Tuesday, July 16, 2019

Lesson 2 - Cameras & Lenses - Part 2

It's been a while since my last post, been busy building a website. However, here is more info.

All cameras have at least three things in common; film/sensor, aperture, and shutter speed. Let's take a look at each:

FILM and/or SENSOR - each film or digital sensor has a rating established by the film or camera manufacturer. This rating is commonly called the ISO rating of each. These letters stand for the International Organization for Standardization, the group that has classified film/sensor ratings since the late 1980's. 

With film, which I use exclusively, the ISO is built into the film as its produced. The ISO of a digital camera is a setting that's within the camera and can be changed by the photographer as seen fit for any particular image. 

The higher the ISO, say ISO 3200, the more that rating is sensitive to light. It will take less time and light to get a proper exposure. Typical setting for night photography for example. ISO 25, on the other hand, is the exact opposite. This setting requires more time and light to achieve a correct exposure. You might well need a tripod to create an image using the low ISO rating, also called ISO speed by some. Your best mage at this rating would be bright light outdoors.

The most common ISO ratings are 50, 100, 200, 400, 800, 1600, and 3200. You'll notice that each number is twice or half the other. For example, ISO 200 has twice the "speed" of ISO 100 meaning less light/less time for a proper exposure, half as much. In other words, if a good exposure at ISO 100 takes 2 seconds of time, at ISO 200 it would only take 1 second. Likewise, ISO 1600 is twice as slow as ISO 3200. A good exposure using ISO 3200 at 1 second would mean an exposure of 2 seconds at ISO 1600. Can seem a little confusing but once you get in the habit taking your own meter readings, instead of shooting "automatic-let the camera do it", you'll become very familiar with the ISO ratios.

APERTURE - this term refers to how much or how little you open the diaphragm that's built into each lens. The diaphragm typically has metal leaves that open or close as you set your f stop. This terms refers to focal, as I understand it, but more than the name is the function. 

Picture if you will the human eye. When exposed to bright light, your eye closes down and in the dark, it opens up to constantly control the amount of light you see. Another way to look at it is to think of a faucet. The more you open it, the greater the water flow. When you shut it down, you get less water. Your control of the f stops does the same thing in your camera. 

These f stop settings can be most often found on the exterior barrel of your lens. The full line of f stops is f/1, f/1.4,  f/2,  f/2.8,  f/4,  f/5.6,  f/8,  f/11,  f/16,  f/22,  f/32,  f/44,  f/64. Most modern day cameras have a range of f/2.8 through f/16 or f/22. Important fact for you to always remember is that the lower f stop you choose, the greater the diaphragm opening (more light/"water") and the higher the f stop number, the less light is passed through. 

Think of it this way, at f/1.4, your aperture is a big as a half dollar, let's say, while at f/64, your aperture is barely a pin hole. Critical principle, opening up one full f stop ( f/11 to f/8 ) doubles the amount of light entering the camera while closing down one full f stop ( f/16 to f/22 ) cuts the light in half. Numbers going down, more light. Numbers going up, less light.

SHUTTER SPEED - this term refers to the amount of time your camera shutter remains open allowing the light to come through the f stop you chose and then ending at the film our sensor within your camera. This timing can be in minutes, seconds, or fractions of a second depending upon the limitations of your particular camera. Many cameras today can give you multiple minutes of shutter speed and as quick as 1/1000's of a second or even faster. 

There is a shutter speed dial on most every camera that allows you to choose the speed you wish. The speeds can be 1 second,  1/2,  1/4,  1/8,  1/15,  1/30,  1/60,  1/125,  1/250,  1/500, and 1/1000 of a second. Of course, many cameras have a slower speed than 1 second and a faster speed than 1/1000 of a second but the key thing to remember is the ratios again. Just like ISO and APERTURE, shutter speeds have the same relationship. Slower the speed, the more time light has to enter the camera. Faster shutter speeds reduce that amount of time. Each speed is either twice that of another or it's half.

