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11-03-2015, 08:33 AM   #1
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Q and C Mount Lenses

I suspect this question has been asked many times before but I could not find any note of it.

I have a Q10 with 02 and 06 lenses and a Chinese PK to Q adapter, however I find the K lenses a bit heavy and out of scale with the Q unless you go the whole hog and mount the outfit on a tripod which I dislike carrying which seems to me to defeat the idea of a small lightweight outfit.

I was wondering therefore about C mount Cine lenses but I have no idea of equivalent focal lengths e.g. what do, say, 10mm and 25mm C mount lenses work out on the Q (approximately of course)

I have noticed too that all C mounts do not appear to be the same, there seems to be quite a difference between those made for for Bolex and Arriflex cameras for example and then again there are TV lenses.

I would appreciate any advice.

Thank you.

CD

11-03-2015, 08:53 AM   #2
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QuoteOriginally posted by PenPusher Quote
I have a Q10 with 02 and 06 lenses.

what do, say, 10mm and 25mm C mount lenses work out on the Q
A 10mm C mount lens will be like your 02 set at 10mm.

A 25mm C mount lens will be like your 06 set at 25mm.

If you're only working with one system
(in this case, the "crop sensor Q" 1/2.3" sensor),
you don't need to worry about equivalence.
11-03-2015, 09:12 AM   #3
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Yep, focal length is a lens property. The sensor size can crop the apparent field of view, but on a given camera, all 10mm or 50mm lenses will give the same field of view. The question is just whether they will render sharp edges (if the lens is made for a smaller sensor, then it might not fully cover a larger sensor).

Here is a thread for photos taken with C and D lenses: https://www.pentaxforums.com/forums/136-pentax-q/176991-c-d-mount-lens-club.html

If you decide to buy one, I suggest you search the forums to see if it was successfully used on a Q before, or at least a similar lens. There is some variation, as you said, but I am not quite sure about the specifics Hopefully someone else will fill this in

There are some Cmount lenses at the PF marketplace right now btw: https://www.pentaxforums.com/forums/24-photographic-equipment-sale/302246-sal...imes-more.html
https://www.pentaxforums.com/forums/24-photographic-equipment-sale/303209-sal...jinon-6mm.html
11-03-2015, 09:53 AM   #4
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I have several C-mount lenses for my Q-system. I'm shooting the Cosmicar 16mm f1.6 now in a challenge on the forum. So far, I'm not impressed with it on the Q7 but I've really only begun to work with it. Seems like for mine, the distance focus is soft. I have to try more close up images though.

11-03-2015, 11:04 AM   #5
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Thank you for the information, much appreciated.

CD
11-03-2015, 02:57 PM   #6
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For C mount lenses, look for the following brands:

Kern Paillard Switar/Pizar
Kodak Ektar
Wollensak Raptar
Som Berthiot Paris
Angenieux
Cosmicar
Fujinon (esp machine vision lenses)

They all come in a variety of focal lengths and IMO will give you the best results. IMO, Cosmicar and Fujinon are the only CCTV lenses worth using. The chinese CCTV lenses are pretty much universally crap. The rest are 16mm film lenses and tend to be of much higher quality. They are more expensive, but you can often get deals on them if you can find them attached to old cameras. Some people are also fond of Pentax-110, but I find them to be a pain to use due to the necessity to use separate aperture discs.

In my experience, 16mm lenses are the way to go:
Here are some pics I took with a Kodak Cine Ektar 25mm.
This page shows some shots I took with a 12.6mm Macro Switar, which is a bit soft in the corners but ridiculously sharp in the center.
11-04-2015, 10:57 AM   #7
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QuoteOriginally posted by dcshooter Quote
For C mount lenses, look for the following brands:

Kern Paillard Switar/Pizar
Kodak Ektar
Wollensak Raptar
Som Berthiot Paris
Angenieux
Cosmicar
Fujinon (esp machine vision lenses)

They all come in a variety of focal lengths and IMO will give you the best results. IMO, Cosmicar and Fujinon are the only CCTV lenses worth using. The chinese CCTV lenses are pretty much universally crap. The rest are 16mm film lenses and tend to be of much higher quality. They are more expensive, but you can often get deals on them if you can find them attached to old cameras. Some people are also fond of Pentax-110, but I find them to be a pain to use due to the necessity to use separate aperture discs.

In my experience, 16mm lenses are the way to go:
Here are some pics I took with a Kodak Cine Ektar 25mm.
This page shows some shots I took with a 12.6mm Macro Switar, which is a bit soft in the corners but ridiculously sharp in the center.
Thank you for this information I shall poke around and see what I can find.

On another thread you mentioned that Kern RX lenses required the C mount to be modified because of a non standard flange to film plane distance, do you know if it's more or less than standard

Regards

CD
11-04-2015, 11:53 AM   #8
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The lenses have to be brought closer to the sensor plane. The mod involves machining down the front of a standard C adapter to make it thinner. There are standard C mount Kerns, too.


QuoteOriginally posted by PenPusher Quote
Thank you for this information I shall poke around and see what I can find.

On another thread you mentioned that Kern RX lenses required the C mount to be modified because of a non standard flange to film plane distance, do you know if it's more or less than standard

Regards

CD


11-17-2015, 10:44 AM   #9
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I just bought a CCTV lens and adapter for my Q7, and I will be posting up a thread shortly. It just came in the mail late yesterday so I really haven't had much chance to try it out, but around the house it seems very promising.
11-17-2015, 03:19 PM   #10
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I have two TV lenses, a 35mm f/1.6 and a 9mm f/1.4 - I usually look for lenses marked "APS-C" - I assume that this means they can cover the APS-C sensor format. Examples here later when my Pentax Q7 arrives.
11-18-2015, 11:17 AM   #11
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QuoteOriginally posted by Professor Batty Quote
The TV lenses may cover but quite often have degraded resolution at the corners. I've got a Fujinon 9mm f1.4 and it does work on a Q7 but with severe coma at the edges, especially wide open. The c mount lenses from 16mm cine cameras cover edge to edge.
Are the Pentax "Toy" lenses any good ?
11-19-2015, 02:11 AM   #12
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QuoteOriginally posted by PenPusher Quote
I suspect this question has been asked many times before but I could not find any note of it.

I have a Q10 with 02 and 06 lenses and a Chinese PK to Q adapter, however I find the K lenses a bit heavy and out of scale with the Q unless you go the whole hog and mount the outfit on a tripod which I dislike carrying which seems to me to defeat the idea of a small lightweight outfit.

I was wondering therefore about C mount Cine lenses but I have no idea of equivalent focal lengths e.g. what do, say, 10mm and 25mm C mount lenses work out on the Q (approximately of course)

I have noticed too that all C mounts do not appear to be the same, there seems to be quite a difference between those made for for Bolex and Arriflex cameras for example and then again there are TV lenses.

I would appreciate any advice.

Thank you.

CD
If you mean the "crop factor" effect (or 35mm film-camera equivalent), I use 5x as a rough guide for a Pentax Q camera - so a 10mm lens is like a 50mm lens on a full 35mm sized sensor. More exactly it is about 5.6x (Q & Q10) or 4.7x (Q7 & QS1).
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