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01-11-2010, 09:33 AM   #1
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K Mount Lens Question

I am looking at K Mounts on eBay and am running accross a few 2x lens. I am assuming that would turn a 80-200 into a 160-400.

My question is can I use two of those and get a 320-800?

01-11-2010, 09:43 AM   #2
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QuoteOriginally posted by MikesChevelle Quote
I am looking at K Mounts on eBay and am running accross a few 2x lens. I am assuming that would turn a 80-200 into a 160-400.

My question is can I use two of those and get a 320-800?
you are talking about teleconverters.

In theory yse you can stack them together and get a 310-800mm lens out of you 80-200, but even if you have an 80-200 F2.8, it would be a 320-800 F11.

You sould need a ton of light to use it, or gery hiogh ISO

Additionally each TC will degrade the image slightly, so unless you get very very good lenses and TCs, the image quality would be very bad.

Other issues are even if both the lenses and TCs were auto focus, no camera in the world can work with an F11 lens and autofocus. the real limit is about F6.7 whish is why even kit lenses are this fast, and why many TC manufacturers will state clearly a TC will cause loss of AF.
01-11-2010, 09:50 AM   #3
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Answer to question is yes. You could do it but it is not recommended.
Your question is something like: could you eat bugs, yes but not palatable or recommended.
The problem with the tele-converters is that their multiplier factor also multiplies the f-stop of the lens..hence your 80-200mm f:3.5-6.3 maybe would become for the first 2x an f:7-13 plus if you stack another 2x to that then that f:7 x 2 becomes f:14 at the start of the zoom and f:26 at the end of the lens zoom.
That means less light going in the lens and camera, translating to very slow shutter speed..this is granting that you will be using high end tele-converter glass.
If you just stack so-so 2x glass TC then imagine how horrible that image would be.
The answer is definitely yes..but..
01-11-2010, 10:09 AM   #4
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the only reason you would do this is if there was no other way to get a shot,

possible yes, recommended no.

01-11-2010, 01:10 PM   #5
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QuoteOriginally posted by Lowell Goudge Quote
the only reason you would do this is if there was no other way to get a shot,

possible yes, recommended no.
You'd probably be better off using a single teleconverter and just cropping than trying to stack two teleconverters, though.

Make that, 'assuredly better-off.'

Instead of buying two teleconverters on a zoom, in fact, you might well expect better results out of the cheapest 500 or 800mm lens available.
01-11-2010, 03:23 PM   #6
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Thats more what I was thinking.

There are some cheap 100-500 K Mounts on ebay and with as cheap as the K Mount teleconverters are I thought it would be a cheap experiment.

Im looking for a 3 lens set up. I already my "regular" lens as it came with a 28-80. The other two that I would like to pick up would be a super zoom and super macro
01-11-2010, 03:57 PM   #7
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QuoteOriginally posted by MikesChevelle Quote
Thats more what I was thinking.

There are some cheap 100-500 K Mounts on ebay and with as cheap as the K Mount teleconverters are I thought it would be a cheap experiment.

Im looking for a 3 lens set up. I already my "regular" lens as it came with a 28-80. The other two that I would like to pick up would be a super zoom and super macro
You sound like you might be a good candidate for like a 75-300 or 55-300 zoom. That'll be as long as you could plausibly need without wanting to carry a dedicated long prime. (Or a 'bigma.' )

Mind you, you can experiment. Teleconverters+zooms tend to suck badly, anyway. A 1.4x of quality can be useful, but they'll cost more than what you want to back up with it at this point.

If you want to go really long, there are fun cheesy mirror and long-tube lenses you can still get. Nothing to write home about, but... Fun. I kind of intend to indulge yself sooner or later with one, anyway.

What would you like to do with all this, anyway?

Last edited by Ratmagiclady; 01-11-2010 at 04:05 PM.
01-11-2010, 04:16 PM   #8
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Moved to Beginners Forum.

@OP, welcome to the forum, please be careful where you post. If you're not sure, post in 'Everything Else' and a moderator will move it if necessary. Thanks.

01-11-2010, 05:31 PM   #9
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Thank you will do.

Can someone explain to me how I know if a lens is macro. I assume its not the "zoom" number but some sort of focus distance.

Thank you
01-11-2010, 05:53 PM   #10
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QuoteOriginally posted by MikesChevelle Quote
Thank you will do.

Can someone explain to me how I know if a lens is macro. I assume its not the "zoom" number but some sort of focus distance.

Thank you
It will say Macro on the lens and will also have 1:1 or 1:2 on the side. Some zooms will say Macro but this is really only a close focus feature and won't offer quite the same magnification as a true macro (1:1 or 1:2)
01-11-2010, 07:42 PM   #11
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I'd recommend visitng a library and reading the introductory chapters on any beginning book on photography - that will explain all the basics of termonology and lenses and so forth.
01-12-2010, 09:56 AM   #12
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QuoteOriginally posted by Ratmagiclady Quote
You sound like you might be a good candidate for like a 75-300 or 55-300 zoom. That'll be as long as you could plausibly need without wanting to carry a dedicated long prime. (Or a 'bigma.' )

Mind you, you can experiment. Teleconverters+zooms tend to suck badly, anyway. A 1.4x of quality can be useful, but they'll cost more than what you want to back up with it at this point.

If you want to go really long, there are fun cheesy mirror and long-tube lenses you can still get. Nothing to write home about, but... Fun. I kind of intend to indulge yself sooner or later with one, anyway.

What would you like to do with all this, anyway?
Well I just want to be able to take all kinds of pics. from really far to really close.
01-12-2010, 07:30 PM   #13
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QuoteOriginally posted by MikesChevelle Quote
Well I just want to be able to take all kinds of pics. from really far to really close.
Get a good pair of walking shoes then.
01-13-2010, 06:18 PM   #14
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QuoteOriginally posted by Damn Brit Quote
Get a good pair of walking shoes then.
Or a lot of money........ 300mm f2.8 $3000. plus Big Ma $1100 and that isnt fast.
Close14mm 500. plus 105mm macro 100. plus and that is only a drop in the bucket and even with that lineup you still need a good pair of running shoes. There is no one lens that can do it, nor is there a zipper on ones skull so someone can unzip it and dump in instructions. jim

Last edited by jmc7104; 01-13-2010 at 06:21 PM. Reason: add text
01-13-2010, 08:02 PM   #15
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QuoteOriginally posted by MikesChevelle Quote

There are some cheap 100-500 K Mounts on ebay and with as cheap as the K Mount teleconverters are I thought it would be a cheap experiment.
The quality of your pictures depends on the quality of the lens you use. If I were you I would really do some research before buying a cheap 100-500 zoom. There is an extensive lens review section here and reviews can be found for most quality lenses you might find on the used market. Very good lenses cost an arm and a leg but you can find some good ones that will set you back only a digit or two. If the 100-500 you saw is new and costs less than $500-600 it is probably not too good. Using a crappy lens would be like painting your Chevelle with spray cans.

Please disregard my advice if you did paint your car with spray cans.
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