Lens MTF Conclusions

The Holding Tank

Hardware

MTF Study

| Lens MTF Area Summary and Figure of Merit |

| MTF Data Overview | Photodo / Canon MTF Cross Validation |

| Contax, Nikkor and Leica R lenses vs Canon |

| List of Canon Data Comparisons | List of Photodo Data Comparisons |

| Database Download |

Macro Compare

| Figure of Merit | MTF Area Average | Conclusions |

Conclusion

Note that the USA web plot for the 100mm Macro is not the same as in the Eyes of EOS book which shows a better plot. The web plot is quite poor and is more what would be expected from a commercial zoom.

In this section I take a look at the relative MTF performance based on Canon’s data for the 100mm f2.8 Macro, 180mm f3.5L macro (also with the EF 1.4X and EF 2X teleconverters) and the MP-E 65mm Macro Photo.

My assumptions are that the MTF data applies at infinity focus and not close-up but that the data provides some relative indications of sharpness.

As teleconverters are involved it should be noted that the Canon data for stopped down may have different set apertures, also it seems that for the MP-E 65mm the quoted f2.8 aperture is at infinity although the lens can not focus any further away than 1X.

The following table summarizes the aperture information at 1X magnification (as this is common to all configurations) in exposure terms :

Lens	Max Ap Set	Max Ap Eff 1X	SD Set	SD Chart inf	SD Eff 1X
EF 100mm f2.8 Macro USM	f2.8	f5.6	f8	f8	f16
EF 180mm f3.5L Macro USM	f3.5	f7	f8	f8	f16
EF 180mm f3.5L Macro USM +1.4X	f3.5	f10	f5.7	f8	f16
EF 180mm f3.5L Macro USM +2X (SD is f16)	f3.5	f14	f8	f16	f32
MP-E 65mm f2.8 Macro Photo	f2.8	f5.6	f8	f8	f16

We can see from the above that the stopped down data is comparable in terms of exposure for all cases except the EF 180mm f3.5L Macro USM + EF 2X where the maximum aperture performance should be compared in terms of equal exposure.

We can see that both the EF 180mm f3.5 Macro and the MP-E 65mm f.28 Macro Photo are very sharp lenses even compared to the relatively sharp 100mm f2.8 Macro.

The addition of the teleconvertors to the 180mm f3.5L naturally degrades the lens performance.

For the EF 1.4X performance remains excellent over all of the APS-C frame and almost all of the 35mm frame.

For the EF 2X performance is good over all of the APS-C frame and satisfactory of most of the 35mm frame although there is some fine detail loss away from the frame centre.

Based on these data using the Canon matched teleconverters with the EF 180mm f3.5L would seem to provide very acceptable results.

However, comparison of the Photodo measurements with the Canon data suggests the detail performance to not be as good as expected. The same thing is seen comparing the photozone data for the 180mm and the 100mm. It must be noted however that these measurements may not reflect the actual performance at macro distances.

The EF-S 60mm lens has been added, in general the stopped down fine detail is similar to the 100mm in the centre but worse at the edges as might be expected of an APS-C lens compared to a full frame lens.

MTF Study

| Lens MTF Area Summary and Figure of Merit |

| MTF Data Overview | Photodo / Canon MTF Cross Validation |

| Contax, Nikkor and Leica R lenses vs Canon |

| List of Canon Data Comparisons | List of Photodo Data Comparisons |

| Database Download |

| Figure of Merit | MTF Area Average | Conclusions |

Last Updated 05/06/2008

All material is supplied as is and without warranty, use at your own risk.

All opinions stated are the authors own.

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