Digital Photography 101

In some ways digital cameras are very similar to film cameras and in other ways they are very different.  The idea here is to look at the basic things required to get a good image.

An email to someone who was getting started:

1. In order to see into shadows what's called High Dynamic Range (HDR) is what works.  But rather than trying to do this using stacking multiple exposures, just use RAW (.NEF in the case of Nikon cameras) and set the bits per channel to the highest possible value (14 bits for the D300s camera).  Note a .jpg has, by definition, 8 bits per color channel so 14 bits per color channel adds 6 full stops.  When you "develop" the RAW file in Photoshop there are sliders for exposure and fill light (as well as color balance) since you are getting all the information from the imaging chip, i.e. the camera is not doing any image processing.
http://www.prc68.com/I/DigitalPhotography201StackingImages.shtml#HDR

2.  One cause of shadows is a light that's looks like a point source, for example the sun.  So instead you want a very "flat" light source.  If using a flash gun, use a diffuser and/or aim it at the ceiling.  I have a studio flash with a 51" umbrella plus a diffuser setup next to a light table.
http://www.prc68.com/I/PhotoStudioStrobeSystem.shtml#E640

3. Often the background can be a distraction from the main subject.  Before I got the light table, and even now with it, I often use Photoshop to manually erase the background (See below).  You will find this very difficult if there is a black shadow next to a black background, so this also is a learning experience in exposure and "developing".
http://www.prc68.com/I/PhotoStudioStrobeSystem.shtml#Light_Table

4.  I've done "object removal stacking" as an experiment so know it's works.  So if you know about it and there's people in some photos, you can take extra photos of the same subject and erase them later.
http://www.prc68.com/I/DigitalPhotography201StackingImages.shtml#ORS

5. A polarizing filter can eliminate some reflections.
http://www.prc68.com/I/Nikon.shtml#Filter62mm

6. There are a couple of things you can do to reduce blur.  If hand holding the camera use a short time delay to release the shutter.  I use 3 seconds.  That way there is no camera shake caused by the hand movement of pressing the shutter.  If you have a SLR and are doing tripod supported close up photography use the mirror lock to prevent "mirror flop".

The difference between a snap shot and an artistic photograph has to do with all aspects of the image.  With film cameras there was a technical challenge in getting a good exposure and with the focus on the desired subject and not focus on the undesired background.  With the advent of modern digital cameras the technical part can be overcome by knowing how to use the camera, but the artistic part is up to the photographer.

2X4

I choose the photography classes at De Anza Jr. college that were part of the Communications branch rather than the classes at San Jose State that were part of the science branch.  The instructor (H.W. "Wick" Wichers) taught philosophy along with photography which I liked.  He told the story:

Framing

This has to do with panning the camera up-down-left-right zooming in-out and/or rotating the camera.  There are different ideas on how to do this.  For example most portraits in the U.S. are head shots where all of the head is in the frame.  In Europe it's common that the shot it tighter cutting off part of the head.

Composition

Includes framing and also includes changing your point of view, i.e. moving to somewhere else.

A common mistake when taking a portrait is having something in the background that's distracting such as a telephone pole coming out of the subjects head.  Taking a few steps to the left or right will eliminate the problem.

Subject Background Separation

Ken Rockwell

Ken Rockwell starts off with the idea of FART before taking a photograph. 
F: You get a Feeling that this is something worthwhile as a subject for a photograph
A: Ask yourself why this would make a good photograph
R: Refine the image to bring out the quality that's attracted you
T: Take the photo

Then goes into what makes a great photograph,
then Composition: Sex and Balance, You can never get too much.

Portraits

Product Photography

The key is to set your camera for the highest quality image (largest file size) AND use RAW, .tif or any format other than jpg.  Then look for even flat lighting, not direct sun so that all of the subject is illuminated and there are no harsh shadows.  A room with North facing windows at midday or best of all inside a white tent.  Let me do the background erasing.  To make that easier set the subject up on something like a short 2x4 or other spacer so any shadows are not right next to the subject.

Motorcycle Show

On 29 Aug 2011 there was a motorcycle show in the Applebee's parking lot here in Ukiah.  I went knowing that the photographic problem would be to separate the subject from the background.  It turned out that one of the motorcycles was one I had seen in the magazines in the early 1970s and one was at the show.  I ended up taking dozens of photographs of this one motorcycle.  It later occurred to me that I should have taken more photos of it and totally ignored all the other motorcycles at the show.  This example was in pristine condition and very photogenic.  There was no way to take a photograph showing all of the motorcycle without also getting a lot of clutter from the motorcycles that were to it's left and right.

