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02-11-2010, 03:46 PM   #1
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Is there something that can make my lens into a zoom lens?

If I have a Pentax-FA 50mm 1.4 can I buy an adapter to allow it to zoom in so I can have pictures further away when I cannot physically move.

02-11-2010, 04:03 PM   #2
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QuoteOriginally posted by CrossStealth Quote
If I have a Pentax-FA 50mm 1.4 can I buy an adapter to allow it to zoom in so I can have pictures further away when I cannot physically move.
If it wasn't for the last part of your statement I would have suggested using your feet. I think though that you'll be going with one of the teleconverter options (1.4x 1.5x 1.7x 2x 3x). Each has it's strengths and weaknesses, the weakest of each is that good ones for Pentax are very difficult (and expensive) to find.

There are also the front teleconverters that are basically heavy magnifying glasses but I don't know much about them, nor, how the plastic thread on the FA will handle them.

Instead of going through all that though, you might just be better off with a zoom or telephoto lens. Remember that with a TC, your f1.4 does not Stay at f1.4. A 2x for instance, your lens will become an f2.8 lens. I don't think it has the nice rendering of the FA50 but you can get a Pentax 135 f2.5 (or 2.8?) Takumar (bayonet) for less than the cost of most decent teleconverters. In fact you can probably buy 2 or 3 of them.

Good luck..
02-11-2010, 05:11 PM   #3
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Just use your 18-55 as your zoom and save your fast 50 for indoors and portraits.

Last edited by jimH; 02-12-2010 at 12:29 PM.
02-11-2010, 05:42 PM   #4
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You can do better than buy a (nonexistent) adapter - you can buy a zoom lens!

02-11-2010, 07:12 PM   #5
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The Pentax 135 2.8 is a screw mount isnt it? I think Id need an adapter. If I could find a good priced zoom that would be cool. My kit zoom 18-55 isnt quite far enough so I think Id need the next zoom up. Any suggestions?
02-11-2010, 07:28 PM   #6
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This is the one I'm talking about.. It's a 2.5, my mistake but they also did a 2.8..

Edit

The 2.5 is a bit of a doorstop wide open so it's usefullness would depend on what you really want to do with it. Honestly, if you want to zoom from 50mm, you might be better off saving your quarters nickels and dimes and going after a 50-135 DA*, or in the slightly longer general range (as a used one) one of the 70-200 f2.8 lenses from Tamron or Sigma.

Last edited by JeffJS; 02-11-2010 at 07:37 PM.
02-11-2010, 08:35 PM   #7
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The DA 50-200 goes for what, $100 used? I would expect the DA-L to be even cheaper. Either would go well with the 18-55. There are lots of decent older zooms (with or without AF or A contacts) available for $100 or less. The question is always going to be, how much are you willing to spend?
02-11-2010, 09:36 PM   #8
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The short answer is, NO, there is no way to turn a prime (fixed) lens into a zoom.
The snide answer is, walk forwards or backwards -- if you're physically able, of course.

As said above, decent zooms can be bought for not-too-much money -- unless you want a zoom as fast as your 50/1.4, which probably can't be had for ANY price, unless you're the NSA or CIA. Zooms are necessarily slower than the fastest primes. Fairly fast zooms are made, and are quite large and costly. The long, fast zooms used by sports photographers require a tripod or two, and cost as much as some new cars.

Modern kit-lens zooms are quite good, better (and much smaller, lighter, cheaper) than most of the best pro zooms of a generation ago. Older lenses use heavy glass. Modern lenses use light-weight plastics molded in complex shapes that are impossible for glass. These complex shapes make affordable (and carryable) superzooms possible.

The slowness of consumer vs pro zooms is a problem of physics and optics -- fast zooms must have very wide lenses, difficult to make whether glass or plastic. As long as lenses are made of solid optical materials, the problem will remain. Radical designs are in the works, involving computer-driven micro-lens and micro-mirror arrays, squishable soft lenses, etc, which should eventually result in exotic fast lenses -- but don't expect to see these on the market anytime soon.

Get a good kit zoom. Have fun.

02-12-2010, 03:27 AM   #9
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Correct use of terminology will clarify your quest.
A zoom lens covers a range of focal lengths and 'zooms' between them.
Lenses that bring a relatively distant subject apparently closer are telephoto lenses not zooms per se.
Prime lenses have a single focal length.
Telephoto lenses can be obtained in a single focal length or as a zoom.

Both types can be used with teleconverters which add an extra lens or two between the camera body and the lens. They also slightly slow the lens down as in stop some light coming in and causing you to slow the shutter speed or increase the ISO or open the aperture to compensate if not already wide open.

Now re-read the posts above and see if that helps you with the details offered.
02-12-2010, 03:36 AM   #10
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QuoteOriginally posted by CrossStealth Quote
If I have a Pentax-FA 50mm 1.4 can I buy an adapter to allow it to zoom in so I can have pictures further away when I cannot physically move.
There is a very easy way to convert it: send me that lens and I send you back my Exakta 28-200mm 1:3.8-5.6 zoom lens in exchange.
02-12-2010, 06:39 AM   #11
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QuoteOriginally posted by CrossStealth Quote
If I have a Pentax-FA 50mm 1.4 can I buy an adapter to allow it to zoom in so I can have pictures further away when I cannot physically move.
Yes, You can add a 1.5X adapter behind the lens It will increase the focal length to 75mm and also increase the f-stop by a factor of 1.5 (ie. 1.4 -> 2.1)

It is a practical thing to do; F:2.1 is still suitable for many low light situations & 75mm is a nice focal length.

This is not a Zoom adapter in the sense of just turning something on the lens, you've got to physically put the adapter on & off.

I think it is theoretically possible to make a zoom adapter (imagine putting an afocal Zoom telescope in front of a camera lens.) While possible, it is likely not a practical thing to do.
02-12-2010, 10:40 AM   #12
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QuoteOriginally posted by 16N64 Quote
There is a very easy way to convert it: send me that lens and I send you back my Exakta 28-200mm 1:3.8-5.6 zoom lens in exchange.
I was going to offer something similar

Seriously, that 50mm prime is worth a lot more than most budget zooms. Either sell it, or just supplement it with a zoom. I picked up my Quantaray zoom on eBay for under $100 shipped, and it got solid reviews in the lens database...
02-12-2010, 12:24 PM   #13
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QuoteOriginally posted by Steinback Quote
The DA 50-200 goes for what, $100 used? I would expect the DA-L to be even cheaper. Either would go well with the 18-55. There are lots of decent older zooms (with or without AF or A contacts) available for $100 or less. The question is always going to be, how much are you willing to spend?
The DA 50-200 is a fairly usable lens in combination with the 18-55 and could be bought used for around $100 or so. I used one for several years until I got my Tamron 70-200 2.8. I still pack it around when I don't want the weight of the Tammy.
02-13-2010, 06:45 AM   #14
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Roller skates.
02-14-2010, 05:24 AM   #15
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thank you for all the responses I will just buy a zoom. Looking at a few that go beyond the 55mm mark. Im just very hesitant to buy a non pentax brand lens
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