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09-18-2016, 03:37 PM - 2 Likes   #91
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QuoteOriginally posted by clackers Quote
?

Halogen lamps are incandescent.
Technically, yes, you're correct. But in the lighting industry halogen means something quite different to incandescent. A halogen bulb generates a very different temperature light to a standard incandescent bulb. In a halogen bulb, the temperature in the envelope is much higher and the process of evaporation of the tungsten filament is different in that particles more effectively re-deposits onto the filament, resulting in a much longer lifespan.

09-18-2016, 04:02 PM   #92
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QuoteOriginally posted by MarkJerling Quote
Technically, yes, you're correct. But in the lighting industry halogen means something quite different to incandescent. A halogen bulb generates a very different temperature light to a standard incandescent bulb. In a halogen bulb, the temperature in the envelope is much higher and the process of evaporation of the tungsten filament is different in that particles more effectively re-deposits onto the filament, resulting in a much longer lifespan.
I think Norm's essential point is that DxoMark's tests are a uniform artificial light source in a studio environment - they are setup to be a controlled test rather than mirror our real shooting environments.

It's what they should do, IMHO, so as long as we all understand how they generate the numbers, fine. :-)

09-18-2016, 04:27 PM   #93
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QuoteOriginally posted by clackers Quote
I think Norm's essential point is that DxoMark's tests are a uniform artificial light source in a studio environment - they are setup to be a controlled test rather than mirror our real shooting environments.

It's what they should do, IMHO, so as long as we all understand how they generate the numbers, fine. :-)
Absolutely. At least with halogen, they're getting as near as sunlight as (cheaply) possible with an artificial light source.
09-18-2016, 11:14 PM   #94
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QuoteOriginally posted by clackers Quote
I think Norm's essential point is that DxoMark's tests are a uniform artificial light source in a studio environment...
He said much more than that.

He said that their methodology is broken because the light source they are using lacks power in the blue part of the spectrum and that that's the reason why their resolution figures are bogus.

Changing from halogen light (or even incandescent light) to sunlight does not provide a 10MP vs 100MP difference as he suggested.

09-19-2016, 12:37 AM   #95
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QuoteOriginally posted by Winder Quote
Some manufacturers are exposing for 12% gray and some are exposing for 18% gray. It's not that they are cheating ISO, they are simply using a slightly different standard.
There is no such thing as a slightly different standard. There is only one standard. As far as I know, nobody follows the standard exactly, even Pentax. But some companies and camera models are closer to it then others. I believe Pentax' secret to slightly outperforming others are partly in software optimizations and partly in having a better color filter array: Better color separation combined with better transparency at the right wavelengths.

Edit: There is actually two standards, here is the other and more info:

https://en.wikipedia.org/wiki/Film_speed#Current_system:_ISO
http://www.cipa.jp/std/documents/e/DC-004_EN.pdf
http://www.imatest.com/docs/sensitivity_ei/
https://www.dpreview.com/forums/thread/2838786

Last edited by Simen1; 09-19-2016 at 12:56 AM.
09-19-2016, 05:33 AM   #96
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QuoteOriginally posted by Simen1 Quote
There is no such thing as a slightly different standard.
Read the last link that you posted.

"The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model’s EI choices arbitrarily"

They are using the same standard, but the standard allow for variation. REI is what all DSLR manufacturers use.
10-02-2016, 03:52 AM   #97
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QuoteOriginally posted by Winder Quote
Read the last link that you posted. "The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model’s EI choices arbitrarily" They are using the same standard, but the standard allow for variation. REI is what all DSLR manufacturers use.
That's a choice, of course. Shifted ISO versus the standard levels that were used for film can be an issue. Take for example the guide numbers for flash lights. With Pentax, I can use a flash guide number and quickly set the correct flash power , given distance, iso and aperture and get correct flash exposure. Then, if it were camera with ISO rating not being consistent with a film ISO reference, flash guide number wouldn't be valid anymore.
10-02-2016, 05:56 AM   #98
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QuoteOriginally posted by biz-engineer Quote
That's a choice, of course. Shifted ISO versus the standard levels that were used for film can be an issue. Take for example the guide numbers for flash lights. With Pentax, I can use a flash guide number and quickly set the correct flash power , given distance, iso and aperture and get correct flash exposure. Then, if it were camera with ISO rating not being consistent with a film ISO reference, flash guide number wouldn't be valid anymore.
All the manufacturers do it a little different, but they have to keep it with in a stop or hand held light meters would make it obvious. Some manufacturers are using 18% gray, some are using 12% gray. The original point however is that sensors don't actually have variable ISO settings.

10-02-2016, 06:30 AM   #99
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QuoteOriginally posted by clackers Quote
?

Halogen lamps are incandescent.
The hacker how-to website has a conversion that requires only non-toxic body paint and a sparkler.

---------- Post added 10-02-16 at 07:34 AM ----------

QuoteOriginally posted by monochrome Quote
"The Nikon D810 just edges the K-1 for both color depth and dynamic range, but the results are very close, and the K-1 trumps the Nikon by around a third of a stop for ISO, with scores of ISO 3280 vs. ISO 2853, respectively.

