Here's what I did: Subject is the front of the old (1870) church in Corrales, New Mexico. (The front of the church has fine details for such a test.) Film: Provia 100F. Tripod. All lenses set at f8. Scanned as TIFF files on a Nikon LS-2000 at 2720 dpi. Image cleaning turned off. All images had Nikon contrast correction applied. A couple of images had to be brightened or darkened a little. All assessments are my subjective evaluation of image sharpness, onscreen in Photoshop, at enlargements of 200% or 300%. The monitor is a new, sharp Sony, 17 inch, at 1024 x 768.
The lenses are:
FA* 24 f2.0 FA 28 f2.8 FA 35 F2.0 FA 50 F1.7 FA 20-35 F4.0 FA Power Zoom 28-105 F4.0-5.6 Tokina AT-X AF Pro 28-80 F2.8 Arsat 35 f2.8 tilt/shift (tested in normal position)
For 24 and 28 mm. I evaluated corner sharpness. For other focal lengths, the subject I evaluated is closer to the center of the lens.
The tests below list lenses from most sharp, at the top, descending to least sharp.
24 mm.
FA 20-35 @ 24 mm. FA 24
28 mm.
FA 28 Tokina 28-80 @ 28 mm. FA 20-35 @ 28 mm. FA PZ 28-105 @ 28 mm.
35 mm.
Tokina 28-80 @ 35 mm. Arsat 35 (The first two were very close; evaluated at 300%) FA PZ 28-105 @ 35 mm. FA 20-35 @ 35 mm. FA 35 (These last three were also very close; evaluated at 300%)
50 mm.
FA 50 f1.7 Tokina 28-80 @ 50 mm. (The first two were quite close; evaluated at 300%) FA PZ 28-105 @ 50 mm.
80 mm.
Tokina 28-80 @ 80 mm. FA PZ 28-105 @ 80 mm. (These were close; evaluated at 300%)
On close tests, I enlarged to 300% to ensure that I was not mistaking differences in contrast for differences in sharpness.
It is surprising that the much-vaunted FA* 24 and FA 35 did not perform better. The FA 28 looks good. We are often asked about this lens on the list. I feel we can recommend it. Also very good, as we already knew, is the FA 20-35.
These is a very limited test. I did not consider other apertures, other distances, or such factors as flare control, light fall-off, or contrast.
These are relative rankings only, done at great enlargement. A low rank does not mean that the lens is not good. All of the Pentax lenses here have fine reputations. All will give fine results at moderate enlargement. The weakest performer, the FA PZ 28-105, is considered one of Pentax's best zooms, and a fine lens. (I have two of them.) Despite the limited nature of the test, some conclusions seem warranted:
- The Arsat tilt/shift looks like a promising lens. - The Tokina 28-80 is clearly a winner. - Prime lenses do not necessarily outperform zooms.
I don't have a web site to put the images on. If someone else would like to put them up, please contact me:
jtainter at mindspring dot com
Joe
