 5 shots for AEB capture gives an exposure range that is wide enough for many HDR scenes--something that is so lacking on too many models, including the Canon EOS 5D Mark II!
5.2 frames per second burst, offers fast capture of the AEB sequence.
User-selectable Adobe DNG RAW mode is already compatible with all HDR programs without waiting for the next round of RAW support upgrades.
This set of features alone is enough to the make the Pentax K-7 a 2009 HDR SLR All-Star. Add the impressive in-camera HDR processing to the mix, and it's in a league of its own.
In-Camera HDRI with the Pentax K-7
HDR Capture mode is accessed via the Menu button on the back of the camera, and is available in most shooting modes, except for Green, bulb, and video modes, for obvious reasons. It works with Live View or through the eyepiece framing, and works with all metering modes--just like Auto Exposure Bracketing. Honestly, until the shutter is fired, you wouldn't even know that you are in HDR Capture mode 1 (standard) or 2 (strong). You've just got to focus, frame, meter and fire the shutter, and the K-7 does the rest.
Here's what happens once you press the shutter: The mirror locks up, and the camera fires the shot based upon the current settings–just as it would fire off a single shot based on the current settings–but then it fires off a -3 EV and +3 EV shot on either side, for an effective estimated 17 EV merged captured range at ISO 100 (this etimate is based upon the DXOMark tests of the 14.6 Megapixel CMOS chip in the K20D at approximately 10.75 EV at ISO 100. We will update and append this article when DXOMark tests are completed on the K-7.)
Then it's all into the proverbial and actual black box with the three images. (I pried Pentax for details, but they wouldn't share the in-camera magic.) What comes out of the Black Box is an image crunched from the very wide dynamic range of the three source images that's tone mapped without excessive haloing, hypersaturation, or inversions, in JPEG format. There's no alignment, no deghosting, and no sensor-shift stabilization during HDR Capture. Use a tripod.
Note that I say the output image is JPEG format. It is also worth noting that HDR Capture is only accessible when the K-7 is set to JPEG-only capture output. Note that this does not necessarily mean that the K-7 is creating an HDR from three JPEGs and then tone mapping or simply applying low-bit Exposure Blending to three JPEGs rendered from the originally captured burst. All I can tell you with absolute certainty is that the output image from the HDR capture mode on the K-7 is an eight-bit JPEG. It wouldn't be practical or perhaps even possible for the three merged and mapped shots to be output as PEFs or DNGs, now would it?
It stands up to reason after reviewing several experimental images that that the K-7 is taking the linear RAW data from the three source shots and making a single high-bit High Dynamic Range Image that is then tone mapped during the 10-12 second processing time per HDR capture image. Creating JPEGs from the RAW data after A/D conversion would add an extra step. The only reason to think the merged image is sourced from JPEGs would be to shave some bits from the merging--but then the JPEG conversion would be adding a touch of time to the equation. Only the Pentax engineers know for sure, and they aren't telling us what's happening!

05-29-2009, 01:13 PM   #24
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QuoteOriginally posted by nulla Quote
I read that article when it came out - great review and it was what convinced me that the K-7 HDR is nothing more than a toy. You take the three shots and end up with an 8-bit JPEG you can't do anything more with. Blending and anti-ghosting takes real processing power, and can't really be done in camera. You either need a try HDR sensor (seems a long, long way off) or the ability to take the multiple exposures as fast as possible and combine them into a file that can be processed later.
05-30-2009, 10:27 AM   #25
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QuoteOriginally posted by jfsavage Quote
I read that article when it came out - great review and it was what convinced me that the K-7 HDR is nothing more than a toy. You take the three shots and end up with an 8-bit JPEG you can't do anything more with. Blending and anti-ghosting takes real processing power, and can't really be done in camera. You either need a try HDR sensor (seems a long, long way off) or the ability to take the multiple exposures as fast as possible and combine them into a file that can be processed later.
I don't consider multi-exposure fusion to be a "toy" any more than I consider a raw processor to be a "toy" - they both produce 8-bit JPEGs which look more like what I saw through the viewfinder than the best in-camera JPEG. Of course, if I'm looking for something to complain about I'm sure something will come to mind and I can do my "dismissive wave"...

In related news, I have a camera sitting next to me with a "true" HDR sensor (Spheron AG's "SpheroCAM HDR") which can capture 27 noiseless stops at a time. It's also a panoramic camera, so the resulting images are very useful for my 3D work (and I'm glad my employer bought one!). But the un-tonemapped SPH images it produces cannot be viewed on any mass-produced display, or printed, or edited like a "regular" photograph (today, anyways). Due to this early stage of the technology, all true HDRI captures are either an "intermediate" photographic file (like a PEF), or useful for non-photographic simulation applications like the ones I design. (Go figure, this is what the "Radiance" in the file format referred to earlier actually is!)

