Are Pentax K-mount teleconverters universally compatible with all K-mount lenses?

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

K-mount teleconverters effectively come in three or four versions.

1. The most basic. Will have a mechanical aperture linkage but no contacts to feed back aperture information to the camera body. How important this is will depend on which body you're using. If your camera doesn't have any contacts on the lens mount then one of these will be fine. Tamron made a good quality 2x like this.

2. As above, but with six electrical contacts to feed back aperture information, but still no a/f capability. Available from several brands.

3. As 2, but with seven electrical contacts and mechanical a/f "screw-drive" coupling.

4. As 3, but also with the two power contacts in the throat to support power zoom and in-lens focus motors.

Provisos :-

Some teleconverters were dedicated to just one, or a specific range of lenses. Sigma and Vivitar did this, maybe others as well.

Some lenses have a rear element that simply protrudes too far and can foul the teleconverter. This could get expensive if you're not careful!

Most focus confirmation indicators, be they electronic, as on a more modern camera, or purely optical, as with a split-image or micro-prism, will struggle at apertures less than f/5.6. This means that any lens smaller than f/2.8, when fitted with a 2x adaptor (making it effectively less than f/5.6) will be difficult to focus except with a high-contrast subject in good light. Here you'll probably need to revert to focussing on the ground glass … a viewfinder magnifier can prove beneficial

I think that covers most points … any further detail, please ask

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

One asterisk is that the current HD-DA 1.4x TC is designed for APSC and won't properly cover 35mm film / FF. You don't need its capabilities in any case if you're using a K2 and MF lenses. Just a FYI.

Doug

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

With a 2x TC you will loose lots of light and the image quality will basically not become any better. In fact you effectively reduce the pixels to half their size, taking 4x less light, then hope that the lens is good enough to show that better resolution as well. So for the zoom lenses you mention I fear a bit for disappointment. The 600/6.7 will become a 1200/13.5 , nice for moonshots but not a guaranteed better image than a cropped part out of a 600/6.7 shot.

hanhait said:

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

With a 2x TC you will loose lots of light and the image quality will basically not become any better. In fact you effectively reduce the pixels to half their size, taking 4x less light, then hope that the lens is good enough to show that better resolution as well. So for the zoom lenses you mention I fear a bit for disappointment. The 600/6.7 will become a 1200/13.5 , nice for moonshots but not a guaranteed better image than a cropped part out of a 600/6.7 shot.

Click to expand...

I'm aware that a 2X TC cuts light significantly and doesn't exactly do wonders for image quality. Moonshots is primarily what I'd be interested in using it for, and in suitably excellent daylight, with a film camera, not a digital camera. I know this is technically the digital K-mount forum, but I did state in the OP that I'd be using it with a vintage MF SLR, not a modern digital Pentax. Additionally, the TC comes as a pack-in with a 50/1.4 that's in excellent condition, so I see it more as an added bonus than the main thing I'm buying.

not all legacy Pentax teleconverters are compatible with a wide range of lenses ( most are) as stated above, specifically watch out for those with large protruding glass which can only be mounted on specific lenses. be careful when buying and or mounting to avoid damaging your lenses.

some examples:



see:

cyanhue said:

not all legacy Pentax teleconverters are compatible with a wide range of lenses ( most are) as stated above, specifically watch out for those with large protruding glass which can only be mounted on specific lenses. be careful when buying and or mounting to avoid damaging your lenses.
some examples:

http://kmp.pentaxians.eu/teleconverters/a1-4x-l/

http://kmp.pentaxians.eu/teleconverters/a2x-l/

see:

http://kmp.pentaxians.eu/teleconverters/

Click to expand...

Ah, yes - the protruding front element of the TC is why the Fujifilm X-mount TCs only work with a few lenses. The specific TC I see for sale here is not one of these, though those two reportedly would work better with the 135-600. Those two -L ones also look to be much harder to find. I'll keep my eye out for those in the future but try my luck with the cheaper one for now, probably.

hanhait said:

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

With a 2x TC you will loose lots of light and the image quality will basically not become any better. In fact you effectively reduce the pixels to half their size, taking 4x less light, then hope that the lens is good enough to show that better resolution as well. So for the zoom lenses you mention I fear a bit for disappointment. The 600/6.7 will become a 1200/13.5 , nice for moonshots but not a guaranteed better image than a cropped part out of a 600/6.7 shot.

Click to expand...

This is not entirely true.

A 2x converter magnifies the central part of the image - the OP is using a film camera, so a section which would have covered the central 18mm X 12mm is now covers 36x24. And the light is spread over 4x the area making 1/4 as bright. So far so good. But the TC uses all the film (or pixels) to record half the image that is printed, and without TC the printed part only uses half the film to record the same half image.

