After re-reading the first article on Portrait and Landscape photography, it occurred to me that many
of the digital cameras in use today are generally set in ‘Automatic’ mode. In ‘Automatic’ mode, many
of the palm-size digitals cameras are preset to accommodate both types of imaging. Although, this is
convenient for use, it also can compromise the image quality. I also neglected to provide an e-mail
address for you to send in questions and images to discuss. This will be added at the end of this
article.
Okay, so back to the technical side of things. Last article talked about Depth Of Field; shallow or
extended. Most cameras have an ‘f-stop’ inside the lens. The f-stop is an adjustable iris, which limits
the amount of light entering the camera. The lower the f-stop number (Portrait) the more light that
of the digital cameras in use today are generally set in ‘Automatic’ mode. In ‘Automatic’ mode, many
of the palm-size digitals cameras are preset to accommodate both types of imaging. Although, this is
convenient for use, it also can compromise the image quality. I also neglected to provide an e-mail
address for you to send in questions and images to discuss. This will be added at the end of this
article.
Okay, so back to the technical side of things. Last article talked about Depth Of Field; shallow or
extended. Most cameras have an ‘f-stop’ inside the lens. The f-stop is an adjustable iris, which limits
the amount of light entering the camera. The lower the f-stop number (Portrait) the more light that
enters the camera. The higher the f-stop number (Landscape) the
less light entering the camera. Sports photographers use high ISO
numbers (we’ll talk about that momentarily), lower f-numbers and
high shutter speeds to ‘freeze’ very fast events, such as a
professional football player making a goal line catch. With high ISO
numbers such as 400 or 800, lots of light entering the lens and a
high-speed shutter allows the camera to capture things the human
eye cannot see. The flip side of this Landscape which generally
uses lower ISO numbers, such as 200 or less, high f-numbers and
slow shutter speeds, that create striking images from naturescapes
to cityscapes. There are upsides and downsides to both. It is up to
the photographer to understand what they are trying to capture.
less light entering the camera. Sports photographers use high ISO
numbers (we’ll talk about that momentarily), lower f-numbers and
high shutter speeds to ‘freeze’ very fast events, such as a
professional football player making a goal line catch. With high ISO
numbers such as 400 or 800, lots of light entering the lens and a
high-speed shutter allows the camera to capture things the human
eye cannot see. The flip side of this Landscape which generally
uses lower ISO numbers, such as 200 or less, high f-numbers and
slow shutter speeds, that create striking images from naturescapes
to cityscapes. There are upsides and downsides to both. It is up to
the photographer to understand what they are trying to capture.
I’m going to assume that many of you reading this have a small digital camera made by Nikon, Canon
or any of the popular models. Each of these cameras has an automatic setting and some have
presets on a small thumbwheel on the top of the camera body. These presets might be bright
daylight (little sun), landscape (mountains, etc), or portrait (a head w/face). Your owner’s manual can
give you more details. Try taking a couple of images of a landscape with the camera in both
landscape mode and a portrait mode. Chances are that landscapes will image better in landscape
mode. Try several images and critique your work. Have someone else also critique your work. See if
you can come to an agreement on the quality of the image depending on the settings.
If you have a more sophisticated camera where ISO speeds, f-stops and speeds can be adjusted or
or any of the popular models. Each of these cameras has an automatic setting and some have
presets on a small thumbwheel on the top of the camera body. These presets might be bright
daylight (little sun), landscape (mountains, etc), or portrait (a head w/face). Your owner’s manual can
give you more details. Try taking a couple of images of a landscape with the camera in both
landscape mode and a portrait mode. Chances are that landscapes will image better in landscape
mode. Try several images and critique your work. Have someone else also critique your work. See if
you can come to an agreement on the quality of the image depending on the settings.
If you have a more sophisticated camera where ISO speeds, f-stops and speeds can be adjusted or
manually set, try some of the following: ISO speed at 100, f-stop at 4
and use the internal light meters to set the correct shutter speed.
Next try the same image and process only with the ISO speed at
1000. Examine your images. Chances are the image with the high ISO
number will have a higher contrast: more pronounced bright and
dark areas with less neutral colors. Are the objects near the subject
in focus? Are the objects in the background ‘soft’? Try to identify
what the soft objects are. Repeat the same test, now changing only
the f-stop to 11; the general focus of the entire image should
improve. Were most of the objects in the image(s) in focus?
and use the internal light meters to set the correct shutter speed.
Next try the same image and process only with the ISO speed at
1000. Examine your images. Chances are the image with the high ISO
number will have a higher contrast: more pronounced bright and
dark areas with less neutral colors. Are the objects near the subject
in focus? Are the objects in the background ‘soft’? Try to identify
what the soft objects are. Repeat the same test, now changing only
the f-stop to 11; the general focus of the entire image should
improve. Were most of the objects in the image(s) in focus?
Resolution is an element to consider. The best resolution in a camera system is determined by the
weakest element in the optical system, including the chip in the cameras. All classical optical
systems have a theoretical limit know as the Rayleigh Limit (http://en.wikipedia.
org/wiki/Optical_resolution#Lens_Resolution). Essentially, this limit begins to occur when image
quality breaks down at the finest point of resolution. Further analysis can be come very
mathematical so we won’t go there. If you have a good quality camera body with a 6 megapixel or
greater chip and
weakest element in the optical system, including the chip in the cameras. All classical optical
systems have a theoretical limit know as the Rayleigh Limit (http://en.wikipedia.
org/wiki/Optical_resolution#Lens_Resolution). Essentially, this limit begins to occur when image
quality breaks down at the finest point of resolution. Further analysis can be come very
mathematical so we won’t go there. If you have a good quality camera body with a 6 megapixel or
greater chip and
a low quality lens, then do not expect to capture great images, because the limiting
factor is the optics. Generally, the optics in modern cameras is very good and we
should not have to worry about this. The next thing to consider is high or
low-resolution image capture. If you want to capture a large number of images on a
single memory card, the camera is set to low resolution. This is great for a
vacation, not scientific imaging. If you want to capture high quality, digitally
magnifyable images, the camera should be set to high resolution. In-other-words, if
factor is the optics. Generally, the optics in modern cameras is very good and we
should not have to worry about this. The next thing to consider is high or
low-resolution image capture. If you want to capture a large number of images on a
single memory card, the camera is set to low resolution. This is great for a
vacation, not scientific imaging. If you want to capture high quality, digitally
magnifyable images, the camera should be set to high resolution. In-other-words, if
you have a 6 megapixel chip in your camera, your camera should be set to capture all 6 megapixels,
anything less will lower the image quality.
Homework: Try capturing some ‘close’ and ‘distant’ images with your camera. Download them to
your computer. Determine if you can identify the ‘soft’ parts of the image. Magnify those images on
your computer and see if you can identify more objects.
You can also send me (starxplror@comcast.net) your images for review and comment. Also, we can
post them on the Blog (with your permission of course) and have the rest of the team comment.
Hopefully next time, I’ll have some images that have objects that would appear ‘suspect’.
Fred
anything less will lower the image quality.
Homework: Try capturing some ‘close’ and ‘distant’ images with your camera. Download them to
your computer. Determine if you can identify the ‘soft’ parts of the image. Magnify those images on
your computer and see if you can identify more objects.
You can also send me (starxplror@comcast.net) your images for review and comment. Also, we can
post them on the Blog (with your permission of course) and have the rest of the team comment.
Hopefully next time, I’ll have some images that have objects that would appear ‘suspect’.
Fred