2 Important K10 Issues that need to be settled for good!! (Please read!)

Started Jan 5, 2007 | Discussions thread
Brett St Pierre
Brett St Pierre Veteran Member • Posts: 7,033
Jeff

JeffJS wrote:

you get a little more exposure with that FA 50 1.4.. Being one of
the first lenses I purchased after deciding to go Pentax Dslr (see
sig for which one), I was very anxious to try it out. I've noticed
several situations, particularly dark room lighting, where this
lens Hunts A LOT for a focal point. Sometimes gets it right,
sometimes not. I doubt it's the camera

here is a comment that gets debated occassionally and I am not convinced but it has some merit...

.. AF rwquires a degree of subject contrast for the AF system to get enough data to process a lock, you see this when you try to focus on a flat object like a plain wall, it just won't do it. The FA50/1.4 images at f/1.4 produce very low contrast, it doesn't start to get normal lens contrast until stopped down f/2 or more (but not as bad as say the 50/1.2) - it's just the nature of a very fast aperture lens. What is the very low contrast of the lens (because at AF time it is wide open) disadvantages the cameras AF system to get sufficient contrast in certain conditions?

Just an idea... would the out-of-production FA50/1.7 be better in that regard? (don't know, I sold mine to get the f/1.4 version and I had had no trouble with either but then i don't put them under any AF stress, i MF in tricky conditions)

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Brett
http://www.pbase.com/shreder

The Journey is the Thing

 Brett St Pierre's gear list:Brett St Pierre's gear list
Pentax K-1 Pentax smc DA* 55mm F1.4 SDM Pentax smc DA 15mm F4 ED AL Limited Pentax smc DA* 50-135mm F2.8 ED (IF) SDM Pentax smc DA 21mm F3.2 AL Limited +7 more
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