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04/22/2013 12:44:11 PM · #1 |
Simply question is not just about money!
below is considered for full frame body only!
I was looking at Kenko and saw they 12mm, 20mm, and 36mm. Let's say I use 100mm Macro with 12mm adapter so my 100mm would actually will behave like 112mm right? AND if I put all three of them then it would be 168mm, right?
On other end looking at Canon 2.x III and I do same math then 100mm would behave like 200mm.
is above theory good? Why would I use 12mm, 20mm or 36mm or any combination over a fixed increase by 2.0? which one would be good for long term?
Any inputs would help for next shopping!
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04/22/2013 12:49:07 PM · #2 |
No. They don't do the same thing. Extension tubes are used to decrease your minimum focal plane's distance to subject, not increase focal range.
Eta: on phone, please forgive the spelling.
Message edited by author 2013-04-22 12:51:12. |
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04/22/2013 12:58:02 PM · #3 |
Originally posted by bohemka:
No. They don't do the same thing. Extension tubes are used to decrease your minimum focal plane's distance to subject, not increase focal range.
Eta: on phone, please forgive the spelling. |
Scott's right- to get more detailed about it:
Extension tubes are used to change the focal distance for your lens. So you can take a lens that normally has a minimum focus distance of say 1m and make it so it can focus as close as .3m or perhaps even closer. Extension rings are used to enable you to use the same lens for subjects which are spatially closer to you. This results in a larger representation on your sensor. You will lose infinity focus with extension tubes as a result.
A teleextender like the Canon 2.0 is used to increase the REACH of your lens. It will not enable you to focus closer, but it will make your lens behave like a longer focal length, and in that fashion, increase the size of representation on your sensor. If used on your 100 2.8, your lens will behave as a 200mm 5.6. Always remember that teleextenders multiply your minimum aperture as well as your focal length, and will therefore effect your autofocus. Teleextenders are essentially an additional magnifying element coupled between your camera and your lens. Because they contain glass, they are of varying qualities. Further, the combination of some lenses with certain teleextenders will work better than others. You'll see many people comment that one lens takes such and such teleextender horribly, but works nicely with a different one. It's worth looking into.
ETA: As for which is more useful longterm and more flexible... it depends. Extension tubes are useful if you enjoy shooting macro a lot, but have a somewhat limited application outside of that. You can use them on any lens to make it focus closer, so you may be able to apply them in portraiture or something, but I've not tried. Teleextenders are useful if you can't get close to your subject or you really want to force perspective by collapsing the depth of your image. Many wildlife photographers use teleextenders because they allow the lens more reach, which means they can stay further away and not scare their subject. Which is better depends upon which you prefer.
Message edited by author 2013-04-22 13:02:37. |
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04/22/2013 12:58:22 PM · #4 |
You're confusing extension tubes with teleconverters which serve two different purposes.
EDIT: beaten to the punch.
Message edited by author 2013-04-22 12:59:08.
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04/22/2013 01:29:58 PM · #5 |
| Think Macro versus zoom. Extension Tubes=Macro. Teleconverters=Zoom. |
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04/22/2013 01:52:33 PM · #6 |
The math is not so intuitive. Both teleconverters and extension tubes can indeed be used to increase maximum magnification. Teleconverters work by magnifiying the image emerging from the back of the macro lens, and re-projecting it. Extension tubes work by decreasing the minimum focusing distance, which increases magnification. Take a look at this:
As you can see, adding 25+12 = 38mm of extension gets you to about 1.5x, whereas a 2x teleconverter and 12mm tube will get you to 2.5x. Note that I don't list the 2x teleconverter alone. This is because it will not mount directly to the 100 macro (there is mechanical interference). The only way you can mount the two together is to mount a 12mm or larger extension tube in between.
Unless you are a masochist I don't recommend the more extreme combinations listed. They get awfully hard to work with. If you are looking for a moderate increase in magnification, I recommend starting with extension tubes. If you need more than about 1.75x, consider reversing a lens, or just spring for the MP-E65 which will give you 1x to 5x (but is macro-specific because it does not focus to infinity)
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04/22/2013 02:47:42 PM · #7 |
| Teleconverters only work with specific lens as well they don't work for all of them, generally the bigger focal lengths my sigma 2x goes on my 70-200 2.8 and my 120-300 2.8 but it wouldn't go on my 24-70 say |
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04/22/2013 03:03:59 PM · #8 |
So stupid question, how do you focus a reversed 50 if you can't access the focus ring due to the step up adapter?
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04/22/2013 03:07:44 PM · #9 |
Originally posted by Garry:
So stupid question, how do you focus a reversed 50 if you can't access the focus ring due to the step up adapter? |
With your feet? |
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04/22/2013 03:20:44 PM · #10 |
Originally posted by bohemka:
Originally posted by Garry:
So stupid question, how do you focus a reversed 50 if you can't access the focus ring due to the step up adapter? |
With your feet? |
Fancy! Would it matter if you are focused to infinity or minimal focus distance?
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04/22/2013 05:57:04 PM · #11 |
Originally posted by Garry:
Originally posted by bohemka:
Originally posted by Garry:
So stupid question, how do you focus a reversed 50 if you can't access the focus ring due to the step up adapter? |
With your feet? |
Fancy! Would it matter if you are focused to infinity or minimal focus distance? |
Not much. At all. |
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04/22/2013 05:59:05 PM · #12 |
Thank you all! This is definitely a good piece of information!
Message edited by author 2013-04-22 18:00:40. |
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04/22/2013 06:01:20 PM · #13 |
Great table, by the way Fritz. Very useful!
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04/22/2013 07:37:00 PM · #14 |
Originally posted by kirbic:
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Wouldn't the "100 + reversed 50 + 2x tc + tubes" have a focus point that was somewhere inside the body of the camera? IIRC, I think the time I tried my 105 + 2x + reversed 50, the end of the lens was bumping the subject. |
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04/22/2013 07:52:52 PM · #15 |
Originally posted by Ann:
Wouldn't the "100 + reversed 50 + 2x tc + tubes" have a focus point that was somewhere inside the body of the camera? IIRC, I think the time I tried my 105 + 2x + reversed 50, the end of the lens was bumping the subject. |
I don't know quite how it works, but when my camera is in "SuperMacro" mode it will focus as close as the front surface of the lens; in this shot I sprinkled the dry leaves onto the lens and pointed it up at the light.  |
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04/22/2013 10:14:38 PM · #16 |
Originally posted by Ann:
Wouldn't the "100 + reversed 50 + 2x tc + tubes" have a focus point that was somewhere inside the body of the camera? IIRC, I think the time I tried my 105 + 2x + reversed 50, the end of the lens was bumping the subject. |
With much more than 12mm of extension, I'm pretty sure you'd be absolutely correct, Ann! The key here is that the teleconverter really does not affect the focus point, and the 12mm of extension is minimal compared to the 100mm focal length of the main lens.
ETA: If you want a chuckle, check out when my little magnification table was uploaded ;-)
Message edited by author 2013-04-22 22:18:01. |
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