Thoughts after the show:

• Studying a single subject (motorcycle) in great detail may result in better photographs than trying to cover the entire show.
  
• Using Active-D Lighting (High Dynamic Range HDR) may have improved the images.
• Using a tripod and Mirror Up might have improved the image sharpness.
• Using stitching might have allowed a full image, but it's doubtful that they would be at the same perspective.
• Asking the owner to move the motorcycle to separate it from the other nearby bikes would have allowed better shots.
• It may be that some of the same shots could have been made by being, for example, more than twice as close and taking a number of overlapping shots then stitching them together.  The advantage in doing this would be to allow a poster-board print that was 20" x 30" that would still have very fine detail.  The  11" x 14" poster prints had good detail, but might not if blown up much larger.
• Using A exposure mode and setting the f/stop to the sweet range of F/8 to f/12 for the 105mm lens might have resulted in sharper images.

Driving

For display on a wall an 8x10" print is about the minimum size, 11x14, 16x20 or 20x30 are much better.  The problem is how to get very sharp images that large.  It takes some effort.  The print sizes shown below are based on 300 pixels per inch.  This is the print resolution needed for inspection from about 6".  If a print will only bee seen from a much greater distance then the resolution can be proportionally degraded.

Camera	Max Resolution	Theory Print	Real Print
D300s	4288 x 2848	14.3 x 9.5	12 x 8
D60	3872 x 2592	12.9 x 8.6	10 x 8
	4200 x 3300		14 x 11
D300s 2x2	6000 x 4800		20 x 16
D300s 3x3	9000 x 6000		30 x 20

If this is correct then stitching a number of images together will be needed to get the required image resolution for large (20 x 30) prints.
For a 30 x 20 print it would be best to use a 3x3 mosaic of D300s images with some overlap for stitching.
The problem with stitching (2x2, 3x3 above) is that the camera needs to be moved in translation, not panning to avoid distortion.  There may be a way around this by using Photoshop perspective correction, but it's not easy if it is possible.

Giclée (Wiki)

This is a term that means using a dot matrix printer for art quality prints .  For example the Epson Professional Printers.
The Epson Stylus Pro 4900 uses 10 pigment inks and prints up to 17" wide.

Dye-sublimation printer (Wiki)

Each dot can be any color, thre's no dithering like in a dot matrix printer.  That's to say it's a continuous-tone technology, where each dot can be any color.

Computer Printers (Wiki)

The most common type is the gray scale laser printer that works by fusing toner (very small black particles).

Minilab (Wiki)

These use classical photographic chemical processes for the negative and print (two separate machines).  They are fully automated and about the size of a chest type freezer.  The print size may be limited to 4x6 or smaller, but some can do up to 8x12.

Required for decent results

• Tripod
• ISO 1000 (instead of the stock 200)
• Mirror Up release mode
• Noise Reduction (Nikon: Shooting Menu\Long Exposure noise reduction: On)
• flashlight
• cable release
• moonless night

	Orion's belt, Nikon 300mm f/2.8 3 sec ISO 1000 Arri Tripod with Camera pointing opposite direction & handle reversed.
	24 Sep 2011 D300s + 300mm f/2.8, Mirror Up, Manual exp f/2.8 3 sec, ISO 2000, Long Exposure Noise Reduction ON Arri Tripod with legs as short as they go (and rubber removed from top of QR adapter plate). In this image you can see Jupiter and 3 moons. There's a little streaking from star movement at 3 seconds and a lot of streaking for longer exposure times. Need to try ISO 3200. A Polar aligned star tracking mount would allow longer exposures without star trails.
	The Sky6 sky map showing the field of view of the Nikon D300s with the 300mm f/2.8 lens Supplied by Paul.
	Orion's belt 24 Sep 2011 0313:53 PDT Nikon D300s w/300mm lens ISO 2000, 2 sec f/2.8 Note there is a small amount of star trailing at 2 seconds
	I saw a photo taken by Chris Pugh that showed what looked like a daytime scene, but it was taken at midnight on a moonless night. The thing that was striking was there were stars in the sky.  he said it was a 30 second time exposure.  I had just been reading: How to Shoot the Night Sky (Introduction to Astrophotography) where the Rule of 600 is mentioned. Rule of 600 Exposure of stars in order to avoid trails is 600 / (Focal Length in mm). So if Chris used a 30 second exposure he must have been using a 20mm lens.  The photo at left was done using a 17 mm FL. 30 seconds, F3.5, ISO 3200 Exp Comp +5, Long Exposure Noise Reduction ON, Tripod