Sadly, the results of "processing the HDR file later" rarely lead to decent representations of visual reality, but more often just show how painfully new the field of HDR image processing really is with their exaggerated visual artefacts. As stated above, I've had a very recent and rather exhaustive experience with just how true this is by testing *all currently available* tonemappers. Pentax still offers the best "bracket for the buck" of any camera maker if that's your want, but this new feature will hopefully spur more people into trying out some of the more "mature" methods of representing the greater dynamic range that our eyes can see.
05-30-2009, 12:50 PM   #26
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QuoteOriginally posted by panoguy Quote
I don't consider multi-exposure fusion to be a "toy" any more than I consider a raw processor to be a "toy" - they both produce 8-bit JPEGs which look more like what I saw through the viewfinder than the best in-camera JPEG.
The analogy with JPEG is a good one. It is not that there is anything wrong with JPEG - most of my pictures end up in JPEG form at the end of the day. The problem with JPEG is that it limits your options - RAW gives you more to play with. If the HDR option was to do the in camera mapping AND save the original RAW files, it would be very cool. I don't think I would use it as it stands, as I can't go back and change anything.

A similar issue exists with noise reduction - I much prefer the Pentax approach of applying very little NR. I can then do my own NR to suit the image later. I consider Pentax high ISO images superior to even the Canon 5D M2 - the Canon has less noise, but less detail as well.

Pentax K20D Review: 18. Photographic tests (Noise): Digital Photography Review
Canon EOS 5D Mark II Review: 21. Photographic tests (Noise): Digital Photography Review


QuoteOriginally posted by panoguy Quote
As stated above, I've had a very recent and rather exhaustive experience with just how true this is by testing *all currently available* tonemappers. Pentax still offers the best "bracket for the buck" of any camera maker if that's your want, but this new feature will hopefully spur more people into trying out some of the more "mature" methods of representing the greater dynamic range that our eyes can see.
Do you have any reviews or advice on tonmapping software? I've used some, but I'd love any insight you might have.

I also agree completely - Pentax has the best cameras (and lenses) for the buck, and the best HDR (bracketing) cameras.
06-01-2009, 05:21 PM   #27
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QuoteQuote:
Do you have any reviews or advice on tonmapping software? I've used some, but I'd love any insight you might have.
My best advice or insight would be to not use HDR in the first place unless your camera or rendering system is natively HDR. The reason is that exposure fusion (Enfuse, or the method in the K-7) is so much better for photographic imaging needs without all the "over analyzed crap" and artefacts, and we almost always start with the separate exposures in the first place. (And yes, alignment and ghosting removal are part of some GUIs for exposure fusion!)

That said, if you already have an HDR, Photomatix 3 has a pretty good version of the Reinhard/ Devlin photoreceptor algorithm (also called "Reinhard 2" since Erik's earlier one was "photographic", not based on photoreceptors). For some reason, Geraldine insisted on calling it a "Tone Compressor" which is fairly generic, but that what it's called in Photomatix. (If you can't tell, the tonemapping world is pretty small on the software end of things. Erik is a genius, but goes off the deep-end sometimes , and Mlle. Joffre can spin gold from straw in making this technology "pleasing to the mass market.")

If you want to see a pretty exhaustive list of tonemappers in action, Bernhard Vogl has put up a great comparison site (requires shockwave for the panorama viewing) that is only about 3 years back in technology, which isn't really missing much aside from recent "tests" and mixtures of the TMOs. I just put together a "photoreceptor/logarithmic" TMO as the suggested standard, so it's not uncommon.
06-01-2009, 10:00 PM   #28
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What's bracketing?
06-01-2009, 11:24 PM   #29
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QuoteOriginally posted by jct us101 Quote
What's bracketing?
Exposure bracketing: taking a photo at normal exposure, then another with negative EV compensation (darker), then another with positive (brighter).

Many cameras have Auto Exposure Bracketing in some form, where you just hit the shutter once to have it take the 3 (or more) images. The amount of EV compensation used in both directions is configurable, usually in the range of 0.3 to 2 EV. The K20D has a dedicated button for this.
06-02-2009, 01:39 AM   #30
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(My post was kind of a sarcastic joke)

I've never used bracketing.
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