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| 105mm Macro + 2x Teleconverter = 210mm Macro? | |
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| Tweet Topic Started: Mar 9 2009, 03:17 AM (366 Views) | |
| lenrek | Mar 9 2009, 03:17 AM Post #1 |
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I just want to know, if I have a 2x teleconverter, would it make my Sigma 105mm Macro be a 210mm Macro? Would it reduce the sharpness of the picture? |
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| Ming | Mar 9 2009, 07:17 AM Post #2 |
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90609866
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I think its not practical to do this ba ... ? How far you want to stand to shoot at the subject ... And i think we always want to get closer to the subject for Macro , no point adding a 2x TC but Extension Tubes are different .Maybe you should try out this combo , see how are you comfortable with the Focusing , check on the results then decide whether you will still go on with it .
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| tankm | Mar 9 2009, 06:37 PM Post #3 |
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Always Newbie
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Yes, it will be 210mm in focal length. Minimum focus distance still the same but your widest aperture is now f5.6. Sharpness reduce, most likely with a 2x TC. |
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| lenrek | Mar 9 2009, 11:51 PM Post #4 |
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Oh? I thought it would also increase the minimum focus distance. I try just now, the sharpness seems not much diff, since I set F @ 8 and was doing manual focus. Though, think I would do some real world test sometime over the weekend. |
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| Ming | Mar 10 2009, 04:02 AM Post #5 |
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90609866
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Its fine to ask when you ae in doubt , get some answers first then go to the try out in the 'Real World' better .
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Ask ... Absorb ... Equip ... Execute N E X with M I N G HERE ! A P - Ming HERE ! Macro-Ming HERE ! Pano-Ming HERE ! Food ! Food ! Foods ! HERE | |
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| Trigger Happy | Mar 14 2009, 12:26 AM Post #6 |
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Alpha Jedi Member
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lenrek, yes, but at apertures like f8 the image degradation will become obvious esp if the tc's glass element is of poor quality. then there's the issue of focal length. for most macro shots i've found 50mm ideal, 90mm ok and anything beyond that is pushing it in terms of shutter speed vs handshake unless you use flash for everything. and a tripod will become a cumbersome necessity. if you want to stand further back for macro shots (safety?) then something like the sigma 75-300mm f/4 - f/5.6 (macro from 200-300mm) at abt $200-$300 will be a better investment, plus you have a telephoto lens. Edited by Trigger Happy, Mar 14 2009, 12:29 AM.
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| tankm | Mar 14 2009, 07:51 AM Post #7 |
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Always Newbie
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Are you referring to "reducing" instead of "increase the minimum focus distance" ? |
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| yannh | Mar 14 2009, 01:26 PM Post #8 |
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Alpha Sniper Member
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With 2x teleconverter, focal length seems become double. But actually teleconverter cropped the middle portion and enlarge it. So resolution reduce for sure, and sharpness reduce as well. If you don't realize it, that means still within your tolerance limit, good for you. Minimum focus distance (MFD), in general measure from the sensor plan to the focused object. So it actually increase with the thickness of your teleconverter. But if you are measuring from the tip of your lens, then this MFD does not change while adding teleconverter. You loose light while adding teleconverter. For 2x, usually you loose 2 stops. That does not means if you're using f/8, you will get the DOF of f/32. You still get the DOF of f/8, yet with exposure as if f/32. Since increasing DOF is very important for macro, and lighting is very important as well, I believe this setup is hard to control. Just my opinion. |
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And i think we always want to get closer to the subject for Macro , no point adding a 2x TC but Extension Tubes are different .
8:43 AM Jul 11