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03-07-2008, 09:19 AM   #1
Ed in GA
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90/100/105mm Macro lens & Extension tubes

I just wonder if anyone has ever used the Tamron/Pentax/Sigma 90/100/105mm Lens with an extension tube or bellows?

If so, what was the result? And, were you pleased with it?

03-07-2008, 09:31 AM   #2
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ed

I use the SMC-M 100mm F4 l;ens with a set of vivitar auto-extension tubes

Tube set is 12mm, 20mm, 36mm.

"Auto" means there is apature cooupling so you can focus wide open, but stop lens down when shooting.

No AE contacts on my set, fully manual.

They work just fine, after all, they are just hollow, not like a TC where added glass reduces image quality.

You really need to use a tripod, because with the full 68mm of extension, plus the 50mm of extension built into the 100mm F4 you are working at greater than 1:1 and depth of field is measured in microns! (not quite but you get the idea)

With this arrangement it is best to also have a focusing rack and pinion, between camera and tripod, so the camera body can be moved aslo to assist in focusing. it is easier to control than moving the tripod.

you are OK on vertical without this as you can always use the tripod center post
03-07-2008, 10:13 AM   #3
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I've used a Vivitar 2x Macro TC along w/ my DFA100/2.8 macro before, the results were pretty good.

Here is one w/o the 2x macro TC at closest distance:


Here is one w/ the TC at closest distance:


Center crop of the one w/ TC:



And mag ratio comparion:


The right bottom one is the full size taken w/ the TC. You can see the total mag ratio would be slightly bigger than 2:1 when this TC is used

I also used a 25mm Kenko AF extension tube (still have it w/ me) along w/ a FA100/2.8, but the difference wasn't too obvious than w/o the tube. Probably a 50mm tube would be a better option.
03-07-2008, 10:37 AM   #4
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I used the same TC with the tamron DI 90 f2.8 and it looked good also. I tried with the vivitar 135 f2.8 close focusing (1:2 without the TC; 1:1 with the TC) and the sharpness was not bad but with contrasty things the CA was quite big.

03-07-2008, 12:39 PM   #5
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QuoteOriginally posted by Ed in GA Quote
I just wonder if anyone has ever used the Tamron/Pentax/Sigma 90/100/105mm Lens with an extension tube or bellows?

If so, what was the result? And, were you pleased with it?
I have a 50mm extension tube. I use it on my 400 to reduce the close focus distance (5 m/ 16.5 ft) to get a bit larger subject size. I also use it on the 100 Macro to get it to the range between 1:2 and 1:1. The macros are designed to work at close range; there is no IQ drop that I have ever noticed. I have, however, noticed that the depth of field is so slim that a focusing rail is on my list of needs.
03-07-2008, 07:14 PM   #6
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Use the Pentax DFA 100 macro on a Kenko Uni-plus 25 extension tube all the time. It works perfectly. Has electrical contacts and even af screw drive. No loss of quality vs lens by itself.
Use the Pentax bellows sometimes. No af or open aperture metering. Built a converter to allow use of mechanical double cable release on dslr. Slow to work with vs extension tubes, but much greater magnification possible. Bellows has built in focusing stage which is mandatory for 3X plus mag.

thanks
barondla
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03-08-2008, 04:34 AM   #7
roy
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i do macros also with ETs.. they work well with my viv105. they also work well with my M200/4.. hers's a shot with the 200mm/63mm of ETs.. this is around 1:3-4



here's one with a viv105mm with 63mm of ETs and a 2x TC... you don't want to use this setup much because of the weight on the camera mount.. this is about 3-4:1



i really like off camera flash for macros.. it's the best way to go.......

Last edited by roy; 03-08-2008 at 04:41 AM.
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