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Forum: Post Your Photos! 01-27-2017, 04:37 PM  
Best of 2016 The Path Less Traveled
Posted By crussellsprout
Replies: 2
Views: 327
Thanks eaglem, the lighting really caught my eye as well, that's why I like this one a lot. Taken looking off to the side of my bike commute route :)
Forum: Post Your Photos! 01-27-2017, 04:13 PM  
Best of 2016 The Path Less Traveled
Posted By crussellsprout
Replies: 2
Views: 327
Forum: Pentax K-1 08-22-2016, 04:39 PM  
The superiority of FF over APS-c re: Depth of Field
Posted By crussellsprout
Replies: 230
Views: 13,828
Actually, both the sensor size and the pixel size ARE part of the DxO normalization, since the quantity they use to normalize by, N=number of pixels, is almost exactly the ratio of sensor area to pixel area (moreso for recent sensors than those from the early days when there would be more wasted space around each pixel -- now the wasted space is quite negligible)! (I made a similar comment before, here: https://www.pentaxforums.com/forums/169-pentax-full-frame/315763-k-1-so-what-...ml#post3577426 )

The intention of the print score is to be able to compare sensors fairly. As DxO says "Normalizing by pixel resolution makes it possible to compare actual sensor performance, similar to printing two images on the same printer." This is much more useful than simply comparing per-pixel performance.

If the DxO print score was instead calculated using a normalization based around the ratio of pixel area, rather than #pixels, THEN it would be true that it would not be affected by sensor size at all. But that would be silly, as it wouldn't serve the intended purpose of their normalization. They already have the screen score which is the one that only depends on pixel area.

Further emphasis of why users should pay attention to Print sensor scores rather than Screen scores when comparing sensors (from http://www.dxomark.com/Reviews/DxOMark-Camera-Sensor2/How-fair-is-DxOMark):

"Print versus Screen modeTo compare DxOMark Camera Sensor scores between cameras with different resolutions, you need to look at the “Print” results. The overall DxOMark Camera Sensor score is “Print” level only, which is fine. For the next level of detail a viewer gets to choose between Print and Screen. This is less fine: Screen is not normally useful for end users (it can be useful for debugging your own calculations). The lowest level of data is presented in “Screen” mode only, but is not labeled as such. I would prefer to see all data to be labeled Print/Screen or –better yet– Normal/100%. Normal would stress that this is what matters. And 100% is similar to pixel peeping: here you look at the noise at the 100% crop level and loose the overview of what it means at the image level."
Forum: Pentax K-1 06-29-2016, 11:05 AM  
K-1 media coverage around the world - post links here
Posted By crussellsprout
Replies: 331
Views: 35,107
Forum: Pentax K-1 05-03-2016, 04:44 PM  
Time lapse video shot with K-1 in Japan
Posted By crussellsprout
Replies: 8
Views: 864
Yes, the zooming I believe he did in post-processing, but at least some of the panning was apparently done with this motion-control device attached to the tripod mount:

https://syrp.co.nz/products/genie-mini
Forum: Pentax K-1 05-03-2016, 01:36 PM  
Time lapse video shot with K-1 in Japan
Posted By crussellsprout
Replies: 8
Views: 864
Came across this video and thought others may also be interested:

PENTAX K-1 Time Lapse Test















You Tube



Forum: Pentax K-1 05-03-2016, 10:33 AM  
K-1 media coverage around the world - post links here
Posted By crussellsprout
Replies: 331
Views: 35,107
Here is a video review of the K-1 that was made recently, by digiDIRECT.com.au:

https://www.facebook.com/digidirect/videos/1166161016761291/
Forum: Pentax K-1 04-29-2016, 04:16 PM  
First full review of K-1
Posted By crussellsprout
Replies: 35
Views: 4,951
I'm not so sure they reviewed the video very closely -- maybe it's just me, but when I watched the short clip they posted I noticed a very odd jump in the footage just before the 6 second mark. I would attribute this to the software image stabilisation, but I'm not sure...didn't look smooth regardless of what caused it.
Forum: Pentax K-3 04-19-2016, 12:13 PM  
D500 vs K-3 size comparison
Posted By crussellsprout
Replies: 83
Views: 8,804
Yes, although I'm not sure a dedicated button for 'image quality' aka JPEG compression is really necessary :D
Forum: Pentax Full Frame 04-15-2016, 10:09 AM  
FroKnows Photo talking about K-1
Posted By crussellsprout
Replies: 210
Views: 15,004
Oh, if it was design awards that you were all in a tizzy about, you should have just said so! We could have allayed your fears about Pentax/Ricoh much earlier :)

