Mike Davis

Lives in United States Dallas, TX, United States
Has a website at http://www.accessz.com
Joined on Jun 12, 2002

Comments

Total: 52, showing: 1 – 20
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On photo Tactical Approach in the Wildlife - Birds in Flight challenge (35 comments in total)
In reply to:

gbdz: You need to be a bit lucky to get a shot like this as well.
Congratulations.

It's obvious you didn't mean to diminish the skill involved here, but "lucky" is what people say when a golfer makes a hole-in-one, which I've only witnessed, just once, never done myself. The fact remains, every hole-in-one is the result of someone's absolute intent to put the ball into that distant cup. This shot is a hole-in-one!

Link | Posted on Apr 16, 2016 at 14:52 UTC
On photo Tactical Approach in the Wildlife - Birds in Flight challenge (35 comments in total)

What they said!!

Link | Posted on Apr 16, 2016 at 14:45 UTC as 4th comment
On photo On the Cat Walk in the My Best Photo of the Week challenge (13 comments in total)

A great capture and deserving of first place, but you're editing was a bit sloppy along the length of the right leg (seen at 100%).

Link | Posted on Mar 30, 2016 at 21:03 UTC as 1st comment
On challenge ND, or not too ND? (6 comments in total)

You win! Thanks for giving us a nice comparison.

Link | Posted on Mar 30, 2016 at 20:38 UTC as 1st comment
On photo The road to heaven in the The Ice road challenge (1 comment in total)

In my impotent opinion, this image deserved 1st Place among the others. It's superbly crafted and it inspires me.

Link | Posted on Nov 20, 2015 at 16:26 UTC as 1st comment

Quoting the article, above: "The reporter is also amazed that the screw heads in the body of JH Darumeya’s stereo camera from 1860 are all perfectly aligned. "

JH Darumeya? LOL

His name was JH Dallmeyer - search for it.

"Darumeya" is how an English-speaking Japanese national would pronounce "Dallmeyer." The reporter needs to do his homework.

Link | Posted on Sep 20, 2015 at 00:06 UTC as 2nd comment | 1 reply
In reply to:

flektogon: Achievements in the electronics are growing almost exponentially, but what about the optical achievements? A sensor with such density would be able to register details equivalent to up to 200 lpm of the lens resolution. Does Canon (or someone else) have such extremely sharp lens? The best lenses for the 35mm film format went up to 100 lpm. How much improvement can we see in the lens design?

The f-Number at which diffraction will begin to inhibit a desired print resolution at an anticipated enlargement factor can be calculated as
f-N = 1 / desired res in lp/mm / enlargement factor / 0.00135383
If (and please don't overlook this "if") we wanted to produce an uncropped, unresampled 360dpi print (the equivalent of 5 lp/mm after enlargement) from this 19,580x12,600 pixel sensor, it would measure 54.4 x 35.0 inches, requiring 44x enlargement, thus the f-Number at which diffraction would begin to inhibit our desired resolution of 5 lp/mm in the final print would be:
f-N = 1 / 5 / 44 / 0.00135383 = 3.36. So... we would not be able to use f/4 or larger f-Numbers without causing diffraction to inhibit our desired print resolution. (This formula assumes the print resolution has been selected for viewing at a distance of 10 inches, so if you are willing to view the print no closer than 20 inches, you can perceive equiv. detail and shoot at f/8 without fear of diffraction (f/7.2)

Link | Posted on Sep 9, 2015 at 23:51 UTC
On photo Waterfall in the Assynt in the Tilt Shift challenge (3 comments in total)

Hi gidgetto!

At this point in time, with 24 submissions thus far, yours is the ONLY submission to this challenge that makes traditional use of Tilt-Shift.

For that, I thank you!

This is just my opinion, of course, but the Tilt-Shift miniaturization fad is getting old, real old.

Link | Posted on Apr 7, 2015 at 17:51 UTC as 3rd comment
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

mike earussi: With a pixel size of 2.2um, diffraction will start to destroy the resolution after f2.8, so I really don't see this having any practical application for regular photographers. Nor do I think any lens currently on the market can shoot at this level of resolution at f2.8. So this is a technical achievement, not a practical one, unless it's considered for it's PR value or for bragging rights.

I'd be far more impressed by Canon increasing the DR of its sensors, which would have practical value, instead of just their MP count.

Well said, despite the lack of specifying the enlargement factor and desired print resolution at which f/2.8 would begin to be an issue.

Link | Posted on Feb 15, 2015 at 16:47 UTC
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

John Crawley: When is the industry going to learn that more MP isn't the answer.

I agree with James123 and mosc. Your posts are like a breath of fresh air.

