October 21, 2014, 06:27:30 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - privatebydesign

Pages: 1 2 [3] 4 5 ... 171
31
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 16, 2014, 09:35:41 AM »
Resolving power and noise.

Funny, that isn't what my actual crops illustrate.


About 50-70% depending on the full-frame camera.  I have a 5D.  The 7D2 will have about 90% more linear pixel density, and that most certainly will make a huge difference.

I've tested this myself, and even the difference between my T2i, 20D and 5D is a near-linear improvement with pixel density.  Teleconverters wouldn't work if this weren't true, but they do work.

Linear pixel density is a figure quoted by people who don't do same generation comparisons. I just posted a genuine unaltered same generation comparison and there is no 50-70% difference in either. On the other hand you believe a comparison is valid if you just go on pixel numbers or pixel size regardless of sensor generation, nobody else does.

The differences you will see between a 5D and a 7D MkII are down to the nine years difference in sensor tech and technique, nothing else. Compare a cropped 6D and a 7D MkII and I am fairly sure we will see the same differences I illustrate, practically none.

Indeed that 6D and 7D MkII is the spiritual upgrade for the thousands of people that owned both the 5D MkII and 7D.

There are real benefits to getting a crop camera, especially one like the 7D MkII for focal length limited situations, but 'Resolving power and noise' are not two of them, resolving power can get a nod in ideal situations, noise never seems to. The true benefits are AF, frame rate, viewfinder framing, and cost.

32
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 16, 2014, 08:52:26 AM »
Pro FF:
+DR
+DoF
+Better high ISO performance (pixels are 2x larger on 5D Mkiii than on 70D for example)

Pro APS-C
+much cheaper in general

Crop factor 1.6x is not really an advantage. If your take just the center of the 5D Mkiii frame you get ~9.4MP which is enough to print A2 pictures without quality loss. But on the other side in good like conditions you can crop the image form an APS-C sensor too.

This brings me the following question. For wildlife which is better? APS-C or FF?

And when I want the center 30% of an APSc frame?

Crop wins for focal length limited situations.

Naive and simplistic. What does crop 'win'?

With regards outright IQ technique will have a much larger impact on your images than a crop camera or cropping a ff camera. If you have a ff camera getting a crop camera will give you a very very small realisable resolution difference in focal length limited situations. It will give you different AF, framing, and fps figures which might very well have more impact.

If you have a 1Dx getting a 7D MkII for 'focal length limited situations' will almost certainly make little sense, if you have a 6D or a 5D MkIII it makes a much more complimentary tool.

Here are images I have posted many times, same generation 1Ds MkIII and 7D files from a focal length limited setup, the 7D crop has well over twice the pixels on target as the ff crop, but the differences in non optimally processed images, even at greater than 100%, are minimal.

33
EOS Bodies / Re: 7D MkII RAW sample images
« on: October 15, 2014, 10:44:28 PM »
Blotchy, scratchy, lacking in color fidelity. :(

Not sure how one can tell color fidelity from those images. After all, there is WB adjustments in RAW conversion etc.

Blotchy, scratchy... Are we sure Nikon D7100 APS-C sensor won't show the same limitations at high ISO in a side-by-side comparison?

+ A lot.

'Colour fidelity' is an anachronism and entirely meaningless in the digital camera age. If you don't like the colours, change them, if you want accurate then profile your camera it takes a few seconds, if you want to shoot jpegs then use the incredible custom capabilities freely available in your Picture Styles Editor App that came free with your camera or can be downloaded for free from Canon. It did have much more meaning in the days of film and 'atmospheric' lens coatings, but not now.

34
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 10:03:57 PM »
actually, I think I can see PBD's point of view on this - you can't average a bunch of zeros and get a lower zero.
but you can average  bunch of slightly above zero shades+noise which has the effect of increasing effective DR because now there's more useable tonality.

I think the difference in arguments is the threshold chosen for the base
 numerical 0 = black vs SNR=1 = black.

Yes, you guys call 'useable toanlity' 'sensor DR', I have never understood that to be a way of stating 'photographic DR', I only know and understand the difference in recordable luminosity values.

Again, I think this is an area where the technologists have confounded and annoyed the photographers. When I, and millions of others, think of photographic DR we are thinking about the difference in scene luminosity we can actually record, not the point at which the dark tones become noisy. Replicating that capability on devices with a much smaller luminosity range is not and never has been the question.

