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: Can Pentax make A Decent Lens? Ricoh have not fixed QC issues...
In reply to justin23, 7 months ago

justin23 wrote:

I'm sure there are some valid faulty lenses, but given many have 20+ Pentax lenses without fault, yet the OP who would be in the minority has mostly faulty lenses, something doesn't quite add up.

I currently have 3 Pentax lenses and 2 Pentax cameras.

The lenses are the 18-55 kit lens, which is sharp in the centre and softer on the sides - not a problem.

I also have the FA28-70 f4.0 which is softer on the sides than the 18-55 but it renders in such an amazing way that I bought a K200D to go with it!  I haven't had a chance to really use it yet.

I shoot low light as a rostered job almost every week, usually twice on the one day.  I bought the DA50 f1.8 to do that job.  Both the Nikon D200 and the Pentx K200D use last generation CCD sensors which can run at their max ISO1600, which is enough for me to use.

I sold everything else Pentax I had 4 or 5 years ago and swore never to touch them again.

But that 28-70 keps on calling to me. 

I tested other brands and fixed lens cameras I had at the time after I discovered the problem with my Pentax lenses.

No one could really help me, if I recall, when I first raised the issue, which was why I chased down ways to show it up.

I used a test target like this back then:

but a week ago I realised that a sound mixer was far superior and needed no setup.

View at max size and scroll from one side to the other while noting where focus starts and stops.  You'll see that the focus is skewed and uneven (deeper on one side than the other).

Both the K200D and the K-x I replaced it with would show focus errors (soft on one side) but oddly enough, the K7 which CRK loaned me at the time seemed to focus in the middle so that one side was generally not noticeably sharper than the other.

Even Panasonic lenses for the G1 weren't perfect, but only had a small amount of skew which never resulted in soft side(s) on a wide test target.

As mentioned elsewhere some of my Nikon lenses are soft on both sides, but evenly so.  That is not the same problem.

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

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