Tilt-shift lenses provide a very unique function for photography, allowing the photographer to adjust the direction of the lens relative to the image plane. This practice provides very interesting results, allowing the photographer to correct image perspective as well as have much greater control over depth of field. Nikon calls this type of lens a ''Perspective control'' lens. It's a little bit beyond the scope of this review to explain how tilt-shift lenses work.
Until 2008, Nikon lagged behind other manufacturers in its output of Tilt-shift lenses. Now that has changed, with their introduction of 24mm, 45mm and 85mm PC-E lenses. All Nikon PC-E lenses cover the 35mm film or FX frame; on a DX-sensor body the 24mm ƒ/3.5 PC-E will give an equivalent coverage of 36mm.
The 24mm ƒ/3.5 PC-E comes standard with a bayonet-mounted bowl-shaped lens hood, a lens pouch, and a price tag just shy of $2,000.
Update (February 2, 2009): We've removed the DX(D200) data.
Sharpness
The 24mm ƒ/3.5 PC-E is a very sharp lens, but for $2,000, you'd expect it to be. However, before we examine the sharpness of the lens we need to devote a paragraph or two to our testing methodology with this lens.
In short, it wasn't an easy lens to test. Our testing software, DxO Analyzer, works by analyzing JPEG images of a test chart shot with a given lens. For most of the time, we feed fairly easy images into Analyzer; sometimes however, we create images of those charts on which Analyzer will choke. The 24mm ƒ/3.5 PC-E was no exception.
Our original intention was to shoot the lens in its various shifted and tilted positions and see if there was a substantial degradation in quality. Our plans were foiled in various ways - mainly, it was just that Analyzer refused to analyze some of the images we attempted to feed it. In the end, try as we might, we could not get data for a tilted image. We did, however, get data by shifting the lens to the left and right ends of the spectrum.
With the lens in its default position, it's pretty obvious to see that it's very, very sharp. The results of the lens on the full-frame D3 shows a performance reminiscent of regular prime lenses; sharp, to be sure, when used wide open at ƒ/3.5, but with increasing sharpness as you stop down and hitting an optimal setting of ƒ/5.6. Diffraction limiting seems to set in after this point, losing accuity as the lens is stopped down, but still under 2 blur units by ƒ/22. At ƒ/32, it's just over 3.
But using this lens without shifting or tilting would be like buying a Ferrari to use as a commuter car. There is some definite corner softness in the shifted corner. On the full-frame D3, the lens seems to be capable of producing extremely sharp images on this platform. When used wide open at ƒ/3.5, ''central sharpness'' - or what would be central if the lens wasn't shifted - is still very good, at 1 blur unit, with the corners on the shifted side rising up to about four blur units. Sharpness improves dramatically at ƒ/5.6, and is almost tack-sharp at ƒ/8. Diffraction limiting again sets in at ƒ/11, with a small drop in sharpness, but even at ƒ/22 the lens doesn't exceed 2 blur units. At ƒ/32, we see between 3 and 4 blur units.