The C and D mount lens club

NoRules · 07-06-2014, 08:20 AM

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Hi,
1 Inch sounds strange. You could loosen the set screws to see if the lens is adjuste as a macro lens. Kern did a lot of adjustments for customers ... Here is a link to an image of my f.2,5 12,5mm in the mount. It protrudes, or brake the flange plane, with about 1/2mm to 1mm. Yours should look the same. http://gfsnt.no/oen/foto/_IMP7219.jpg

Transit · 07-06-2014, 04:51 PM

Originally posted by NoRules

As stated in my original post on the Kern Paillard subject, I always sand my adapters down 1 mm, then I add shims as needed. Adapters are of soft aluminium alloy or something. Very easy to sand. Stay with it! Don't give up!

Ah thankyou, I didn't understand by your post the adapter was to be thined.

---------- Post added 07-07-14 at 11:55 AM ----------

Originally posted by rafoarc

the thing is, if it focuses at 1 inch now, then it needs to get quite a lot closer, I am not sure if 1mm will help, but then you never know. but i think that there might be some other issue there... can you post a photo of the back of the lens and of the lens on the adapter?

i agree.

This is not the 2.5 lens.
it is the 2.8

which seems to be a special case for the Bolex movie camera it was kited with.
If my reading is correct D mount flange focal distance is 12.29 mm
Yet with the 12.5 /2.8 K-P Yvar it is 7.8 mm...
so I have to find 4and half mil ?
Pete
ps will put up shot in a tic, none of the 12.5 2.8 images online look exactly like it

rafoarc · 07-06-2014, 06:22 PM

ok.... so you have this one:
Yvar 12.5mm f/2.8 (DESIGNED FOR L-8)

Quote:

"This lens was intended for use on L-8 cameras. It was available in both fixed focus and focus mount versions; the fixed focus lens is pictured here. Although the thread diameter is identical to a normal D-mount lens (15.8mm or 5/8"), the optical distance from film plane to lens seat is 7.8mm (0.3075"). "

(link here)
I am afraid that this will be really hard to work. The flange dist. for the Q is 9.2mm. unless you could have an adapter with an optical element i guess...

Transit · 07-07-2014, 01:56 AM

1.4 mm needs to come off the adapter then?
should still clear the sensor then

vignette tho I spose
thanks for the link, same specs but different body

---------- Post added 07-07-14 at 09:28 PM ----------

Originally posted by NoRules

Hi,
1 Inch sounds strange. You could loosen the set screws to see if the lens is adjuste as a macro lens. Kern did a lot of adjustments for customers ... Here is a link to an image of my f.2,5 12,5mm in the mount. It protrudes, or brake the flange plane, with about 1/2mm to 1mm. Yours should look the same. http://gfsnt.no/oen/foto/_IMP7219.jpg

mine protrudes a similar amount but the rear element is more recessed

Last edited by Transit; 07-07-2014 at 02:04 AM.

rafoarc · 07-07-2014, 06:51 AM

Originally posted by Transit

1.4 mm needs to come off the adapter then? should still clear the sensor then

Not really. You need 5,1mm. No only the adapter that you have is useless, but you need 1.4mm less than the actual Q mount flange distance. So, I think it is a little difficult. But... maybe you can use it as a macro lens :-)

NoRules · 07-07-2014, 08:29 AM

This might not be a fix focus lens. The focus might be stuck. If not I think it's a special order. Try loosen the set screws and look inside. Not much you can do wrong, except touching internal element surface. You can even add lubricant with the tip of a toothpick, becaus the aperture has no auto mechanism and no internal shutter. I have two or three Kern lenses with oil on aperture blades. No problem as long as it stays there. keep us informed on the progress!

Transit · 07-07-2014, 02:20 PM

Originally posted by rafoarc

Not really. You need 5,1mm. No only the adapter that you have is useless, but you need 1.4mm less than the actual Q mount flange distance. So, I think it is a little difficult. But... maybe you can use it as a macro lens :-)

oh bugger, maybe i'll put it back on the Bolex and look for a collector

---------- Post added 07-08-14 at 09:22 AM ----------

Originally posted by NoRules

This might not be a fix focus lens. The focus might be stuck. If not I think it's a special order. Try loosen the set screws and look inside. Not much you can do wrong, except touching internal element surface. You can even add lubricant with the tip of a toothpick, becaus the aperture has no auto mechanism and no internal shutter. I have two or three Kern lenses with oil on aperture blades. No problem as long as it stays there. keep us informed on the progress!

ok thanks, I'll have a look

---------- Post added 07-08-14 at 09:24 AM ----------

our friend Gub might be along shortly suggesting er machining and glueing options

rendition · 07-07-2014, 04:34 PM

another solution would be to file it down all the way to near rear last element and use a CS-to-C mount ring and attach it (either glue or lathe) and it will work on pentax Q using C-to-Q adapter. Either using CS-to-C mount ring OR using another D-mount with larger mouth ring but I doubt you can find those readily.