Here are just a few design awards Ricoh/Pentax have won in recent years, that a quick search turned up:

Ricoh Theta and Pentax 645Z named winners at Germany’s iF Design Awards 2016 | Pentax Rumors

GR digital compact camera and RICOH THETA spherical imaging device named winners at Germany?s iF Design Awards 2014. - RICOH IMAGING EUROPE S.A.S -- "GR digital compact camera and RICOH THETA spherical imaging device have been selected as winners at the internationally respected iF Design Awards 2014"

Best Camera Pentax-Q10 - T+L Design Awards 2013 | Travel + Leisure -- "Best Camera Pentax-Q10"

Good Design Australia 2013 - PENTAX MX-1 -- "Pentax MX-1 Good Design Award"

And even the K-01 :D
Red Dot Design award for the PENTAX K-01 - Press Releases - RICOH IMAGING - European Hub Site -- "Red Dot Design award for the PENTAX K-01" (2012)


Of course, there are plenty of overall camera awards (which generally consider both form and function) that Pentax DSLRs have won over the years as well, so they must be doing SOMETHING right ;)
Forum: Pentax Full Frame 04-14-2016, 02:41 PM  
FroKnows Photo talking about K-1
Posted By crussellsprout
Replies: 210
Views: 15,004
Of course, not everyone agrees with your assessment of Pentax ergonomics/usability being inferior, in fact many of us find this to be a huge advantage to Pentax cameras. Even for your comparison of D600 (circa 2012) with K20D (circa 2008), I would highlight for example that DPReview rated the K20D an 8.5/10 for ergonomics and handling, while giving only 9/14 (or ~6.5/10) to the D600...
Forum: Pentax K-1 04-04-2016, 03:01 PM  
Question about 5-axis Stabilization possibility
Posted By crussellsprout
Replies: 8
Views: 1,337
I think what was being referred to may have been the video at that link (Features2 | PENTAX K-1 | RICOH IMAGING) which actually shows the sensor being stabilized to resist those five axes of camera motion -- ie. it actually does show the camera being rotated with respect to the sensor for the pitch and yaw motions!

This is almost certainly a misleading video and not reflective of the actual degrees of freedom of the sensor SR motion, since as you implied such pitch/yaw sensor rotation would tilt much of the sensor out of the imaging plane and really ruin the focus (unless you were going for that effect, a la the OP's feature question). It's a shame that the feature specifications do not explain how the SR II system works more clearly, to avoid such confusion.
Forum: Pentax K-1 03-30-2016, 01:48 PM  
Dear Ricoh! Please add this awesome feature to your K-1!
Posted By crussellsprout
Replies: 32
Views: 2,939
In this case I think the multiple exposure feature in-camera can offer a clear advantage over post-processing exposure compositing, because it allows you to better fit the image composition at the time of shooting. In post, you have no control over adjusting perspective, framing*, etc. while with the OP's described feature you can play around with this until you get a desired combination/alignment between your multiple exposures.

Edit:
Ideally, the individual exposures could also be saved separately or be able to be extracted from the multiple exposure shot, so that fine tuning of the compositing could be performed in post, thus providing the advantages of both techniques.

*Of course you can crop in to adjust the frame in post, but this is more limited than the flexibility afforded while shooting and also reduces the image resolution.
Forum: Pentax Full Frame 03-19-2016, 11:48 PM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By crussellsprout
Replies: 312
Views: 18,772
Sorry, my earlier post was inaccurate in language when I said that the DxO normalization process did not 'directly' involve the sensor size (but I went on to show examples to explain how despite that, the Print scores always show that larger sensors have better performance for a common sensor tech/age). The examples are fine, but what I should have said initially was that the DxO normalization process does not APPEAR to directly involve sensor size. But it actually does, because it involves the number of megapixels, which itself is simply the ratio between sensor area and pixel area. With N = number of pixels, A_s = sensor area, and A_p = individual pixel area, N=A_s/A_p. I apologize for glossing over this fact, which may have certainly helped some people to accept how it is that Print SNR truly does reflect gains in performance due to a larger sensor size.

