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04-15-2009, 02:58 PM   #1
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Teleconverter for M42 Takumar 300mm and K10d?

I imagine what I want to do is possible but would like your opinions on what would be the best solution.

I have a K10d and just picked up an M42 Super Takumar 300mm F4 and genuine Pentax M42 to K adapter. I would like to use this combo with a teleconverter but am not sure which converter would be the best choice. Do I get an M42 converter or a K mount converter? 1.4x or 2.0x ? What brand of converter would you recommend? Any I should be aware of that would not work in this case? I have read that some teleconverters are not compatible with certain lenses.

OR am I trying to do something that you would recommend I NOT try to do?

Any suggestions would be much appreciated. I have learned a lot from this forum and hope to someday know enough to be able to throw my two cents in.

Dave

04-15-2009, 03:18 PM   #2
Ira
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You can do it, but you're getting into a funky area of extreme light loss and diminished quality.
04-15-2009, 03:20 PM   #3
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From what I have read in these forums, the lens should be mounted on the adapter before being put on the digital camera. You would have to manually adjust the apature in any case, so buying a new teleconverter with contacts puts more cost on you - unless you'd want to use the TC with other K mount lenses (DA, FA, etc.).

Just a note: most 2x TC cost less than the 1.4's do. I know there's reasons why 1.4 are better, but I don't use them much myself.

I'm sure you will get better replies than mine, but since i'm first reply, I thought to give you some info than leaving your question unanswered.

(OK, not first reply, but I typed in alot more. lol).
04-15-2009, 03:22 PM   #4
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Ira, would a 2x TC stop down to f8 in this?

04-15-2009, 03:31 PM   #5
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QuoteOriginally posted by chalion Quote
Ira, would a 2x TC stop down to f8 in this?
Yep--you usually lose about 2 stops.

Mind you, this could work for you . It's just that you're going to have to make compromises in ISO setting and shutter speed, and simply won't be as good as getting a longer prime. I have an m42 400mm Vivitar 4.5 that I only paid like 50 bucks for on eBay, the cost or less of a converter.

They're just not all that great.
04-15-2009, 03:50 PM   #6
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Gampa,

Check you PM.
04-15-2009, 05:34 PM   #7
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Thank you all very much. I was wondering if I would lose too much going this route in regards to light and shutter speed and by the comments it looks like I was correct.

I would have prefered a 400mm or 500mm but thought I'd try to take a low road approach right now. The 300mm didn't set me back all that much and right now was about all I could afford to shell out. The plan is to go up to a 400 or 500 in the future so I get the impression I'd be better off sticking with the 300 and no teleconverter at this time.

SOldBear, what does "Check you PM" mean? Sorry, I'm a forum rookie!

Dave
04-15-2009, 06:25 PM   #8
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In the upper right-hand corner of your screen, you'll see "Private Messages."

PM is short for that.

04-15-2009, 06:30 PM   #9
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Ira,

Thank you. I did say I was a forum rookie and boy did it just show. I guess I better go get that nametag that says, "Hello, My Name Is DUH"!!!

Dave
04-15-2009, 06:35 PM   #10
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you might want to consider the 1.7x AF TC

I use it on my K300 F4

see the following posts
https://www.pentaxforums.com/forums/558748-post4.html
https://www.pentaxforums.com/forums/557712-post2.html
04-15-2009, 06:45 PM   #11
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QuoteOriginally posted by Lowell Goudge Quote
you might want to consider the 1.7x AF TC

I use it on my K300 F4

see the following posts
https://www.pentaxforums.com/forums/558748-post4.html
https://www.pentaxforums.com/forums/557712-post2.html
I would second on Lowell's recommendation. It is probably the best TC that I have used. Unfortunately, it usually cost around 300. But that TC turns a K/M42 lens into AF lens when you manual focus to close proximity of the target. I used it today in another thread on Photonsiper.


Pentax-F 1.7x AF TC

Aluminium Foil is needed
for the AFA to kick in AF
Focus trap also function with the M42



But you need to know about the general caveats with TC so that your expectation is set right in the thinking and planning
  • you lose 1.5 stop in the F-1.7x TC, or 2.0 stops in the 2x tc
  • M42 tele-lens may have a even more difficult time to confirm focus as all blades are closed down in manual diaphragm -- but you can try to focus in f/4.5 and turn aperture to smaller setting before the shutter release
  • some lost of detail and contrast in using TC
  • more showing of PF/CA especially when your lens are prone to CA

Other TC that are worth to consider includes Tamron Pz-AF 1.4x TC, Promaster 1.7x AF TC, Kenko Teleplus MC7 TC and perhaps others.

