Photography Workshop II

Show us your graphic talents, photos or multimedia creations. Expect critiques and suggestions.
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Crow
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Photography Workshop II

Postby Crow » 15 Nov 2006, 17:42

It's been awhile since we had Photography Workshop I, featuring the work of Drakonaria.

Eoin Dubh has graciously submitted to me a project for Photography Workshop II, which I shall reproduce for you here. Many thanks, Eoin!
Why worry about ISO settings with a digital camera?

ISO setting:
  • “A measure of how sensitive a camera's film--or CCD, for digital cameras--is to light. Film for 35mm cameras comes in a wide range of speeds, from ISO 25 up to ISO 1600. The speed or light-sensitivity of a digital camera's CCD is rated in ISO numbers as well. The lower the number, the slower the response to light. Higher ISO numbers indicate a higher sensitivity to light, so less time is needed to expose a picture. Most digital cameras let you control the ISO setting to allow the use of higher shutter speeds and/or smaller apertures, according to circumstances.”
    CNET Glossary http://reviews.cnet.com/4520-6029_7-616 ... ml?tag=txt
The ISO setting controls your camera's sensitivity to light. Most cameras have a variety of choices for this, including:
  • Auto
    100
    200
    400
    800
    1600
Your camera's settings may vary from this listing. It may have more or fewer; it all depends on what the manufacturer thinks their sensor can handle.

What is an ISO setting?
Basically, the larger the ISO number, the more light is captured in a given time. At a given setting, increasing the ISO setting from 100 to 200 will roughly cut the required exposure time in half. Each halving of the shutter speed is called 1 stop, each change in ISO from 100 to 200 to ISO 400, etc., is called a I-stop increase.

Digital noise.
High ISO settings, especially in consumer digital cameras, generate a lot of digital noise. So, what is digital noise you ask?
"One of the major difference between a consumer digital camera and a digital Single Lens Reflex (dSLR) is that the former produces images with a lot of noise when using high ISOs and long exposure times, and the latter is practically noise-free. Noise is apparent by the presence of color speckles where there should be none. For example, instead of a blue sky, you notice faint pink, purple and other color speckles amongst the otherwise blue sky. " from the Photoexls website http://www.photoxels.com/tutorial_noise.html which has a tutorial on how to minimize it.
Always shoot the lowest ISO possible. This is the basic rule to minimize digital noise is to always shoot at the lowest ISO setting possible.
For the most part, I recommend keeping your camera on Auto ISO for general picture taking. Most cameras adjust the ISO for the best combination of low noise and hand-holdable shutter speed (so you don't need a tripod). However, there are exceptions:
1. If you're shooting with flash and your subject is to far away to get good flash coverage.
Try overriding the camera's "Auto" ISO setting. Manually adjust it to one of the higher settings and you'll get a little more mileage out of your flash (most cameras shoot low ISO when flash and Auto ISO are engaged).
2. If you are using a tripod.  

If you're taking a photo using existing light using a tripod, you should manually adjust your ISO to the lowest settings. Most of the time, an Auto ISO selection will try to compensate for low light by cranking up the ISO. It wants to insure you have enough shutter speed to handhold the camera (there is no tripod sensor). Since you don't need any help keeping the camera steady, why put up with excess noise? Lower the ISO manually.
3. If you are taking action shots.
If you're shooting fast moving action, you may need to increase your ISO. The "Auto" ISO setting will try to give you a good shutter speed to hand-hold the camera with, but it's not necessarily trying to give you the camera's top speed either. So, if you're shooting photos of birds as they fly and play and find you're just not "stopping" them, crank up the ISO a notch and see if it helps. You might also try switching to "Action" or "Sports" mode if your camera has them.

Practicum:
Get out your camera and set the ISO setting to 100. If you have a film camera, do this even if you have a roll of film in the camera (we won't actually be taking a picture). (Do not forget to set the ISO speed back to the correct number when you are done.) Set the shutter aperture to F/8, and with the camera pointed at something that is well illuminated, adjust your shutter speed until a correct exposure is indicated in the viewfinder. Write down the shutter speed. Now set the ISO setting to 200 and repeat the test. Continue testing with each ISO setting that your camera has, writing down the resulting exposure times.

