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08-18-2009, 12:16 PM   #16
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QuoteOriginally posted by audiobomber Quote
I don't have a TC but that's not what I was told. I thought you could get 1:1 with a longer working distance, or keep the same working distance and get a multiple of the magnification (i.e. a 1.4X TC would give 1.4:1 at the DFA 100's normal close focus distance.)

Yes, the Raynox 250 is a bit close for insects on the end of a macro lens, but with the right subject it works well and provides macro significantly beyond 1:1 (I believe about 2.5:1) and automatic operation, so it has its advantages.
Dan, you are basically right. A tc only changes focal length (aka increases it), whereas the minimum focusing distance of the lens is preserved. That means, for a 2x tc, you double the max. magnification of the lens. If you use a Tamron 90mm at 1:1, you will get a 180mm 2:1 at the same working distance.

The extension tubes work the other way round: they preserve the focal length, but change the minimum focusing distance. So you see the catch immediately: to achieve higher magnification with extension tubes, you need to go much nearer to the subject, witzh all the problems associated with that.

Ben

08-19-2009, 12:53 PM   #17
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Thanks for the information everyone!
08-19-2009, 01:02 PM   #18
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Another way to go beyond 1:1 with the Tamron 90mm is to use a bellows.
08-20-2009, 07:41 AM   #19
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QuoteOriginally posted by Xcom Quote
I recently bought myself a tamron 2.8 90mm macro. My only problem is that I am a little addicted to macro shots. Have seen some impressive results at 2:1 to 3:1. I need some advice on how to get more mag. I have some options and would like some advice.

Some sites suggest different methods in doing so. I am considering adding my 50mm 1.4 to the 90mm macro useing a 55 and 49mm macro coupling ring. However most sites state that coupling works best with normal lenses not macros. Is this true? Not all the research I have done on the subject suggests useing only normal lenses.

I can also buy manual extension tubes or the vivatar 2x tc. The coupling ring would be dirt cheap. Only 8 bucks for the 55-49 male to male coupling ring. Not intrested right now in a bellows. However thats another option. Any suggestions to max out my tamron 90mm? Anyone have some experience using it coupled to a 1.4 50mm?
QuoteOriginally posted by Blue Quote
Another way to go beyond 1:1 with the Tamron 90mm is to use a bellows.
Op, is not interested in a bellows.

08-20-2009, 08:45 AM   #20
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QuoteOriginally posted by brecklundin Quote
Op, is not interested in a bellows.
I'm not the only one that has mentioned a bellows hoss. However, I thought perhaps after looking into other options, the OP may re-evaluate the bellows since they essential work like an extension tube with more potential reach. However, the Raynox and Canon diopters are good for ~ 1:1 or maybe to 2:1, I think quality goes down a bit.

The other options to push the magnification comes down to reversing lens or stacking lens if bellows are ruled. However, stacking lenses is an excellent way to get high quality magnification but it takes soem practice. I recommend people start out and try a bellows and then go to reversed lenses and then possible to stacked lenses. Due to the availability of high quality macros lenses in the 50 to 105mm range, many people have gotten away from these techniques.

The only lens I know of off hand that has greater than 1:1 in native configuration is the MP-E 65mm macro lenses Canon has out that can go from 1:1 to 5:1.
08-20-2009, 10:03 AM   #21
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QuoteOriginally posted by Ben_Edict Quote
Dan, you are basically right. A tc only changes focal length (aka increases it), whereas the minimum focusing distance of the lens is preserved. That means, for a 2x tc, you double the max. magnification of the lens. If you use a Tamron 90mm at 1:1, you will get a 180mm 2:1 at the same working distance.

The extension tubes work the other way round: they preserve the focal length, but change the minimum focusing distance. So you see the catch immediately: to achieve higher magnification with extension tubes, you need to go much nearer to the subject, witzh all the problems associated with that.

Ben
Thanks Ben, very clear explanation.
08-20-2009, 10:04 AM   #22
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on a 90mm macro if you reverse a fast 17-40ish zoom rather than a prime that gives from about 2:1 up to 5:1. I used a 24-60 reversed on a 180mm Sigma to get 7.5:1 to 3:1 ratio...it was fun to play with (and even funnier to look at! hehehe) but reversing does not give pristine results no matter how you wish to spin it the IQ suffers. Tubes (and of course a bellows which is just the first idea of tubes... ) are the only way to get more than the native ratio w/o IQ loss.

Reversing a zoom can result in some serious vignetting at max magnification under around f8 though...still it was fun to play with 7.5:1...

funny you mention the MPE-65 I almost kept my 40D just to buy that lens, but I decided to buy a 50-135 instead and just sent it because because the SDM is failing already...so maybe I might pick up a 20D and an MPE-65 since a 20D is really cheap now and the MPE-65 is not really expensive at all ...plus I miss spending hours focus stacking.
08-29-2009, 04:24 PM   #23
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I'm going to have a crack at this soon with my Tammy x.1.4 TC on my Tammy 90mm Macro .... I have been meaning to for quite sometime now ... but haven't had the chance. Also gives me a good excuse to use it as well.

08-30-2009, 08:38 AM   #24
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QuoteOriginally posted by clawhammer Quote
FWIW, I've heard of people taking the glass out of a teleconverter and using that for an extension tube. I've been tempted to try that with my cheapo 2x tc, but haven't had the guts (I don't like to reduce things from a known-working state to a possibly-working state) to try it yet.
Totally new to macro here, but I found a cheap 2x TC just yesterday and took its optics out before mounting to my M 50mm f1.7. Here's a shot from this morning of a moth butterfly which I think was about 3/4th of an inch.

At f4, 1/80, resized. No PP.


100% crop.


I also got a true macro lens (D FA 100mm f2.8) just recently, just haven't used it yet for its intended purposes. I'd like to see how images from it will compare to those taken with cheap extension tubes (made out of 2x TC) and a 50mm lens.

May be I will also try these extension tubes on my 50mm f1.4 some time!

I think macro is kinda fun

Last edited by EsBee; 08-30-2009 at 08:43 AM.
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