Digital photography, leading us to discuss the benefits comparing to SLR film photography
you can make hundreds of images, don’t need to change film, preview images on the screen, if you do not like some, can delete them immediately.
First successful digital camera series production
The first commercially available digital camera in the United States was the 1990 Dycam Model 1; it was originally a commercial failure because it was black and white, low in resolution, and cost nearly $1,000 (about $2000 in 2013 money). It later saw modest success when it was sold as the Logitech Fotoman in 1992. It used a CCD image sensor, stored pictures digitally, and connected directly to a computer for download.
Some abilities which analog film cameras do not have:
- Pro series camera’s protected from moisture
- Shoot in computer recognizable format raw, tiff, jpg
- Transfer, print, or share images wireless (Wi-Fi or Bluetooth)
- Make panoramic images- we can make panoramic images post-processing
- HDR– high dynamic range function, build-in camera software
- Time lapse– we can now make a movie of sequence images
- Make color or black& white images, build-in camera function
- Digital camera sensors have a larger dynamic range than film (ISO)
- We can make a movie (multi-functional device)
- Less noise on the image
And a lot more…
Megapixels in the digital camera
This value in the digital camera world used widely to describe, as a factor quality of the image. But there are other factors affecting quality. Why we get better images using expensive L- class lenses or pro series DSLR?
More megapixels- larger print you can make. Let’s say my old canon 550d maximum resolution is width: 5184 pixels, height: 3456 pixels. Multiplying these values get 17915904 pixels, converting to mega (divide from 1000000), we get ~18megapixels.
For sharp print, we need from 300 to 240 PPI (pixels per inch). Anything below will be looking soft.
Consider this: there are picture manufacturing standards, and should be based on the calculation of how many megapixels we need. Let’s say we want photo 4*6 inches on 300 PPI. So 4x300x6x300=21600000/1000000(to get mega value)=2.16. We need about 2.2 megapixels to make such print.
|Print size (inches)||300 PPI||240 PPI|
Aspect ratio in digital photography
In digital photography most commonly used aspect ratio formats 4:3 and 3:2, rarely 16:9. Medium and large camera’s format uses 5:3, 5:4, 1:1.
I will continue with the Canon 550d resolution to be clear. Pixel width divide from a height. 5184/3456=1.5 my DSLR using 3:2 aspect ratio format, 3/2=1.5 the same value.
Check your camera aspect ratio:
Print size aspect ratio calculated the same way. Let’s say 4*6 photo print 6 divides to 4 equal 1.5- The same aspect ratio as my camera original format.
Pixel size in the digital camera
Each camera may have a different pixel size. Let say Canon 550d sensor size is 22.3mm on 14.9mm. The highest resolution is width: 5184 pixels, height: 3456 pixels.
22.3 divide 5184= 0.0043mm/pixel=4.3 microns/pixel
Comparing to Canon eos 5d mark 3; the sensor size is 36mm on 24mm. max resolution 5760x 3840. 36/5760=0.0062mm/pixel=6.2microns/pixel. Larger pixels collect more light, and our image has less noise, looks better. Pixel size answers the question: why the resolution is not so important to get better quality pictures and why pro series DSLR cameras cost so expensive.
Crop factor in a digital camera
Old SLR cameras got film size 36*24 (35mm). This becomes a basic point to compare these values to sensor size.
The crop factor is directly related to the size of the camera sensor. Since most digital SLR cameras (DSLR) and some system cameras have a sensor 1.5-2 times lower than the standard 35mm tape (or full-frame SLR), on placing the cursor and all the standard 50mm lens, lens angle of view will be lower by 1.5-2 times. This is because the smaller sensor “cuts” only the central frame, which recorded a full-frame sensor part. Yes, and there is often used to recount millimeter lens, in fact, the lens is the image and convey the outlook is no different, only the narrow viewing angle.
How to calculate lens focal length by crop factor?
I know that my Canon eos 550d crop factor is 1.6. So If I am using a 100mm lens, I should multiply 100*1.6=160mm comparing to a full-frame sensor.