m42 question

ixc · 02-18-2010, 04:12 PM

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.

Is there anyway to tell for sure if a lens is m42?

I purchased this lens since it said "screw mount" in the listing. It arrived today but only threads about halfway down (1.5 full turns) into my m42 adapter. is this normal?

it seems to work ok except for the face that I am really seeing how unsteady my hands are. :X

GoremanX · 02-18-2010, 04:29 PM

Originally posted by ixc

Is there anyway to tell for sure if a lens is m42?

I purchased this lens since it said "screw mount" in the listing. It arrived today but only threads about halfway down (1.5 full turns) into my m42 adapter. is this normal?

it seems to work ok except for the face that I am really seeing how unsteady my hands are. :X

sounds like a T screw mount, needs a T or T-2 adapter, not an M42

SOldBear · 02-18-2010, 04:33 PM

It's a T-mount. You need an adapter like this.

ixc · 02-19-2010, 08:16 AM

Originally posted by GoremanX

sounds like a T screw mount, needs a T or T-2 adapter, not an M42

is there a difference between t and t-2?

the adapter s0ldbear linked mentions both, but is it pretty much universal?

noblepa · 02-19-2010, 02:51 PM

Originally posted by ixc

is there a difference between t and t-2?

the adapter s0ldbear linked mentions both, but is it pretty much universal?

No, there is no difference. As a matter of fact, I doubt that you could find a true T adapter. They're all T2.

The original T adapter was machined out of a single piece of metal. The T2 adapters have an inner ring with the 42mm x 0.75tpm thread to attach to the lens. The outer, larger piece has the camera-specific mount and holds the inner ring in place with three small screws. The screws can be loosened to rotate the lens, so that the focus and aperture markings are on top of the lens, when it is mounted on the camera.

In you search, you might come across a T4 or TX adapter. Those are entirely different animals

fccwpe · 02-20-2010, 11:05 PM

Could it be an Leica type M39???

RioRico · 02-21-2010, 02:07 AM

Originally posted by fccwpe

Could it be an Leica type M39???

An x39 lens won't begin to thread onto a M42 mount. If the lens starts to thread, but sticks, it's either 1) a T-mount or 2) a bent M42. If the lens just sits loose in the mount, then it's an x39 of some sort. NOTE: An M39 lens can use a 39/42 adapter and a M42/PK adapter for mounting on a Pentax-type cam. An L39 or LTM (Leica thread-mount) has a different register (lens-to-sensor-plane distance) and can NEVER be adapted to a Pentax, except as Yet Another Macro Lens (YAML).

ixc · 02-25-2010, 10:18 AM

just wanted to say thanks for all the input. I received my t2 adapter yesterday and the lens screws right in and mounts to the camera.

02-18-2010, 04:12 PM	#1
ixc New Member Join Date: Feb 2008 Location: Las Vegas, NV Posts: 20	m42 question 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. Is there anyway to tell for sure if a lens is m42? I purchased this lens since it said "screw mount" in the listing. It arrived today but only threads about halfway down (1.5 full turns) into my m42 adapter. is this normal? it seems to work ok except for the face that I am really seeing how unsteady my hands are. :X

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
M42 to K Converter question	MikesChevelle	Troubleshooting and Beginner Help	17	02-10-2010 01:13 PM
M42 Helios 44-2 question	wowtip	Pentax SLR Lens Discussion	16	10-12-2009 02:22 AM
M42 Adapter Question	greenboy	Pentax SLR Lens Discussion	16	03-28-2009 01:28 PM
M42 to PK Question	wtlwdwgn	Pentax SLR Lens Discussion	13	01-24-2009 06:17 PM
M42 on K10D question	sabarrett	Pentax SLR Lens Discussion	20	05-29-2008 03:01 PM

02-18-2010, 04:29 PM	#2
GoremanX Veteran Member Join Date: Dec 2009 Location: Georgia, VT Photos: Albums Posts: 1,657	Originally posted by ixc Is there anyway to tell for sure if a lens is m42? I purchased this lens since it said "screw mount" in the listing. It arrived today but only threads about halfway down (1.5 full turns) into my m42 adapter. is this normal? it seems to work ok except for the face that I am really seeing how unsteady my hands are. :X sounds like a T screw mount, needs a T or T-2 adapter, not an M42

02-18-2010, 04:33 PM	#3
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	It's a T-mount. You need an adapter like this.

02-19-2010, 08:16 AM	#4
ixc New Member Join Date: Feb 2008 Location: Las Vegas, NV Posts: 20 Original Poster	Originally posted by GoremanX sounds like a T screw mount, needs a T or T-2 adapter, not an M42 is there a difference between t and t-2? the adapter s0ldbear linked mentions both, but is it pretty much universal?

02-19-2010, 02:51 PM	#5
noblepa Veteran Member Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,142	Originally posted by ixc is there a difference between t and t-2? the adapter s0ldbear linked mentions both, but is it pretty much universal? No, there is no difference. As a matter of fact, I doubt that you could find a true T adapter. They're all T2. The original T adapter was machined out of a single piece of metal. The T2 adapters have an inner ring with the 42mm x 0.75tpm thread to attach to the lens. The outer, larger piece has the camera-specific mount and holds the inner ring in place with three small screws. The screws can be loosened to rotate the lens, so that the focus and aperture markings are on top of the lens, when it is mounted on the camera. In you search, you might come across a T4 or TX adapter. Those are entirely different animals

02-20-2010, 11:05 PM	#6
fccwpe Veteran Member Join Date: Mar 2009 Location: Perris, CA Photos: Gallery Posts: 380	Could it be an Leica type M39???

02-21-2010, 02:07 AM	#7
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by fccwpe Could it be an Leica type M39??? An x39 lens won't begin to thread onto a M42 mount. If the lens starts to thread, but sticks, it's either 1) a T-mount or 2) a bent M42. If the lens just sits loose in the mount, then it's an x39 of some sort. NOTE: An M39 lens can use a 39/42 adapter and a M42/PK adapter for mounting on a Pentax-type cam. An L39 or LTM (Leica thread-mount) has a different register (lens-to-sensor-plane distance) and can NEVER be adapted to a Pentax, except as Yet Another Macro Lens (YAML).

02-25-2010, 10:18 AM	#8
ixc New Member Join Date: Feb 2008 Location: Las Vegas, NV Posts: 20 Original Poster	just wanted to say thanks for all the input. I received my t2 adapter yesterday and the lens screws right in and mounts to the camera.