Now let's do a hypothetical case to show the correlation of ISO, aperture, and shutter:

1) We'll use ISO 200 either by buying that film or setting our digital camera as such
2) We'll take a meter reading in bright sunlight at a park, meter set to ISO 200
3) Metering reading equals:  ISO 200 - f/16 (aperture) - 1/250 (shutter speed)
4) We set our camera to ISO 200 (film/sensor) - lens to f/16 - set speed dial to 1/250
5) Great shot - good exposure

Now let's change things a little leaving ISO 200 the same: 

1) We get the exact same shot by choosing f/11 @ 1/500 (more light, faster speed)
2) We get the exact same shot by choosing f/22 @ 1/125 (less light, slower speed)
3) If we change the ISO (faster/slower) we get the exact same shot by adjusting the f stop/speed 

I trust this information will prove helpful for you. Thanks for stopping by!


Sunday, January 6, 2019

Lesson 2 - Cameras & Lenses - Part 1

There are at least 8 to 10 different types of cameras in use today. Some small, some bigger, and some that require rather large tripods to be used properly. They can be grouped as:
  1. Automatic cameras 35mm and/or digital - most everything preset and controlled by the camera itself using unique installed computer type components.
  2. Rangefinder - antique folding type, 35mm, and digital. Often allows for interchangeable lenses, not common to automatic camera, which permits for more manual control. The viewfinder is set off from the line of site of the lens and, even with the best correction for that, you may not get capture exactly the same image you see.
  3. 35mm Single-Lens-Reflex camera (film or digital, SLR & DSLR) - here the camera has a through the lens viewfinder which yields an image just as you see it through the finder. Lenses are interchangeable and accessories abound. Most give you the choice of fully automatic or manual operation. Tend to be light weight and somewhat compact. Perhaps the most popular type of camera presently in use.
  4. 2 1/4 Single-Lens-Reflex camera - this camera utilizes 120 format film and produces a 2 1/4" square negative, hence the term medium format camera as opposed to 35mm or digital. My wife and I used them years ago for portraits & weddings. Absolutely a superb camera, none better. Great for wall size enlargements. Expensive and bulky compared to a 35mm/digital SLR but very reliable. No need to rotate the camera from landscape to portrait mode since the square negative covered each. Interchangeable lens and all types of accessories were available. Not necessarily a "hobby" camera but our Hasselblads were cash cows for us. 
  5. 2 1/4 Twin-Lens-Reflex camera - medium format like #4 above but lighter and less expensive as the Hasselblads. The viewing lens was mounted directly above the "picture taking" lens. Interchangeable lenses (not on all models) were expensive since you had to change both the "viewer" and the "taker" lens as a single unit. Popular in the 1930's and 40's but then displaced by Hasselblads, 35mm, and digital cameras.
  6. Polaroid camera - amazing units that produced instant paper prints on the spot in either black & white or color. All automatic, no creative control, no interchangeable lenses, and little if any accessories. Great amateur camera but of little value to professionals. The only real pro use was with special polaroid backs used on pro cameras to get a "test" shot back in the film days. FUJI has bought the name and reintroduced camera & film.
  7. The View Camera - remember seeing a photographer from long ago with a large tripod, black cloth his/her head, and a strange looking camera, awaiting to shoot a static subject of some kind? Well, that's what the modern day view camera looks like. They have two major parts; one plate up front holds the lens and the rear plate holds the film. Connecting the two is a long black bellows. These are large format cameras as opposed to 2 1/4 cameras, using sheet film in typical sizes such as 4x5, 5x7, and 8x10. These are not hand held cameras but require a very sturdy tripod to capture any particular image. They are the heaviest, largest, and most bulky of all cameras. However, if you want a negative that can produce a billboard size print, the view camera might do it for you. 
  8. Video camera - captures motion by actually capturing "still" frames in very rapid succession. The expansion of digital photography and its technology has made video cameras very popular and easily accessible. Many are built into cell phones.
  9. Cell Phone camera - as I like to refer to it, it's a hand held camera with a phone attached. My guess is more images are caught with a cell phone that all of the above listed cameras combined. Not yet fully accepted by us professionals, to my knowledge, but the cell phone will only expand in capabilities and convenience of use as time goes on.
Part 2 - we'll explore the makings of a camera, all have something in common