Why are there so many different lens options?  They have advantages when used for certain types of photographs.  The key parameters are: What camera mounting, output image (chip) size (full frame FX or half frame DX, or one of the newer fractional frame sizes), Focal Length +(fixed or zoom), smallest and largest f/stop (manual or automatic), focusing modes (manual, in camera motor, in lens motor), Image Stabilization, ED glass, optical transfer function (Wiki), weight, price, filter thread size, compatibility with cameras (i.e. an older lens may need to be modified to be used on a modern camera or will have limited functionality).

Wiki: Camera Lens, Photographic Lens Design,  Optical Lens Design

DxOMark Lens Ranking -

Chip Size

A normal 35mm film camera runs the film left to right and the frame size is 24mm high x 36 mm wide.  It's expensive to make Full Size (FX) imaging chips that are that big and they only appear on professional DSLR cameras.  A more common imaging chip for high end DSLR cameras is the half frame (DX) size.  If the view angle of a lens on a 35mm film camera is X degrees, then when that lens is used on a DX type DSLR the view angle will be X/2, i.e. it's as if a 2X tele-extender was added to the lens.

Important Note:  The aspect ratio of 35mm film is 2:3 or 1.5.   This is different from 8x10 which is 4:5 or 1.25.  So using an 8x10 aspect ratio print with a digital camera image means you must crop (cut away some of the image.  That means that when shooting you need to know that's going to happen or else you will end of cropping the print.

When making a full size print from a Digital Camera (where the most common aspect ratio is 1.5) requires a paper size with the same aspect ratio.  If some other aspect ratio is used then part of the image is being thrown away.  This is OK for most things, except where high image resolution is desired.
Common Print sizes in this ratio are (See Costco below): 4x6, 8x12, 12x18, 16x24 (not from Costco), 20x30.

The Golden Ratio (Wiki) is an aspect ratio that's very pleasing to the human eye an is 1.618....  The DSLR (35mm film) aspect ratio of 1.5 comes closer to the golden ratio than does the first generation sheet film ratio of 1.25.  So from an artistic perspective using the newer aspect ratio paper sizes makes sense.

Focal Length

This is a measure of the magnification of the lens.  The longer the focal length the closer the subject appears.
For a full frame (FX) 35mm film camera the "standard" 50mm lens has a focal about equal to the diagonal of the frame (43mm).
For a half frame (DX) digital camera a standard lens would be 25mm.
A lens with a focal length less than the standard would be called a wide angle lens and one with a longer than standard focal length would be called a telephoto lens.

The focal length is the distance from the optical center of the lens to the focal plane when the lens is focused on a subject at infinity (very far away).
When a lens is focused at the closest possible subject it is two focal lengths between the center and the subject and two focal lengths between the center and the image, or four focal lengths between the subject and it's image.  Most normal lens focus mechanisms do not have enough extension to do that so extension tubes can be added between the lens and camera body for close up work.  The better close up extension kits include a way to reverse the lens to improve it's optical performance when used for close up work.  A "close up" or macro (Nikon: micro) lens has more focus travel and typically a different optical design so it will work well when focused on close subjects.

Example

Rule of Thumb: For a non image (i) stabilization (vibration reduction VS) lens the shutter speed should be faster than 1 / (focal length in mm).
For example for a 105mm lens the shutter speed should be faster than 1/100 sec.  But with vibration reduction turned on the shutter speed can be a stop or two slower, say 1/50 sec. 

Note that the fastest possible shutter speed on many film cameras was 1/500 sec.  That meant that the longest telephoto lens  you could hand hold was 500mm.  But modern digital cameras now have shutter speeds that are a number of stops faster.  Nikon D300s to 1/8,000 and the D60 to 1/4,000.  That means you can hand hold a much longer telephoto lens.  The addition of image stabilization adds to that.  Some modern cameras have a large optical zoom capability allowing extreme telephoto shots while hand holding the camera, something a cold war spy only could dream about.

