Month: May 2015

Eye resolution test

Posted on by EskeRahn

I have made a simple test image to test the resolution of your eyes on a phone, phablet, tablet, laptop or PC!

The most common result is it is pointless to go beyond around 1/12000 of the viewing distance

Be SURE it is shown in the screens native resolution. e.g. 960 pixels should fill half a FullHD display. (or use one of the added ones with your screens resolution)

Be SURE that your browser or your windows settings doesn’t do any scaling/zooming/smoothing, i.e. one pixel in the image is one pixel on the display. (If in doubt take a magnifying glass -or macro camera- and look closely on the screen, it should be like the mock-up later in this post)

ResolutionTestText_qFHD

 

It is the point where the single line pair is indistinguishable from the double line we are looking for (that is: where it looks like one continuous thick line)

You will most likely find the finest resolution using the red or green figure.

Use any prescribed glasses that you normally would for the distance – we are testing resolution, not focusing ability.

NOTE: If you got a PenTile display, usually the green will do fine! Have a look at this on different subpixel arrangements. Several pixel arrangement exists out there, that could have similar issues…

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Digital camera sensor sizes – selling elastic bands by the metre

Posted on by EskeRahn

When a sensor is advertised/sold as 1/2.3″ most people would think that is the diagonal of the sensor. Well it is NOT! It might even vary drastically between manufacturers.

For historical reasons the diameter of a fictitious Vidicon tube with the same active area is what is advertised!!

ccdsizes[1]
From  http://www.dpreview.com/news/0210/02100402sensorsizes.asp

Unfortunately, it is even more confusing than that…

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Megapixel-craze and tiny sensors & lenses. Myths & Facts

Posted on by EskeRahn

This is an attempt to replace some of the common myths, urban legends and misunderstandings with some facts.
(last updated 20181103)

There are at least three physical issues and one biological that are interesting:

1) Rayleigh’s criterion and sensor width.

F * √N < W , (N number of sensors in Mpixels, W in mm, red light F numerical aperture)

AR-principles[1] Airy_disk_spacing_near_Rayleigh_criterion[1]

2) The eye’s real life resolution

Resolution beyond 1/12000 of viewing distance is pointless for most

3) Thermal noise.

Relative noise increases by 1/d, (+)almost √n and √T, (N number of sensors in Mpixels, d sensor diameter, T in kelvin, i.e. °C+273.15)

4) Effective pixel count

The effective pixel count falls with the amount of light, the less the pixel size the worse.

5) Stacking images

Stacking can compensate, but can not perform miracles.

 

6) Thickness of device versus sensor size

The angle of light to the sensor edges binds max sensor size to thickness.

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Panasonic TZ70, Review

Posted on by EskeRahn

Panasonic Lumix TZ70 (ZS50 in the US)

Upgrade of TZ60 with larger/fewer pixels, RAW and better viewfinder, but removed GPS.

This post is likely to be enhanced/edited over the next days and weeks

Eske Rahn 2015-04-25

Overall: Really satisfied. 10/10

1426237696653[1] 1420186774799
The only real competition today is the upcoming HX90V from Sony, that haven’t got RAW, and have pixels as small as the TZ60

Overview

The TZ60 took much beating due to the small pixels, And Panasonic answered that by increasing the pixelsize by a factor 150%, and thus reducing the pixelcount by the same to 12MP.
This is an obvious upgrade from Fujifilm F900EXR, that are beaten or on par in all areas, less triffles.
See my review of the F900EXR here. On which this review to some extend will be based.
Practically the whole plus-list could be repeated, and most of the cons are not there!!
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