Thanks,
Hin

Last edited by hinman; 04-15-2009 at 07:07 PM.
04-15-2009, 07:51 PM   #12
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300 + TC's?

If you'll give me a few days to do it right, I'm in the process of comparing my 300's and yours is one of 'em.

The choice of converters, M42 or P/K, and which position they take in the stack, will depend mostly on the individual components in YOUR hands.

Here's a shot with the SupTak 300/4 at f8 and at 70 feet under poor light conditions while figuring out the target layout. No PP applied here, just trying to find a homemade target that works.This project isn't going to be a 'lens test', just a subjective and relative ranking of my equipment possibilities in the 300mm arena the way I use 'em. Numbers on the grid are the font size in MS Word. This is typical of MY 300/4 right out of the camera.

Ultimately, there'll be five 300's, a 400 and five TC's in the matrix. Nothing will be * quality, just economical user lenses.

H2
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04-16-2009, 05:19 AM   #13
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Lowell and Hin,

Thank you for your suggestions. It sounds like the 1.7 is a nice converter. But the more I read all of the responses on this post and think about what it is I would ultimately like to accomplish, I'm starting to talk myself into taking that money and stash it away for a better, longer lens. I may pick up a cheaper converter and experiment but in the long run would rather invest the majority of the money in a nicer/longer lens.

See, I told you I learned a lot from these forums!

Dave

with
QuoteOriginally posted by hinman Quote
I would second on Lowell's recommendation. It is probably the best TC that I have used. Unfortunately, it usually cost around 300. But that TC turns a K/M42 lens into AF lens when you manual focus to close proximity of the target. I used it today in another thread on Photonsiper.


Pentax-F 1.7x AF TC

Aluminium Foil is needed
for the AFA to kick in AF
Focus trap also function with the M42



But you need to know about the general caveats with TC so that your expectation is set right in the thinking and planning
  • you lose 1.5 stop in the F-1.7x TC, or 2.0 stops in the 2x tc
  • M42 tele-lens may have a even more difficult time to confirm focus as all blades are closed down in manual diaphragm -- but you can try to focus in f/4.5 and turn aperture to smaller setting before the shutter release
  • some lost of detail and contrast in using TC
  • more showing of PF/CA especially when your lens are prone to CA

Other TC that are worth to consider includes Tamron Pz-AF 1.4x TC, Promaster 1.7x AF TC, Kenko Teleplus MC7 TC and perhaps others.

Thanks,
Hin
04-16-2009, 05:23 AM   #14
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That would be great! I'd love to see the difference between your lenses with and/or without converters. Your time and input are much appreciated.

Dave

QuoteOriginally posted by pacerr Quote
If you'll give me a few days to do it right, I'm in the process of comparing my 300's and yours is one of 'em.

The choice of converters, M42 or P/K, and which position they take in the stack, will depend mostly on the individual components in YOUR hands.

Here's a shot with the SupTak 300/4 at f8 and at 70 feet under poor light conditions while figuring out the target layout. No PP applied here, just trying to find a homemade target that works.This project isn't going to be a 'lens test', just a subjective and relative ranking of my equipment possibilities in the 300mm arena the way I use 'em. Numbers on the grid are the font size in MS Word. This is typical of MY 300/4 right out of the camera.

Ultimately, there'll be five 300's, a 400 and five TC's in the matrix. Nothing will be * quality, just economical user lenses.

H2
04-16-2009, 05:48 AM   #15
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QuoteOriginally posted by Gampa Quote
Lowell and Hin,

Thank you for your suggestions. It sounds like the 1.7 is a nice converter. But the more I read all of the responses on this post and think about what it is I would ultimately like to accomplish, I'm starting to talk myself into taking that money and stash it away for a better, longer lens. I may pick up a cheaper converter and experiment but in the long run would rather invest the majority of the money in a nicer/longer lens.

See, I told you I learned a lot from these forums!

Dave

with
not to discourage you but a cheap TC is just that. I know, I have 3 of them I never use
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