**GUB** · 07-07-2014, 08:38 PM

Originally posted by Transit

our friend Gub might be along shortly suggesting er machining and glueing options

Yeah seems like we are only allowed to talk about dentists on our home thread

Na looks like a tough one transit-- the flange focal distance is closer than the Q.
Bolex Collector | Lenses | Kern Paillard 1940s and Flange focal distance - Wikipedia, the free encyclopedia
Rendition's idea may work though as the back element seems to be a long way from the mount thread

Transit · 07-07-2014, 10:40 PM

yes I thought all that back element recess looked redundant.
There is plenty of thread, takes 3 full turns into the adaptor.
Will undo the wee screws and have a squise inside, might be able to whip the arse end off for a spot of turning

rendition · 07-07-2014, 11:43 PM

Originally posted by Transit

yes I thought all that back element recess looked redundant.
There is plenty of thread, takes 3 full turns into the adaptor.
Will undo the wee screws and have a squise inside, might be able to whip the arse end off for a spot of turning

by the look of your len's recess you will probably have to take all the recess parts out, and I am fairly certain you will need a new mount/replacement for infinity focusing.

**GUB** · 07-08-2014, 01:44 AM

Kind of depends what is under your focus ring. Figure you would have to cut the bottom off the focus ring.
According to those links above the flange would have to be moved 4.5mm which is not agreeing with rafoarcs 5.1mm?
This would be my plan of attack :

rafoarc · 07-08-2014, 04:51 AM

ooops, you are correct GUB, it is 4.5mm (4.49 if we want to be precise). I don't know how I came up with the 5.1mm :-)

rafoarc · 08-04-2014, 12:34 PM

Hello again!
Does anyone knows what kind of mount is this one? I have an elgeet 11/2" f3.5 that has the same adapter attached to it. Only that mine does not come out (or it is stuck) so it is unusable (which is a shame because it is in very good condition)... any information will be helpful!

paulie_ · 03-31-2020, 03:25 PM - **1 Like**

Hi, please could you recommend me some c-mount or d-mount TELE lens around 25-35mm (not 50mm), that is really sharp and cheaper than 06? Is it possible to find something like this?
Thanks!

07-06-2014, 04:51 PM	#47
Transit Pentaxian Join Date: Aug 2007 Location: Whanganui NZ Photos: Gallery \| Albums Posts: 4,624	Originally posted by NoRules As stated in my original post on the Kern Paillard subject, I always sand my adapters down 1 mm, then I add shims as needed. Adapters are of soft aluminium alloy or something. Very easy to sand. Stay with it! Don't give up! Ah thankyou, I didn't understand by your post the adapter was to be thined. ---------- Post added 07-07-14 at 11:55 AM ---------- Originally posted by rafoarc the thing is, if it focuses at 1 inch now, then it needs to get quite a lot closer, I am not sure if 1mm will help, but then you never know. but i think that there might be some other issue there... can you post a photo of the back of the lens and of the lens on the adapter? i agree. This is not the 2.5 lens. it is the 2.8 which seems to be a special case for the Bolex movie camera it was kited with. If my reading is correct D mount flange focal distance is 12.29 mm Yet with the 12.5 /2.8 K-P Yvar it is 7.8 mm... so I have to find 4and half mil ? Pete ps will put up shot in a tic, none of the 12.5 2.8 images online look exactly like it Last edited by Transit; 07-06-2014 at 04:57 PM.

07-08-2014, 01:44 AM	#57
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Kind of depends what is under your focus ring. Figure you would have to cut the bottom off the focus ring. According to those links above the flange would have to be moved 4.5mm which is not agreeing with rafoarcs 5.1mm? This would be my plan of attack : Attached Images

08-04-2014, 12:34 PM	#59
rafoarc New Member Join Date: Feb 2014 Posts: 24	unidentified mount attached on D Hello again! Does anyone knows what kind of mount is this one? I have an elgeet 11/2" f3.5 that has the same adapter attached to it. Only that mine does not come out (or it is stuck) so it is unusable (which is a shame because it is in very good condition)... any information will be helpful!

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07-06-2014, 08:20 AM	#46
NoRules Junior Member Join Date: Feb 2014 Location: Nissedal (Goblin Valley) Photos: Gallery Posts: 38	Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Hi, 1 Inch sounds strange. You could loosen the set screws to see if the lens is adjuste as a macro lens. Kern did a lot of adjustments for customers ... Here is a link to an image of my f.2,5 12,5mm in the mount. It protrudes, or brake the flange plane, with about 1/2mm to 1mm. Yours should look the same. http://gfsnt.no/oen/foto/_IMP7219.jpg

07-06-2014, 06:22 PM	#48
rafoarc New Member Join Date: Feb 2014 Posts: 24	ok.... so you have this one: Yvar 12.5mm f/2.8 (DESIGNED FOR L-8) Quote: "This lens was intended for use on L-8 cameras. It was available in both fixed focus and focus mount versions; the fixed focus lens is pictured here. Although the thread diameter is identical to a normal D-mount lens (15.8mm or 5/8"), the optical distance from film plane to lens seat is 7.8mm (0.3075"). " (link here) I am afraid that this will be really hard to work. The flange dist. for the Q is 9.2mm. unless you could have an adapter with an optical element i guess...

