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03-15-2011, 06:45 PM   #1
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Which tubes, extenders, teleconverter?

I've decided to go for extension tubes, possible reverse-stacking, and a quality teleconverter to go with my not-so-excellent lenses.

I can't find the Tamron 1.5x teleconverter, but I've found plenty of 1.4x and 2x; I don't know which one will fit a Pentax K10 - one made for Minolta, Nikon, Canon…I googled Pentax 1.7x teleconverter and got something called ProMaster 2x teleconverter. No Pentax 1.7x on Adorama either.

As for getting extension tubes, I've read about the loss of light, but I just can't afford a new macro lens right now, and I don't know mind going all manual; it's the best way to learn IMO. I don't know what sizes to get. I'm not using AF lenses so I don't think I can get the Pentax auto extension tube set K.

I'd love to get into reverse-stacking, but again, I don't know what I need.

Oh, and hello!

03-15-2011, 08:29 PM   #2
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If you are looking for extension tubes for macro work, I use the Pentax Auto Extension Tubes K. These make the attached lens look like an A, F or FA lens with the aperture set to a value rather than to "A".

The same applies to a reverse adapter. I use the Pentax Reverse Adapter K in 49mm and 52mm sizes.

The above items I have bought of eBay for reasonable prices.

For teleconverters, I use the Pentax Rear Converter A in 1.4 and 2.0 models. These loose one or two stops of light respectively. They allow the use of lenses with the aperture set "A", but you loose Auto-Focus.

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Chris Stone
03-15-2011, 09:11 PM   #3
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I have a 58mm 2.5x Telephoto lens, not sure how to use it. It blurs the outer parts of the photo. How should this lense be used for the best pictures?
03-16-2011, 05:34 AM   #4
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QuoteOriginally posted by t.stone Quote
I've decided to go for extension tubes,......

As for getting extension tubes, I've read about the loss of light, ...
You'll get the same loss of light with a macro lens at the same focal length and f-stop - it is physics & unavoidable.

03-16-2011, 05:40 AM   #5
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QuoteQuote:
I'd love to get into reverse-stacking, but again, I don't know what I need.
For reverse stacking you need a "reverse adapter ring" see: reverse adapter ring items - Get great deals on Cameras Photo, Computers Networking items on eBay.com!

Buy one that fits the filter threads of both lenses - or buy one that fits your primary lens and appropriate step-up or step-down adapter rings.
03-16-2011, 05:42 AM   #6
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What are you attempting to do

Note that for any macro work the magnification, regardless of how it is achieved results in loss of light. Using any single lens regardless of how you achieve any magnification ratio the loss will be similar

Just so you understand the difference
Extension tubes alter the focusing range of your lens but retain the same focal length, by extending the lens away from the camera they allow closer focus and higher magnification with the loss of infinity focus
Teleconverters change the effective focal length but retain the focusing range of the lens
03-16-2011, 05:45 AM   #7
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QuoteOriginally posted by emetcalf Quote
I have a 58mm 2.5x Telephoto lens, not sure how to use it. It blurs the outer parts of the photo. How should this lense be used for the best pictures?
It will never give pictures not blurred at the edges. Such lenses are typically not very good - fine for videos but not for critical work - some are better than others but none I've seen do not degrade the image.
03-16-2011, 06:08 AM   #8
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Thanks, Chris! This information is what I needed; exactly what I was looking for

03-16-2011, 06:13 AM   #9
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Can the loss of light be made up for by adding flash? Rense posted an excellent tutorial on creating a flash diffuser for macro work.
03-16-2011, 06:14 AM   #10
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Thank you Newarts, and especially for the link.
03-16-2011, 06:20 AM   #11
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QuoteOriginally posted by t.stone Quote
Can the loss of light be made up for by adding flash? Rense posted an excellent tutorial on creating a flash diffuser for macro work.
Yes and it will be a big help if you use an A type lens (and A type adapter, tubes etc if any) - that way the automatic flash function will work - otherwise you'll need to adjust the flash manually.

The simplest set-up is a reversed lens on an A type (zoom is preferable I think) camera lens. What lenses do you have now?
03-16-2011, 06:29 AM   #12
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Lowell Goudge - I want to use the extension tubes for macro, and a teleconverter for zooming.

I have a Pentax SMC-A 70-210 and a Pentax SMC-A 200 that I'd like to use for birds; 200mm just doesn't get close enough (right now it's yard birds, and I can get up to 20ft to the bird feeder but how many shots of cow birds and house finches does one really need?!). I live on the Coast. I really want to start getting shots of the Blue Herons, Brown Pelicans, Cormorants, etc.

The Pentax 70-210 is also a macro and I have a Gemini 28-80mm macro. Both are fair. Extension tubes would do the job, I think.

I'm at the point where I'm still experimenting and learning but sub-par lenses aren't going to cut it much longer.

HAVING SAID THAT…there is something about using sub-par lenses and DIY equipment that I'm drawn to. It's because there are so many variables what with light loss, auto focus loss, etc., I'm forced to stop and ask myself, "What went wrong? What could I do to make it better? What if I did this…or this…" and I really enjoy the experimentation and possible artistic results.
03-16-2011, 06:39 AM   #13
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I have a 18-55mm, 50mm, 200mm, and 70-210mm. The only one that is a new digital lens is the 18-55mm (kit). The others are Pentax SMC-A.
03-16-2011, 07:15 AM   #14
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QuoteOriginally posted by t.stone Quote
I have a 18-55mm, 50mm, 200mm, and 70-210mm. The only one that is a new digital lens is the 18-55mm (kit). The others are Pentax SMC-A.
I recommend you try a $50 Raynox DCR 150 lens on your 70-210. It will give a broad range of macro magnifications (up to more than 1:1). Auto flash will work and manual focus will be pretty easy.

Your 50mm lens on extension tubes will work well too - it be a little harder to use than the Raynox on Zoom but will cost less for simple $10 (non-Pentax-A) tubes plus be sharper at the edges. (Edge sharpness for macros of natural objects is very rarely needed because natural objects are not flat). Auto flash will not work with $10 tubes but the photos will be just as good - just not as easy because you'll have to manually adjust for flash.

Raynox on zoom is likely the best option when you are out in the field. The lens is quick to snap on and takes little storage space - I always carry one "just in case." At home when you have time for set-up and space for storage the tubes may be best.

See the "Raynox Club" here:
03-16-2011, 07:59 AM   #15
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So, I got curious and reverse-stacking. I got out my 50mm and 200mm. I didn't have reversing rings, but i did have stepping rings! They worked well enough with me holding the lens.

Here are the results:
200mm attached to camera with 50mm
https://picasaweb.google.com/tiffany.stone.cre8tif/Mar162011#5584690904183548818

50mm attached to camera with 200mm
https://picasaweb.google.com/tiffany.stone.cre8tif/Mar162011#5584691394762796658
https://picasaweb.google.com/tiffany.stone.cre8tif/Mar162011#5584691474223856290
https://picasaweb.google.com/tiffany.stone.cre8tif/Mar162011#5584692250912993906

I did not do any post process work just cropped out the black. Pretty sweet!

Last edited by t.stone; 03-16-2011 at 08:30 AM.
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