Leaving the Shutter Open...

I breifly mentioned the two available choices for controlling the light that falls on a sensor in an earlier blogpost here. Lets dig in to the shutter speed settings and what it can do for your photos?

Leaving the shutter open for longer period means more light gets a chance to illuminate the sensor of your camera. As many cameras allow you to open the shutter for as long as 30 sec or even more, this could be a solution to any low light photography scenario except that it has certain limitations. We'll come to that in a second but let me introduce you to the terminology of slow and fast shutter speed. Fast shutter speed means that shutter opens and closes very quickly hence the exposure time is very small (generally 1/100 of a second or less). Slow shutter speed means that shutter is moving slow and there is more time between shutter opening and closing (generally 1/30th of a second or more). The terms exposure time, shutter speed and shutter opening are different terms defning the same thing - a period of time.

Now, as this period of time gets longer (shutter is slow), certain issues creep in to the photo - related to motion artifacts. These are basically of the following two type:

1. Any motion/shake of the camera will cause the image of the object to move on the sensor (sensor is in the camera so moving camera means sensor is moving relative to the subject). This produces blur in the image which is in general not desirable. Mounting the camera on a tripod or resting it on a table/other objects usually is a solution for this problem.

2. Any motion of the subject will again cause the image on the sensor to move resulting in blurry image. This is where the photographer has little control. Images of people can not remain sharp at shutter speeds of less than 1/20th of a second. Motion artifacts will be unavoidable. Shooting stationary objects, however, is not problamatic. Have a camera mounted on a tripod, and you can take a 30 second shot of a building. It will remain sharp and nice!

Now, in some cases, the blur is desired and shutter speeds are lowered intentionally to get the blur. This slow speed in conjunction with camera or subject movement can create wonderful results. Examples are, a water spring where flowing water becomes cloudy, a moving vehicle headlights and breaklights show streaks of lighting, stars in the night sky become arcs and many more. Or in case of moving the camera with subject to keep the subject sharp while blurring the background (generally referred to as panning). We have seen all these elements as part of some great photographs. So, when used correctly, the blur of a slow shutter can be used to our advantage. For most of the portrait work, however, motion artifacts take away the sharpness of the images and are generally undesirable.

A shoot video

Here is a video clip from last weekend's shoot that shows me in action at a shoot. The clip was graciously done by a friend of my client. What a nice gesture! Really appreciate it.
I'll post the pics from this shoot in a day or so.

Color-Managed Workflow

Why we photographers want to be in the print selling business? I am sure you must have asked that question. Just give me the images, and let me print these. I won't deny that some of us might have monetory reasons to keep images and sell prints but in most cases, the urge to sell prints is pushed by negative feedback from clients. Clients that got their prints and just did not like the images. Photographer thinks the images were great, but client doesn't agree when seeing the prints. Many clients in this situation blame the photographer.

The issue however, is Color Management and it begins as soon as images leave the camera and get to a computer display screen. Even when viewing on a monitor, the images could appear different. Every display device (monitor or printer) has its own color profile (more on these here) that means unless otherwise ensured same images on two different devices will never appear the same. In many cases the differences, however, are subtle and do not get noticed. But every once in a while, it creates customer dissatisfaction. Specially with prints as customers pay for those and they don't turn out to be good. The photographer has no control on managing color for such printing as he or she can not tell what printer will be used? We (photographers) take pains in keeping our monitors calibrated so the red for me is not orange for a printer. We acquire printer profiles and create images with that profile embedded so the printer interprets the color information correctly. This is the only way of ensuring consistency between the photographer and client's view. Otherwise, a client just may not see the picture that the photographer sees.

Therefore, next time when I or another photographer recommends buying prints from us, lets not think we want to make more money (I don't make any money on prints and will get you 2 prints of 8x10 for $4). This ensures color is managed correctly and Happy Clients :)

Controls for Light

Technically it is about a method of controlling and using the Light. Easy to cover the techniques so I'll get them past you first. Two fundamental categories here.
First is to modify/control the light you have. A vast topic where people's creativity comes out and we keep seeing new ways to accomplish this every day. Few of the more popular ones are listed to give you an idea.

• Moving under a shade to reduce the light
• Using reflectors or diffusers to change the nature of light
• Using strobes or flash to add light. Adding flash gels or gobos to change the light from the flash

Second category is to set your camera to control the amount of light it receives from a scene. Being an engineer, the second category is easier to explain. Also, it is easier because no matter what camera you have, there have always been only three ways to do it. These are given below in the order in which they act on the light entering a camera body.:

1. Aperture Size: Entry point for light in the body is the camera lens and aperture is a circular opening in the lens. The diameter of the opening can be varied to allow less or more light in the body.
2. Shutter speed: Shutter is the gate that sits in front of your digital sensor or the camera film. It is a gate between the light coming from the lens and the sensor of the camera. It opens and closes to allow the light to fall on the sensor that converts the light in to pixels and store it as an image. Shutter speeds on most cameras have a range of around 50 msec to 30 seconds. This for most cameras is the control element that provides the most flexible control for light.
3. ISO setting: A property and setting for the sensor that sets the sensitivity to light. A smaller number means less sensitive to light. Hence, the same amount of light at ISO 100 will produce darker image than at ISO 400 (4 times darker). However, ISO changes don't come for free as aperture and shutter speed settings mostly do. Increasing ISO always increase the noise in the image. However, with today's technology sensors handle noise very well and one can get usable images from cameras even at ISO 800. Still, bumping up the ISO should only be considered after exhausting options with aperture size and shutter speed.

It is the second category that photographers have the most control over and although it appears that there are only 2 variables to play with ( the third one, ISO setting should be kept at the lowest possible setting), it is still a very complex equation to balance. The same shot can usually be acheived by multiple combinations of aperture and shutter settings. It is the skill of a photographer to know what is the best combination of these two settings that will produce the desired result. More on that in some later post...