Speed

How fast is that lens?  The lens speed is a measure of how much light it can gather.  This is expressed by the wide open f/stop of the lens.  A classical glass lens will have a typical speed for a given focal length, for example 300mm and f/4.  A more modern "Extra-low Dispersion" (ED) lens designs uses one or more Fluoride glass (Wiki) lens elements.  They are a faster lens, for example 300mm and f/2.8.  They are also much more expensive.  Some film 35mm lenses were made as fast as f/0.9.

Bokeh (Wiki) (Ken Rockwell)

 This is a lens property that has to do with how out of focus areas of an image look. Nikon makes Defocus Control, or DC lenses which allow manual adjustment of the spherical aberration so that  you can control bokeh.  These are NOT for getting a soft focus image, but rather to control the out of focus background.  They tend to be pricey.  I think only available in 105mm and 135mm focal lengths.

5841590 Aberration controllable optical system, Nikon Corp, Nov 24, 1998, 359/763 ; 359/659; 359/764
7715118 Macro Lens System, Hoya Corp, May 11, 2010, 359/754 ; 359/791 - a macro lens with controlled spherical aberration
6950246 Imaging optical system and apparatus using the same, Olympus Corp, Sep 27, 2005, 359/771 ; 359/772; 359/773

Resolution

Optical resolution (Wiki) is a measure of how fine a detail the lens will show.  There are different ways to measure this, one is called Modulation Transfer Function (Wiki) and another is a test chart (Wiki) (for example the ISO 12233 Test Chart).

There's a limit to resolution based on the diameter of the objective (primary) lens.  The larger the lens the higher the resolution.  So as a perfect lens is stopped down the resolution will degrade.  But most lenses are not made perfectly and so have better resolution when stopped down 2 or 3 stops from full open.  Note this is different than depth of field where stopping down a lens causes increased depth of field, but at the same time lowers resolution.

This is one of the reasons astronomical telescopes have such large primary optics (typically a mirror) to separate stars that are close together.

DigitUnderstanding image sharpness part 1: Introduction to resolution and MTF curves by Norman Koren

 
About ISO 12233 Chart Data and Sample Images - Digital SLR and Lens Image Quality Comparison -as you move the mouse the arrow points to the right or left so you can compare two lenses.  I haven't checked all the other lenses but the Nikon 300mm f/2.8 seems to be the sharpest of them all.

For most lens designs there is a range of f/stops where the lens performs best and that's in the middle of it's range of f/stops.  For example the Nikon 105mm Micro Nikkor has a range of f/2.8 to f/36 but has the best resolution between f/8 and f/12.

A standard camera lens can only focus as close as a foot to two so the scale of the recorded image is much smaller than the subject.  A macro (Nikon calls them Micro) lens typically can make an image that's the same size as the subject (a 1:1 ratio).  True Micro photography is where the image is larger than the subject.  But with modern digital cameras it's possible to take a macro image (i.e. <= 1:1) and then display it on a computer screen and now it's a micro image that's larger than life.

There are special considerations needed to take good macro photographs such as flowers.

Microscope Objective or C-mount Lens for Macro photography

Telephoto photography has it's own special considerations.

Extension Rings, Tele-Converters & other Lens Related Accessories

The lowest cost cameras have a fixed lens, i.e. there is no provision to focus.  The lens is preset to the hyperfocal distance (Wiki).  All other cameras have some provision to control the focus of the lens.  When a lens is focused at infinity the film is behind the lens a distance called the focal length.  The closest a subject can be is twice the focal length of the lens and then the film is also two focal lengths behind the lens.  The range of focus for most lens designs is typically not enough to get the lens two focal lengths in front of the film and that's why using extension rings between the camera body and lens allows closer focusing for macro photography.  When doing micro photography the lens is very close to the subject and the film/imaging chip is far from the lens.

When the focus of a lens is adjusted the lens is moved back and forth relative to the imaging chip.  This changes the magnification.  The amount of magnification change is very small if the subject is many many focal distances in front of the lens.  For example when using a 50mm lens to take a photo of a subject that's 10 feet in front of the lens the radio of object distance to lens FL is about 61 which is much greater than 10.

But when doing macro photography where the subject to lens distance is close to the lens focal length the change in magnification is significant.  This may be a problem if you want to do focus stacking because the plate scale (Wiki) will be different for each image.  To avoid that problem when focus stacking the lens is not adjusted and the whole camera is moved between exposures, hence the StackShot.

