Just received a DA 70 Limited from a member here, and while I can already tell this will be my main lens for shooting people, I've noticed it is a focal length I often use with my DA 18-135 and DA 55-300. So the question that came to my mind is if the DA 70 has enough of an IQ advantage at f5.6 to justify changing the lens for pictures where no one will be intimidated by the extension of my lens and I don't want shallow depth of field. Here is the scene as shot.
All these pictures were cropped to about one quarter of the original pixels, I've used the built-in correction profiles in Lightroom where I could and I adjusted exposure by up to 3/4 of a stop to try to make everything equal. As much as I enjoyed Norm's double blind taste tests, I haven't hid EXIF information, so I might as well tell you which lens took which picture. They are in order of time when the picture was taken (just follow the ladybug).
DA 18-135. This is with exposure increased by 3/4 of a stop.
HD DA 55-300 WR. Increased exposure by half a stop. All six photos were exported with the same settings (1024 pixels on the longest side, low sharpening for screen), so any difference in image dimensions is because of my erratic cropping.
Takumar A 28-80 f3.5-4.5 zoom I used as my walk-around lens with my film cameras. Exposure reduced by 1/3 stop, tried focusing with highlighted edges in Live View as well as focus confirmation in the viewfinder, didn't seem to work any better either way, but at f5.6, I shouldn't have to nail focus.
Another MF lens, Pentax SMC A 70-210 f4. No adjustments to exposure, focused with the red square in the viewfinder.
SMC DA 70 Limited. Exposure reduced by half a stop. I am colour blind in one blue-green hue (it looks grey to me), but based on the weathered plastic flower pot and the tea candle holders, this picture has the truest colours. I didn't adjust colour temperature ("as shot" in Lightroom and AWB on my camera) and the adjustments to tint made by Lightroom are very subtle (setting automatically changed within the range of 12 to 16 based on recorded colour temperature).
Tamron SP AF90 Di Macro. It's not a 70mm lens, but I wanted something equally sharp to compare my DA 70 to and I've noticed differences in colour rendering with it as well. Exposure was decreased by 1/3 of a stop.