Help pentax q7 with c-mount adapter

Michi Joel · 05-04-2015, 08:43 AM

I bought a c- mount adapter but I can not focus on my lens, or even close to infinity , in any way, or screwing to the end or just a little. Anyone can recommend me one with which you can focus on good, nice and cheap infinity?
A photo of this adapter + lens:

tnx

**blackcloudbrew** · 05-04-2015, 10:08 AM

I don't have an immediate answer for you as my c-mount adapter for my Q system is at home. However, IIRC, the few c-mount lenses I have have been hit or miss focus wise. Seems to be more the lens than the adapter. Had the same problem with an M39/42 adapter for the Q-system for my really old Leica lenses. Just doesn't focus right. Clearly it's got to be the optics and distances etc. but I've not taken much time to consider what to do about it, if anything can be done.

tvdtvdtvd · 05-04-2015, 10:16 AM

Are you sure that's a C-Mount lens and not a CS-Mount? They have the same mount thread size but different
flange focal distances.

Most all my C-mount lenses achieve infinity focus. A few require a slight turn in the mount to achieve infinity.
I see a lot more variability with D-mount lenses.

C mount - Wikipedia, the free encyclopedia
Note that the difference between C-mount and CS-mount is about 5mm.

Michi Joel · 05-04-2015, 11:01 AM

thanks for the replies guys. I bought this as c-mount lens, but from what you say I'm doubting it's the right mount. So far I have not found Internet many references to this lens. I'll keep investigating

romay · 05-04-2015, 01:04 PM

Good C-mount primes for the Q7 are the Schneider Kreuznach Xenon 1:0.95 (17mm / 25mm / 50mm) and Cinegon lenses, the Steinheil Quinon (with optional focal reducer) as well as the Pentax C814-5M.
If you want a nice zoom, try Beaulieu Optivaron zoom lenses, they usually come with a macro switch. I own the 6-66mm and it's great. They internal-focus designs, so you may need a shim in your adapter for maximum sharpness (rear element doesn't move, sharpness depends 100% on flange distance).

Michi Joel · 05-04-2015, 02:19 PM

Tnx romay.
My lens is CS-mount!!

can someone recommend me a good adapter for my lens?

Michi Joel · 05-05-2015, 11:12 AM

tomorrow I will return this lens

Last edited by Michi Joel; 05-05-2015 at 11:43 AM.

VisualDarkness · 05-07-2015, 03:41 PM

Or use it as a close focus one!

**Lowell Goudge** · 05-07-2015, 05:06 PM

If you know a machinist he can take a c mount and turn 5.026mm off the adaptor (lens side)

Michi Joel · 05-09-2015, 08:00 AM

tnx guys, i returned this lens, i'll buy another in c-mount

05-04-2015, 08:43 AM	#1
Michi Joel Veteran Member Join Date: Mar 2012 Location: Catalonia Photos: Albums Posts: 441	Help pentax q7 with c-mount adapter I bought a c- mount adapter but I can not focus on my lens, or even close to infinity , in any way, or screwing to the end or just a little. Anyone can recommend me one with which you can focus on good, nice and cheap infinity? A photo of this adapter + lens: tnx

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
PKQ Adapter concerns with Q7	Wired	Pentax Q	3	01-09-2014 10:19 PM
Help: Pentax Adapter Q for K mount lenses	GXRUser	Pentax Q	9	11-17-2013 09:52 PM
Q7 and C-mount lenses	nater	Pentax Q	3	08-04-2013 05:10 AM
C/Y to K mount adapter	toukan	Pentax SLR Lens Discussion	8	07-26-2013 04:30 PM
For Sale - Sold: C-Mount Adapter for Pentax-K Lenses - Free (Worldwide)	dgaies	Sold Items	2	05-19-2011 06:01 PM

05-04-2015, 10:08 AM	#2
blackcloudbrew Loyal Site Supporter Join Date: Mar 2009 Location: Cotati, California USA Photos: Gallery \| Albums Posts: 4,460	I don't have an immediate answer for you as my c-mount adapter for my Q system is at home. However, IIRC, the few c-mount lenses I have have been hit or miss focus wise. Seems to be more the lens than the adapter. Had the same problem with an M39/42 adapter for the Q-system for my really old Leica lenses. Just doesn't focus right. Clearly it's got to be the optics and distances etc. but I've not taken much time to consider what to do about it, if anything can be done.

05-04-2015, 10:16 AM	#3
tvdtvdtvd Veteran Member Join Date: Jan 2010 Posts: 1,665	Are you sure that's a C-Mount lens and not a CS-Mount? They have the same mount thread size but different flange focal distances. Most all my C-mount lenses achieve infinity focus. A few require a slight turn in the mount to achieve infinity. I see a lot more variability with D-mount lenses. C mount - Wikipedia, the free encyclopedia Note that the difference between C-mount and CS-mount is about 5mm.

05-04-2015, 11:01 AM	#4
Michi Joel Veteran Member Join Date: Mar 2012 Location: Catalonia Photos: Albums Posts: 441 Original Poster	thanks for the replies guys. I bought this as c-mount lens, but from what you say I'm doubting it's the right mount. So far I have not found Internet many references to this lens. I'll keep investigating

05-04-2015, 01:04 PM	#5
romay Senior Member Join Date: Nov 2014 Posts: 113	Good C-mount primes for the Q7 are the Schneider Kreuznach Xenon 1:0.95 (17mm / 25mm / 50mm) and Cinegon lenses, the Steinheil Quinon (with optional focal reducer) as well as the Pentax C814-5M. If you want a nice zoom, try Beaulieu Optivaron zoom lenses, they usually come with a macro switch. I own the 6-66mm and it's great. They internal-focus designs, so you may need a shim in your adapter for maximum sharpness (rear element doesn't move, sharpness depends 100% on flange distance).

05-04-2015, 02:19 PM	#6
Michi Joel Veteran Member Join Date: Mar 2012 Location: Catalonia Photos: Albums Posts: 441 Original Poster	Tnx romay. My lens is CS-mount!! can someone recommend me a good adapter for my lens?

05-05-2015, 11:12 AM	#7
Michi Joel Veteran Member Join Date: Mar 2012 Location: Catalonia Photos: Albums Posts: 441 Original Poster	tomorrow I will return this lens Last edited by Michi Joel; 05-05-2015 at 11:43 AM.

05-07-2015, 03:41 PM	#8
VisualDarkness Veteran Member Join Date: Nov 2011 Location: Uppsala, Sweden Photos: Gallery Posts: 4,439	Or use it as a close focus one!

05-07-2015, 05:06 PM	#9
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,887	If you know a machinist he can take a c mount and turn 5.026mm off the adaptor (lens side)

05-09-2015, 08:00 AM	#10
Michi Joel Veteran Member Join Date: Mar 2012 Location: Catalonia Photos: Albums Posts: 441 Original Poster	tnx guys, i returned this lens, i'll buy another in c-mount