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03-27-2012, 06:42 AM   #16
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QuoteOriginally posted by Lowell Goudge Quote
you will note in my comment i state MAY not DOES.

I do not know how much impact the stray light inside the mirror box bothers things, it is a theoretical possibility. The same is true about rear element coatings on digital lenses, often touted as a necessity, but in my collection of 45 lenses (where only 6 are digital era designed lenses) i have not had a lot of issues with either.

BTW, of my 45 lenses only 3 are designed for ASP-C, all the rest are full frame lenses, and I do still use them on my film bodies (principally my PZ-1) from time to time

45???????? wow. talk about LBA. i did find your comments helpful... i tend to believe reviews that are based on actual use,,, feel/touch... real world photography and not lab based...

03-27-2012, 08:01 AM   #17
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QuoteOriginally posted by Lowell Goudge Quote
you will note in my comment i state MAY not DOES.
I know, it just sounded perfectly plausible to me. But thanks for the explanation.

I do a lot of focus stacking for macro shots using microscope lenses mounted on my K5. I mount those with a RMS to M42 adapter, followed by a M42 to PK adapter, followed by one or two full sets of extension tubes. (Depending on which lens I use.) You'll amazed what lengths I have to go through to stop light from bouncing around inside that contraption.

That's why I believed you right away.
03-27-2012, 08:14 AM   #18
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QuoteOriginally posted by Clavius Quote
I know, it just sounded perfectly plausible to me. But thanks for the explanation.

I do a lot of focus stacking for macro shots using microscope lenses mounted on my K5. I mount those with a RMS to M42 adapter, followed by a M42 to PK adapter, followed by one or two full sets of extension tubes. (Depending on which lens I use.) You'll amazed what lengths I have to go through to stop light from bouncing around inside that contraption.

That's why I believed you right away.
the only cases I have seen, are things posted here with some older K lenses, usually when doing macro, some with adaptors and also one lens that I bought.

In the case of my lens, (XR Rikenon 135/2.8 M42 mount) it had a big low contrast donut in the miages when shooting outdoors,(oddly it did not show up when using flash). I finally tracked it down to a bright black anodized rear element mounting ring. Once I painted that flat black, those issues went away, although the lens just sits because in the process I picked up a tele lentar 135/2.8 preset that is much much better to begin with.

There was also a forum member that had a 645 to K adaptor that had bright bits internally, and caused the same thing.

Overall, my personal opinion is it is details such as this, and not rear element reflection that cause loss of contrast, hence my comment about additional light.
03-27-2012, 08:38 PM   #19
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QuoteOriginally posted by tristan Quote
45???????? wow. talk about LBA. i did find your comments helpful... i tend to believe reviews that are based on actual use,,, feel/touch... real world photography and not lab based...
You should talk to a few of the more serious addicts on this board. I know there are a few that have collections that read like indexes of all Pentax compatible lenses. I'm talking three digit numbers for lens count where the first digit isn't always a one.

03-27-2012, 09:59 PM   #20
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QuoteOriginally posted by PPPPPP42 Quote
You should talk to a few of the more serious addicts on this board. I know there are a few that have collections that read like indexes of all Pentax compatible lenses. I'm talking three digit numbers for lens count where the first digit isn't always a one.
I have 30 Asahi-Pentax-made lenses. I have twice that many (each) of PK-mount and M42 lenses, and those make up about 1/2 my accumulation. I have 50 Fifties. And I'm a piker compared to some here. At least one, maybe two members, own more Fifties than I have lenses. And I've only been accumulating glass for under 4 years.

One might ask, "If only half the lenses are PK or M42, what are the others?" Well, they're stuff I've adapted or modded for PK or M42, or that I mount in bellows or tubes, or that are auxiliaries like the Raynox. I have very few lenses left that I can't mount on my K20D. Most such unusable glass gets sold off -- that's another 120-odd lenses. They help pay for the keepers, eh?

[ ObTopic: And of what I have left, about 95% will project a FF image. ]

I suspect that others here have also had hundreds of lenses pass through their hands. Keep some, sell some, buy some more, see what works and what sings and what sucks. Keep some luzers until maybe they're worth selling in a year or three.

Lenses are not magic. They're tools. Some are works of high craft. I must keep those!

Last edited by RioRico; 03-27-2012 at 10:38 PM.
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