6.A44 Computational Photography

Frédo Durand
Electrical Engineeering and Computer Science

Due Monday 10/17

Get the formula for slide 12

Take a high-dynamic range picture.

For this assignment, you can use your own camera if it has manual controls.

Get HDRShop

Use v1 (free)

Calibrate the camera response curve (you can share the curve)

You need many pictures for this (e.g. 10 every 1/3 stop)
Use manual mode (M)
Set small aperture
Vary shutter speed in 1/3 stops, that is, one step at a time (e.g. from 1/10 to 1/13 to 1/16 to 20, etc.) Take maybe 10 images from underexposed to overexposed. Avoid moving the camera when you change the shutter speed. Of course, use the tripod
Save images on computer and go to HDRShop
Go to menu Create>Calibrate camera curve
Select image sequence (you might need to select them in small groups)
Indicate increment between images (click on 1/3 F-stop)
Click Go
When the curve looks nice, press stop and save curve.

Use the bracketing mode on the camera to take a sequence of 3 pictures

Find a scene with high contrast. A good example is a scene with both indoor and outdoor parts. Check that the scene is too contrasted by taking a picture and checking on the back LCD that part of it is under- or over-exposed.

Press BKT (top left) and rotate the back dial to set it on.
Put the top-left dial on "C" (continuous) so that when you keep the shutter pressed, it takes the series of 3 pictures. Use the remote shutter release to avoid camera shake.

Assemble a high-dynamic-range image using HDRShop

Create>Assemble HDR from image sequence
Load images, indicate increment (e.g. 3 stops)
Change camera response curve (custom curve, Browse to select your new curve)
Press generate Images
Play with the view menu, in particular with exposure
Save as .hdr

Due Monday 10/3

Take one picture and explain your choices of aperture and shutter speed.

Due Monday 9/19

Four pictures
- Shallow depth of field to isolate the subject
- Long depth of field to relate elements at different depths
- Fast shutter speed to freeze motion
- Slow shutter speed for motion blur

Brendan <bmfay@MIT.EDU> is in charge of managing the camera sharing schedule.

Nikon D1 101:

Press the mode button and rotate the front dial at the same time to switch between exposure modes. You are interested in A (aperture priority) and S (Shutter speed priority) where you set one parameter and the camera will do the rest.

You set the aperture with the front dial and the speed with the rear dial.

The camera is autofocus, but you can turn it off (e.g. by setting the lens AF switch to off).

I have provided a USB card reader, downloading images should be foolproof. The battery is probably not well charged.

The tripod might come handy for the long exposures. In partciular, when you want long depth of field, you stop down the lens (big f stop number, small aperture) which means that you need longer exposure time.

You can change the camera sensitivity by opening the little door on the lower left of the camera back, pressing the ISO button and rotating the (back I believe) dial. 200 iso is good for slow shutter speed, 800 or 1600 iso is good for dark scenes and small aperture.

If you get an FEE error, it means that you must set the aperture ring on the lens to the highest number and lock it with the little orange knob.