EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

Started May 25, 2007 | Discussions
Lars Berglund Regular Member • Posts: 270
EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

I currently have the EF 180 F/3.5L and a Canon 5D. It's a great combo!

I have been wondering how the EF 25 Extension Tube will impact the focusing distance and magnification, and what the impacts would be by using a 1D camera (given it have a 1.3 "crop factor").

1) Will the closest focusing distance change depending on the camera (i.e. FF vs 1.3 crop)?

2) With a FF at the closest focusing distance there is an 1:1 magnification. Is this still true for a crop camera or will the maginification be bigger at the closest focusing distance?

3) How much is the magnification increased with the EF 25 Extension Tube on this lens with FF vs Crop Camera?

Any help to sort this out would be much appreciated...

Thanks, LB

cjed Senior Member • Posts: 2,039
Re: EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

Lars Berglund wrote:

I currently have the EF 180 F/3.5L and a Canon 5D.
I have been wondering how the EF 25 Extension Tube will impact the
focusing distance and magnification, and what the impacts would be
by using a 1D camera (given it have a 1.3 "crop factor").

1) Will the closest focusing distance change depending on the
camera (i.e. FF vs 1.3 crop)?

No.

2) With a FF at the closest focusing distance there is an 1:1
magnification. Is this still true for a crop camera or will the
maginification be bigger at the closest focusing distance?

Magnification will be the same, however, the size of a subject that fills the frame will be different (i.e. at 1:1 magnification on the 5D, a 36mm long subject will fill the frame, at 1:1 magnification on a 1D, a 28.7mm long subject will fill the frame).

3) How much is the magnification increased with the EF 25 Extension
Tube on this lens with FF vs Crop Camera?

There will be no difference between a FF and crop camera - the figures for the 180mm f3.5 Macro and the EF-25 tube are :

Maximum magnification : 1.21:1 (increased from 1:1)
Closest focusing distance 480mm (working distance 222mm)
Furthest focusing distance 1501mm (Working distance 1243mm)
(Note that you will loose infinity focus with this combination)

A better bet than the Canon tubes (12 and 25mm) would be a set of Kenko extension tubes (3 tubes giving a total of 65mm extension and a maximum magnification of about 1.5:1) or a 1.4x Teleconvertor (which would increase the maximum magnification to 1.4:1, but keep the current closest focusing distance and retain infinity focus).

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OP Lars Berglund Regular Member • Posts: 270
Re: EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

Thanks for the detailed response to my questions!

Here's are a couple of followup's:

1) Can the 1.4x extender be combined with the EF 25 Extenstion Tube and if so would the total magnification be > 1.5?

2) And what about the 2.0x extender... I can see in the Canon lens specifications that AF will not be possible with this extender on the EF 180 F/3.5L Macro, even though the effective F stop on the combo is below F8. I would have assumed the 1D series camera should be able to AF as long as the effective F stop is below 8... Can someone confirm?

3) The EF 500 F/4L have a closest focusing distance of 14.8" which I sometimes which would be shorter when being close to birds, snakes and other anlimals. How much closer would I be able to go if using the EF 25 extension tube on the 500 lens?

In general, is there a formula or information sheet that I can use to figure out the impacts on focusing distance and maginification by using the EF 25 extension tube on the Canon lenses?

LB

cjed Senior Member • Posts: 2,039
Re: EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

Lars Berglund wrote:

1) Can the 1.4x extender be combined with the EF 25 Extenstion Tube
and if so would the total magnification be > 1.5?

Yes, total magnification should be 1.21 x 1.4 = 1.7 (approx.)

2) And what about the 2.0x extender... I can see in the Canon lens
specifications that AF will not be possible with this extender on
the EF 180 F/3.5L Macro, even though the effective F stop on the
combo is below F8. I would have assumed the 1D series camera should
be able to AF as long as the effective F stop is below 8... Can
someone confirm?

Yes, I've no personal experience of this, but the 1D should be able to AF with that combination. The 300/350/400D and 20/30D bodies won't AF above f5.6

3) The EF 500 F/4L have a closest focusing distance of 14.8" which
I sometimes which would be shorter when being close to birds,
snakes and other anlimals. How much closer would I be able to go if
using the EF 25 extension tube on the 500 lens?

I think you mean 14.8' (feet not inches) - new miniumum focus distance with the EF-25 is 3591mm (13 feet approx). The longer the focal length of the lens the less impact a specific extension has on the magnification and minimum focus distance.

In general, is there a formula or information sheet that I can use
to figure out the impacts on focusing distance and maginification
by using the EF 25 extension tube on the Canon lenses?

Indeed there is, it's here :-
http://www.bobatkins.com/photography/eosfaq/closeup.htm

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You want macros? We got 'em! Check out:
http://www.pbase.com/cjed

OP Lars Berglund Regular Member • Posts: 270
Re: EF 180 F/3.5L Macro with EF 25 II Extension Tube and Crop camera?

Thanks again for your complete answers and the link provided was exactly what I needed!!

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