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

Started 2 months ago | Discussions thread
jf_tea
Contributing MemberPosts: 805
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Re: Please use better experiment protocol
In reply to Trevor G, 2 months ago

Trevor G wrote:

jf_tea wrote:

shallow DOF at f/1.8

subject distance at left vs. right is significantly different.

Not a very good guess, jf. I'm sorry I didn't post the full image as well so that you could see the layout.

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

Please use better experiment protocol.

Hmmm...now that you can see what I did, do you still feel the same way?

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

Thanks for posting the whole picture!

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

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).

Unless you made a "control test" with a lens which you know is perfect (or near perfect), you cannot be sure what is the cause of massive visual aberrations at that distance, with a lot of heat absorbing and reflecting bodies between the camera and the whole width of the subject.

Actually, it would be good to read some serious professional documentation about how to test a lens at this point. Relying on the opinions of dozens of people in a forum for such a simple precise task has proven improductive. IMHO.

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.

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