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Tiny flowers with FA 100/2.8+ext tube · 04:37 PM

Courtesy of pcarfan (thanks mate), these puny flowers were captured with an extension tube (converted from an A-capable TC) and my FA 100/2.8 macro.

Interestingly, the 'extension tube' being about 25mm long provides minimal further magnification to the macro lens alone. I found this by testing the lens with and without the ext. tube fitted on a tripod shooting the same subject. How much magnification would one expect with a 25mm ext. tube? What FL equivalent does a 100mm lens become with the ext. tube?

Taff · 10-20-2009, 06:51 PM

if a 100mm macro gives 1:1 then you would need 100mm of extension to give 2:1
if a 50mm macro gives 1:1then you would need 50mm of extension to get 2:1
Do you get the idea?

**Ash** · 10-20-2009, 07:35 PM

Yes Taff. Thanks.
Now where's my FE lens so I can get 5:1 macro?!?

Taff · 10-20-2009, 11:13 PM

i didnt realise it was you posting Ash, there is a question mark ya know lol

**Douglas_of_Sweden** · 10-21-2009, 02:46 AM

Originally posted by Taff

if a 100mm macro gives 1:1 then you would need 100mm of extension to give 2:1
if a 50mm macro gives 1:1then you would need 50mm of extension to get 2:1
Do you get the idea?

Well, this applies for an ordinary 100mm and 50mm lens. But does it apply if they are already capable of 1:1 or 1:2 from the start?

Tamron adaptall 2 SP 90mm f2.5 macro 1:2 certainly don't need a 90 mm tube to get to 1:1. The dedicated adaptall 2 tube is only about 4 cm.
When I've been playing around with my SMC Pentax-DFA 100mm f2.8 macro 1:1 with tube and maximal close up (set to 1:1) it appears that I get 2:1 already with a tube of about 4cm length, not 100mm (I've been measuring actual size of subject and it's size on the picture knowing the sensor size and calculated the macro dimension).

So I think this problem is more complex for macro lenses.

**Ash** · 10-21-2009, 04:28 AM

I pondered this but found it hard to quantitate.
Certainly a 25mm tube on a 100mm macro lens doesn't get much further away from 1:1...

pcarfan · 10-21-2009, 07:30 AM

3rd and 4th are nice images. I have no clue on the magnifications, but I know it does well with even the F135/2.8 and with the 77/1.8 (which I don't use with the ext.tube).

**Ash** · 10-21-2009, 07:41 PM

Thanks S,
It doesn't matter too much to me - just curious.

Jimbo · 10-21-2009, 09:12 PM

Love the first one Ash though I may have cropped the top a bit. JIM

**Ash** · 10-21-2009, 09:13 PM

Thanks Jim,
I cropped a little but agree, a little more from the top would suit well.
Cheers.

Ash
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10-20-2009, 06:51 PM	#2
Taff Veteran Member Join Date: Aug 2008 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 1,612	if a 100mm macro gives 1:1 then you would need 100mm of extension to give 2:1 if a 50mm macro gives 1:1then you would need 50mm of extension to get 2:1 Do you get the idea?

10-20-2009, 07:35 PM	#3
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920 Original Poster	Yes Taff. Thanks. Now where's my FE lens so I can get 5:1 macro?!?

10-20-2009, 11:13 PM	#4
Taff Veteran Member Join Date: Aug 2008 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 1,612	i didnt realise it was you posting Ash, there is a question mark ya know lol

10-21-2009, 02:46 AM	#5
Douglas_of_Sweden Site Supporter Join Date: Apr 2008 Location: Stockholm Photos: Gallery Posts: 3,374	Originally posted by Taff if a 100mm macro gives 1:1 then you would need 100mm of extension to give 2:1 if a 50mm macro gives 1:1then you would need 50mm of extension to get 2:1 Do you get the idea? Well, this applies for an ordinary 100mm and 50mm lens. But does it apply if they are already capable of 1:1 or 1:2 from the start? Tamron adaptall 2 SP 90mm f2.5 macro 1:2 certainly don't need a 90 mm tube to get to 1:1. The dedicated adaptall 2 tube is only about 4 cm. When I've been playing around with my SMC Pentax-DFA 100mm f2.8 macro 1:1 with tube and maximal close up (set to 1:1) it appears that I get 2:1 already with a tube of about 4cm length, not 100mm (I've been measuring actual size of subject and it's size on the picture knowing the sensor size and calculated the macro dimension). So I think this problem is more complex for macro lenses.

10-21-2009, 04:28 AM	#6
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920 Original Poster	I pondered this but found it hard to quantitate. Certainly a 25mm tube on a 100mm macro lens doesn't get much further away from 1:1...

10-21-2009, 07:30 AM	#7
pcarfan Veteran Member Join Date: Sep 2007 Location: Dayton, Ohio Photos: Gallery \| Albums Posts: 2,978	3rd and 4th are nice images. I have no clue on the magnifications, but I know it does well with even the F135/2.8 and with the 77/1.8 (which I don't use with the ext.tube).

10-21-2009, 07:41 PM	#8
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920 Original Poster	Thanks S, It doesn't matter too much to me - just curious.

10-21-2009, 09:12 PM	#9
Jimbo Veteran Member Join Date: Dec 2007 Location: Maple Ridge BC Canada Photos: Gallery Posts: 11,368	Love the first one Ash though I may have cropped the top a bit. JIM

10-21-2009, 09:13 PM	#10
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920 Original Poster	Thanks Jim, I cropped a little but agree, a little more from the top would suit well. Cheers.

Macro Tiny flowers with FA 100/2.8+ext tube

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