"The Nikon D810’s achieves its fractionally-higher headline dynamic range (Landscape) score of 14.8 EV at its base ISO of 64. The K-1 achieves a very close 14.6 EV at ISO 100, however, and between ISO 100 to ISO 800, offers greater dynamic range than both the Nikon D810 and Sony A7R. All three 36Mp sensors offer good dynamic range of over 10 EV up to ISO 3200."

"Signal-to-Noise Ratio (SNR 18%) analysis shows that for printed results, the K-1, D810, and A7R broadly offer the same levels of noise at all sensitivities. Excellent SNRs are achieved up to ISO 400, with well-controlled noise on RAW files at ISO 1600, too. At the higher sensitivities, noise becomes more prevalent, with the Sony A7R performing slightly better at ISO 25,600 and the Pentax K-1 showing its lowest SNR of 7.1dB at ISO 204,800."
Looking at the graphs, The K-1 offers a little more dynamic range.. maybe not by much, but the point on the ISO axis is closer to marked sensitivity by what looks to be 1/3 stop or a hair more.. if the graph scale is linear. If I understand the graph correctly, I think the extra 1/3 to 1/2 faster shutter for the same or bit more DR is more impressive than considering 0.2 or 0.3 stops more DR alone.
10-02-2016, 06:48 AM   #100
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As per previous discussion, the consensus seems to be that you really couldn't tell the difference between a difference of 5 points or less on the DxO tests. You probably should not be reading too much into the numbers of those at the top, they don't mean much.
10-02-2016, 03:27 PM   #101
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For an extra dose of DxOMark related geekery, Bill Claff has also added the K-1 DxOMark data into his charting engine at Photons to Photos:

Photons to Photos

So now one can play with interactive charts with titles like:

- DxOMark Photographic Dynamic Range Chart (2016-09-21)
- DxOMark ISO Sensitivities (2014-10-31)
- DxOMark Derived Measured ISO Chart (2016-09-21)
- DxOMark Gain Analysis (2014-11-05)
- DxOMark Derived Gain Chart (2016-09-21)
- DxOMark Read Noise Analysis (2014-11-09)
- DxOMark Derived Read Noise in DNs Chart (2016-09-21)
- DxOMark Derived Input-referred Read Noise Chart (2016-09-21)
- DxOMark Derived Sensor Characteristics Chart and Table (2016-09-21)
- DxOMark Sports Score Audit (2016-09-21)

I don't know what it all means though, particularly the stuff at:

DxOMark Derived Sensor Characteristics
10-03-2016, 12:42 PM   #102
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I'm still impressed by how much the pixel shift feature can do for still scenes. Try DPReview's side by side comparison with the mighty 25x more expensive Phase One XF 100 Mp. Here are my analysis:

QuoteQuote:
It may be ridiculous to compare a Pentax K-1 to the 25x more expensive XF 100 Mp, but if I do, I'm surprised how well K-1 with the pixel shift feature on competes in IQ.

Note the lens induced differences like much more CA with K-1. As expected from a Schneider lens.

At low ISO the XF100Mp are clearly more crisp and have clearer colors then the K-1 w/PS, except on repeating patterns that causes moiré on the XF100Mp. Thats expected as pixel shift eliminates the bayer induced moiré. PS also causes very good readability on the fine text, two BW drawings and 20 schilling bill. However on other fine details the XF100Mp are clearly better. Some wins some looses for K-1.

When increasing the ISO the XF100Mp surprisingly struggles with much color noise compared to K-1 w/PS. The pixel shift feature are "cheating" with having four exposures, but for some still scenes like this test scene, and for sure some real life scenes, it produces incredibly good results for a 2k$ camera.
10-03-2016, 01:05 PM   #103
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Regarding CA, the Pentax lens is a 77mm...
10-03-2016, 01:06 PM   #104
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QuoteOriginally posted by Simen1 Quote
I'm still impressed by how much the pixel shift feature can do for still scenes. Try DPReview's side by side comparison with the mighty 25x more expensive Phase One XF 100 Mp. Here are my analysis:
that's a fascinating comparison - thanks for linking to it - yes, the difference is much less than format, Mp and price would suggest - and people sneer at PS!
10-03-2016, 02:02 PM   #105
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This comparison made me want a Phase One XF 100 Mp, an enormous printing budget, and enormous walls to put things on. It's definitely clearer than the K-1 at low iso, the texture details it picks up from the playing cards is pretty astonishing. The 645z seems to sit between the two for detail, the pentax offerings certainly punch above their price tags though. Can we hope to see a pixel shifting medium format pentax in the future?

QuoteOriginally posted by Simen1 Quote
When increasing the ISO the XF100Mp surprisingly struggles with much color noise compared to K-1 w/PS. The pixel shift feature are "cheating" with having four exposures, but for some still scenes like this test scene, and for sure some real life scenes, it produces incredibly good results for a 2k$ camera.:
When would you use pixel shift with a high iso or is this just a theoretical comparison?
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