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03-05-2009, 07:45 PM   #1
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Help with Extension Tube 18F Tamron SP 90/2.5 52B

Assistance please from anyone with experience.

I just acquired this lens/tube/hood matched set from a Forum member - beautiful lens, and enough to let me sell most of the stuff I have picked up over the years and just shoot with two or three manual lenses. There is an issue, though ->

Trying to use the extension tube, I cannot seem to get anything to focus, at any distance from the subject.

I have mounted my Adaptall-2 converter to the matched extension tube 18F; mounted the tube to the 90/2.5 lens - and - NOTHING.

Can someone offer guidance?

03-05-2009, 08:14 PM   #2
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QuoteOriginally posted by monochrome Quote
Assistance please from anyone with experience.

I just acquired this lens/tube/hood matched set from a Forum member - beautiful lens, and enough to let me sell most of the stuff I have picked up over the years and just shoot with two or three manual lenses. There is an issue, though ->

Trying to use the extension tube, I cannot seem to get anything to focus, at any distance from the subject.

I have mounted my Adaptall-2 converter to the matched extension tube 18F; mounted the tube to the 90/2.5 lens - and - NOTHING.

Can someone offer guidance?
I would imagine the extension tube will bring you very close to the subject. Try

1. turn your focus ring to the minimum focusing distance -- around 1.3 feet marker on the left end

2. move camera close to your 1:1 shooting subject and to position your camera with back and forth slow motion like from 0.5 to 2 feet from the subject.

The extension tube will draw you closer to your subject, and you won't get infinity focus. Others please correct me if I wrong about this. And when I tried the extension tube on my Tamron SP 90mm f/2.5 1:2 Macro adaptall-2 52BB,




I dial in a SR focal length like 135mm and I still need to confirm if that is the correct focal length. To bring the 52B from 1:2 to 1:1, the (extension length)/(lens focal length) should be 1/2 to make the ratio from 1:2 to 1:1 and hence, I assume the extension length is 45mm.

Last edited by hinman; 03-05-2009 at 08:36 PM.
03-05-2009, 08:37 PM   #3
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You will get 1:1, but you will have to work at shorter distance than with the 01F 2x converter, on the other hand you will loose less ligth with the tube than with the converter (180mm f5.0 is kind of slowish).
03-06-2009, 07:19 PM   #4
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QuoteOriginally posted by hinman Quote

Try

1. turn your focus ring to the minimum focusing distance -- around 1.3 feet marker on the left end

2. move camera close to your 1:1 shooting subject and to position your camera with back and forth slow motion like from 0.5 to 2 feet from the subject.

The extension tube will draw you closer to your subject, and you won't get infinity focus. Others please correct me if I wrong about this.
Thank you Hinman. That did the trick. I just sold a spotless Pentax Manual Extension Tube K set because I had never used them. Now I know why I never used them I may possibly let go of my Viv S1 105/2.5 if this is good enough. I think I need a macro rail to make this work.

QuoteOriginally posted by Douglas_of_Sweden Quote
You will get 1:1, but you will have to work at shorter distance than with the 01F 2x converter, on the other hand you will loose less ligth with the tube than with the converter (180mm f5.0 is kind of slowish).
Please don't tempt me (01F 2x converter) - Tamron Adaptall is a whole new field of toys. I have bad enough addiction as it is.


Last edited by monochrome; 03-07-2009 at 06:21 AM.
03-07-2009, 04:21 AM   #5
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The first thing I did when I got some screw mount extension tubes was to use them in combo with a 2x extender and a Tak 50/1.4 - it was fun and results aren't all bad.

I haven't mounted both the Tamron tube and 2x converter together... yet.... I think I shall, today

I'm glad you got things sorted out - you do have a bit more working distance available with the tube, as there's no LAW stating you can only shoot at 1:1! See what focusing to near infinity does...
03-08-2009, 08:44 PM   #6
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QuoteOriginally posted by monochrome Quote

Please don't tempt me (01F 2x converter) - Tamron Adaptall is a whole new field of toys. I have bad enough addiction as it is.
I think I have a spare 01F if you are interrested?

Yes Adaptall is fun. I have the 24mm/2.5 and 28mm/2.5 as well, and the very much underrated SP35-80/2.8-3.8 (that goes to 1:2.5 or 1:1.125 with the converter or the tube). All nice lenses available for small money and with A-functionality if one have the right adapter. Looking for the SP 500mm mirror lens. I think the adaptall system was genious. A pity someone invented autofocus
03-08-2009, 08:57 PM   #7
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Tamron 01F and SP 55B 500/8

Thanks for the offer - I have a line on one right now, but if it falls through I'll PM you. My Forum seller also provided a 17A 35~70/3.5, which gave me some really nice images today. These lenses expose differently than Pentax lenses on the DSLR's but its just a matter of learning how much compensation to use (1 - 2 stops under, it seems)..

Here's a link to an eBay auction on a SP 55B 500/8.

Tamron SP 55B 500mm f/8 Catadioptric Tele-Macro

It is Singapore, but then it is a really nice, complete package. I'm not bidding, so you have the floor
11-02-2010, 03:49 PM   #8
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does someone know where i can get this tube ? or can i use another too ?
thanks asa14

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