07-07-2014, 01:56 AM	#49
Transit Pentaxian Join Date: Aug 2007 Location: Whanganui NZ Photos: Gallery \| Albums Posts: 4,624	1.4 mm needs to come off the adapter then? should still clear the sensor then vignette tho I spose thanks for the link, same specs but different body ---------- Post added 07-07-14 at 09:28 PM ---------- Originally posted by NoRules Hi, 1 Inch sounds strange. You could loosen the set screws to see if the lens is adjuste as a macro lens. Kern did a lot of adjustments for customers ... Here is a link to an image of my f.2,5 12,5mm in the mount. It protrudes, or brake the flange plane, with about 1/2mm to 1mm. Yours should look the same. http://gfsnt.no/oen/foto/_IMP7219.jpg mine protrudes a similar amount but the rear element is more recessed Last edited by Transit; 07-07-2014 at 02:04 AM.

07-07-2014, 06:51 AM	#50
rafoarc New Member Join Date: Feb 2014 Posts: 24	Originally posted by Transit 1.4 mm needs to come off the adapter then? should still clear the sensor then Not really. You need 5,1mm. No only the adapter that you have is useless, but you need 1.4mm less than the actual Q mount flange distance. So, I think it is a little difficult. But... maybe you can use it as a macro lens :-)

07-07-2014, 08:29 AM	#51
NoRules Junior Member Join Date: Feb 2014 Location: Nissedal (Goblin Valley) Photos: Gallery Posts: 38	This might not be a fix focus lens. The focus might be stuck. If not I think it's a special order. Try loosen the set screws and look inside. Not much you can do wrong, except touching internal element surface. You can even add lubricant with the tip of a toothpick, becaus the aperture has no auto mechanism and no internal shutter. I have two or three Kern lenses with oil on aperture blades. No problem as long as it stays there. keep us informed on the progress!

07-07-2014, 02:20 PM	#52
Transit Pentaxian Join Date: Aug 2007 Location: Whanganui NZ Photos: Gallery \| Albums Posts: 4,624	Originally posted by rafoarc Not really. You need 5,1mm. No only the adapter that you have is useless, but you need 1.4mm less than the actual Q mount flange distance. So, I think it is a little difficult. But... maybe you can use it as a macro lens :-) oh bugger, maybe i'll put it back on the Bolex and look for a collector ---------- Post added 07-08-14 at 09:22 AM ---------- Originally posted by NoRules This might not be a fix focus lens. The focus might be stuck. If not I think it's a special order. Try loosen the set screws and look inside. Not much you can do wrong, except touching internal element surface. You can even add lubricant with the tip of a toothpick, becaus the aperture has no auto mechanism and no internal shutter. I have two or three Kern lenses with oil on aperture blades. No problem as long as it stays there. keep us informed on the progress! ok thanks, I'll have a look ---------- Post added 07-08-14 at 09:24 AM ---------- our friend Gub might be along shortly suggesting er machining and glueing options

07-07-2014, 04:34 PM	#53
rendition Senior Member Join Date: May 2014 Posts: 123	another solution would be to file it down all the way to near rear last element and use a CS-to-C mount ring and attach it (either glue or lathe) and it will work on pentax Q using C-to-Q adapter. Either using CS-to-C mount ring OR using another D-mount with larger mouth ring but I doubt you can find those readily.

07-07-2014, 08:38 PM	#54
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by Transit our friend Gub might be along shortly suggesting er machining and glueing options Yeah seems like we are only allowed to talk about dentists on our home thread Na looks like a tough one transit-- the flange focal distance is closer than the Q. Bolex Collector \| Lenses \| Kern Paillard 1940s and Flange focal distance - Wikipedia, the free encyclopedia Rendition's idea may work though as the back element seems to be a long way from the mount thread

07-07-2014, 10:40 PM	#55
Transit Pentaxian Join Date: Aug 2007 Location: Whanganui NZ Photos: Gallery \| Albums Posts: 4,624	yes I thought all that back element recess looked redundant. There is plenty of thread, takes 3 full turns into the adaptor. Will undo the wee screws and have a squise inside, might be able to whip the arse end off for a spot of turning

07-07-2014, 11:43 PM	#56
rendition Senior Member Join Date: May 2014 Posts: 123	Originally posted by Transit yes I thought all that back element recess looked redundant. There is plenty of thread, takes 3 full turns into the adaptor. Will undo the wee screws and have a squise inside, might be able to whip the arse end off for a spot of turning by the look of your len's recess you will probably have to take all the recess parts out, and I am fairly certain you will need a new mount/replacement for infinity focusing.

07-08-2014, 04:51 AM	#58
rafoarc New Member Join Date: Feb 2014 Posts: 24	ooops, you are correct GUB, it is 4.5mm (4.49 if we want to be precise). I don't know how I came up with the 5.1mm :-)

03-31-2020, 03:25 PM - 1 Like	#60
paulie_ New Member Join Date: Apr 2017 Posts: 16	Hi, please could you recommend me some c-mount or d-mount TELE lens around 25-35mm (not 50mm), that is really sharp and cheaper than 06? Is it possible to find something like this? Thanks!