Can Pentax make A Decent Lens? Ricoh have not fixed QC issues...

Started 7 months ago | Discussions thread
Trevor G
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Re: Please use better experiment protocol
In reply to jf_tea, 7 months ago

jf_tea wrote:

Samples shown earlier cropped from each side of this image...

Thanks for posting the whole picture!

The subject is far enough that hot air turbulence can fuzz out minute details.

But it wasn't happening in this case.  It's Autumn here.

The building is behind an asphalt covered parking lot. Was warm or hot or cool ? Whatever is the answer, it's enough to fuzz out details at that distance. The turbulence would affect each picture taken a bit differently. (Quite interesting if that's one wants to get).

I have taken many hundreds of pictures here and do not ever remember seeing temperature diffraction effects.

In any case, the asphalt is the same on both sides. Thermal diffraction does not make one side sharp and the other fuzzy, especially when another lens on another camera at the same time shows the centre in focus and both sides relatively the same out of focus amount.

Thermal diffraction (I think it is called) normally results in wavy lines, not out of focus effects.

My enthusiasm for long lens is less since I have seen how distance affect pictures taken at different times of the day, in different season.

I don't recall seeing diffraction effects at this distance.  It is not summer here.  That makes a big difference.

Good suggestion but you miss the main prize...sorry. 

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Cheers
Trevor G
Silkypix tutorials at: http://photo.computerwyse.com

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