Viewfinder

Older cameras have a provision to add a diopter correction lens to the viewfinder to correct for your eyes.  Modern cameras have an adjustment that allows making a correction for your vision.  I have my camera set so that no glasses are worn when taking photos.  When looking into the viewfinder adjust the focus so that the non image features (digital readouts, fiducial marks (Wiki) in the field of view) are in sharp focus.  Then activate the auto focus feature and now both the image and features should all be in sharp focus.

Dominant Eye (Wiki)

Most people have a strong eye and a weaker eye.  To determine which of your eyes is dominant, with both eyes open point you finger at some object then, without moving your hand, use your left and right eye to view the scene by closing one eye.  With one eye the object will be lined up and with the other eye it will not be lined up.  When looking through the camera viewfinder it's best to use your dominant eye.

Self Timer

Pressing the shutter button is one of the most disruptive things you can do in terms of moving the camera.  That's going to blur the image, so I'm putting this note under Focus.  For hand held shooting my standard self timer setting is 3 seconds.  So after pressing the shutter I pay attention to framing and being still.

Hyperfocal Distance

Most 35mm Single Lens Reflex cameras (Wiki: SLR) support the use of an interchangeable lens that contains a means of focusing and setting the f/stop.  It was common to have a distance scale for focusing work against an index mark.  Adjacent to the index mark there were other depth of focus (Wiki) index marks in different colors.  Acceptable focus would be obtained between the two depth of focus marks for the selected f/stop.

The Nikon lens Aperture is set to f/22 and the focus is set so that infinity is on the left yellow depth of field index.  That brings the best focus point to about 50 feet while the depth of focus extends to 30 feet, i.e. it's set at the hyperfocal distance. Note that when set at f/11 (green depth of focus index lines) the depth of focus is narrower (maybe infinity to 50 feet) so for the maximum depth of focus you want the smallest aperture setting (highest f/number). When taking portraits where you want the background to be out of focus setting the f/stop to the largest aperture (smallest f/number) is the thing to do.  Also using a mild to strong telephoto lens helps to separate the subject from the background in terms of focus.  This may cause parts of the head to be out of focus, so normally you should focus on the eyes.

The method of focusing a digital SLR camera has changed as they have evolved.  Basically the camera body has a computer that looks at how the image changes as the focus is adjusted and sets the focus automatically.  But, there are times when it just does not work.  For example if there is not enough light or the scene does not have straight lines running in the correct orientation, etc.  In these cases switching to manual focus is a solution.  There are number of different ways this is done that are covered by many patents.

Focusing Modes

Speed of focusing

The early auto focusing was done by means of a motor contained inside the camera body that drove the focus mechanism in the lens.  The advantage of this method was lower lens cost since only one motor was needed.  But a disadvantage was that for a large lens the time to focus was slower than you could get by using a larger motor in the lens.  The newer family of lenses has the focus motor in the lens and they are faster and quieter than the camera body focus motor system.

Depth of Field (=Depth of Focus)

A digital camera operates under the same laws of optics (Wiki: optics, camera lens) as a film camera and there's a limit to the depth of focus that can be obtained for a given exposure (see: hyperfocal above).  Cameras are limited to what can be done in a single exposure to the hyperfocal distance.  Digital cameras can generate images that have a much higher depth of field by taking a number of images, all with the same settings including focus my moving the camera, and then stacking the images (Wiki) (Digital Photography 201: Image Stacking) using post processing of those images in something like Photoshop.  Note: changing the focus changes the magnification making stacking difficult to impossible.

Focus Lock

This allows aiming the camera at the subject and setting and locking focus.  Then  you can re-frame the scene so the subject is no longer at the focus point in the frame.  On the Nikon D300s you can lock the focus by a half press of the shutter.

Mirror Up

See Mirror Up under Release Modes.

Tripod

Even though the 105mm lens has image stabilization (Vibration Reduction VR in Nikon speak) there's a limit to what it can accomplish.  Even a tripod is not as stable as you would desire.  Some things that can be done to improve the stability of a tripod are:

• lower and lock the crank up top extension
• collapse the legs to their shortest length
• lock down all the clamps
• use the camera's built in timer rather than a cable release or the worse thing, pressing the shutter manually

Close Up Photography

There are some special considerations involved in close up photography.

Magnification

Depth of Focus

In photography exposure is the total amount of light that is allowed to reach the light sensor either film or digital.  It's the product of brightness and time.  The camera settings that control the exposure are the f/stop and shutter speed.