Link | Posted on Feb 15, 2015 at 16:44 UTC
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

Frank_BR: Many good lenses produce details in the center of the field which can only be revealed by a sensor resolution from 200 to 500 MP. Therefore, the increase in sensor resolution is most welcome. Many people who use the argument of diffraction against increasing sensor resolution forget that the impact of diffraction is gradual, and much of the falling of the response can be compensated via digital processing.

8 lp/mm is generally accepted as the highest resolution any adult with healthy vision can appreciate at a viewing distance of 10 inches. So, even if you desire a print resolution of 8 lp/mm (in a non-resampled 576 dpi print), there's no point in having a 120 MP sensor if you intend to make prints smaller than 15.9 x 23.1 inches - the size you'd get using all 120 MP to secure 8 lp/mm - and remember, even this size print, at this resolution, demands that you avoid stopping down below f/4.6 - thanks to diffraction making all those pixels useless if you do so.

If you intend to make lower than 5 lp/mm resolution prints at that enlargement factor with a 120 MP sensor, then again, you don't need 120 MP.

In short, the only way to actually take advantage of all those pixels on so small a sensor is to forget about using most of the f-Numbers offered by your lenses - thanks to diffraction. Never mind the signal-to-noise ratios suffered with such a tiny pixel pitch.

Link | Posted on Feb 15, 2015 at 16:24 UTC
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

Frank_BR: Many good lenses produce details in the center of the field which can only be revealed by a sensor resolution from 200 to 500 MP. Therefore, the increase in sensor resolution is most welcome. Many people who use the argument of diffraction against increasing sensor resolution forget that the impact of diffraction is gradual, and much of the falling of the response can be compensated via digital processing.

At f/9, with this 32.1x enlargement factor, you might as well have used a 60MP sensor, because diffraction will reduce your print resolution to 2.5 lp/mm, the equivalent of 180 dpi after AA and RGBG losses.

At f/18, you'd have been fine with a 30MP sensor, because diffraction will reduce your print resolution to 1.25 lp/mm, the equivalent of 90 dpi after AA and RGBG losses.

Is the print too large in my example, above? If you intend to make smaller prints with a 120 MP sensor, then you don't need 120 MP, unless you desire more than the 5 lp/mm (360 dpi) resolution at the print, used in my example - when most people are making large prints at lower resolutions, because they either don't have the pixels to warrant larger prints and/or they assume no one is going to be scrutinizing them from a distance of only 10 inches.

Link | Posted on Feb 15, 2015 at 16:24 UTC
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

Frank_BR: Many good lenses produce details in the center of the field which can only be revealed by a sensor resolution from 200 to 500 MP. Therefore, the increase in sensor resolution is most welcome. Many people who use the argument of diffraction against increasing sensor resolution forget that the impact of diffraction is gradual, and much of the falling of the response can be compensated via digital processing.

Yes, the effect of diffraction comes on gradually, but the f-Number at which diffraction will just begin to inhibit a desired print resolution in lp/mm, at an anticipated enlargement factor can be calculated as follows:

Max. f-Number = 1 / desired print resolution / anticipated enlargement factor / 0.00135383

Running the numbers for a desired print resolution of 5 lp/mm (equivalent to 360 dpi after AA and RGBG losses), we get

Max f-Number = 1 / 5 / 32.1 = 4.6

Thus, with a 32.1x enlargement factor (for a 25.5 x 36.9-inch 360 dpi print), any attempt to use f-Numbers larger than f/4.6 will reduce the print resolution, thanks to the gradual onset of diffraction.

No amount of post-processing can restore genuine subject detail that was lost due to diffraction at the time of exposure. Acuity (edge sharpness) can be improved, but lost resolution (actual subject detail) cannot be created from nothing.

Link | Posted on Feb 15, 2015 at 16:24 UTC
On article CP+ 2015: Canon shows off prototype 120MP CMOS sensor (255 comments in total)
In reply to:

Frank_BR: Many good lenses produce details in the center of the field which can only be revealed by a sensor resolution from 200 to 500 MP. Therefore, the increase in sensor resolution is most welcome. Many people who use the argument of diffraction against increasing sensor resolution forget that the impact of diffraction is gradual, and much of the falling of the response can be compensated via digital processing.

Despite the gradual onset of diffraction, if anyone tries to use a 120MP capture to make non-resampled 360 dpi prints (equivalent to 5 lp/mm after losses in resolution caused by the AA filter and RGBG algorithm), the resulting print would measure 25.5 x 36.9 inches, while suffering an outrageous enlargement factor of 32.1x from the smaller than full-frame sensor measuring only 20.2 x 29.2mm.