So who has some RAW step wedge files to upload?

35
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 09:36:34 PM »
What it won't do is have a brighter bright or darker dark, and surely that is the measure of DR, not how many divisions that same range is divided into?

actually, it may be an oversimplification but yes, downsampling will give you darker dark tones as the noise (which lightens them) is averaged out.
Therefor, greater effective DR, when measured as the ratio of light/dark at some SNR limit.

Daniel already covered that point, and we all agree, some dark tones are liberated by noise mitigation, but that doesn't alter the fact that black and white still have the same luminance values.

Going back to my initial question, if a single pixel has a well capacity of 14 stops of DR recording capacity how can downsampling that give me a brighter or darker luminescence? If 0 equals black and white is 16,384 where is the extra capacity? What is being said is that a 'noisy' sensor can't record detail below 0-1,000 (for example) by comparison a 'clean' sensor can record greys in the 500-1000 range 'so it has more DR', I say not, I say the total range from black to white is still the same, the clean sensor has more tonality between black and white, but it doesn't have more luminosity range between black and white.

Maybe that is where the difference is, I and everybody since, ever, has equated photographic DR to the range of luminosity values and the sensor geeks insist on referring to it as levels of tonality.

36
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 09:17:31 PM »
Sorry, I keep forgetting the science, I really must stop looking at pictures............


37
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 08:48:51 PM »


Meh, another DR war...

Well I was hoping somebody would explain to me how making something smaller increases its luminosity recording capacity, which is the common way of determining 'photographic DR' as per my earlier link, it seems all posters seem to want to do is come back with 'sensor DR'.

38
Reviews / Re: Arthur Morris' blog - Birds as Art
« on: October 14, 2014, 06:54:45 PM »
I find that taking an hour or two to learn the PS way of doing it pays off big in the long run. I have Topaz but rarely (never) use it, because I end up doing a YouTube search on how to do the same thing in PS and invariably there are a few videos that demonstrate it.

Besides, knowing why something works as it does can really help rather than just pushing a slider.

But as you say, we each find our own best way of getting there.

I'm sure that there is a lot that can be done better when you dig into the PS interface.  Its a really powerful and extensive program.  Some of the methods are really time consuming like making tone masks to do micro contrast adjustments when compared to adjusting some sliders in Topaz Detail.  I agree that knowing what's happening helps you in PP rather than just slamming the "Make Awesome" slider all the way to the right in some plugin.  Before I got a bunch of the Topaz plugins I was doing multichannel noise reduction and tone masked contrast adjustments and all that stuff so I kind of know whats going on a little bit.  Enough to recognize that Topaz Denoise was basically doing the same actions but with the controls laid out more simply in a single window with some other tools (like detail recovery and color correction) close at hand.  But of course, YMMV as always.

We are definitely painting from the same brush Steve  :)

I don't find making tone masks time consuming though, and it is a great example, once you know how to make and target your own it can work out faster.

http://www.youtube.com/watch?v=DPszOHLmSws


39
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 04:08:45 PM »
..
So theoretical, I can follow you that you can increase the DR by adding multiple pixels together. But how can I see that in my photo?

By viewing your image from a greater distance so you no longer can see each individual pixel, then the smallest object your eye can resolve will consist of multiple pixels (and more of them in the case of the higher mp sensor) and the sum of which can hold many more of those RGB combinations than a single pixel can. The normalized DXO DR score is based on an assumption of your eye being able to resolve 8 megapixels.

No, DXO DR "score" is based on an 8"x12" print at 300ppi. It has nothing to do with pixel visibility or human acuity. 8MP is an entirely randomly chosen number, because at the time 'all' cameras had 8MP. They could just as easily go up, or down. I can assure you the eye cannot resolve a pixel in an 8"x12" print at normal viewing distance (normally considered to be the diagonal of the print), even before the printer algorithm introduces its dithering. You need a very good magnifying glass to see the micro dots of layered ink on a print.

Quote
"Sensor Overall Score is normalized for a defined printing scenario—8Mpix printed on 8"x12" (20cmx30cm) at 300dpi resolution. Any other normalization, even at a higher resolution, would lead to the same ranking, given that any camera that could not deliver the chosen resolution would be eliminated from the comparison."
At least implicitly they also make assumptions about viewing distance. Viewed from 5m distance the viewed DR would obviously be higher.

Also the apple retina displays are around 300PPI and some are around the size of that print so doubt you need that good magnifying glass.

