Brief:- Put your camera on a tripod or stable surface. Set to manual mode. Make a photo of anything you like at the optimum exposure according to the light meter reading. Now deliberately under-expose by one f-stop or by reducing shutter speed (e.g. 1/30th sec to 1/60th sec). Take another shot, underexposing by an f-stop. Now take a shot over-exposing from the initial optimum exposure by one f-stop or increasing the shutter speed. Take another shot over-exposing one stop further. Upload these photos to your computer to view them better.

I followed the brief as outlined, but have arranged the photos from under exposed to correctly exposed and then over exposed. For most series I took five images. I will begin with my favourite series.

Exp 5

I do not like photographing in churches, as the light meter on my camera does not work properly when I am shooting in higher ISO settings. I initially tated with an ISO of 800, but with the light setting showig the correct exposure, the image was over exposed. So I dropped down to ISO 640, and underexposed by 2 stops. I was using a tripod, my camera set to spot metering, and white balance to cloudy, and apature at f10. The focal point was the stained glass window. The initial photo was taken at 1/60sec and the final image at 0.5sec.

It is really apparent that there are details in the highlights on the first image, and the colours can be made out in the stained glass window with hardly any light or detail in the shadow. The final image has detail in the shadow and is correctly exposed for the areas nearer to the camera and the ceiling, but the rest of the image is over exposed, the window highlights have some clipping and that creates flare on the stained glass.

I have then opened the images in lightroom and combined them to make an HDR image, with auto tone, removed chromatic abberation and enabled profile corrections. Finally I used the vertical transform to correct the uprights. I have not made an HDR image before so I am really pleased with the result.

HDR From EXP Comp (1 of 1)-2

Learning:- buy a remote trigger so that I do not have blurring from the movement of pressing the button, and shoot in MUP (mirror up).

The second series was taken the same way but without a tripod.

EXP 6

Image 1 – f5 1/10sec- Image 5 – f5 0.4sec – all images ISO 800.

HDR From EXP Comp (1 of 1)

The HDR image is of poor qaulity, I was not using a tripod, so the lights are blurred. I had the ISO to high for this series.

Here are the other series that I made for this exercise.

EXP 3

ISO 400, f9, Image 1 – 1/8sec – Image 5 – 0.5sec

EXP 1

ISO 200, f13, Image 1 – 1/160sec – Image 5 – 1/50sec

Exp 2

ISO 200, f13, Image 1 – 1/500sec – Image 5 – 1/125sec

Exp 4

ISO 100, f9, Image 1 – 1/200sec – Image 3 – 1/25sec

EXP 7

ISO 500, f5, Image 1 – 1/20sec – Image 5 – 1/5sec

The key learning for me has been to ensure that I use a tripod wherever possible. I do not always take one with me and I need to do this more often. I could increase the ISO and use faster shutter speeds so that I reduce handshake, but that does not work when bracketing exposure. For bracketing images, where the focus is to take the same photo with different exposures, a tripod is a must. The point of bracketing exposures is so that you can review the detail in the highlights and shadows in different images, and then develop them from the photo that has the detail in the area that you wish for it to be. Bracketed exposure also leaves the ability to create HDR images, where you can retain detail and smooth exposure through the whole of the image, and again, to do so a tripod is required. Increasing the ISO for a single where exposure compensation is not required, can be useful to use a faster shutter speed and eliminate vibration, but increasing the ISO means that the sensor has increased sensitivity to noise, so grain will be increased.

I am very pleased with the HDR image of the church – but I must use a remote shutter release.

Advertisements

2 thoughts on “Exercise 1.8 – Bracketing Exposure

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s