Am I asking too much?

Started Apr 4, 2013 | Discussions thread
emem
emem Veteran Member • Posts: 4,216
More complex than one might think .....

... this whole question of focus accuracy and fine adjustment.

It is something I have struggled with for years. I was unhappy with the K10D and tried the debug fix but eventually shelled out for the K20D, just to get the lens fine adjustment capability. That camera was, and still is, a fine tool to shoot with. My favourite body to be honest. I actually prefer its' feel to my K-5 and still use it with my longer zooms. Before getting the K-5 I shot 90% of my photographs with the Sigma 17-70 and was quite happy with the results.

I have had the K-5 for over a year now. I used the Sigma lens to begin with but replaced that with the same model Sigma after an unfortunate accident. The replacement lens isn't as good (sample variation?) and I'm now using the Pentax DA18-135 with the K-5 and getting quite good results.

A few observations. I usually "fiddle" with a new lens/camera combo fine adjustment for some time before I'm happy with the output. I only use zoom lenses and tend to adjust them to focus sharply at around 20 to 25 feet and at the most used focal length - generally F5.6 to F8. Most shots focused on a point much further than that are getting into landscape distances (in my case) and depth of field probably takes care of minor inaccuracies. I have a strong feeling (not very scientific, I know) that cameras seem to improve over time with a particular lens. (Without further adjustment). I've noticed this now with several lenses on both cameras. I also believe that the focusing ability or accuracy of a camera definately changes over time. It is further complicated, I believe, by varying light levels and intensities affecting focus. Perhaps the temperature of the gear also affects the focus ability. Here in Australia it can get down to just below zero in the mornings in Winter or the inside of a car can get up to 40 to 50C. There has to be some expansion/contraction in that range of temperature, surely?

And finally, I have noticed that some people here on the forum are less demanding when it comes to sharpness than others.

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Mike M. (emem)
www.veritasmea.com

 emem's gear list:emem's gear list
Pentax *ist DS Pentax K10D Pentax K20D Nikon D300S Pentax K-5 IIs +12 more
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