No it wouldn't. The difference between the lightest light and darkest dark would be identical so the DR would be the same.
Quote
Dynamic range, abbreviated DR or DNR,[1] is the ratio between the largest and smallest possible values of a changeable quantity,

The largest and smallest values are constant, there is, and can be, no change in DR.

The averaging you are talking about does not result in 'more DR' it results in a greater number of values within that same range, or put another way, greater tonality that is so small in increments it is beyond our eyes capacity to differentiate.

Quote
Photographers use "dynamic range" for the luminance range of a scene being photographed, or the limits of luminance range that a given digital camera or film can capture, [32] or the opacity range of developed film images, or the "reflectance range" of images on photographic papers.

You could update that to include the contrast ratios of screens too, but that is still fixed.

40
EOS Bodies / Re: EOS 6D Mark II to Move Upmarket? [CR1]
« on: October 14, 2014, 04:00:56 PM »

Ahh, but the real money is in lens sales. While there will always be throttled feature sets for up-sell within a brand, the real concern is to lose sales to other competitors.  Canon knows this, and I don't believe there will be a significant premium in price for the next-gen 6D.

No the real money is in Rebel kits, and whilst I am no corporate adviser and I hate when people proclaim what Canon 'need' to do, I would venture that they do need to keep the Asian Rebel/entry market happy and buoyant with new and better mirrorless cameras. The USA and European market can be fobbed off with 6D/5D iterations for years, the Asian and expanding markets will not put up with sub par mirrorless cameras.

Maybe. But what no one knows is whether the Asian and expanding markets are "leading" or "trailing." People assume that the markets where mirrorless bodies are popular are on the front end of the technology trends. But, we don't know that.

Trends and fashions change. It is very possible that after a few years of playing with small mirrorless cameras, Asian customers, especially in China where the economy and middle-class is still growing, will trade in their little mirrorless toys for "big boy and girl" DSLRs. Like customers in Europe and the Americas, they may find that if they want to shoot sports, wildlife and birds it's a lot easier to do that with a DSLR.

I doubt it, it ends up being about the tech you grow with and that gets the job done. Think India and mobile phones, they are vastly more ubiquitous and useful than landlines, thought the connection quality often isn't 'as good' that will change too.

In truth there is no overriding reason to still be tied to the SLR design, especially for the introductory range and even above, and if you never used one the issues they present become glaring, as opposed to 'us' who started with the design and see mirrorless as the tech left wanting.

41
EOS Bodies / Re: EOS 6D Mark II to Move Upmarket? [CR1]
« on: October 14, 2014, 03:36:38 PM »

Ahh, but the real money is in lens sales. While there will always be throttled feature sets for up-sell within a brand, the real concern is to lose sales to other competitors.  Canon knows this, and I don't believe there will be a significant premium in price for the next-gen 6D.

No the real money is in Rebel kits, and whilst I am no corporate adviser and I hate when people proclaim what Canon 'need' to do, I would venture that they do need to keep the Asian Rebel/entry market happy and buoyant with new and better mirrorless cameras. The USA and European market can be fobbed off with 6D/5D iterations for years, the Asian and expanding markets will not put up with sub par mirrorless cameras.

42
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 03:24:25 PM »
..
So theoretical, I can follow you that you can increase the DR by adding multiple pixels together. But how can I see that in my photo?

By viewing your image from a greater distance so you no longer can see each individual pixel, then the smallest object your eye can resolve will consist of multiple pixels (and more of them in the case of the higher mp sensor) and the sum of which can hold many more of those RGB combinations than a single pixel can. The normalized DXO DR score is based on an assumption of your eye being able to resolve 8 megapixels.

No, DXO DR "score" is based on an 8"x12" print at 300ppi. It has nothing to do with pixel visibility or human acuity. 8MP is an entirely randomly chosen number, because at the time 'all' cameras had 8MP. They could just as easily go up, or down. I can assure you the eye cannot resolve a pixel in an 8"x12" print at normal viewing distance (normally considered to be the diagonal of the print), even before the printer algorithm introduces its dithering. You need a very good magnifying glass to see the micro dots of layered ink on a print.

Quote
"Sensor Overall Score is normalized for a defined printing scenario—8Mpix printed on 8"x12" (20cmx30cm) at 300dpi resolution. Any other normalization, even at a higher resolution, would lead to the same ranking, given that any camera that could not deliver the chosen resolution would be eliminated from the comparison."