What do the results show us?
When you changed from ISO 100 to ISO 200 the shutter speed changed. You doubled the number of light collectors and since the aperture was the same, it took half the time to collect the proper amount of light for the exposure. And so on as the ISO settings increase.
You can do this exercise just as easily with the shutter speed constant and changing the aperture. If you choose to stay in auto-exposure mode, select the shutter-priority mode, set your shutter speed to 1/125 sec., and the camera will set the correct aperture for you.
If you have a digital camera, repeat the exercise but take a shot at each setting. Do this inside using natural light or outside in a shaded area. How do the pictures change as you increase the ISO setting?

Examples:
The following shots were taken with the camera mounted on a tripod on a trail in the hills above our house. The day was clear and sunny but the trail was in deep shade from the trees. The exposure details follow the photos.

ISO 100
Image
File Name: IMG01860.X3F
File Type: X3F
Image Dimensions: 1134 x 756
File Size: 1.19 MB
Exposure Mode: M - Manual Exposure
Exposure Compensation: -3
ISO Setting: 100
White Balance Setting: Auto
Flash: Off
Shutter Speed: 1/60s
Aperture Value: F4
Metering Mode: Center Area Metering
Focus Setting: M - Manual Focus
Focal Length: 55 mm
Resolution: Low
Drive Mode: Single Frame Shooting

ISO 200
Image
File Name: IMG01861.X3F
File Type: X3F
Image Dimensions: 1134 x 756
File Size: 1.23 MB
Exposure Mode: M - Manual Exposure
Exposure Compensation: -2.75
ISO Setting: 200
White Balance Setting: Auto
Flash: Off
Shutter Speed: 1/60s
Aperture Value: F4
Metering Mode: Center Area Metering
Focus Setting: M - Manual Focus
Focal Length: 55 mm
Resolution: Low
Drive Mode: Single Frame Shooting

ISO 400
Image
File Name: IMG01862.X3F
File Type: X3F
Image Dimensions: 1134 x 756
File Size: 1.13 MB
Exposure Mode: M - Manual Exposure
Exposure Compensation: -1.75
ISO Setting: 400
White Balance Setting: Auto
Flash: Off
Shutter Speed: 1/60s
Aperture Value: F4
Metering Mode: Center Area Metering
Focus Setting: M - Manual Focus
Focal Length: 55 mm
Resolution: Low
Drive Mode: Single Frame Shooting

ISO 800
Image
File Name: IMG01863.X3F
File Type: X3F
Image Dimensions: 1134 x 756
File Size: 1.21 MB
Exposure Mode: M - Manual Exposure
Exposure Compensation: -0.7
ISO Setting: 800
White Balance Setting: Auto
Flash: Off
Shutter Speed: 1/60s
Aperture Value: F4
Metering Mode: Center Area Metering
Focus Setting: M - Manual Focus
Focal Length: 55 mm
Resolution: Low
Drive Mode: Single Frame Shooting

Proper Exposure
Image
File Name: IMG01859.X3F
File Type: X3F
Image Dimensions: 1134 x 756
File Size: 2.04 MB
Exposure Mode: M - Manual Exposure
Exposure Compensation: -0.875
ISO Setting: 100
White Balance Setting: Auto
Flash: Off
Shutter Speed: 1/8s
Aperture Value: F4
Metering Mode: Center Area Metering
Focus Setting: M - Manual Focus
Focal Length: 62 mm
Resolution: Low
Drive Mode: Single Frame Shooting

Now go out and do some shooting! It is especially easy with a digital camera to go out and experiment with different settings. Get to know all the quirks and features of your camera and most of all, have fun.

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Beith
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Postby Beith » 15 Nov 2006, 19:03

This is fantastic! Please give a big thank you to Eoin Dubh. I have a digital but am a technophobe so I don't really know how to use it properly and I am not familiar with all the terminology and technical stuff.  This will be really helpful! Go raibh maith agat Eoin!

Beith

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Amethyst
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Postby Amethyst » 16 Nov 2006, 00:42

Wonderful! Thank you Eoin - you have shed light on a topic that I never could figure out! :hug:

... I'm printing this off for my husband who's a photgraphy nut...

Amethyst :D

oaktree

Re: Photography Workshop II

Postby oaktree » 29 Nov 2010, 13:45

HI all

Sorry if this is in the wrong place, perhaps someone could move it appropriately. My husband and I have started our own wedding photography business in the past 2 years and have decided to offer handfasting photography too. I am wondering if there is anyone out there who would not mind submitting a photograph of their handfasting that we could have permission to use on our website. Here is the link
http://stevesweddingphotography.com/?load=flash

BB

Oaktree


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