How much does minimum distance change?

[SunTsu]

The Canon site, http://www.usa.canon.com/app/pdf/lens/Lens_Extender_chart_new.pdf
lists the minimum focussing distance of the 100mm macro as 1 foot. There have been times when I've wished I could have gotten a bit closer to the subject. I couldn't find any specific specs so I'm wondering if anyone knows how much the extension tubes will decrease the min focusing distance to. I'm wondering about the 12 and the 15 Canon tubes. Thanks

[Pete-eos]

The Canon site, http://www.usa.canon.com/app/pdf/lens/Lens_Extender_chart_new.pdf
lists the minimum focussing distance of the 100mm macro as 1 foot. There have been times when I've wished I could have gotten a bit closer to the subject. I couldn't find any specific specs so I'm wondering if anyone knows how much the extension tubes will decrease the min focusing distance to. I'm wondering about the 12 and the 15 Canon tubes. Thanks


Sorry I can't answer the original question but buy a 65mm set of Kenko tubes and you'll be able to get much closer than with one of the canon tube...

[Wilt]

With a lens with a conventional helicoid focus mechanism, it can be computed if one knows actual length added to Infinity focus distance for close focus via the helicoid threads. With an internal focus lens, like the 100mm f2.8 macro, the computation is problematic.

[gasrocks]

Closer is not always a better thing. You can put a Tamron /Kenko 1.4x on your 100 macro and get more "power" form the same distance. Close-up lens will get you closer.

[John_B]

SunTsu,
I also suggest a set of Kenko extension tubes (get three tubes of air for the same price as one Canon tube of air).
With a full set of Kenko extension tubes you can achieve 2:1 macro with a distance of 5 inches from lens glass to subject.

[SunTsu]

Thanks, JohnB. Do you mean putting the entire stack of all three Kenko tubes on?

[John_B]

SunTsu,
Yes, I meant the entire stack (68mm) of Kenko extension tubes (although you can use less for less magnification). This will give you 2:1 macro with a subject 5" from lens glass. Here on my web page I take many images of a ruler with different macro setups from tubes to TC to give the general idea of magnification possible. <-- click to see (http://johnbdigital.com/macro/lens_compare/macro_variations.htm)

[DocFrankenstein]

With a lens with a conventional helicoid focus mechanism, it can be computed if one knows actual length added to Infinity focus distance for close focus via the helicoid threads. With an internal focus lens, like the 100mm f2.8 macro, the computation is problematic.
You can treat it as a single lens system and get a very good approximation.

[MagentaJoe]

I regularly use the 100mm macro with a full set of Kenko tubes. You can get very close. This is a good example. the stem on this, on the bottom right, is only a few mm wide. The little bug on there was too small for me to see him as anything other than a little spec of orange dust. Which is what I thought he was. This is hand held too. The background is white siding on a house about 30 feet away :-).

http://www.ceretti.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=19052&g2_serialNumber=2

[MagentaJoe]

SunTsu,
Yes, I meant the entire stack (68mm) of Kenko extension tubes (although you can use less for less magnification). This will give you 2:1 macro with a subject 5" from lens glass. Here on my web page I take many images of a ruler with different macro setups from tubes to TC to give the general idea of magnification possible. <-- click to see (http://johnbdigital.com/macro/lens_compare/macro_variations.htm)

Great and useful stuff there!

[John_B]

Great and useful stuff there!
MagentaJoe,
Thanks :)

Here is a photo I took recently with the Canon 100mm f/2.8 (my favorite lens :) ) and a full set of Kenko extension tubes on a FF DSLR.

Paper Wasp
http://johnbdigital.com/macro/wasp1.jpg
click for specs (http://johnbdigital.com/macro/wasp1.htm)

[Wilt]

Quote:
Originally Posted by Wilt http://photography-on-the.net/forum/images/buttons/viewpost.gif (http://photography-on-the.net/forum/showthread.php?p=3123011#post3123011)
With a lens with a conventional helicoid focus mechanism, it can be computed if one knows actual length added to Infinity focus distance for close focus via the helicoid threads. With an internal focus lens, like the 100mm f2.8 macro, the computation is problematic.



You can treat it as a single lens system and get a very good approximation.

With a helicoid focus lens, you can measure the distance that the elements move away from the focal plane, then add that distance to the extension tube length, and compute the subject distance. With internal focusing lens, you have no idea of how much/little the focus mechanism moves, and you know only the length of the extension tube...which is why I called it problematic to do.

[SunTsu]

I regularly use the 100mm macro with a full set of Kenko tubes. You can get very close. This is a good example. the stem on this, on the bottom right, is only a few mm wide. The little bug on there was too small for me to see him as anything other than a little spec of orange dust. Which is what I thought he was. This is hand held too. The background is white siding on a house about 30 feet away :-).

http://www.ceretti.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=19052&g2_serialNumber=2

That's a great shot. Can you share how much physical space that frame is? Also, if it's a crop, what percentage of the whole frame was it to start with? Thanks. :)

[MagentaJoe]

That's a great shot. Can you share how much physical space that frame is? Also, if it's a crop, what percentage of the whole frame was it to start with? Thanks. :)

Thanks! The stem in the bottom right is about 3mm wide and the shot is cropped from a little bit less than 1/4 of the frame from the 5D.

[MagentaJoe]

Here is a photo I took recently with the Canon 100mm f/2.8 (my favorite lens :) ) and a full set of Kenko extension tubes on a FF DSLR.

I love the catchlight! That's one freaky looking eye.

[snajczuk]

MagentaJoe,
Thanks :)

Here is a photo I took recently with the Canon 100mm f/2.8 (my favorite lens :) ) and a full set of Kenko extension tubes on a FF DSLR.

Paper Wasp
http://johnbdigital.com/macro/wasp1.jpg
click for specs (http://johnbdigital.com/macro/wasp1.htm)


Were you using a macro ring on that or is that available light? Awesome pic.

[John_B]

MagentaJoe,
Thanks, yea it had a wild looking eye :)

snajczuk,
Thanks, I used a Canon 580ex with the off shoe cord. :)