So to summarize, while SNR_screen only takes into account per-pixel noise (which is only related to A_p, not to A_s or sensor size at all), SNR_print certainly does take both A_p AND crucially A_s into account. This is why the normalized Print measures are much more useful, especially when comparing sensors of different sizes.

SNR_print (aka SNR_norm) = SNR_screen + 20 log sqrt(N/N_ref) = SNR_screen + 20 log sqrt( (A_s / A_p) / N_ref)

If you increase sensor size, ie. A_s, then SNR_print increases, EVEN IF keeping the ratio between A_s/A_p constant (ie. maintaining the number of pixels). This is because if you increase pixel area A_p in proportion to A_s in order to maintain # of pixels, then while the second term in the above equation (the + 20 log sqrt... part) doesn't change, the SNR_screen DOES INCREASE, due to the larger pixel area.
Forum: Pentax Full Frame 03-18-2016, 09:34 PM  
K-1 So What Is Full Frame Going To Provide Over A Crop Frame DSLR
Posted By crussellsprout
Replies: 312
Views: 18,772
I'm not sure where you got some of these ideas, and feel the need to assert them so strongly, when there doesn't seem to be any evidence for them. The technical explanation behind the normalization scaling performed by DxOMark to get the Print scores from the Screen scores quite clearly does not take viewing distance into account at all, it simply normalizes to a common output resolution (N_0 = 8 MP). Detailed computation of DxOMark Sensor normalization - DxOMark

Furthermore, while the normalization 'process' itself does not take into account sensor size directly in that step, that does NOT mean that the normalized or Print scores will not yield higher scores for larger sensors than smaller ones (of a common sensor tech/age). To see this, first consider the initial Screen scores which reflect the per-pixel noise levels. Per-pixel noise will be lower for larger pixels than for smaller ones of the same tech age. Now consider some examples of APS-C vs FF sensor combinations that we would like to compare.

1. 16 MP APS-C vs 16 MP FF
2. 24 MP APS-C vs 16 MP FF
3. 16 MP APS-C vs 36 MP FF

In case 1, the FF sensor will yield a higher Screen SNR score thanks to it's larger pixel pitch. Then the normalization step will treat both sensors equivalently, since they have the same number of pixels, and thus the normalized Print scores will show the same trend as seen with the Screen scores -- the FF will still be better.

In case 2, the FF will yield a relatively even higher Screen SNR score than the APS-C since it's pixels are even more relatively large compared to the 24 MP APS-C sensor. This time the normalization step will even the playing field a bit, however, as the larger number of pixels for the APS-C sensor will bring it's Print score more in line with the FF's Print score. (In fact the 24 MP APS-C Print score should be quite similar to the 16 MP APS-C score for the same sensor tech/age.)

In case 3, the FF will yield about the same Screen SNR score as the APS-C since they have about the same pixel size. However, this time the normalization step will reveal the big advantage of the larger sensor, as the much larger number of pixels will result in higher Print score for the FF than the APS-C.

So from these examples we can see why sensor size will lead to improved ie. reduced image noise when using an output image at the same size (the normalization step is required in order to do this comparison properly), as indicated by its higher Print score.

We can also see how (at least with current sensor tech -- it didn't used to strictly be the case) for a given sensor size, the number of pixels does not really matter for output image noise, as the effect of noiser per-pixel levels for a higher resolution sensor will be negated during the normalization step in which the higher resolution sensor has it's noise 'averaged out' and ends up with about the same Print score as the lower resolution sensor. So, the only down side to a higher resolution sensor is typically cost, and intermediate image file sizes, while the up side is higher resolution in some situations (at least at low ISO's).

These are general rules of thumb and of course if sensors have significantly different tech or are customized in significant ways relative to each other, performance may deviate somewhat from these guidelines.

I hope this is relatively clear and helpful. :)
Forum: Pentax Full Frame 03-18-2016, 02:20 PM  
Full Frame cropping performance.
Posted By crussellsprout
Replies: 17
Views: 1,749
Robert Capa - Magnum Photos Photographer Portfolio


Magnum Photos Photographer Portfolio

The colours are all washed out, and there is considerable noise visible even at small display sizes in a lot of these shots, but he seems to make it work...
Forum: Pentax K-3 03-18-2016, 12:15 PM  
K3 sample shots ... post here !
Posted By crussellsprout
Replies: 9,069
Views: 1,060,750
repaap, great sunset shot through the trees with the moon above, I love that one!

