Forum: Pentax SLR Lens Discussion
11-03-2015, 06:20 PM
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I think that's a helpful chart to see quickly at at glance optimal center and edges. I suspect that there may be some variation depending on the camera and the integrity (based on quality control) of the lens used, but this chart matches exactly my findings I did by subjective testing with my camera and lenses I have. Popular Photography uses a chart like the one below. It is fairly easy to visualize the strength of a lens, but it doesn't reflect center/border quality like yours does. (BTW, the chart was for a Tokina AT-X 24-70 f2.8. I couldn't find a Pentax lens to show.) |
Forum: Pentax SLR Lens Discussion
11-03-2015, 09:00 AM
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I'm guessing many of you have done a similar thing, but here are my lenses with a summary of notes I've made to myself. I print this out on a halfsheet of card stock. I also include EV info where applicable. References to "Kenko" are to my Kenko 1.4x teleconverter. LENS SUMMARY Rokinon 8mm Fisheye
Use 5.6-8; set approx. near focal length Sigma 10-20 f4.5-5.6
~f8-11 @10; ~6.3-11 @15mm; 5.6-9 @20mm Pentax DAL 18-55 f3.5-5.6
Use f8-11 for best Pentax DA 18-135
Use f5.6>8 at wide end; f8-11 at long end
Either Focal 2x (? metering) or Kenko 1.5x provides tele advantage Pentax DA 21 f3.2 limited
f3.2 ok but improves to 5.6-8 for best Tamron 24-135 f3.5-5.6
Use at least f5.6; better f8-11 Aetna Rokunar MC Auto 28mm f2.8 M42
Soft but ok at 2.8 < 4 < 5.6-8 > 11 > 16 Sigma Mini-Wide II 1:2.8 f=28mm Macro
Soft but ok at 2.8 < 4 < 5.6-8 ~> 11 ~> 16
EV: Dim light: -1/3; Bright: +1/3?? Vivitar 28mm f2.8
Avoid f2.8; best at f8; EV -2/3 Sigma UC 28-70mm f3.5-4.5
Meters well; fine @3.5 but better 5.6-8 Pentax DA 35 f2.4
Great at f2.4 but improvement at f3.2-8; best at f4-5.6; still good at f8 Pentax F35-70 f3.5-4.5
Fine open but use f5.6-8 Auto Chinon 45mm f2.8 Pancake
Useable @2.8 and 13; best at 5.6-9.5;
use -1 or -2/3 EV SMC Pentax 50 f4 Macro
Can use f4 and shoot A but slightly better at 5.6-11; use -2/3 or -1 EVF Pentax M50 f1.7
Use f2/2.8 at minimum; best at f8 Pentax A50 f1.7
Use f2/2.8 at minimum; best at f8; may need +1/3 or +2/3 EV Pentax DA50 f1.8
Use f2.8 at minimum < 4 < 5.6-8 > 11 Super-Takumar 55mm F1.8
at least f2.8; best f5.6-8, f16ok Pentax DAL 55-300
Best at f8/11 & even f16 @ long end for far
With Kenko 1.5x, use f11 Pentax M 75-150
Best f5.6-9.5 but f4 ok and f11-13 acceptable
EV -2/3 Tokina SZ-X 80-200 f4.5-5.6 – shoot w/ A
@wide: f8 moving to f5.6 (6.3 more contrast; less CA) @200; focus up;
Focal (or Kenko) @200 @5.6 Tamron 90 f2.8
Sharp @ 2.8 < 4 < 5.6-11 > 16 > 22 > 32 S-M-C Takumar 1:3.5/135mm M42
3.5<4<5.6>8>11 but really very good at all f Takumar 135 f2.5 Bayonet
Use f2.8 minimum; acceptable @f8; best @f11-13 Super Takumar 150mm F4 M42
Very good at f4 but does sharpen to f8 > f11 TeleTakumar 200 f5.6 M42 – shoot w/ A
Use f8 at least; best @ f11
Focal 2x TC works best @ f8 or f11 SMC Pentax-M 200mm F4
f5.6 at least; best results at f8 +/- FiveStar 500mm
Best at f11 (or 16); Kenko @f11; Viv2x @f8
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