Pentax SMC-FA* 300mm f/4.5 ED [IF] - Review / Lab Test Report - Analysis
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The level of distortion (0.07%) is only detectable in a lab environment and not field-relevant.

The chart above has a real-world size of about 120x80cm.


As a full format lens the FA* 300mm f/4.5 enjoys a sweet spot advantage on the K10D and vignetting is basically a non-issue here even at wide-open aperture.

MTF (resolution)

The FA* 300mm f/4.5 produced pretty impressive MTF figures just like you would expect it from a professional grade fix-focal (this applies to the 2nd sample). The resolution is generally very good to excellent from f/4.5 all the way up to f/11.

Please note that the MTF results are not directly comparable across the different systems!

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are low and generally not field relevant at all tested aperture settings.


The Pentax SMC FA* 300mm f/4.5 ED [IF] showed a very solid performance in all tested characteristics. The resolution is generally very good to excellent. Distortions, vignetting as well as CAs are very low and not field relevant. The build quality is excellent and the AF speed is very high. Interestingly Pentax decided to stick to an unusually slow max. aperture of f/4.5 vs the f/4 mainstream. You may debate this decision but as a positive side effect the FA* 300mm f/4.5 is comparatively compact and light-weight.

Optical Quality:    
Mechanical Quality:
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