Here are some photos from my commute by bike to work yesterday, on a beautiful sunny day :)


Mist in the Sun by C R, on Flickr











Forum: Pentax Full Frame 03-17-2016, 09:52 AM  
DFA* 70-200 f2.8 price
Posted By crussellsprout
Replies: 54
Views: 3,690
The Canon non-IS lens is still in production so I wouldn't call it an antique per se, even though the design is not that recent, but I understand your stance on this.

This analysis indicates that the optical performance of the Tamron 70-200 is somewhere in between the Canon non-IS and IS II lenses -- let's hope the Pentax coating and tweaks have made it even better optically :)
Just the Lenses: The Great 200mm Shootout
Forum: Pentax Full Frame 03-16-2016, 05:20 PM  
DFA* 70-200 f2.8 price
Posted By crussellsprout
Replies: 54
Views: 3,690
Well to be fair the earlier comment was regarding the price for a non-OIS lens, and B&H does also advertise the non-IS Canon 70-200 f/2.8 at $1249, which is substantially cheaper.

I don't know how the lens performance differs between the Canon IS and non-IS versions, however. Apparently the non-IS version has a different, older coating, and I don't know if it has the same level of weather/dust resistance.
Forum: Pentax Full Frame 03-16-2016, 04:05 PM  
Crop lens on FF ISO performance
Posted By crussellsprout
Replies: 128
Views: 6,294
You are right, it is not terribly difficult, but it does require a little bit of reading to understand how DOF is defined. If you read the following two links which explain how to use equations to estimate DOF, you will see that one of the variables in any of the equations for DOF is 'c' which represents the size of the circle of confusion which in turn varies with image format (assuming the same viewing size). When you crop an image, you are changing the image format being used to capture or represent the image, so DOF changes because 'c' changes.

https://en.wikipedia.org/wiki/Depth_of_field#DOF_formulae

https://en.wikipedia.org/wiki/Circle_of_confusion#Circle_of_confusion_diamet...in_photography
Forum: Pentax Full Frame 03-16-2016, 03:36 PM  
Crop lens on FF ISO performance
Posted By crussellsprout
Replies: 128
Views: 6,294
Ah, but you HAVE changed your perception of the image, and since DOF is a perceptual measure it is also changed. The fundamental thing is to realize that DOF is defined in terms of perception of acceptably sharp or 'in focus' areas, thus if your perception of these areas changes (such as by cropping/enlarging), so does DOF.
Forum: Pentax Full Frame 03-16-2016, 03:28 PM  
Crop lens on FF ISO performance
Posted By crussellsprout
Replies: 128
Views: 6,294
Wrong, actually. DOF is a perceptual measure, and your ability to perceive areas as acceptably in focus or not changes depending on the enlargement of the image. Thus, when you crop an image, and enlarge the crop to the match the same viewing size as the uncropped version, the DOF of the image will be 'less' in that some areas which you perceived to be acceptably in focus in the uncropped image will no longer be so.

An example of a decent demonstration of this is here: DOF and cropping/enlargement: Open Talk Forum: Digital Photography Review

Of course, this point is not terribly practical, since most would agree that the change in image composition when cropping is MUCH more apparent than the different DOF and renders close comparison between the cropped vs. uncropped images rather difficult!
Forum: Pentax Full Frame 03-15-2016, 03:38 PM  
Why the 'screen tab' on DXO was not meant to represent camera output
Posted By crussellsprout
Replies: 58
Views: 3,090
Certainly, it seems difficult to have any reliable general rule in terms of sensor improvements over time. Even within Pentax's own offerings, it took 3 subsequent model generations until they came out with the K-5 whose sensor finally performed better than the K10D sensor -- the K20D and K-7 generally compared about the same or worse than the older K10D (Pentax K7 vs Pentax K20D vs Pentax K10D).
Forum: Pentax News and Rumors 02-29-2016, 11:59 PM  
My report from CP+ 2016
Posted By crussellsprout
Replies: 161
Views: 17,381
It is quite silly that they are still using that excuse -- they include external mic inputs on their cameras, but don't know how to use them? :D That is simply no reason not to let the user use real SR during video if they so choose...
Forum: Pentax Full Frame 02-18-2016, 02:06 PM  
Which legacy Pentax lenses have corrections built in to the K-1?
Posted By crussellsprout
Replies: 30
Views: 2,483
Not as sad as the fact that I have only one of those (FA 50) :o

Thanks for that list -- I really hope they allow these correction profiles to work on the K-3 too with a firmware update!
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