35mm Summilux pre-ASPH, calibrate or not?

[Churro]

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Not too long ago I purchased a 35lux pre-asph V2 titanium and sent it off to Don at DAG Camera for calibration and a CLA as the focus ring was a little sticky around infinity. Don seems to have calibrated the lens to be optimal at f1.7. 

If I put my camera on a tripod and use live view to focus on an item that's about 1.2 meters away at f1.7 and then look through the rangefinder, the rangefinder patch is perfectly aligned with the item I'm focused on. If I repeat process at f1.4 the rangefinder patch is ever so slightly off, it's so minimal that it doesn't matter as the lens is already soft at 1.4. With the camera calibrated in this fashion, the results are excellent when focusing with the rangefinder patch from f1.4 - f2. But once I start getting up to F2.8 and above I have to make adjustments to achieve optimal sharpness. From F2.8 and above I first use the rangefinder patch to be perfectly aligned with what I intend to focus on and then I have to pull focus to the left slightly. The amount by which I need to pull is very subtle at F2.8 but it's a decent amount at F5.6 - F8. I've essentially memorized the adjustments by practicing on a tripod, but I'd encourage you to do the same so you understand how your lens behaves so that you can optimize sharpness at the various f-stops. This obviously doesn't matter if you use an EVF or live view, but it's very helpful to know if you use the rangefinder patch. 

I was surprised by this. So I ended up repeating the process on several of my lenses. I found my 35mm Summicron v4 has a similar behaviour. I get much better sharpness out of it at F4 and above now that I understand it. 

I just realized this whole conversation wrapped up 7 years ago... whoops. 

Edited August 13, 2024 by Churro

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