Modulation Transfer Function or "MTF" is a measurement of the optical performance potential of a lens.

On EOS cameras with a built-in flash , some partial restrictions may apply to the shift and rotation functions

Sample Image

About the Shift Knob Cap

• Shifting will be easier if the supplied shift knob cap is mounted. However , for EOS cameras with built-in flash, the cap will come in contact with the camera during the lens mounting/detaching or during shift/rotation operation. The shift knob cap is recommended for use with EOS-1, EOS-1D,EOS1Ds  and EOS 5D series.

• Remove the shift knob screw
• Mount the cap by squeezing it into the shift knob and then fix it using the supplied screw. To remove the cap, remove the screw and pull out the cap

• Removing - To remove the cap, hold down the button on the side and turn the cap in the direction of the arrow until the position mark on the cap aligns with the red dot.
• Attaching - To attach the cap, align the cap's attachment position mark with the red dot on the front of the lens, then turn the cap as shown by the arrow until the lens' red dot is aligned with the cap's stop position mark

Tilt Function

• Tilting inclines the lens relative to the  image plane. When the tilt scale is set to the "0" position, the focusing and imaging planes are parallel. However,tilting puts the focusing plane at an angle to the imaging plane

• To shoot so that all of an extensive subject is in focus, you must normally use a small aperture to obtain a large depth of field. But tilting allows you to keep all of the subject in focus even when there is insufficient depth of field
• By Tilting in the opposite direction , you can focus on a specific part of the subject

Using Tilt 

• To keep the tilt scale locked in the "0" position ,slide the tilt lock button in the direction of "LOCK", then turn the tilt lock knob in the direction of the arrow

1. Slide the tilt-lock button in the direction of arrow A . Loosen the tilt lock knob by turning it in the direction of arrow B
2. Turn the tilt knob to adjust the amount of tilt. Focus the shot by turning the focusing ring
3. Turn the tilt lock knob in the direction of the arrow to lock the amount of tilt for the shot

Shift Function

• Shifting moves the optical axis of the lens in parallel off the center of the imaging plane. Shift can be used to good effect in the situations below.

• If you photograph a subject such as building with a normal lens, the top of the building tapers way. But by placing the camera parallel to the building and shifting the lens, you can correct this tapering effect.
• When you are shooting a reflective subject, you can move the camera to a position where the camera does not appear in the shot and then use shift to take the picture. This lets you keep the camera out of the shot without having to change the shot composition.

Using Shift

1. Loosen the shift lock knob by turning it in the direction of the arrow
2. Turn the shift knob to adjust the amount of shift. Focus the shot by turning the focusing ring
3. Turn the shift lock knob in the direction of the arrow to lock the amount of shift for the shot

Specifications:

• Focal Length & Maximum Aperture..................17mm 1:4
• Minimum Aperture ........................f/22
• Lens Construction......................18 elements in 12 groups
• Diagonal Angle of View .............104° (without tilt or shift)
• Image circle diameter.......................67.2mm
• Focus Adjustment...........................Manual focus, rear focusing system with focusing cam (with floating system)
• Closest Focusing Distance...............0.82 ft./0.25m (maximum close-up magnification: 0.14x)
• Aperture Control..............................EMD with 8 blade iris diaphragm, circular aperture
• Max. Diameter x Length, Weight ..............3.5 x 4.2 in./88.9 x 106.7mm (maximum lens length), 28.9 oz./820g
• Lens Cap, Lens Hood and Pouch.....................Lens cap and pouch provided. (No lens hood available.)