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10-04-2011, 11:08 AM   #1
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C mount lenses - some answers needed

Seems to me that we are in a whole new ball-game if we can attach C mount lenses to the Q - maybe that's what it is partly about
With some very interesting ones available for not very much money

Check this one
A Pentax branded equivalent for the Q of 280mm, f1.4 - but of course no auto-focus

Pentax C25011KP 1" C Mount 50mm F1.4 Manual Iris C25011KP

Trouble is
Compatibility of the various "sensor-sized C mount lenses" with the Q sensor
Terminology - eg what is an auto-iris and will it work on the Q
Quality - will the Q or the lens be the determinant of final IQ

There are some fairly technical-minded and trained people on this site so any observations would be welcome

I personally think C mount lenses might be a source of massive creative potential

Trevor

10-04-2011, 11:34 AM   #2
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QuoteOriginally posted by climbertrev Quote
Seems to me that we are in a whole new ball-game if we can attach C mount lenses to the Q - maybe that's what it is partly about
With some very interesting ones available for not very much money

Check this one
A Pentax branded equivalent for the Q of 280mm, f1.4 - but of course no auto-focus

Pentax C25011KP 1" C Mount 50mm F1.4 Manual Iris C25011KP

Trouble is
Compatibility of the various "sensor-sized C mount lenses" with the Q sensor
Terminology - eg what is an auto-iris and will it work on the Q
Quality - will the Q or the lens be the determinant of final IQ

There are some fairly technical-minded and trained people on this site so any observations would be welcome

I personally think C mount lenses might be a source of massive creative potential

Trevor
Forget auto-iris lenses. You have to use full manual lenses. Auto-iris is automatic aperture control, but there is no support for this on Q with C-mount lenses.

All lenses made for sensors of 1/2" and larger should work on Q. Lenses made for 1/3" or 1/4" sensor is no good.

Final IQ? Don't know. Most C-mount lenses is made for low resolution video, but there are of course good ones, too. I am waiting for a Pentax 4,2/1,6 and a Pentax 6/1,2 lens. I hope they are good, but I don't know.

Does anyone here have a clue about the Pentax 8-48/1,0 lens?
10-04-2011, 02:35 PM   #3
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QuoteOriginally posted by StigVidar Quote
Final IQ? Don't know. Most C-mount lenses is made for low resolution video, but there are of course good ones, too. I am waiting for a Pentax 4,2/1,6 and a Pentax 6/1,2 lens. I hope they are good, but I don't know.

Does anyone here have a clue about the Pentax 8-48/1,0 lens?
I have that Pentax 6mm F/1.2 lens. It's very odd in that it only focusses properly if you have the lens half screwed in. I've seen this problem mentioned in the B&H review of the lens. Not sure what do with it. Maybe some rubber washers?
10-04-2011, 09:21 PM   #4
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Since Pentax makes CCTV lenses, I think it would be a good idea for them to develop and release a C>Q adapter, then do some compatibility tests with the Q and their C mount lenses with the intention of marketing the adapter with a list of their C mount lenses that exhibit acceptable or better IQ as a supplemental line of Pentax MF lenses in the Q system. This should be a no-brainer -- minimal R&D, minimal additional mfg cost (just the adapter), and it would enhance and expand the Q system with a variety of compact Pentax-made MF lenses at virtually no cost.

Scott

10-05-2011, 08:57 AM   #5
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QuoteOriginally posted by devorama Quote
I have that Pentax 6mm F/1.2 lens. It's very odd in that it only focusses properly if you have the lens half screwed in. I've seen this problem mentioned in the B&H review of the lens. Not sure what do with it. Maybe some rubber washers?
Do you have a link to this review?
10-05-2011, 10:43 AM   #6
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QuoteOriginally posted by StigVidar Quote
Do you have a link to this review?
I was wrong. The comment is about the Pentax 4.8mm lens.
B&H page
10-05-2011, 11:31 AM   #7
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QuoteOriginally posted by devorama Quote
I was wrong. The comment is about the Pentax 4.8mm lens.
B&H page
It could also be your adapter not being thick enough. Is it the Kipon adapter?

I have the lens, but no adapter so I can't test myself. But I will as soon as I receive it, of course :-)

What you can do is buying Loctite and more or less glue the lens to the adapter in the correct position.
10-20-2011, 04:26 PM   #8
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okay - here's another question: the standard 8.5mm Q lens has a leaf shutter - therefore, no shutter in the Q body itself (I'm assuming...)

is this a concern when using C Mount (or D Mount) lenses with the Q?

Do all of the Pentax Q lenses have leaf shutters incorporated?

Trying to get all this straight before I buy, as this seems like a very fun system on which to use old 16 and 8mm movie lenses... thanks.

10-20-2011, 08:13 PM   #9
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QuoteOriginally posted by emergo Quote
okay - here's another question: the standard 8.5mm Q lens has a leaf shutter - therefore, no shutter in the Q body itself (I'm assuming...)

is this a concern when using C Mount (or D Mount) lenses with the Q?

Do all of the Pentax Q lenses have leaf shutters incorporated?

Trying to get all this straight before I buy, as this seems like a very fun system on which to use old 16 and 8mm movie lenses... thanks.
Hi, only the prime lens that comes with the Q and 02 Zoom lens have a built in shutter. In the case of the toy lenses, c, d, or K mount lenses the electronic shutter is used. But know that with the electronic shutter the maximum shutter time is 2 seconds to 1/8000 of a second and no shake reduction.
10-20-2011, 10:38 PM   #10
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QuoteOriginally posted by knightzerox Quote
Hi, only the prime lens that comes with the Q and 02 Zoom lens have a built in shutter. In the case of the toy lenses, c, d, or K mount lenses the electronic shutter is used. But know that with the electronic shutter the maximum shutter time is 2 seconds to 1/8000 of a second and no shake reduction.
i figured it was probably an electronic shutter, but it seems strange to me that there are also leaf shutters in some of the lenses. but hey, why not?

thanks for the info!
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