Because the exposure needs to be four times as long, subject motion or camera shake might be a factor. IIRC, you gain D.o.F with a TC (because the circle of confusion doubles in size with the 2xTC but quadruples with a lens of 2x the focal length), so you can use a wider aperture, not just a longer shutter speed.
If that isn't an issue recording a magnified image is better than magnifying a recorded image from the same lens.

wantfastcars said:

hanhait said:

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

With a 2x TC you will loose lots of light and the image quality will basically not become any better. In fact you effectively reduce the pixels to half their size, taking 4x less light, then hope that the lens is good enough to show that better resolution as well. So for the zoom lenses you mention I fear a bit for disappointment. The 600/6.7 will become a 1200/13.5 , nice for moonshots but not a guaranteed better image than a cropped part out of a 600/6.7 shot.

Click to expand...

I'm aware that a 2X TC cuts light significantly and doesn't exactly do wonders for image quality. Moonshots is primarily what I'd be interested in using it for, and in suitably excellent daylight, with a film camera, not a digital camera. I know this is technically the digital K-mount forum, but I did state in the OP that I'd be using it with a vintage MF SLR, not a modern digital Pentax. Additionally, the TC comes as a pack-in with a 50/1.4 that's in excellent condition, so I see it more as an added bonus than the main thing I'm buying.

Click to expand...

See my reply to that comment. The TC magnifies before capturing the image, and so you use all the film. Without a TC the crop magnifies the film [more], so you only use part of the film. That's why TCs exist

cyanhue said:

not all legacy Pentax teleconverters are compatible with a wide range of lenses ( most are) as stated above, specifically watch out for those with large protruding glass which can only be mounted on specific lenses. be careful when buying and or mounting to avoid damaging your lenses.
some examples:

http://kmp.pentaxians.eu/teleconverters/a1-4x-l/

http://kmp.pentaxians.eu/teleconverters/a2x-l/

see:

http://kmp.pentaxians.eu/teleconverters/

Click to expand...

Even TCs without protruding front element can be an issue if the protuding element is on the side of the lens, for example the laowa 28 f/2.8 5X can't mount on the HD DA TC x1.4 nor the AF TC X1.7 (and probably same with others, but it's the ones I have). Not that it would be a good idea to do that, but you can't anyway :-D

James O'Neill said:

hanhait said:

wantfastcars said:

James O'Neill said:

wantfastcars said:

I'm coming from Fuji's X-mount where their native TCs only work with a small handful of lenses. I have an opportunity to pick up a vintage K-mount 2x TC (Teleplus MC7) for pretty cheap, but I'm wondering if it'd be compatible with the other K-mount lenses I currently have and any other possible ones I'd pick up in the future. I don't care about lack of AF since I'd be using it on an old film SLR, but I figured since I'm asking about the mount that this forum would still be acceptable.

So, title - if I buy this old TC, can I use it with any (or at least any first-party) lens?

Click to expand...

Simple answer; "yes" for your case,

If a lens doesn't work with a film camera directly, no TC exists to fix that. If it does and camera body and not an aperture-ring position sets the aperture, the TC will need to have electrical contacts for that to work.

So for example if you have a K1000, combining a TC with any lenses you already use will work. If you have a Super A and an A-Series lens, some TCs won't support program mode, but will let you use Manual or Aperture priority.

Click to expand...

Brilliant, exactly what I needed to hear. I'm only interested in MF lenses since my camera is a K2, and I was curious if I'd be able to use the TC (since it's bundled with a 50/1.4) with my extant 80-200 zoom (yes I'm aware that's basically unusable handheld) or with the 135-600/6.7, since there's a pretty decent deal available on that locally and like, when would I ever have the opportunity to get one again? I also might pick up a 105 or 135 since those both get a lot of praise.

Click to expand...

With a 2x TC you will loose lots of light and the image quality will basically not become any better. In fact you effectively reduce the pixels to half their size, taking 4x less light, then hope that the lens is good enough to show that better resolution as well. So for the zoom lenses you mention I fear a bit for disappointment. The 600/6.7 will become a 1200/13.5 , nice for moonshots but not a guaranteed better image than a cropped part out of a 600/6.7 shot.

Click to expand...

This is not entirely true.

A 2x converter magnifies the central part of the image - the OP is using a film camera, so a section which would have covered the central 18mm X 12mm is now covers 36x24. And the light is spread over 4x the area making 1/4 as bright. So far so good. But the TC uses all the film (or pixels) to record half the image that is printed, and without TC the printed part only uses half the film to record the same half image.

Because the exposure needs to be four times as long, subject motion or camera shake might be a factor. IIRC, you gain D.o.F with a TC (because the circle of confusion doubles in size with the 2xTC but quadruples with a lens of 2x the focal length), so you can use a wider aperture, not just a longer shutter speed.
If that isn't an issue recording a magnified image is better than magnifying a recorded image from the same lens.

Click to expand...

Not so sure about the DOF, some compact tele lenses have effectively a TC inside (maybe the 135-600 has one). Another consideration may be taking a 4x less sensitive film that will be finer-grained, but maybe not 2x (laterally). Anyhow: just try and see, the moon will be nice anyhow.