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Προβολή αναρτήσεων από 2012

Timelapse video flicker

In timelapse photography, when light changes fast and towards one direction (towards night-sunsets, or towards daylight-sunrises), if you use the aperture priority mode of your camera then there will be frames-photos lighter or darker than the nearby photos in the series. The drastic change in brightness will cause flickering in the timelapse video. This problem occurs because the light metering system isn't perfect.
The best way to deal with flickering caused by the light metering system of your camera is to avoid the aperture priority mode (or other auto modes) and change shutter speed (or aperture and ISO) manually (you could use spot-metering, but this is quite difficult to master..).
In order to do this you will need an extra device (another camera or a light meter) to meter the scene and your camera to take the photos. You take the meter indications, you average them and slowly increase or decrease exposure (by changing shutter speed, aperture or ISO). It is difficult to ch…

Dynamic range (data table)

Sunlit scene: around 17 stops
HDR file: from 16 to 20 stops
my Nikon D90: 12.5 stops

use the following link to view the data table:
https://docs.google.com/spreadsheet/pub?key=0AmeXsxxW0BJQdEd6ZW8yYzdfUzVkck1EWEhtb202RVE&single=true&gid=0&output=html

Visualize the field of view of your lens' focal length (DX sensor used)

Εικόνα
Below is a data table I created so that I could understand better the difference between my 18mm Nikkor lens (on my Nikon D90 - DX) and a 11mm wide angle lens..

Let's say that your eye is 10cm away from a plane vertical to the ground and parallel to you. Then by using basic trigonometry you can visualize the field of view of any lens' focal length.


You can use the following link as well:  https://docs.google.com/spreadsheet/pub?key=0AmeXsxxW0BJQdDRtRFhXXzBxTHF4YUJlZzBWc1Y4dlE&single=true&gid=1&output=html



For more data tables about photography use this link:
https://docs.google.com/spreadsheet/pub?key=0AmeXsxxW0BJQdDRtRFhXXzBxTHF4YUJlZzBWc1Y4dlE&output=html



The angle of view (in degrees) at various focal lengths

In order to have more control over my panoramas (when overlapping shots), I created this small data table in Excel.




UPDATE: 
I recreated the data tables in Excel.
You can now find more information below:
https://docs.google.com/spreadsheet/pub?key=0AmeXsxxW0BJQdGUwYlpEU3h2OElTQWZCMnBfZjJockE&output=html

Actual magnification of a camera lens

A 75-300 lens is said to have a 4X zoom range, not a 4x magnification.
The 4X zoom range actually means that 300mm is 4X greater than 75mm (75x4=300).
A 30mm to 300mm lens would have a 10X zoom range, but it would not bring anything closer than the 75 to 300mm lens (with a 4X zoom range), since the maximum focal length in both is the same.
It is generally accepted that for a 35mm film camera, a 50mm lens most closely approximates what our eyes see (in reality it should be 42mm - always using the 35mm format).
By dividing the focal length of your lens by 50, you can estimate the actual magnification.
A 300mm lens (on a 35mm film camera or a full frame digital camera) would have a magnification factor of 7X (300/42=7.1).
When used on a Nikon D90 (smaller sensor than a full frame camera - 1.5 crop factor) then you would have a magnification of 11X (300/28=10.7). You could say that a 300mm lens on a Nikon D90 is roughly the same as using a 11X telescope..
A 1200mm scope will have a zoom …

Max sensor/film resolution in MP for different camera formats

Max sensor/film resolution in MP for different formats.
The results are really interesting..
As you can see from the calculations the max theoretical resolution of a crop sensor (15.8x23.6mm) digital camera is around 72MP (taking in consideration the lie factor in digital cameras, which is around 2x.).
Max film resolution in 35mm is 84MP. In digital full frame cameras you need around 168MP in order to get all the information you see in film....
Max film resolution in a large format camera 5x4 inch is around 1265MP!!!!

I've tried to calculate the different focal lengths as well.
I also calculated some hyperfocal distances.




UPDATE:
I recreated the date tables in Excel.
You can now find more information below:
https://docs.google.com/spreadsheet/pub?key=0AmeXsxxW0BJQdGUwYlpEU3h2OElTQWZCMnBfZjJockE&output=html