43
Reviews / Re: Tony Northrup - D810 vs. 5D Mk3
« on: October 14, 2014, 03:04:41 PM »

But surely, if each pixel has the same well capacity, even though the smaller one performs 'better' for its size, the range of light they can both accurately record is the same, therefore the 'true DR' of the sensor* is the same, for instance the highlights will be blown at the same photon numbers.

*True DR would be the difference in light levels between a pixel that only registers black, to when it is full such that one more photon will not register.
...
Normalization is a nice way of comparing different things, but it doesn't reflect true DR recording capacity, and truthfully shouldn't be labeled DR. This is one of the many reasons there is such a difference of opinion between people who love tests and equations, and people who look at the differences in images.
...

Assuming you view the picture at a normal viewing distance, a normal DSLR will have more pixels than your eye can resolve. So each photo receptor in your eye will receive light from multiple pixels, summed with a weight proportional by how much of their area emits light that reaches that photo receptor. Which is precisely how bilinear downsampling works. So yes you will be able to perceive more DR from the higher MP sensor, unless you pixel peep at 100% which is the only case where per pixel DR is of actual interest in a picture.

I, in my ignorance, disagree.

The brightest bright and the darkest dark will have almost identical values (indeed we have to rely on an output medium and in that case they will be identical), where a downsampled image might achieve increased IQ is in tonality because the averaging, assuming the displaying medium can also differentiate and display the subtleties and your eye can perceive them, will have a greater number of possible combinations.

What it won't do is have a brighter bright or darker dark, and surely that is the measure of DR, not how many divisions that same range is divided into?

To me, in my simple ways, a measure of a cameras DR is the difference in luminosity values between how dark and bright objects can be in the scene and it still record detail in those brights and darks, two pixels with a charge capacity the same have the same DR potential (taking all other things like read noise etc into account) regardless of their size. How is that wrong?

44
Lenses / Re: Which TS-E for NYC?
« on: October 14, 2014, 02:50:03 PM »
Without wanting to start a flaming war here, BUT: I fail to see the purpose of both the TSE17 and TSE24:
  • Correcting for perspective can be done in LR very well. No Shift is needed in the digital age. (Yes, I know, you'll lose some pixels. So, no need for the "S".
  • Tilt is useless on those 2 lenses, because, except for very close close-ups, everything is sharp at any aperture anyway. So no need for the "T".

I can put the tilt to very good use on my TSE90, however, because playing with the focal plane is very useful for me for macro and product photography. It can also be of good use in architecture, but I haven't explored that use yet.

Admittedly, Shift is useless on my TSE90.

So, why not give the TSE-45 or the TSE90 a try instead of the 17 or 24??

Minor shifting can be done very easily in post, bigger corrections eat into IQ surprisingly quickly. Look 2/3 down the page for a perfect example here http://www.northlight-images.co.uk/article_pages/tilt_and_shift_ts-e.html

As for tilt being useless on these focal lengths, that is pure nonsense. Look at the bridge and tower crops here http://www.luminous-landscape.com/reviews/lenses/nikon_24_pc.shtml

Going from my own experiences these differences are noticeable in relatively small prints, certainly in 17" prints.

I would argue, and have, that tilt in a macro situation is of very limited utility, particularly with Canon TS-E's and their mere 8º of tilt which, when combined with the very short J distances often used in macro imagery, make it almost entirely ineffective most of the time.

45
Lenses / Re: Which TS-E for NYC?
« on: October 14, 2014, 01:40:39 PM »
I'd go with the TS-E 17mm.  You can add a 1.4x TC to get to 24mm, IQ remains very good.

For some inspiration:
https://www.flickr.com/photos/chrisk1982/

+1, That is what I did and am very happy. I even upgraded to the MkIII 1.4 TC. I also have the WonderPana CPL for it which is a really nice solution.

My advice always with the TS-E's is very simple, get the focal length you think you will use most, sounds trite but it isn't. You can make a 24 a 17 fov by stitching, you can make a 17 a 24 with a TC. You can't make a 24 an 11 (a shift stitched 17) without rotating the lens for a traditional pano. And the 17 doesn't play as well with the 2xTC as the 24 does with a 1.4. So if your composition favours 24mm get that, it is sharper and takes filters easier, if you favour wider most of the time get the 17.

Pages: 1 2 [3] 4 5 ... 171