The lowest cost cameras had a fixed shutter speed that allowed correct exposure for a normal daytime scene when the recommended film was used.  For example the exposure for a normal outdoor scene in direct sunlight is f/16 at 1/(ASA or ISO film speed).  For example for a film speed of 200 (ASA or ISO) the exposure would be f/16 at 1/200 of a second shutter speed.

Digital cameras replace the film with a Charge Coupled Device (Wiki: CCD) or CMOS image sensor (Wiki:APS).  This sensor determines the quality of the resulting image.  The most common parameter that's advertised is the number of pixels (Wiki).  Generally more is better and costs more.

Exposure Modes

Consumer Cameras

Professional Cameras

Most image sensors (Wiki) are made using either CCD (Wiki) or CMOS (Wiki) technology and are made of Silicon using common semiconductor fabrication (Wiki) methods.  The cost to process a wafer is essentially independent of how many parts are on the wafer so the smaller each part is the lower is it's cost.  For a monochrome image sensor a pixel is one photo diode on the chip, but for a color sensor a pixel is made up of some number of red, green and blue pixels for example the Bayer color filter (Wiki) where there are two green, one red and one blue diode per pixel or a larger number when the camera format is set to output a smaller number of pixels per image.

DxOMark ranking of DSLR image sensors for color depth (portraits), dynamic range (landscapes) and low light - hi ISO (sports).

35 mm film (Wiki) is 24mm high and 36 mm wide (camera in normal landscape position) which is a 1:1.5 aspect ratio.  Only very high end DSLR cameras have full size image sensors because they are expensive.  Most DSLR image sensors are smaller than a 35 mm film frame (Wiki).  If you have a lens that works on a 35 mm camera and use that lens on a DSLR with an image sensor that's smaller than a full frame then the effective magnification is higher than you would get on the 35mm camera.  One way this is expressed is "crop factor" which is 1 for 35 mm film, 1.5 for the Nikon DX sensors, etc.

When the number of pixels is very small the image has grain.  Screen printing is in the 50 lines per inch area and a 600 DPI laser printer is around 100 lines per inch.  High end photographic prints are at 300 DPI.  So to make an 8" x 12" print the image should be 2400 x 3600 pixels which takes a 8.6 Mega pixel image sensor.  So for most practical photographic needs image sensor sizes higher than this don't offer an advantage.

Each pixel is like a bucket that can hold some number of photons.  The smaller the pixel the fewer photons it can hold.  Because of noise there's a radio of the maximum number of photons to the noise level and the number of bits in the analog to digital converter used depends on this ratio.  Cameras that have excellent low light performance (Nikon D3S) are full frame but only 12 Mega pixel chips with a pixel pitch is 8.4 um.

This has to do with how the stutter release will occur.

Single Frame (S)

Continuous Low Speed (C_L)

Continuous High Speed (C_H)

Quiet (Q)

Self-Timer (clock icon)

Mirror Up (M_UP)

A drawback of the SLR design is that the mirror needs to be raised prior to an exposure.  The "mirror slap" does move the camera.  On the Hasselblad it's a real problem.  On the Nikon D300s it's still noticeable, that's why they have a Mirror Up (Mu) option on the Release Mode Dial at the upper left (viewed from behind).  When the shutter is at half press the camera does the auto focus and at full press the mirror locks up.  If you wait about 30 seconds the exposure is made.

In film cameras the color balance (White Balance) is determined by the film.  So if the light does not match the film in terms of color temperature a correction must be made or the color balance will be way off.

It turns out that the Nikon D300s and D60 have AUTOmatic as the default setting for color balance.  So, when a photo is taken of the color test chart (see Bruce Lindbloom below) using strobe lights or an incandescent lamp the resulting images are identical.  That's to say that the AUTO mode works.  The special lens caps & color targets that are available may not be needed for these camera models, or may only be needed for very exacting color rendering requirements.

Note that when using a RAW file format, such as NEF for Nikon cameras, you can make white balance adjustments in the Adobe Camera Raw (ACR) application just by clicking on a part of the scene that you know contains no color, such as a white background or a gray card.  So if when taking photos where color balance might be an issue you may want to include a gray card in the first frame to set white balance.  Then in ACR make a group of all shots taken in that light and as a group set the color balance for all of them based on the gray (or known white) reference.