At that enlargement factor, diffraction's Airy disks, for any given f-Number, will be magnified so much in the final print as to force the use of f-Numbers no greater than f/4.6 to deliver a desired print resolution of 5 lp/mm - to actually make use of the resolution promised by the 120 MP sensor.

Link | Posted on Feb 15, 2015 at 16:23 UTC
On article CP+ 2015: Canon shows off new EOS 5DS and 5DS R (124 comments in total)
In reply to:

MarkByland: Sort of false representation taking 100 photographs, stitching them together, and presenting them as some thing that would come straight out of camera. Why not do side-by-side 1:1 series taken from a MkIII? Or, wait, a D810? Show us what you've got, not what can be done with major digital processing.

Also, does this 5Ds R come with a free, multiple terabyte, cloud based storage account?

I would nevertheless be irritated at seeing those stitched prints. Show me what the camera itself can do with a single exposure.

Link | Posted on Feb 15, 2015 at 15:27 UTC
On article Hasselblad unveils pixel-shifting 200MP H5D-200c MS (231 comments in total)
In reply to:

Mike Davis: For a print resolution goal of 5 lp/mm (unresampled 360 ppi):

In single-shot mode, with 51.3 MP on a 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 5 lp/mm (about 360 ppi) in a 23.0 x 17.2-inch print at f/11.1. (Sensor pixel density is 189 pixels/mm. Enlargement factor for that print size is 13.33x.)

In six-shot mode, with 205.2MP on the same 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 5 lp/mm (about 360 ppi) in a 46.0 x 34.4-inch print at f/5.5. (Sensor pixel density is 377 pixels/mm. Enlargement factor for that print size is 26.65x.)

For a print resolution goal of only 2.5 lp/mm (unresampled 180 ppi):

In single-shot mode, with 51.3 MP on a 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 2.5 lp/mm (about 180 ppi) in a 46.0 x 34.4-inch print at f/11.1. (Sensor pixel density is 189 pixels/mm. Enlargement factor for that print size is 26.65x.)

In six-shot mode, with 205.2MP on the same 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 2.5 lp/mm (about 180 ppi) in a 92.0 x 68.8-inch print at f/5.5. (Pixel density is 377 pixels/mm. Enlargement factor for that print size is 53.3x.)

What size print do you hope to make, at what resolution? Do you need this camera's 6-shot mode and are you willing to shoot at apertures wide enough to exploit the higher pixel density without inhibiting your desired print resolution?

Link | Posted on Aug 22, 2014 at 20:25 UTC
On article Hasselblad unveils pixel-shifting 200MP H5D-200c MS (231 comments in total)

For a print resolution goal of 5 lp/mm (unresampled 360 ppi):

In single-shot mode, with 51.3 MP on a 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 5 lp/mm (about 360 ppi) in a 23.0 x 17.2-inch print at f/11.1. (Sensor pixel density is 189 pixels/mm. Enlargement factor for that print size is 13.33x.)

In six-shot mode, with 205.2MP on the same 43.8x32.9mm sensor, diffraction would begin to inhibit a desired print resolution of 5 lp/mm (about 360 ppi) in a 46.0 x 34.4-inch print at f/5.5. (Sensor pixel density is 377 pixels/mm. Enlargement factor for that print size is 26.65x.)

Link | Posted on Aug 22, 2014 at 20:25 UTC as 47th comment | 2 replies

I suspect the label "Diffraction Correction" exaggerates the effectiveness of this feature. No amount of processing can magically recreate actual subject detail that was lost to diffraction as the light passed through the aperture. It might be able to simulate what appears to be genuine subject detail, but it won't be accurate.

For example, assuming that all other variables affecting resolution are up to the task... If diffraction at a given f-Number is just bad enough to prevent you from discerning the date "2014" on the face of a coin lying on a table several meters from a camera equipped with a normal FL lens when viewing at 100%, "Diffraction Correction" isn't going to reconstruct that data from thin air when the data never got past the aperture in the first place.

You can't make a silk purse from a pig's ear.

Link | Posted on Jul 23, 2014 at 12:18 UTC as 7th comment | 12 replies
On article Stream your photos... via backpack? (34 comments in total)

He looks deservedly smug...

Link | Posted on May 19, 2014 at 13:49 UTC as 15th comment
On article Orion DVC210 DLSR Crane Review (43 comments in total)

For still shots, I'd rather use my Bogen/Manfrotto 3048 and a step ladder to get my camera to a height of 11 feet.

Link | Posted on Mar 30, 2014 at 09:15 UTC as 10th comment | 2 replies
Total: 52, showing: 1 – 20
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