In order for the colors in an image to look like we're used to seeing them the camera needs to be set for the color temperature of the light that falling on the subject and background.  The default camera setting is for daylight as the source of light.  If a photo is taken indoors where the light is from incandescent bulbs the color in the final image will appear to orange.  If the indoor light is from cool white florescent lamps then the image will appear too green. 

There are a number of ways to get the desired color balance.  I say "desired" rather than correct because for artistic reasons you may want to deviate from the "correct" color balance which would render each color in such a way that it was as close as possible to matching the subject so that the final image is more pleasing to the eye.  This usually means warming up the color temperature when there are skin tones in the photo.

http://www.brucelindbloom.com/ - has technical info related to color spaces - After downloading the four reference images, when that folder was selected using the Costco Java applet only two images were in the directory (probably the 8 bit per channel images).  The preview images were very different one had a lot more dynamic range than the other (maybe the gamma 2.2 image).  I've ordered a 16x20 posterboard to both see how it looks and to use as a test subject for White Balance tests.

Camera Color Setting

For Nikon SLR cameras there are color balance settings.  These can be accessed three ways:
1. Pressing the WB button and turning the sub command (front) dial.
2. Using the White Balance menu:
3. Pressing the WB button and turning the Main command (rear) dial.

D300s Shooting Menu White Balance	D60 Shooting Menu White Balance
AUTO	AUTO	Requires "D" (Distance is sent to camera) or "G" (camera controls aperture) lens. Takes into account the built-in camera flash.
Incandescent	Incandescent
Florescent	Florescent
Flash	Flash
Cloudy	Cloudy
Shade	Shade
Choose color temp.	-	1. Pressing the WB button and turning the sub command (front) dial.
PREset Manual	PREset Manual	The white balance is measured using a gray or white subject or is transfered from another image stored in the camera that has the desired color balance.

There are special lens caps with white translucent material (on order 22 Aug 2011) and also special two sided "lens) that has slots (on order 22 Aug 2011).  These are to support the PREset Manual color balance mode where you acutally measure the light.  More on this later.

When the Nikon D300s is set to AUTO color balance it automatically corrects the color balance (white balance).  For example the photos of the test chart when illuminated by studio flash units looks the same as when illuminated by a 4800K tungsten lamp.

Many cameras have built in flash.  Some are always active and others are of the pop-up type that automatically pop-up or that require manual opening.  These are low power (maybe 10 Watt Seconds) and so have limited use.

Red Eye (Wiki)

When the flash is close to the lens it may cause the subject's eyes to glow red.  This typically happens in dim settings with cats, people, etc.  Most cameras with a built-in flash have a Red Eye Reduction mode where there is a short flash that preceeds the exposure that causes the subject's pupils to close down prior to the actual flash exposure.

Distance

The light falls off as the square of distance, so if a subject is properly exposed by the flash at 4 feet then at 8 feet (2 x the distance) the light will be 1/4 as bright.  This effect can be used to cause the background to be black.

Photo taken in the daytime.  Nikon D300s with SB-900 flash. A mode set to f/36.

If you want the light to be brighter at some distance then increase the camera's ISO speed and open to a small f/stop (for example f/2.8).

Fill Flash

It may be possible to control the flash output so that instead of providing all the light on the subject, it will only provide light that's 1 or 2 stops less.  This allows filling in shadows that otherwise would be black to very dark.  This can make outdoor photos much more pleasing.

Watt Seconds

Is the energy stored in the capacitor that discharges into the flash tube to make light.  It is not related to the watt rating shown on a household light bulb.  Watt seconds are the same as Joules (Wiki) (and probably most on camera flash units are similar).  The Nikon SB25 off camera flash uses a 1,400 uF capacitor and charges it to 300 Volts, so WS = 1/2 * 1.4E-9 * 300 * 300 = 63 WS.  Most of these on camera flashes use a smaller capacitor maybe 200 uF so they have more like 10 WS energy.

Guide Number

The Guide Number (Wiki) is a measure of the light output from a flash (bulb, or electronic).  It assumes the shutter is open long enough to capture all the light.  It also assumes the film speed is ISO = 100.  Since this is the linear ISO number multiplying the ISO number by 4 should double the distance (the same as doubling the guide number).

Guide Number = (flash to subject distance) * f/number.  Note guide numbers have a length unit, such as 90 feet or 30 meters.

The lamp converts electrical energy to light at about 40 lumens per watt.

The D300s built-in flash has a guide number of 56 feet when ISO is 200.  The SB-900 guide number varies between 13 meters (42.6 feet) to 57 meters (187 feet) depending on how the flash zoom is set (and at an ISO of 100).  Notice that the built-in flash is specified at ISO 100, but the external flash is at ISO 200 (ISO 200 is the lowest value unless you degrade the image).

The key difference between film photography and digital photography is that with digital you get a file instead of a negative.  The digital file allows doing much more with the image than is possible with a physical negative.  As the number of pixels in the image sensor gets larger so does the file size the camera produces so there's a trade off between how many photos can be stored in the camera vs. the quality of the resulting images.  Some cameras produce images that take up so much file space that they can only hold a single image and so are called "tethered" meaning that they are best used while connected to a computer.  Examples of this are astronomical cameras and Hasselblad digital cameras.

There are advantages to connecting DSLR cameras to a computer when in  a studio setting.

Image Size

Most digital cameras allow the photographer to select what size images will be stored.  The default setting may be a medium size offering a compromise between maximum image quality and maximum number of images on the memory medium.  I set my camera to the maximum available image size and live with whatever the number of images stored.  This way there is the most room to work with the image in post processing.

    Types

    Getting Image Out of Camera

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Flash (external camera mounted & Studio)

Many digital cameras have built-in flash capability and the newer high end DSLR cameras have very sophisticated flash features that go far beyond the first generation Photo-flash equipment.  Nikon has their proprietary Creative Lighting System on the newer cameras and hot-shoe flash units.  But there's not any CLS studio flash equipment.  (see Nikon page CLS)

Direct, bounce, soft box (tent), diffusers, reflectors

Camera Control Software

Post Processing Software (Stacking)

Filters

Movie Mode

3D Photography

Digital Photography 201: Stacking Images
Digital Photography 202: Close-Up, Macro & Micro
Digital Photography 203: Color Management
Digital Photography 204: Studio Flash
High Dynamic Range Photography
Photography
Photoflash
Nikon
Ukiah - a number of photos

Nielsen & Bainbridge
8550 Chetle Ave. Unit B
Whittier, CA 90606
David Trevino - Manager
(562) 986-2000
(562) 968-2038 (fax)
(800) 321-2934

Lytro

"Light Field Camera" - focusing is done after taking the image.

US8279325 System and method for acquiring, editing, generating and outputting video data, Filing date: Nov 20, 2009, 348/345, 396/79, 382/255, 396/89
US8289440 B2 Light field data acquisition devices, and methods of using and manufacturing same, Filing date: Dec 8, 2009,348/349, 348/222.1,348/345,348/340
USD666660 S1 Camera, Filing date: Apr 27, 2011, D16/203
US20120249550 A1 Selective Transmission of Image Data Based on Device Attributes, Filing date: Jun 14, 2012, 345/419, 345/501, 382/276
US2011/0234841 A1 Storage and Transmission of Pictures Including Multiple Frames, Filing date: Jun 8, 2011,  348/222.1; 348/E05.031
13/192,331Reference Objects and/or Facial/Body Recognition, Filing date: Jul 27, 201,  382/118

Patents

6339891 Metal Picture Frame, E. Cox, Jan 22, 2002, 40/785 ; 40/782; 403/294; 403/401 -
Corner joint does not distort when tightening clamp screw (34).


Archival Metal Frames Photography Collection 

Frame Size	11x14	11x14	16x20	16x20
Photo Opening	8x10	5x7	8x10	11x14

• Artcare 8-ply gallery white mat


• Artcare 2-ply mount board
  


• UV glass

Ukiah Area Photo Related

Braggadoon Signs & Graphics
435 North Main Street
Fort Bragg, CA 95437

alan at braggadoon . com

707 964 5050

Can use DNG version _____.


Photo Finish
125 N. State St.
Ukiah, CA 95482
(707) 462-6242

REDIMAT
343 W Robles Ave.
Santa Rosa, CA 95407
(707) 584-9600

Rileystreet Art Supply
103 Maxwell Ct.
Santa Rosa, CA 95401
(707) 526-2416

Tripple-S Camera
260 S. School St.
Ukiah, CA 95482
(707) 462-3163

Mendocino County Photographers Group

DxO Labs - independent tests of lenses and cameras

Brooke's PRC68, Products for Sale, End 2 Party Government
page created 1 Aug. 2011.